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blog.youwen.dev
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<!doctype html>
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<html lang="en">
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<title>a haskellian blog | conditional finality</title>
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<meta name="author" content="Youwen Wu" />
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<meta name="keywords" content="haskell, blog, functional programming" />
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<meta property="og:site_name" content="conditional finality" />
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<meta property="og:title" content="a haskellian blog" />
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<meta property="og:description" content="a purely functional...blog?" />
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<meta property="twitter:site" content="conditional finality" />
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<meta property="twitter:title" content="a haskellian blog" />
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<meta property="twitter:description" content="a purely functional...blog?" />
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<meta property="twitter:creator" content="@youwen" />
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})
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},
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}
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</script>
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</head>
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<body
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class="container max-w-2xl mx-auto px-4 transition-colors duration-[2s]"
|
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>
|
||||
<header class="mt-14 md:mt-24 mb-14">
|
||||
<div class="inline-flex items-center w-full">
|
||||
<h1 class="text-4xl md:text-5xl font-serif font-medium">
|
||||
<a
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||||
href="/"
|
||||
class="dark:hover:text-muted-dark hover:text-muted-light transition-all duration-500 text-nowrap tracking-wide"
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||||
><em>Conditional Finality.</em></a
|
||||
>
|
||||
</h1>
|
||||
<div
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class="w-full flex-grow flex-shrink rounded-lg h-1 bg-muted-light dark:bg-muted-dark mx-4"
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></div>
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</div>
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||||
<p class="mt-8 mb-3 px-1 italic font-light">
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a web-log about computers, math, hacks, and all the rest.
|
||||
</p>
|
||||
<a class="text-sm text-iris-light dark:text-iris-dark hover:text-love-light dark:hover:text-love-dark" href="https://youwen.dev"
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><em>by </em>Youwen Wu</a
|
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>
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<span class="ml-2 font-serif">|</span>
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<button
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id="theme-toggle"
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class="ml-2 text-sm hover:text-accent-light dark:hover:text-muted-dark"
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<span class="ml-2 font-serif">|</span>
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<button
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id="font-toggle"
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class="ml-2 text-sm hover:text-accent-light dark:hover:text-muted-dark"
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></button>
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</header>
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||||
<article>
|
||||
<header>
|
||||
<h1 class="text-4xl">
|
||||
<a href="./a-haskellian-blog.html">a haskellian blog</a>
|
||||
</h1>
|
||||
<p
|
||||
class="mb-1 mt-2 italic font-light text-lg text-accent-light dark:text-accent-dark"
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>
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||||
a purely functional...blog?
|
||||
</p>
|
||||
<div class="mt-2">2024-05-25</div>
|
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<div class="mt-1 text-sm">
|
||||
(last updated: 2024-05-25T12:00:00Z)
|
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</div>
|
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</header>
|
||||
<main class="post mt-4"><p>Welcome! This is the first post on <em>conditional finality</em> and also one that tests all
|
||||
of the features.</p>
|
||||
<p><img
|
||||
alt="conditional finality"
|
||||
src="./images/conditional-finality.png"
|
||||
/></p>
|
||||
<blockquote>
|
||||
<p>A monad is just a monoid in the category of endofunctors, what’s the problem?</p>
|
||||
</blockquote>
|
||||
<h2 id="haskell">haskell?</h2>
|
||||
<p>This entire blog is generated with <a href="https://jaspervdj.be/hakyll/">hakyll</a>. It’s
|
||||
a library for generating static sites for Haskell, a purely functional
|
||||
programming language. It’s a <em>library</em> because it doesn’t come with as many
|
||||
batteries included as tools like Hugo or Astro. You set up most of the site
|
||||
yourself by calling the library from Haskell.</p>
|
||||
<p>Here’s a brief excerpt:</p>
|
||||
<div class="sourceCode" id="cb1"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="ot">main ::</span> <span class="dt">IO</span> ()</span>
|
||||
<span id="cb1-2"><a href="#cb1-2" aria-hidden="true" tabindex="-1"></a>main <span class="ot">=</span> hakyllWith config <span class="op">$</span> <span class="kw">do</span></span>
|
||||
<span id="cb1-3"><a href="#cb1-3" aria-hidden="true" tabindex="-1"></a> forM_</span>
|
||||
<span id="cb1-4"><a href="#cb1-4" aria-hidden="true" tabindex="-1"></a> [ <span class="st">"CNAME"</span></span>
|
||||
<span id="cb1-5"><a href="#cb1-5" aria-hidden="true" tabindex="-1"></a> , <span class="st">"favicon.ico"</span></span>
|
||||
<span id="cb1-6"><a href="#cb1-6" aria-hidden="true" tabindex="-1"></a> , <span class="st">"robots.txt"</span></span>
|
||||
<span id="cb1-7"><a href="#cb1-7" aria-hidden="true" tabindex="-1"></a> , <span class="st">"_config.yml"</span></span>
|
||||
<span id="cb1-8"><a href="#cb1-8" aria-hidden="true" tabindex="-1"></a> , <span class="st">"images/*"</span></span>
|
||||
<span id="cb1-9"><a href="#cb1-9" aria-hidden="true" tabindex="-1"></a> , <span class="st">"out/*"</span></span>
|
||||
<span id="cb1-10"><a href="#cb1-10" aria-hidden="true" tabindex="-1"></a> , <span class="st">"fonts/*"</span></span>
|
||||
<span id="cb1-11"><a href="#cb1-11" aria-hidden="true" tabindex="-1"></a> ]</span>
|
||||
<span id="cb1-12"><a href="#cb1-12" aria-hidden="true" tabindex="-1"></a> <span class="op">$</span> \f <span class="ot">-></span> match f <span class="op">$</span> <span class="kw">do</span></span>
|
||||
<span id="cb1-13"><a href="#cb1-13" aria-hidden="true" tabindex="-1"></a> route idRoute</span>
|
||||
<span id="cb1-14"><a href="#cb1-14" aria-hidden="true" tabindex="-1"></a> compile copyFileCompiler</span></code></pre></div>
|
||||
<p>The code highlighting is also generated by hakyll.</p>
|
||||
<hr />
|
||||
<h2 id="why">why?</h2>
|
||||
<p>Haskell is a purely functional language with no mutable state. Its syntax
|
||||
actually makes it pretty elegant for declaring routes and “rendering” pipelines.</p>
|
||||
<ol>
|
||||
<li>Haskell is cool.</li>
|
||||
<li>It comes with enough features that I don’t feel like I have to build
|
||||
everything from scratch.</li>
|
||||
<li>It comes with Pandoc, a Haskell library for converting between markdown
|
||||
formats. It’s probably more powerful than anything you could do in <code>nodejs</code>.
|
||||
It renders all of the markdown to HTML as well as the math.
|
||||
<ol>
|
||||
<li>It supports KaTeX as well as MathML. I’m a little disappointed with the
|
||||
KaTeX though. It doesn’t directly render it, but simply injects the KaTeX
|
||||
files and renders it client-side.</li>
|
||||
</ol></li>
|
||||
</ol>
|
||||
<h3 id="speaking-of-math">speaking of math</h3>
|
||||
<p>We can have math inline, like so:
|
||||
<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msubsup><mo>∫</mo><mrow><mo>−</mo><mi>∞</mi></mrow><mi>∞</mi></msubsup><mspace width="0.167em"></mspace><msup><mi>e</mi><mrow><mo>−</mo><msup><mi>x</mi><mn>2</mn></msup></mrow></msup><mspace width="0.167em"></mspace><mi>d</mi><mi>x</mi><mo>=</mo><msqrt><mi>π</mi></msqrt></mrow><annotation encoding="application/x-tex">\int_{-\infty}^\infty \, e^{-x^2}\,dx = \sqrt{\pi}</annotation></semantics></math>. This site ships semantic
|
||||
MathML math with its HTML, and the MathJax script to the client.</p>
|
||||
<p>It’d be nice if MathML could just be used and supported across all browsers, but
|
||||
unfortunately we still aren’t quite there yet. Firefox is the only one where
|
||||
everything looks 80% of the way to LaTeX. On Safari and Chrome, even simple
|
||||
equations like <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><msqrt><mi>π</mi></msqrt><annotation encoding="application/x-tex">\sqrt{\pi}</annotation></semantics></math> render improperly.</p>
|
||||
<p>Pros of MathML:</p>
|
||||
<ul>
|
||||
<li>A little more accessible</li>
|
||||
<li>Can be rendered without additional stylesheets. I just installed the Latin
|
||||
Modern font, but this isn’t even really necessary</li>
|
||||
<li>Built-in to most browsers (#UseThePlatform)</li>
|
||||
</ul>
|
||||
<p>Cons:</p>
|
||||
<ul>
|
||||
<li>Isn’t fully standardized. Might look different on different browsers</li>
|
||||
<li>Rendering quality isn’t as good as KaTeX</li>
|
||||
</ul>
|
||||
<p>This site has MathJax render all of the math so it looks nice and standardized
|
||||
across browsers, but the math still displays regardless (like say if MathJax
|
||||
couldn’t load due to slow network) because of MathML. Best of both worlds.</p>
|
||||
<p>Let’s try it now. Here’s a simple theorem:</p>
|
||||
<p><math display="block" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mi>a</mi><mi>n</mi></msup><mo>+</mo><msup><mi>b</mi><mi>n</mi></msup><mo>≠</mo><msup><mi>c</mi><mi>n</mi></msup><mspace width="0.167em"></mspace><mo>∀</mo><mspace width="0.167em"></mspace><mrow><mo stretchy="true" form="prefix">{</mo><mi>a</mi><mo>,</mo><mspace width="0.167em"></mspace><mi>b</mi><mo>,</mo><mspace width="0.167em"></mspace><mi>c</mi><mo stretchy="true" form="postfix">}</mo></mrow><mo>∈</mo><mstyle mathvariant="double-struck"><mi>ℤ</mi></mstyle><mo>∧</mo><mi>n</mi><mo>≥</mo><mn>3</mn></mrow><annotation encoding="application/x-tex">
|
||||
a^n + b^n \ne c^n \, \forall\,\left\{ a,\,b,\,c \right\} \in \mathbb{Z} \land n \ge 3
|
||||
</annotation></semantics></math></p>
|
||||
<p>The proof is trivial and will be left as an exercise to the reader.</p>
|
||||
<h2 id="seems-a-little-overengineered">seems a little overengineered</h2>
|
||||
<p>Probably is. Not as much as the old one, though.</p></main>
|
||||
</article>
|
||||
|
||||
<footer class="mt-14 md:mt-24 pb-12 font-light">
|
||||
<hr
|
||||
class="border-0 dark:bg-muted-dark bg-muted-light rounded-xl h-0.5 mb-4"
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||||
/>
|
||||
<p class="text-sm leading-relaxed">
|
||||
© 2024 Youwen Wu. Generated by
|
||||
<a
|
||||
href="https://jaspervdj.be/hakyll/"
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
>Hakyll.</a
|
||||
>
|
||||
View the source
|
||||
<a
|
||||
href="https://github.com/couscousdude/blog"
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
>on GitHub.</a
|
||||
>
|
||||
</p>
|
||||
<p class="text-sm leading-relaxed mt-2">
|
||||
Content freely available under
|
||||
<a
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
href="https://creativecommons.org/licenses/by-nc-sa/4.0/deed.en"
|
||||
><span class="smallcaps">CC BY-NC-SA</span> 4.0</a
|
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>
|
||||
unless otherwise noted.
|
||||
</p>
|
||||
</footer>
|
||||
<script defer src="./out/bundle.js"></script>
|
||||
</body>
|
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</html>
|
||||
383
atom.xml
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atom.xml
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|||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<feed xmlns="http://www.w3.org/2005/Atom">
|
||||
<title>conditional finality</title>
|
||||
<link href="https://blog.youwen.dev/atom.xml" rel="self" />
|
||||
<link href="https://blog.youwen.dev" />
|
||||
<id>https://blog.youwen.dev/atom.xml</id>
|
||||
<author>
|
||||
<name>Youwen Wu</name>
|
||||
<email>youwenw@gmail.com</email>
|
||||
</author>
|
||||
<updated>2024-12-28T00:00:00Z</updated>
|
||||
<entry>
|
||||
<title>Nix automatic hash updates made easy</title>
|
||||
<link href="https://blog.youwen.dev/nix-automatic-hash-updates-made-easy.html" />
|
||||
<id>https://blog.youwen.dev/nix-automatic-hash-updates-made-easy.html</id>
|
||||
<published>2024-12-28T00:00:00Z</published>
|
||||
<updated>2024-12-28T00:00:00Z</updated>
|
||||
<summary type="html"><![CDATA[<article>
|
||||
<header>
|
||||
<h1 class="text-4xl">
|
||||
<a href="./nix-automatic-hash-updates-made-easy.html">Nix automatic hash updates made easy</a>
|
||||
</h1>
|
||||
<p
|
||||
class="mb-1 mt-2 italic font-light text-lg text-accent-light dark:text-accent-dark"
|
||||
>
|
||||
keep your flakes up to date
|
||||
</p>
|
||||
<div class="mt-2">2024-12-28</div>
|
||||
<div class="mt-1 text-sm">
|
||||
|
||||
</div>
|
||||
</header>
|
||||
<main class="post mt-4"><p>Nix users often create flakes to package software out of tree, like this <a href="https://github.com/youwen5/zen-browser-flake">Zen
|
||||
Browser flake</a> I’ve been
|
||||
maintaining. Keeping them up to date is a hassle though, since you have to
|
||||
update the Subresource Integrity (SRI) hashes that Nix uses to ensure
|
||||
reproducibility.</p>
|
||||
<p>Here’s a neat method I’ve been using to cleanly handle automatic hash updates.
|
||||
I use <a href="https://www.nushell.sh/">Nushell</a> to easily work with data, prefetch
|
||||
some hashes, and put it all in a JSON file that can be read by Nix at build
|
||||
time.</p>
|
||||
<p>First, let’s create a file called <code>update.nu</code>. At the top, place this shebang:</p>
|
||||
<pre class="nu"><code>#!/usr/bin/env -S nix shell nixpkgs#nushell --command nu</code></pre>
|
||||
<p>This will execute the script in a Nushell environment, which is fetched by Nix.</p>
|
||||
<h2 id="get-the-up-to-date-urls">Get the up to date URLs</h2>
|
||||
<p>We need to obtain the latest version of whatever software we want to update.
|
||||
In this case, I’ll use GitHub releases as my source of truth.</p>
|
||||
<p>You can use the GitHub API to fetch metadata about all the releases of a repository.</p>
|
||||
<pre><code>https://api.github.com/repos/($repo)/releases</code></pre>
|
||||
<p>Roughly speaking, the raw JSON returned by the GitHub releases API looks something like:</p>
|
||||
<pre><code>[
|
||||
{tag_name: "foo", prerelease: false, ...},
|
||||
{tag_name: "bar", prerelease: true, ...},
|
||||
{tag_name: "foobar", prerelease: false, ...},
|
||||
]
|
||||
</code></pre>
|
||||
<p>Note that the ordering of the objects in the array is chronological.</p>
|
||||
<blockquote>
|
||||
<p>Even if you aren’t using GitHub releases, as long as there is a reliable way to
|
||||
programmatically fetch the latest download URLs of whatever software you’re
|
||||
packaging, you can adapt this approach for your specific case.</p>
|
||||
</blockquote>
|
||||
<p>We use Nushell’s <code>http get</code> to make a network request. Nushell will
|
||||
automatically detect and parse the JSON reponse into a Nushell table.</p>
|
||||
<p>In my case, Zen Browser frequently publishes prerelease “twilight” builds which
|
||||
we don’t want to update to. So, we ignore any releases tagged “twilight” or
|
||||
marked “prerelease” by filtering them out with the <code>where</code> selector.</p>
|
||||
<p>Finally, we retrieve the tag name of the item at the first index, which would
|
||||
be the latest release (since the JSON array was chronologically sorted).</p>
|
||||
<pre class="nu"><code>#!/usr/bin/env -S nix shell nixpkgs#nushell --command nu
|
||||
|
||||
# get the latest tag of the latest release that isn't a prerelease
|
||||
def get_latest_release [repo: string] {
|
||||
try {
|
||||
http get $"https://api.github.com/repos/($repo)/releases"
|
||||
| where prerelease == false
|
||||
| where tag_name != "twilight"
|
||||
| get tag_name
|
||||
| get 0
|
||||
} catch { |err| $"Failed to fetch latest release, aborting: ($err.msg)" }
|
||||
}</code></pre>
|
||||
<h2 id="prefetching-sri-hashes">Prefetching SRI hashes</h2>
|
||||
<p>Now that we have the latest tags, we can easily obtain the latest download URLs, which are of the form:</p>
|
||||
<pre><code>https://github.com/zen-browser/desktop/releases/download/$tag/zen.linux-x86_64.tar.bz2
|
||||
https://github.com/zen-browser/desktop/releases/download/$tag/zen.aarch64-x86_64.tar.bz2</code></pre>
|
||||
<p>However, we still need the corresponding SRI hashes to pass to Nix.</p>
|
||||
<div class="sourceCode" id="cb6"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a>src = fetchurl <span class="op">{</span></span>
|
||||
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span> <span class="op">=</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-x86_64.tar.bz2"</span><span class="op">;</span></span>
|
||||
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span> <span class="op">=</span> <span class="st">"sha256-00000000000000000000000000000000000000000000"</span><span class="op">;</span></span>
|
||||
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a><span class="op">}</span>;</span></code></pre></div>
|
||||
<p>The easiest way to obtain these new hashes is to update the URL and then set
|
||||
the hash property to an empty string (<code>""</code>). Nix will spit out an hash mismatch
|
||||
error with the correct hash. However, this is inconvenient for automated
|
||||
command line scripting.</p>
|
||||
<p>The Nix documentation mentions
|
||||
<a href="https://nix.dev/manual/nix/2.18/command-ref/nix-prefetch-url">nix-prefetch-url</a>
|
||||
as a way to obtain these hashes, but as usual, it doesn’t work quite right and
|
||||
has also been replaced by a more powerful but underdocumented experimental
|
||||
feature instead.</p>
|
||||
<p>The <a href="https://nix.dev/manual/nix/2.18/command-ref/new-cli/nix3-store-prefetch-file">nix store
|
||||
prefetch-file</a>
|
||||
command does what <code>nix-prefetch-url</code> is supposed to do, but handles the caveats
|
||||
that lead to the wrong hash being produced automatically.</p>
|
||||
<p>Let’s write a Nushell function that outputs the SRI hash of the given URL. We
|
||||
tell <code>prefetch-file</code> to output structured JSON that we can parse.</p>
|
||||
<p>Since Nushell <em>is</em> a shell, we can directly invoke shell commands like usual,
|
||||
and then process their output with pipes.</p>
|
||||
<pre class="nu"><code>def get_nix_hash [url: string] {
|
||||
nix store prefetch-file --hash-type sha256 --json $url | from json | get hash
|
||||
}</code></pre>
|
||||
<p>Cool! Now <code>get_nix_hash</code> can give us SRI hashes that look like this:</p>
|
||||
<pre><code>sha256-K3zTCLdvg/VYQNsfeohw65Ghk8FAjhOl8hXU6REO4/s=</code></pre>
|
||||
<h2 id="putting-it-all-together">Putting it all together</h2>
|
||||
<p>Now that we’re able to fetch the latest release, obtain the download URLs, and
|
||||
compute their SRI hashes, we have all the information we need to make an
|
||||
automated update. However, these URLs are typically hardcoded in our Nix
|
||||
expressions. The question remains as to how to update these values.</p>
|
||||
<p>A common way I’ve seen updates performed is using something like <code>sed</code> to
|
||||
modify the Nix expressions in place. However, there’s actually a more
|
||||
maintainable and easy to understand approach.</p>
|
||||
<p>Let’s have our Nushell script generate the URLs and hashes and place them in a
|
||||
JSON file! Then, we’ll be able to read the JSON file from Nix and obtain the
|
||||
URL and hash.</p>
|
||||
<pre class="nu"><code>def generate_sources [] {
|
||||
let tag = get_latest_release "zen-browser/desktop"
|
||||
let prev_sources = open ./sources.json
|
||||
|
||||
if $tag == $prev_sources.version {
|
||||
# everything up to date
|
||||
return $tag
|
||||
}
|
||||
|
||||
# generate the download URLs with the new tag
|
||||
let x86_64_url = $"https://github.com/zen-browser/desktop/releases/download/($tag)/zen.linux-x86_64.tar.bz2"
|
||||
let aarch64_url = $"https://github.com/zen-browser/desktop/releases/download/($tag)/zen.linux-aarch64.tar.bz2"
|
||||
|
||||
# create a Nushell record that maps cleanly to JSON
|
||||
let sources = {
|
||||
# add a version field as well for convenience
|
||||
version: $tag
|
||||
|
||||
x86_64-linux: {
|
||||
url: $x86_64_url
|
||||
hash: (get_nix_hash $x86_64_url)
|
||||
}
|
||||
aarch64-linux: {
|
||||
url: $aarch64_url
|
||||
hash: (get_nix_hash $aarch64_url)
|
||||
}
|
||||
}
|
||||
|
||||
echo $sources | save --force "sources.json"
|
||||
|
||||
return $tag
|
||||
}</code></pre>
|
||||
<p>Running this script with</p>
|
||||
<div class="sourceCode" id="cb10"><pre class="sourceCode bash"><code class="sourceCode bash"><span id="cb10-1"><a href="#cb10-1" aria-hidden="true" tabindex="-1"></a><span class="fu">chmod</span> +x ./update.nu</span>
|
||||
<span id="cb10-2"><a href="#cb10-2" aria-hidden="true" tabindex="-1"></a><span class="ex">./update.nu</span></span></code></pre></div>
|
||||
<p>gives us the file <code>sources.json</code>:</p>
|
||||
<div class="sourceCode" id="cb11"><pre class="sourceCode json"><code class="sourceCode json"><span id="cb11-1"><a href="#cb11-1" aria-hidden="true" tabindex="-1"></a><span class="fu">{</span></span>
|
||||
<span id="cb11-2"><a href="#cb11-2" aria-hidden="true" tabindex="-1"></a> <span class="dt">"version"</span><span class="fu">:</span> <span class="st">"1.0.2-b.5"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-3"><a href="#cb11-3" aria-hidden="true" tabindex="-1"></a> <span class="dt">"x86_64-linux"</span><span class="fu">:</span> <span class="fu">{</span></span>
|
||||
<span id="cb11-4"><a href="#cb11-4" aria-hidden="true" tabindex="-1"></a> <span class="dt">"url"</span><span class="fu">:</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-x86_64.tar.bz2"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-5"><a href="#cb11-5" aria-hidden="true" tabindex="-1"></a> <span class="dt">"hash"</span><span class="fu">:</span> <span class="st">"sha256-K3zTCLdvg/VYQNsfeohw65Ghk8FAjhOl8hXU6REO4/s="</span></span>
|
||||
<span id="cb11-6"><a href="#cb11-6" aria-hidden="true" tabindex="-1"></a> <span class="fu">},</span></span>
|
||||
<span id="cb11-7"><a href="#cb11-7" aria-hidden="true" tabindex="-1"></a> <span class="dt">"aarch64-linux"</span><span class="fu">:</span> <span class="fu">{</span></span>
|
||||
<span id="cb11-8"><a href="#cb11-8" aria-hidden="true" tabindex="-1"></a> <span class="dt">"url"</span><span class="fu">:</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-aarch64.tar.bz2"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-9"><a href="#cb11-9" aria-hidden="true" tabindex="-1"></a> <span class="dt">"hash"</span><span class="fu">:</span> <span class="st">"sha256-NwIYylGal2QoWhWKtMhMkAAJQ6iNHfQOBZaxTXgvxAk="</span></span>
|
||||
<span id="cb11-10"><a href="#cb11-10" aria-hidden="true" tabindex="-1"></a> <span class="fu">}</span></span>
|
||||
<span id="cb11-11"><a href="#cb11-11" aria-hidden="true" tabindex="-1"></a><span class="fu">}</span></span></code></pre></div>
|
||||
<p>Now, let’s read this from Nix. My file organization looks like the following:</p>
|
||||
<pre><code>./
|
||||
| flake.nix
|
||||
| zen-browser-unwrapped.nix
|
||||
| ...other files...</code></pre>
|
||||
<p><code>zen-browser-unwrapped.nix</code> contains the derivation for Zen Browser. Let’s add
|
||||
<code>version</code>, <code>url</code>, and <code>hash</code> to its inputs:</p>
|
||||
<div class="sourceCode" id="cb13"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb13-1"><a href="#cb13-1" aria-hidden="true" tabindex="-1"></a><span class="op">{</span></span>
|
||||
<span id="cb13-2"><a href="#cb13-2" aria-hidden="true" tabindex="-1"></a> <span class="va">stdenv</span><span class="op">,</span></span>
|
||||
<span id="cb13-3"><a href="#cb13-3" aria-hidden="true" tabindex="-1"></a> <span class="va">fetchurl</span><span class="op">,</span></span>
|
||||
<span id="cb13-4"><a href="#cb13-4" aria-hidden="true" tabindex="-1"></a> <span class="co"># add these below</span></span>
|
||||
<span id="cb13-5"><a href="#cb13-5" aria-hidden="true" tabindex="-1"></a> <span class="va">version</span><span class="op">,</span></span>
|
||||
<span id="cb13-6"><a href="#cb13-6" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span><span class="op">,</span></span>
|
||||
<span id="cb13-7"><a href="#cb13-7" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span><span class="op">,</span></span>
|
||||
<span id="cb13-8"><a href="#cb13-8" aria-hidden="true" tabindex="-1"></a> <span class="op">...</span></span>
|
||||
<span id="cb13-9"><a href="#cb13-9" aria-hidden="true" tabindex="-1"></a><span class="op">}</span>:</span>
|
||||
<span id="cb13-10"><a href="#cb13-10" aria-hidden="true" tabindex="-1"></a>stdenv.mkDerivation <span class="op">{</span></span>
|
||||
<span id="cb13-11"><a href="#cb13-11" aria-hidden="true" tabindex="-1"></a> <span class="co"># inherit version from inputs</span></span>
|
||||
<span id="cb13-12"><a href="#cb13-12" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> version<span class="op">;</span></span>
|
||||
<span id="cb13-13"><a href="#cb13-13" aria-hidden="true" tabindex="-1"></a> <span class="va">pname</span> <span class="op">=</span> <span class="st">"zen-browser-unwrapped"</span><span class="op">;</span></span>
|
||||
<span id="cb13-14"><a href="#cb13-14" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb13-15"><a href="#cb13-15" aria-hidden="true" tabindex="-1"></a> <span class="va">src</span> <span class="op">=</span> fetchurl <span class="op">{</span></span>
|
||||
<span id="cb13-16"><a href="#cb13-16" aria-hidden="true" tabindex="-1"></a> <span class="co"># inherit the URL and hash we obtain from the inputs</span></span>
|
||||
<span id="cb13-17"><a href="#cb13-17" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> url hash<span class="op">;</span></span>
|
||||
<span id="cb13-18"><a href="#cb13-18" aria-hidden="true" tabindex="-1"></a> <span class="op">};</span></span>
|
||||
<span id="cb13-19"><a href="#cb13-19" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>
|
||||
<p>Then in <code>flake.nix</code>, let’s provide the derivation with the data from <code>sources.json</code>:</p>
|
||||
<div class="sourceCode" id="cb14"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb14-1"><a href="#cb14-1" aria-hidden="true" tabindex="-1"></a><span class="kw">let</span></span>
|
||||
<span id="cb14-2"><a href="#cb14-2" aria-hidden="true" tabindex="-1"></a> <span class="va">supportedSystems</span> <span class="op">=</span> <span class="op">[</span></span>
|
||||
<span id="cb14-3"><a href="#cb14-3" aria-hidden="true" tabindex="-1"></a> <span class="st">"x86_64-linux"</span></span>
|
||||
<span id="cb14-4"><a href="#cb14-4" aria-hidden="true" tabindex="-1"></a> <span class="st">"aarch64-linux"</span></span>
|
||||
<span id="cb14-5"><a href="#cb14-5" aria-hidden="true" tabindex="-1"></a> <span class="op">];</span></span>
|
||||
<span id="cb14-6"><a href="#cb14-6" aria-hidden="true" tabindex="-1"></a> <span class="va">forAllSystems</span> <span class="op">=</span> nixpkgs.lib.genAttrs supportedSystems<span class="op">;</span></span>
|
||||
<span id="cb14-7"><a href="#cb14-7" aria-hidden="true" tabindex="-1"></a><span class="kw">in</span></span>
|
||||
<span id="cb14-8"><a href="#cb14-8" aria-hidden="true" tabindex="-1"></a><span class="op">{</span></span>
|
||||
<span id="cb14-9"><a href="#cb14-9" aria-hidden="true" tabindex="-1"></a> <span class="co"># rest of file omitted for simplicity</span></span>
|
||||
<span id="cb14-10"><a href="#cb14-10" aria-hidden="true" tabindex="-1"></a> <span class="va">packages</span> <span class="op">=</span> forAllSystems <span class="op">(</span></span>
|
||||
<span id="cb14-11"><a href="#cb14-11" aria-hidden="true" tabindex="-1"></a> <span class="va">system</span><span class="op">:</span></span>
|
||||
<span id="cb14-12"><a href="#cb14-12" aria-hidden="true" tabindex="-1"></a> <span class="kw">let</span></span>
|
||||
<span id="cb14-13"><a href="#cb14-13" aria-hidden="true" tabindex="-1"></a> <span class="va">pkgs</span> <span class="op">=</span> <span class="bu">import</span> nixpkgs <span class="op">{</span> <span class="kw">inherit</span> system<span class="op">;</span> <span class="op">};</span></span>
|
||||
<span id="cb14-14"><a href="#cb14-14" aria-hidden="true" tabindex="-1"></a> <span class="co"># parse sources.json into a Nix attrset</span></span>
|
||||
<span id="cb14-15"><a href="#cb14-15" aria-hidden="true" tabindex="-1"></a> <span class="va">sources</span> <span class="op">=</span> <span class="bu">builtins</span>.fromJSON <span class="op">(</span><span class="bu">builtins</span>.readFile <span class="ss">./sources.json</span><span class="op">);</span></span>
|
||||
<span id="cb14-16"><a href="#cb14-16" aria-hidden="true" tabindex="-1"></a> <span class="kw">in</span></span>
|
||||
<span id="cb14-17"><a href="#cb14-17" aria-hidden="true" tabindex="-1"></a> <span class="kw">rec</span> <span class="op">{</span></span>
|
||||
<span id="cb14-18"><a href="#cb14-18" aria-hidden="true" tabindex="-1"></a> <span class="va">zen-browser-unwrapped</span> <span class="op">=</span> pkgs.callPackage <span class="ss">./zen-browser-unwrapped.nix</span> <span class="op">{</span></span>
|
||||
<span id="cb14-19"><a href="#cb14-19" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> <span class="op">(</span>sources.$<span class="op">{</span><span class="va">system</span><span class="op">})</span> hash url<span class="op">;</span></span>
|
||||
<span id="cb14-20"><a href="#cb14-20" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> <span class="op">(</span>sources<span class="op">)</span> version<span class="op">;</span></span>
|
||||
<span id="cb14-21"><a href="#cb14-21" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb14-22"><a href="#cb14-22" aria-hidden="true" tabindex="-1"></a> <span class="co"># if the above is difficult to understand, it is equivalent to the following:</span></span>
|
||||
<span id="cb14-23"><a href="#cb14-23" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span> <span class="op">=</span> sources.$<span class="op">{</span><span class="va">system</span><span class="op">}</span>.hash<span class="op">;</span></span>
|
||||
<span id="cb14-24"><a href="#cb14-24" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span> <span class="op">=</span> sources.$<span class="op">{</span><span class="va">system</span><span class="op">}</span>.url<span class="op">;</span></span>
|
||||
<span id="cb14-25"><a href="#cb14-25" aria-hidden="true" tabindex="-1"></a> <span class="va">version</span> <span class="op">=</span> sources.version<span class="op">;</span></span>
|
||||
<span id="cb14-26"><a href="#cb14-26" aria-hidden="true" tabindex="-1"></a> <span class="op">};</span></span>
|
||||
<span id="cb14-27"><a href="#cb14-27" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>
|
||||
<p>Now, running <code>nix build .#zen-browser-unwrapped</code> will be able to use the hashes
|
||||
and URLs from <code>sources.json</code> to build the package!</p>
|
||||
<h2 id="automating-it-in-ci">Automating it in CI</h2>
|
||||
<p>We now have a script that can automatically fetch releases and generate hashes
|
||||
and URLs, as well as a way for Nix to use the outputted JSON to build
|
||||
derivations. All that’s left is to fully automate it using CI!</p>
|
||||
<p>We are going to use GitHub actions for this, as it’s free and easy and you’re
|
||||
probably already hosting on GitHub.</p>
|
||||
<p>Ensure you’ve set up actions for your repo and given it sufficient permissions.</p>
|
||||
<p>We’re gonna run it on a cron timer that checks for updates at 8 PM PST every day.</p>
|
||||
<p>We use DeterminateSystems’ actions to help set up Nix. Then, we simply run our
|
||||
update script. Since we made the script return the tag it fetched, we can store
|
||||
it in a variable and then use it in our commit message.</p>
|
||||
<pre><code>name: Update to latest version, and update flake inputs
|
||||
|
||||
on:
|
||||
schedule:
|
||||
- cron: "0 4 * * *"
|
||||
workflow_dispatch:
|
||||
|
||||
jobs:
|
||||
update:
|
||||
name: Update flake inputs and browser
|
||||
runs-on: ubuntu-latest
|
||||
steps:
|
||||
- name: Checkout Repository
|
||||
uses: actions/checkout@v4
|
||||
|
||||
- name: Check flake inputs
|
||||
uses: DeterminateSystems/flake-checker-action@v4
|
||||
|
||||
- name: Install Nix
|
||||
uses: DeterminateSystems/nix-installer-action@main
|
||||
|
||||
- name: Set up magic Nix cache
|
||||
uses: DeterminateSystems/magic-nix-cache-action@main
|
||||
|
||||
- name: Check for update and perform update
|
||||
run: |
|
||||
git config --global user.name "github-actions[bot]"
|
||||
git config --global user.email "github-actions[bot]@users.noreply.github.com"
|
||||
|
||||
chmod +x ./update.nu
|
||||
export ZEN_LATEST_VER="$(./update.nu)"
|
||||
|
||||
git add -A
|
||||
git commit -m "github-actions: update to $ZEN_LATEST_VER" || echo "Latest version is $ZEN_LATEST_VER, no updates found"
|
||||
|
||||
nix flake update --commit-lock-file
|
||||
|
||||
git push</code></pre>
|
||||
<p>Now, our repository will automatically check for and perform updates every day!</p></main>
|
||||
</article>
|
||||
]]></summary>
|
||||
</entry>
|
||||
<entry>
|
||||
<title>a haskellian blog</title>
|
||||
<link href="https://blog.youwen.dev/a-haskellian-blog.html" />
|
||||
<id>https://blog.youwen.dev/a-haskellian-blog.html</id>
|
||||
<published>2024-05-25T00:00:00Z</published>
|
||||
<updated>2024-05-25T12:00:00Z</updated>
|
||||
<summary type="html"><![CDATA[<article>
|
||||
<header>
|
||||
<h1 class="text-4xl">
|
||||
<a href="./a-haskellian-blog.html">a haskellian blog</a>
|
||||
</h1>
|
||||
<p
|
||||
class="mb-1 mt-2 italic font-light text-lg text-accent-light dark:text-accent-dark"
|
||||
>
|
||||
a purely functional...blog?
|
||||
</p>
|
||||
<div class="mt-2">2024-05-25</div>
|
||||
<div class="mt-1 text-sm">
|
||||
(last updated: 2024-05-25T12:00:00Z)
|
||||
</div>
|
||||
</header>
|
||||
<main class="post mt-4"><p>Welcome! This is the first post on <em>conditional finality</em> and also one that tests all
|
||||
of the features.</p>
|
||||
<p><img
|
||||
alt="conditional finality"
|
||||
src="./images/conditional-finality.png"
|
||||
/></p>
|
||||
<blockquote>
|
||||
<p>A monad is just a monoid in the category of endofunctors, what’s the problem?</p>
|
||||
</blockquote>
|
||||
<h2 id="haskell">haskell?</h2>
|
||||
<p>This entire blog is generated with <a href="https://jaspervdj.be/hakyll/">hakyll</a>. It’s
|
||||
a library for generating static sites for Haskell, a purely functional
|
||||
programming language. It’s a <em>library</em> because it doesn’t come with as many
|
||||
batteries included as tools like Hugo or Astro. You set up most of the site
|
||||
yourself by calling the library from Haskell.</p>
|
||||
<p>Here’s a brief excerpt:</p>
|
||||
<div class="sourceCode" id="cb1"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="ot">main ::</span> <span class="dt">IO</span> ()</span>
|
||||
<span id="cb1-2"><a href="#cb1-2" aria-hidden="true" tabindex="-1"></a>main <span class="ot">=</span> hakyllWith config <span class="op">$</span> <span class="kw">do</span></span>
|
||||
<span id="cb1-3"><a href="#cb1-3" aria-hidden="true" tabindex="-1"></a> forM_</span>
|
||||
<span id="cb1-4"><a href="#cb1-4" aria-hidden="true" tabindex="-1"></a> [ <span class="st">"CNAME"</span></span>
|
||||
<span id="cb1-5"><a href="#cb1-5" aria-hidden="true" tabindex="-1"></a> , <span class="st">"favicon.ico"</span></span>
|
||||
<span id="cb1-6"><a href="#cb1-6" aria-hidden="true" tabindex="-1"></a> , <span class="st">"robots.txt"</span></span>
|
||||
<span id="cb1-7"><a href="#cb1-7" aria-hidden="true" tabindex="-1"></a> , <span class="st">"_config.yml"</span></span>
|
||||
<span id="cb1-8"><a href="#cb1-8" aria-hidden="true" tabindex="-1"></a> , <span class="st">"images/*"</span></span>
|
||||
<span id="cb1-9"><a href="#cb1-9" aria-hidden="true" tabindex="-1"></a> , <span class="st">"out/*"</span></span>
|
||||
<span id="cb1-10"><a href="#cb1-10" aria-hidden="true" tabindex="-1"></a> , <span class="st">"fonts/*"</span></span>
|
||||
<span id="cb1-11"><a href="#cb1-11" aria-hidden="true" tabindex="-1"></a> ]</span>
|
||||
<span id="cb1-12"><a href="#cb1-12" aria-hidden="true" tabindex="-1"></a> <span class="op">$</span> \f <span class="ot">-></span> match f <span class="op">$</span> <span class="kw">do</span></span>
|
||||
<span id="cb1-13"><a href="#cb1-13" aria-hidden="true" tabindex="-1"></a> route idRoute</span>
|
||||
<span id="cb1-14"><a href="#cb1-14" aria-hidden="true" tabindex="-1"></a> compile copyFileCompiler</span></code></pre></div>
|
||||
<p>The code highlighting is also generated by hakyll.</p>
|
||||
<hr />
|
||||
<h2 id="why">why?</h2>
|
||||
<p>Haskell is a purely functional language with no mutable state. Its syntax
|
||||
actually makes it pretty elegant for declaring routes and “rendering” pipelines.</p>
|
||||
<ol>
|
||||
<li>Haskell is cool.</li>
|
||||
<li>It comes with enough features that I don’t feel like I have to build
|
||||
everything from scratch.</li>
|
||||
<li>It comes with Pandoc, a Haskell library for converting between markdown
|
||||
formats. It’s probably more powerful than anything you could do in <code>nodejs</code>.
|
||||
It renders all of the markdown to HTML as well as the math.
|
||||
<ol>
|
||||
<li>It supports KaTeX as well as MathML. I’m a little disappointed with the
|
||||
KaTeX though. It doesn’t directly render it, but simply injects the KaTeX
|
||||
files and renders it client-side.</li>
|
||||
</ol></li>
|
||||
</ol>
|
||||
<h3 id="speaking-of-math">speaking of math</h3>
|
||||
<p>We can have math inline, like so:
|
||||
<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msubsup><mo>∫</mo><mrow><mo>−</mo><mi>∞</mi></mrow><mi>∞</mi></msubsup><mspace width="0.167em"></mspace><msup><mi>e</mi><mrow><mo>−</mo><msup><mi>x</mi><mn>2</mn></msup></mrow></msup><mspace width="0.167em"></mspace><mi>d</mi><mi>x</mi><mo>=</mo><msqrt><mi>π</mi></msqrt></mrow><annotation encoding="application/x-tex">\int_{-\infty}^\infty \, e^{-x^2}\,dx = \sqrt{\pi}</annotation></semantics></math>. This site ships semantic
|
||||
MathML math with its HTML, and the MathJax script to the client.</p>
|
||||
<p>It’d be nice if MathML could just be used and supported across all browsers, but
|
||||
unfortunately we still aren’t quite there yet. Firefox is the only one where
|
||||
everything looks 80% of the way to LaTeX. On Safari and Chrome, even simple
|
||||
equations like <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><msqrt><mi>π</mi></msqrt><annotation encoding="application/x-tex">\sqrt{\pi}</annotation></semantics></math> render improperly.</p>
|
||||
<p>Pros of MathML:</p>
|
||||
<ul>
|
||||
<li>A little more accessible</li>
|
||||
<li>Can be rendered without additional stylesheets. I just installed the Latin
|
||||
Modern font, but this isn’t even really necessary</li>
|
||||
<li>Built-in to most browsers (#UseThePlatform)</li>
|
||||
</ul>
|
||||
<p>Cons:</p>
|
||||
<ul>
|
||||
<li>Isn’t fully standardized. Might look different on different browsers</li>
|
||||
<li>Rendering quality isn’t as good as KaTeX</li>
|
||||
</ul>
|
||||
<p>This site has MathJax render all of the math so it looks nice and standardized
|
||||
across browsers, but the math still displays regardless (like say if MathJax
|
||||
couldn’t load due to slow network) because of MathML. Best of both worlds.</p>
|
||||
<p>Let’s try it now. Here’s a simple theorem:</p>
|
||||
<p><math display="block" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mi>a</mi><mi>n</mi></msup><mo>+</mo><msup><mi>b</mi><mi>n</mi></msup><mo>≠</mo><msup><mi>c</mi><mi>n</mi></msup><mspace width="0.167em"></mspace><mo>∀</mo><mspace width="0.167em"></mspace><mrow><mo stretchy="true" form="prefix">{</mo><mi>a</mi><mo>,</mo><mspace width="0.167em"></mspace><mi>b</mi><mo>,</mo><mspace width="0.167em"></mspace><mi>c</mi><mo stretchy="true" form="postfix">}</mo></mrow><mo>∈</mo><mstyle mathvariant="double-struck"><mi>ℤ</mi></mstyle><mo>∧</mo><mi>n</mi><mo>≥</mo><mn>3</mn></mrow><annotation encoding="application/x-tex">
|
||||
a^n + b^n \ne c^n \, \forall\,\left\{ a,\,b,\,c \right\} \in \mathbb{Z} \land n \ge 3
|
||||
</annotation></semantics></math></p>
|
||||
<p>The proof is trivial and will be left as an exercise to the reader.</p>
|
||||
<h2 id="seems-a-little-overengineered">seems a little overengineered</h2>
|
||||
<p>Probably is. Not as much as the old one, though.</p></main>
|
||||
</article>
|
||||
]]></summary>
|
||||
</entry>
|
||||
|
||||
</feed>
|
||||
1
css/code.css
Normal file
1
css/code.css
Normal file
|
|
@ -0,0 +1 @@
|
|||
pre>code.sourceCode{white-space:pre;position:relative}pre>code.sourceCode>span{line-height:1.25}pre>code.sourceCode>span:empty{height:1.2em}.sourceCode{overflow:visible}code.sourceCode>span{color:inherit;text-decoration:inherit}div.sourceCode{margin:1em 0}pre.sourceCode{margin:0}@media screen{div.sourceCode{overflow:auto}}@media print{pre>code.sourceCode{white-space:pre-wrap}pre>code.sourceCode>span{text-indent:-5em;padding-left:5em}}pre.numberSource code{counter-reset:source-line 0}pre.numberSource code>span{position:relative;left:-4em;counter-increment:source-line}pre.numberSource code>span>a:first-child::before{content:counter(source-line);position:relative;left:-1em;text-align:right;vertical-align:baseline;border:none;display:inline-block;-webkit-touch-callout:none;-webkit-user-select:none;-khtml-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;padding:0 4px;width:4em;background-color:#232629;color:#7a7c7d}pre.numberSource{margin-left:3em;border-left:1px solid #7a7c7d;padding-left:4px}div.sourceCode{color:#cfcfc2;background-color:#232629}@media screen{pre>code.sourceCode>span>a:first-child::before{text-decoration:underline}}code span{color:#cfcfc2}code span.al{color:#95da4c;background-color:#4d1f24;font-weight:bold}code span.an{color:#3f8058}code span.at{color:#2980b9}code span.bn{color:#f67400}code span.bu{color:#7f8c8d}code span.cf{color:#fdbc4b;font-weight:bold}code span.ch{color:#3daee9}code span.cn{color:#27aeae;font-weight:bold}code span.co{color:#7a7c7d}code span.cv{color:#7f8c8d}code span.do{color:#a43340}code span.dt{color:#2980b9}code span.dv{color:#f67400}code span.er{color:#da4453;text-decoration:underline}code span.ex{color:#0099ff;font-weight:bold}code span.fl{color:#f67400}code span.fu{color:#8e44ad}code span.im{color:#27ae60}code span.in{color:#c45b00}code span.kw{color:#cfcfc2;font-weight:bold}code span.op{color:#cfcfc2}code span.ot{color:#27ae60}code span.pp{color:#27ae60}code span.re{color:#2980b9;background-color:#153042}code span.sc{color:#3daee9}code span.ss{color:#da4453}code span.st{color:#f44f4f}code span.va{color:#27aeae}code span.vs{color:#da4453}code span.wa{color:#da4453}
|
||||
BIN
favicon.ico
Normal file
BIN
favicon.ico
Normal file
Binary file not shown.
BIN
images/conditional-finality.png
Normal file
BIN
images/conditional-finality.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 43 KiB |
220
index.html
Normal file
220
index.html
Normal file
|
|
@ -0,0 +1,220 @@
|
|||
<!doctype html>
|
||||
<html lang="en">
|
||||
<head>
|
||||
<title>youwen wu | conditional finality</title>
|
||||
|
||||
<meta charset="utf-8" />
|
||||
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
|
||||
<meta name="description" content="a weblog about computers, math, hacks, games, and life" />
|
||||
|
||||
|
||||
<meta property="og:site_name" content="conditional finality" />
|
||||
<meta property="og:title" content="youwen wu" />
|
||||
<meta property="og:url" content="https://blog.youwen.dev/index.html" />
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<meta property="og:description" content="a weblog about computers, math, hacks, games, and life" />
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||||
|
||||
<meta property="og:image" content="https://blog.youwen.dev./images/gradient-ascent.jpg" />
|
||||
|
||||
<meta property="og:type" content="website" />
|
||||
|
||||
<meta property="twitter:card" content="summary_large_image" />
|
||||
<meta property="twitter:image" content="https://blog.youwen.dev./images/gradient-ascent.jpg" />
|
||||
|
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<meta property="twitter:site" content="conditional finality" />
|
||||
<meta property="twitter:title" content="youwen wu" />
|
||||
<meta property="twitter:description" content="a weblog about computers, math, hacks, games, and life" />
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||||
|
||||
|
||||
<link rel="shortcut icon" href="/favicon.ico" />
|
||||
<link rel="canonical" href="https://blog.youwen.dev/index.html" />
|
||||
|
||||
<link
|
||||
rel="alternate"
|
||||
href="./atom.xml"
|
||||
title="conditional finality"
|
||||
type="application/atom+xml"
|
||||
/>
|
||||
<link
|
||||
rel="alternate"
|
||||
href="./rss.xml"
|
||||
title="conditional finality"
|
||||
type="application/rss+xml"
|
||||
/>
|
||||
<link rel="stylesheet" href="./out/bundle.css" />
|
||||
<link rel="stylesheet" href="./css/code.css" />
|
||||
<script
|
||||
defer
|
||||
src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/mml-chtml.js"
|
||||
></script>
|
||||
|
||||
<script>
|
||||
if (
|
||||
localStorage.theme === "dark" ||
|
||||
(!("theme" in localStorage) &&
|
||||
window.matchMedia("(prefers-color-scheme: dark)").matches)
|
||||
) {
|
||||
document.documentElement.classList.add("dark")
|
||||
} else {
|
||||
document.documentElement.classList.remove("dark")
|
||||
}
|
||||
window.onload = () => {
|
||||
var themeButton = document.getElementById("theme-toggle")
|
||||
const theme = localStorage.getItem("theme")
|
||||
if (theme === "light") {
|
||||
themeButton.innerText = "theme: light"
|
||||
} else if (theme === "dark") {
|
||||
themeButton.innerText = "theme: dark"
|
||||
} else {
|
||||
themeButton.innerText = "theme: system"
|
||||
}
|
||||
var fontButton = document.getElementById("font-toggle")
|
||||
const font = localStorage.getItem("font")
|
||||
if (font && font === "serif") {
|
||||
document.body.classList.remove("font-sans")
|
||||
document.body.classList.remove("font-serif")
|
||||
document.body.classList.add("font-serif")
|
||||
fontButton.innerText = "serif"
|
||||
}
|
||||
if (font && font === "sans") {
|
||||
document.body.classList.remove("font-sans")
|
||||
document.body.classList.remove("font-serif")
|
||||
document.body.classList.add("font-sans")
|
||||
fontButton.innerText = "sans"
|
||||
}
|
||||
if (!font) {
|
||||
document.body.classList.remove("font-sans")
|
||||
document.body.classList.remove("font-serif")
|
||||
fontButton.innerText = "serif"
|
||||
}
|
||||
}
|
||||
MathJax = {
|
||||
startup: {
|
||||
ready: function () {
|
||||
MathJax.startup.defaultReady()
|
||||
MathJax.startup.promise.then(function () {
|
||||
MathJax.mathml2svgPromise(document.body)
|
||||
})
|
||||
},
|
||||
},
|
||||
}
|
||||
</script>
|
||||
</head>
|
||||
<body
|
||||
class="container max-w-2xl mx-auto px-4 transition-colors duration-[2s]"
|
||||
>
|
||||
<header class="mt-14 md:mt-24 mb-14">
|
||||
<div class="inline-flex items-center w-full">
|
||||
<h1 class="text-4xl md:text-5xl font-serif font-medium">
|
||||
<a
|
||||
href="/"
|
||||
class="dark:hover:text-muted-dark hover:text-muted-light transition-all duration-500 text-nowrap tracking-wide"
|
||||
><em>Conditional Finality.</em></a
|
||||
>
|
||||
</h1>
|
||||
<div
|
||||
class="w-full flex-grow flex-shrink rounded-lg h-1 bg-muted-light dark:bg-muted-dark mx-4"
|
||||
></div>
|
||||
</div>
|
||||
<p class="mt-8 mb-3 px-1 italic font-light">
|
||||
a web-log about computers, math, hacks, and all the rest.
|
||||
</p>
|
||||
<a class="text-sm text-iris-light dark:text-iris-dark hover:text-love-light dark:hover:text-love-dark" href="https://youwen.dev"
|
||||
><em>by </em>Youwen Wu</a
|
||||
>
|
||||
<span class="ml-2 font-serif">|</span>
|
||||
<button
|
||||
id="theme-toggle"
|
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class="ml-2 text-sm hover:text-accent-light dark:hover:text-muted-dark"
|
||||
></button>
|
||||
<span class="ml-2 font-serif">|</span>
|
||||
<button
|
||||
id="font-toggle"
|
||||
class="ml-2 text-sm hover:text-accent-light dark:hover:text-muted-dark"
|
||||
></button>
|
||||
</header>
|
||||
<main>
|
||||
<section>
|
||||
<h2 class="text-3xl">Latest</h2>
|
||||
<hr
|
||||
class="sm:mr-2 max-w-sm border-0 h-0.5 dark:bg-muted-dark bg-muted-light rounded-md mt-2"
|
||||
/>
|
||||
<ul class="mt-6 space-y-4 md:space-y-8">
|
||||
|
||||
<li class="group">
|
||||
<div class="rounded-md p-2">
|
||||
<a
|
||||
href="./nix-automatic-hash-updates-made-easy.html"
|
||||
class="w-fit dark:group-hover:text-iris-dark group-hover:text-iris-light transition-colors"
|
||||
>
|
||||
<h3 class="text-2xl">Nix automatic hash updates made easy</h3>
|
||||
<p
|
||||
class="italic text-accent-light dark:text-accent-dark my-1 group-hover:dark:text-muted-dark group-hover:text-muted-light transition-colors"
|
||||
>
|
||||
keep your flakes up to date
|
||||
</p>
|
||||
<p class="text-sm">2024-12-28</p>
|
||||
</a>
|
||||
</div>
|
||||
<hr
|
||||
class="max-w-[200px] border-0 h-1 dark:bg-accent-dark bg-accent-light rounded-lg px-2 group-hover:max-w-[250px] dark:group-hover:bg-iris-dark group-hover:bg-iris-light transition-all duration-400"
|
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/>
|
||||
</li>
|
||||
|
||||
<li class="group">
|
||||
<div class="rounded-md p-2">
|
||||
<a
|
||||
href="./a-haskellian-blog.html"
|
||||
class="w-fit dark:group-hover:text-iris-dark group-hover:text-iris-light transition-colors"
|
||||
>
|
||||
<h3 class="text-2xl">a haskellian blog</h3>
|
||||
<p
|
||||
class="italic text-accent-light dark:text-accent-dark my-1 group-hover:dark:text-muted-dark group-hover:text-muted-light transition-colors"
|
||||
>
|
||||
a purely functional...blog?
|
||||
</p>
|
||||
<p class="text-sm">2024-05-25</p>
|
||||
</a>
|
||||
</div>
|
||||
<hr
|
||||
class="max-w-[200px] border-0 h-1 dark:bg-accent-dark bg-accent-light rounded-lg px-2 group-hover:max-w-[250px] dark:group-hover:bg-iris-dark group-hover:bg-iris-light transition-all duration-400"
|
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/>
|
||||
</li>
|
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|
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</ul>
|
||||
</section>
|
||||
</main>
|
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|
||||
<footer class="mt-14 md:mt-24 pb-12 font-light">
|
||||
<hr
|
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|
||||
/>
|
||||
<p class="text-sm leading-relaxed">
|
||||
© 2024 Youwen Wu. Generated by
|
||||
<a
|
||||
href="https://jaspervdj.be/hakyll/"
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
>Hakyll.</a
|
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>
|
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View the source
|
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|
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href="https://github.com/couscousdude/blog"
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
>on GitHub.</a
|
||||
>
|
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</p>
|
||||
<p class="text-sm leading-relaxed mt-2">
|
||||
Content freely available under
|
||||
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|
||||
class="external-link-muted"
|
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target="__blank"
|
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href="https://creativecommons.org/licenses/by-nc-sa/4.0/deed.en"
|
||||
><span class="smallcaps">CC BY-NC-SA</span> 4.0</a
|
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>
|
||||
unless otherwise noted.
|
||||
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|
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</footer>
|
||||
<script defer src="./out/bundle.js"></script>
|
||||
</body>
|
||||
</html>
|
||||
435
nix-automatic-hash-updates-made-easy.html
Normal file
435
nix-automatic-hash-updates-made-easy.html
Normal file
|
|
@ -0,0 +1,435 @@
|
|||
<!doctype html>
|
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<html lang="en">
|
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<head>
|
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href="/"
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class="dark:hover:text-muted-dark hover:text-muted-light transition-all duration-500 text-nowrap tracking-wide"
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class="w-full flex-grow flex-shrink rounded-lg h-1 bg-muted-light dark:bg-muted-dark mx-4"
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<p class="mt-8 mb-3 px-1 italic font-light">
|
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a web-log about computers, math, hacks, and all the rest.
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</p>
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<a class="text-sm text-iris-light dark:text-iris-dark hover:text-love-light dark:hover:text-love-dark" href="https://youwen.dev"
|
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><em>by </em>Youwen Wu</a
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<article>
|
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<header>
|
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<h1 class="text-4xl">
|
||||
<a href="./nix-automatic-hash-updates-made-easy.html">Nix automatic hash updates made easy</a>
|
||||
</h1>
|
||||
<p
|
||||
class="mb-1 mt-2 italic font-light text-lg text-accent-light dark:text-accent-dark"
|
||||
>
|
||||
keep your flakes up to date
|
||||
</p>
|
||||
<div class="mt-2">2024-12-28</div>
|
||||
<div class="mt-1 text-sm">
|
||||
|
||||
</div>
|
||||
</header>
|
||||
<main class="post mt-4"><p>Nix users often create flakes to package software out of tree, like this <a href="https://github.com/youwen5/zen-browser-flake">Zen
|
||||
Browser flake</a> I’ve been
|
||||
maintaining. Keeping them up to date is a hassle though, since you have to
|
||||
update the Subresource Integrity (SRI) hashes that Nix uses to ensure
|
||||
reproducibility.</p>
|
||||
<p>Here’s a neat method I’ve been using to cleanly handle automatic hash updates.
|
||||
I use <a href="https://www.nushell.sh/">Nushell</a> to easily work with data, prefetch
|
||||
some hashes, and put it all in a JSON file that can be read by Nix at build
|
||||
time.</p>
|
||||
<p>First, let’s create a file called <code>update.nu</code>. At the top, place this shebang:</p>
|
||||
<pre class="nu"><code>#!/usr/bin/env -S nix shell nixpkgs#nushell --command nu</code></pre>
|
||||
<p>This will execute the script in a Nushell environment, which is fetched by Nix.</p>
|
||||
<h2 id="get-the-up-to-date-urls">Get the up to date URLs</h2>
|
||||
<p>We need to obtain the latest version of whatever software we want to update.
|
||||
In this case, I’ll use GitHub releases as my source of truth.</p>
|
||||
<p>You can use the GitHub API to fetch metadata about all the releases of a repository.</p>
|
||||
<pre><code>https://api.github.com/repos/($repo)/releases</code></pre>
|
||||
<p>Roughly speaking, the raw JSON returned by the GitHub releases API looks something like:</p>
|
||||
<pre><code>[
|
||||
{tag_name: "foo", prerelease: false, ...},
|
||||
{tag_name: "bar", prerelease: true, ...},
|
||||
{tag_name: "foobar", prerelease: false, ...},
|
||||
]
|
||||
</code></pre>
|
||||
<p>Note that the ordering of the objects in the array is chronological.</p>
|
||||
<blockquote>
|
||||
<p>Even if you aren’t using GitHub releases, as long as there is a reliable way to
|
||||
programmatically fetch the latest download URLs of whatever software you’re
|
||||
packaging, you can adapt this approach for your specific case.</p>
|
||||
</blockquote>
|
||||
<p>We use Nushell’s <code>http get</code> to make a network request. Nushell will
|
||||
automatically detect and parse the JSON reponse into a Nushell table.</p>
|
||||
<p>In my case, Zen Browser frequently publishes prerelease “twilight” builds which
|
||||
we don’t want to update to. So, we ignore any releases tagged “twilight” or
|
||||
marked “prerelease” by filtering them out with the <code>where</code> selector.</p>
|
||||
<p>Finally, we retrieve the tag name of the item at the first index, which would
|
||||
be the latest release (since the JSON array was chronologically sorted).</p>
|
||||
<pre class="nu"><code>#!/usr/bin/env -S nix shell nixpkgs#nushell --command nu
|
||||
|
||||
# get the latest tag of the latest release that isn't a prerelease
|
||||
def get_latest_release [repo: string] {
|
||||
try {
|
||||
http get $"https://api.github.com/repos/($repo)/releases"
|
||||
| where prerelease == false
|
||||
| where tag_name != "twilight"
|
||||
| get tag_name
|
||||
| get 0
|
||||
} catch { |err| $"Failed to fetch latest release, aborting: ($err.msg)" }
|
||||
}</code></pre>
|
||||
<h2 id="prefetching-sri-hashes">Prefetching SRI hashes</h2>
|
||||
<p>Now that we have the latest tags, we can easily obtain the latest download URLs, which are of the form:</p>
|
||||
<pre><code>https://github.com/zen-browser/desktop/releases/download/$tag/zen.linux-x86_64.tar.bz2
|
||||
https://github.com/zen-browser/desktop/releases/download/$tag/zen.aarch64-x86_64.tar.bz2</code></pre>
|
||||
<p>However, we still need the corresponding SRI hashes to pass to Nix.</p>
|
||||
<div class="sourceCode" id="cb6"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a>src = fetchurl <span class="op">{</span></span>
|
||||
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span> <span class="op">=</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-x86_64.tar.bz2"</span><span class="op">;</span></span>
|
||||
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span> <span class="op">=</span> <span class="st">"sha256-00000000000000000000000000000000000000000000"</span><span class="op">;</span></span>
|
||||
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a><span class="op">}</span>;</span></code></pre></div>
|
||||
<p>The easiest way to obtain these new hashes is to update the URL and then set
|
||||
the hash property to an empty string (<code>""</code>). Nix will spit out an hash mismatch
|
||||
error with the correct hash. However, this is inconvenient for automated
|
||||
command line scripting.</p>
|
||||
<p>The Nix documentation mentions
|
||||
<a href="https://nix.dev/manual/nix/2.18/command-ref/nix-prefetch-url">nix-prefetch-url</a>
|
||||
as a way to obtain these hashes, but as usual, it doesn’t work quite right and
|
||||
has also been replaced by a more powerful but underdocumented experimental
|
||||
feature instead.</p>
|
||||
<p>The <a href="https://nix.dev/manual/nix/2.18/command-ref/new-cli/nix3-store-prefetch-file">nix store
|
||||
prefetch-file</a>
|
||||
command does what <code>nix-prefetch-url</code> is supposed to do, but handles the caveats
|
||||
that lead to the wrong hash being produced automatically.</p>
|
||||
<p>Let’s write a Nushell function that outputs the SRI hash of the given URL. We
|
||||
tell <code>prefetch-file</code> to output structured JSON that we can parse.</p>
|
||||
<p>Since Nushell <em>is</em> a shell, we can directly invoke shell commands like usual,
|
||||
and then process their output with pipes.</p>
|
||||
<pre class="nu"><code>def get_nix_hash [url: string] {
|
||||
nix store prefetch-file --hash-type sha256 --json $url | from json | get hash
|
||||
}</code></pre>
|
||||
<p>Cool! Now <code>get_nix_hash</code> can give us SRI hashes that look like this:</p>
|
||||
<pre><code>sha256-K3zTCLdvg/VYQNsfeohw65Ghk8FAjhOl8hXU6REO4/s=</code></pre>
|
||||
<h2 id="putting-it-all-together">Putting it all together</h2>
|
||||
<p>Now that we’re able to fetch the latest release, obtain the download URLs, and
|
||||
compute their SRI hashes, we have all the information we need to make an
|
||||
automated update. However, these URLs are typically hardcoded in our Nix
|
||||
expressions. The question remains as to how to update these values.</p>
|
||||
<p>A common way I’ve seen updates performed is using something like <code>sed</code> to
|
||||
modify the Nix expressions in place. However, there’s actually a more
|
||||
maintainable and easy to understand approach.</p>
|
||||
<p>Let’s have our Nushell script generate the URLs and hashes and place them in a
|
||||
JSON file! Then, we’ll be able to read the JSON file from Nix and obtain the
|
||||
URL and hash.</p>
|
||||
<pre class="nu"><code>def generate_sources [] {
|
||||
let tag = get_latest_release "zen-browser/desktop"
|
||||
let prev_sources = open ./sources.json
|
||||
|
||||
if $tag == $prev_sources.version {
|
||||
# everything up to date
|
||||
return $tag
|
||||
}
|
||||
|
||||
# generate the download URLs with the new tag
|
||||
let x86_64_url = $"https://github.com/zen-browser/desktop/releases/download/($tag)/zen.linux-x86_64.tar.bz2"
|
||||
let aarch64_url = $"https://github.com/zen-browser/desktop/releases/download/($tag)/zen.linux-aarch64.tar.bz2"
|
||||
|
||||
# create a Nushell record that maps cleanly to JSON
|
||||
let sources = {
|
||||
# add a version field as well for convenience
|
||||
version: $tag
|
||||
|
||||
x86_64-linux: {
|
||||
url: $x86_64_url
|
||||
hash: (get_nix_hash $x86_64_url)
|
||||
}
|
||||
aarch64-linux: {
|
||||
url: $aarch64_url
|
||||
hash: (get_nix_hash $aarch64_url)
|
||||
}
|
||||
}
|
||||
|
||||
echo $sources | save --force "sources.json"
|
||||
|
||||
return $tag
|
||||
}</code></pre>
|
||||
<p>Running this script with</p>
|
||||
<div class="sourceCode" id="cb10"><pre class="sourceCode bash"><code class="sourceCode bash"><span id="cb10-1"><a href="#cb10-1" aria-hidden="true" tabindex="-1"></a><span class="fu">chmod</span> +x ./update.nu</span>
|
||||
<span id="cb10-2"><a href="#cb10-2" aria-hidden="true" tabindex="-1"></a><span class="ex">./update.nu</span></span></code></pre></div>
|
||||
<p>gives us the file <code>sources.json</code>:</p>
|
||||
<div class="sourceCode" id="cb11"><pre class="sourceCode json"><code class="sourceCode json"><span id="cb11-1"><a href="#cb11-1" aria-hidden="true" tabindex="-1"></a><span class="fu">{</span></span>
|
||||
<span id="cb11-2"><a href="#cb11-2" aria-hidden="true" tabindex="-1"></a> <span class="dt">"version"</span><span class="fu">:</span> <span class="st">"1.0.2-b.5"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-3"><a href="#cb11-3" aria-hidden="true" tabindex="-1"></a> <span class="dt">"x86_64-linux"</span><span class="fu">:</span> <span class="fu">{</span></span>
|
||||
<span id="cb11-4"><a href="#cb11-4" aria-hidden="true" tabindex="-1"></a> <span class="dt">"url"</span><span class="fu">:</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-x86_64.tar.bz2"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-5"><a href="#cb11-5" aria-hidden="true" tabindex="-1"></a> <span class="dt">"hash"</span><span class="fu">:</span> <span class="st">"sha256-K3zTCLdvg/VYQNsfeohw65Ghk8FAjhOl8hXU6REO4/s="</span></span>
|
||||
<span id="cb11-6"><a href="#cb11-6" aria-hidden="true" tabindex="-1"></a> <span class="fu">},</span></span>
|
||||
<span id="cb11-7"><a href="#cb11-7" aria-hidden="true" tabindex="-1"></a> <span class="dt">"aarch64-linux"</span><span class="fu">:</span> <span class="fu">{</span></span>
|
||||
<span id="cb11-8"><a href="#cb11-8" aria-hidden="true" tabindex="-1"></a> <span class="dt">"url"</span><span class="fu">:</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-aarch64.tar.bz2"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-9"><a href="#cb11-9" aria-hidden="true" tabindex="-1"></a> <span class="dt">"hash"</span><span class="fu">:</span> <span class="st">"sha256-NwIYylGal2QoWhWKtMhMkAAJQ6iNHfQOBZaxTXgvxAk="</span></span>
|
||||
<span id="cb11-10"><a href="#cb11-10" aria-hidden="true" tabindex="-1"></a> <span class="fu">}</span></span>
|
||||
<span id="cb11-11"><a href="#cb11-11" aria-hidden="true" tabindex="-1"></a><span class="fu">}</span></span></code></pre></div>
|
||||
<p>Now, let’s read this from Nix. My file organization looks like the following:</p>
|
||||
<pre><code>./
|
||||
| flake.nix
|
||||
| zen-browser-unwrapped.nix
|
||||
| ...other files...</code></pre>
|
||||
<p><code>zen-browser-unwrapped.nix</code> contains the derivation for Zen Browser. Let’s add
|
||||
<code>version</code>, <code>url</code>, and <code>hash</code> to its inputs:</p>
|
||||
<div class="sourceCode" id="cb13"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb13-1"><a href="#cb13-1" aria-hidden="true" tabindex="-1"></a><span class="op">{</span></span>
|
||||
<span id="cb13-2"><a href="#cb13-2" aria-hidden="true" tabindex="-1"></a> <span class="va">stdenv</span><span class="op">,</span></span>
|
||||
<span id="cb13-3"><a href="#cb13-3" aria-hidden="true" tabindex="-1"></a> <span class="va">fetchurl</span><span class="op">,</span></span>
|
||||
<span id="cb13-4"><a href="#cb13-4" aria-hidden="true" tabindex="-1"></a> <span class="co"># add these below</span></span>
|
||||
<span id="cb13-5"><a href="#cb13-5" aria-hidden="true" tabindex="-1"></a> <span class="va">version</span><span class="op">,</span></span>
|
||||
<span id="cb13-6"><a href="#cb13-6" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span><span class="op">,</span></span>
|
||||
<span id="cb13-7"><a href="#cb13-7" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span><span class="op">,</span></span>
|
||||
<span id="cb13-8"><a href="#cb13-8" aria-hidden="true" tabindex="-1"></a> <span class="op">...</span></span>
|
||||
<span id="cb13-9"><a href="#cb13-9" aria-hidden="true" tabindex="-1"></a><span class="op">}</span>:</span>
|
||||
<span id="cb13-10"><a href="#cb13-10" aria-hidden="true" tabindex="-1"></a>stdenv.mkDerivation <span class="op">{</span></span>
|
||||
<span id="cb13-11"><a href="#cb13-11" aria-hidden="true" tabindex="-1"></a> <span class="co"># inherit version from inputs</span></span>
|
||||
<span id="cb13-12"><a href="#cb13-12" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> version<span class="op">;</span></span>
|
||||
<span id="cb13-13"><a href="#cb13-13" aria-hidden="true" tabindex="-1"></a> <span class="va">pname</span> <span class="op">=</span> <span class="st">"zen-browser-unwrapped"</span><span class="op">;</span></span>
|
||||
<span id="cb13-14"><a href="#cb13-14" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb13-15"><a href="#cb13-15" aria-hidden="true" tabindex="-1"></a> <span class="va">src</span> <span class="op">=</span> fetchurl <span class="op">{</span></span>
|
||||
<span id="cb13-16"><a href="#cb13-16" aria-hidden="true" tabindex="-1"></a> <span class="co"># inherit the URL and hash we obtain from the inputs</span></span>
|
||||
<span id="cb13-17"><a href="#cb13-17" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> url hash<span class="op">;</span></span>
|
||||
<span id="cb13-18"><a href="#cb13-18" aria-hidden="true" tabindex="-1"></a> <span class="op">};</span></span>
|
||||
<span id="cb13-19"><a href="#cb13-19" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>
|
||||
<p>Then in <code>flake.nix</code>, let’s provide the derivation with the data from <code>sources.json</code>:</p>
|
||||
<div class="sourceCode" id="cb14"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb14-1"><a href="#cb14-1" aria-hidden="true" tabindex="-1"></a><span class="kw">let</span></span>
|
||||
<span id="cb14-2"><a href="#cb14-2" aria-hidden="true" tabindex="-1"></a> <span class="va">supportedSystems</span> <span class="op">=</span> <span class="op">[</span></span>
|
||||
<span id="cb14-3"><a href="#cb14-3" aria-hidden="true" tabindex="-1"></a> <span class="st">"x86_64-linux"</span></span>
|
||||
<span id="cb14-4"><a href="#cb14-4" aria-hidden="true" tabindex="-1"></a> <span class="st">"aarch64-linux"</span></span>
|
||||
<span id="cb14-5"><a href="#cb14-5" aria-hidden="true" tabindex="-1"></a> <span class="op">];</span></span>
|
||||
<span id="cb14-6"><a href="#cb14-6" aria-hidden="true" tabindex="-1"></a> <span class="va">forAllSystems</span> <span class="op">=</span> nixpkgs.lib.genAttrs supportedSystems<span class="op">;</span></span>
|
||||
<span id="cb14-7"><a href="#cb14-7" aria-hidden="true" tabindex="-1"></a><span class="kw">in</span></span>
|
||||
<span id="cb14-8"><a href="#cb14-8" aria-hidden="true" tabindex="-1"></a><span class="op">{</span></span>
|
||||
<span id="cb14-9"><a href="#cb14-9" aria-hidden="true" tabindex="-1"></a> <span class="co"># rest of file omitted for simplicity</span></span>
|
||||
<span id="cb14-10"><a href="#cb14-10" aria-hidden="true" tabindex="-1"></a> <span class="va">packages</span> <span class="op">=</span> forAllSystems <span class="op">(</span></span>
|
||||
<span id="cb14-11"><a href="#cb14-11" aria-hidden="true" tabindex="-1"></a> <span class="va">system</span><span class="op">:</span></span>
|
||||
<span id="cb14-12"><a href="#cb14-12" aria-hidden="true" tabindex="-1"></a> <span class="kw">let</span></span>
|
||||
<span id="cb14-13"><a href="#cb14-13" aria-hidden="true" tabindex="-1"></a> <span class="va">pkgs</span> <span class="op">=</span> <span class="bu">import</span> nixpkgs <span class="op">{</span> <span class="kw">inherit</span> system<span class="op">;</span> <span class="op">};</span></span>
|
||||
<span id="cb14-14"><a href="#cb14-14" aria-hidden="true" tabindex="-1"></a> <span class="co"># parse sources.json into a Nix attrset</span></span>
|
||||
<span id="cb14-15"><a href="#cb14-15" aria-hidden="true" tabindex="-1"></a> <span class="va">sources</span> <span class="op">=</span> <span class="bu">builtins</span>.fromJSON <span class="op">(</span><span class="bu">builtins</span>.readFile <span class="ss">./sources.json</span><span class="op">);</span></span>
|
||||
<span id="cb14-16"><a href="#cb14-16" aria-hidden="true" tabindex="-1"></a> <span class="kw">in</span></span>
|
||||
<span id="cb14-17"><a href="#cb14-17" aria-hidden="true" tabindex="-1"></a> <span class="kw">rec</span> <span class="op">{</span></span>
|
||||
<span id="cb14-18"><a href="#cb14-18" aria-hidden="true" tabindex="-1"></a> <span class="va">zen-browser-unwrapped</span> <span class="op">=</span> pkgs.callPackage <span class="ss">./zen-browser-unwrapped.nix</span> <span class="op">{</span></span>
|
||||
<span id="cb14-19"><a href="#cb14-19" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> <span class="op">(</span>sources.$<span class="op">{</span><span class="va">system</span><span class="op">})</span> hash url<span class="op">;</span></span>
|
||||
<span id="cb14-20"><a href="#cb14-20" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> <span class="op">(</span>sources<span class="op">)</span> version<span class="op">;</span></span>
|
||||
<span id="cb14-21"><a href="#cb14-21" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb14-22"><a href="#cb14-22" aria-hidden="true" tabindex="-1"></a> <span class="co"># if the above is difficult to understand, it is equivalent to the following:</span></span>
|
||||
<span id="cb14-23"><a href="#cb14-23" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span> <span class="op">=</span> sources.$<span class="op">{</span><span class="va">system</span><span class="op">}</span>.hash<span class="op">;</span></span>
|
||||
<span id="cb14-24"><a href="#cb14-24" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span> <span class="op">=</span> sources.$<span class="op">{</span><span class="va">system</span><span class="op">}</span>.url<span class="op">;</span></span>
|
||||
<span id="cb14-25"><a href="#cb14-25" aria-hidden="true" tabindex="-1"></a> <span class="va">version</span> <span class="op">=</span> sources.version<span class="op">;</span></span>
|
||||
<span id="cb14-26"><a href="#cb14-26" aria-hidden="true" tabindex="-1"></a> <span class="op">};</span></span>
|
||||
<span id="cb14-27"><a href="#cb14-27" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>
|
||||
<p>Now, running <code>nix build .#zen-browser-unwrapped</code> will be able to use the hashes
|
||||
and URLs from <code>sources.json</code> to build the package!</p>
|
||||
<h2 id="automating-it-in-ci">Automating it in CI</h2>
|
||||
<p>We now have a script that can automatically fetch releases and generate hashes
|
||||
and URLs, as well as a way for Nix to use the outputted JSON to build
|
||||
derivations. All that’s left is to fully automate it using CI!</p>
|
||||
<p>We are going to use GitHub actions for this, as it’s free and easy and you’re
|
||||
probably already hosting on GitHub.</p>
|
||||
<p>Ensure you’ve set up actions for your repo and given it sufficient permissions.</p>
|
||||
<p>We’re gonna run it on a cron timer that checks for updates at 8 PM PST every day.</p>
|
||||
<p>We use DeterminateSystems’ actions to help set up Nix. Then, we simply run our
|
||||
update script. Since we made the script return the tag it fetched, we can store
|
||||
it in a variable and then use it in our commit message.</p>
|
||||
<pre><code>name: Update to latest version, and update flake inputs
|
||||
|
||||
on:
|
||||
schedule:
|
||||
- cron: "0 4 * * *"
|
||||
workflow_dispatch:
|
||||
|
||||
jobs:
|
||||
update:
|
||||
name: Update flake inputs and browser
|
||||
runs-on: ubuntu-latest
|
||||
steps:
|
||||
- name: Checkout Repository
|
||||
uses: actions/checkout@v4
|
||||
|
||||
- name: Check flake inputs
|
||||
uses: DeterminateSystems/flake-checker-action@v4
|
||||
|
||||
- name: Install Nix
|
||||
uses: DeterminateSystems/nix-installer-action@main
|
||||
|
||||
- name: Set up magic Nix cache
|
||||
uses: DeterminateSystems/magic-nix-cache-action@main
|
||||
|
||||
- name: Check for update and perform update
|
||||
run: |
|
||||
git config --global user.name "github-actions[bot]"
|
||||
git config --global user.email "github-actions[bot]@users.noreply.github.com"
|
||||
|
||||
chmod +x ./update.nu
|
||||
export ZEN_LATEST_VER="$(./update.nu)"
|
||||
|
||||
git add -A
|
||||
git commit -m "github-actions: update to $ZEN_LATEST_VER" || echo "Latest version is $ZEN_LATEST_VER, no updates found"
|
||||
|
||||
nix flake update --commit-lock-file
|
||||
|
||||
git push</code></pre>
|
||||
<p>Now, our repository will automatically check for and perform updates every day!</p></main>
|
||||
</article>
|
||||
|
||||
<footer class="mt-14 md:mt-24 pb-12 font-light">
|
||||
<hr
|
||||
class="border-0 dark:bg-muted-dark bg-muted-light rounded-xl h-0.5 mb-4"
|
||||
/>
|
||||
<p class="text-sm leading-relaxed">
|
||||
© 2024 Youwen Wu. Generated by
|
||||
<a
|
||||
href="https://jaspervdj.be/hakyll/"
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
>Hakyll.</a
|
||||
>
|
||||
View the source
|
||||
<a
|
||||
href="https://github.com/couscousdude/blog"
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
>on GitHub.</a
|
||||
>
|
||||
</p>
|
||||
<p class="text-sm leading-relaxed mt-2">
|
||||
Content freely available under
|
||||
<a
|
||||
class="external-link-muted"
|
||||
target="__blank"
|
||||
href="https://creativecommons.org/licenses/by-nc-sa/4.0/deed.en"
|
||||
><span class="smallcaps">CC BY-NC-SA</span> 4.0</a
|
||||
>
|
||||
unless otherwise noted.
|
||||
</p>
|
||||
</footer>
|
||||
<script defer src="./out/bundle.js"></script>
|
||||
</body>
|
||||
</html>
|
||||
1
out/bundle.css
Normal file
1
out/bundle.css
Normal file
File diff suppressed because one or more lines are too long
1
out/bundle.js
Normal file
1
out/bundle.js
Normal file
|
|
@ -0,0 +1 @@
|
|||
const e=window.matchMedia("(prefers-color-scheme: dark)").matches,t=()=>{document.documentElement.classList.remove("dark")},s=()=>{document.documentElement.classList.add("dark")};let o="dark"===localStorage.getItem("theme")?2:"light"===localStorage.getItem("theme")?1:0;const a=document.getElementById("theme-toggle");a.addEventListener("click",(()=>{switch(o=(o+1)%3,o){case 0:localStorage.removeItem("theme"),e?document.documentElement.classList.add("dark"):document.documentElement.classList.remove("dark"),a.innerText="theme: system";break;case 1:e?(localStorage.setItem("theme","light"),t(),a.innerText="theme: light"):(localStorage.setItem("theme","dark"),s(),a.innerText="theme: dark");break;case 2:e?(localStorage.setItem("theme","dark"),s(),a.innerText="theme: dark"):(localStorage.setItem("theme","light"),t(),a.innerText="theme: light")}}));const n=()=>{document.body.classList.remove("font-sans"),document.body.classList.remove("font-serif")},m=e=>{e&&"serif"===e&&(n(),document.body.classList.add("font-serif")),e&&"sans"===e&&(n(),document.body.classList.add("font-sans")),e||n()};let c=localStorage.getItem("font");m();const l=document.getElementById("font-toggle");l.addEventListener("click",(()=>{c=localStorage.getItem("font"),"sans"===c?(c="serif",l.innerText="serif",localStorage.setItem("font","serif")):(c="sans",l.innerText="sans",localStorage.setItem("font","sans")),m(c)}));
|
||||
2
robots.txt
Normal file
2
robots.txt
Normal file
|
|
@ -0,0 +1,2 @@
|
|||
User-agent: *
|
||||
Disallow:
|
||||
383
rss.xml
Normal file
383
rss.xml
Normal file
|
|
@ -0,0 +1,383 @@
|
|||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"
|
||||
xmlns:dc="http://purl.org/dc/elements/1.1/">
|
||||
<channel>
|
||||
<title>conditional finality</title>
|
||||
<link>https://blog.youwen.dev</link>
|
||||
<description><![CDATA[on computers, hacks, math, and life]]></description>
|
||||
<atom:link href="https://blog.youwen.dev/rss.xml" rel="self"
|
||||
type="application/rss+xml" />
|
||||
<lastBuildDate>Sat, 28 Dec 2024 00:00:00 UT</lastBuildDate>
|
||||
<item>
|
||||
<title>Nix automatic hash updates made easy</title>
|
||||
<link>https://blog.youwen.dev/nix-automatic-hash-updates-made-easy.html</link>
|
||||
<description><![CDATA[<article>
|
||||
<header>
|
||||
<h1 class="text-4xl">
|
||||
<a href="./nix-automatic-hash-updates-made-easy.html">Nix automatic hash updates made easy</a>
|
||||
</h1>
|
||||
<p
|
||||
class="mb-1 mt-2 italic font-light text-lg text-accent-light dark:text-accent-dark"
|
||||
>
|
||||
keep your flakes up to date
|
||||
</p>
|
||||
<div class="mt-2">2024-12-28</div>
|
||||
<div class="mt-1 text-sm">
|
||||
|
||||
</div>
|
||||
</header>
|
||||
<main class="post mt-4"><p>Nix users often create flakes to package software out of tree, like this <a href="https://github.com/youwen5/zen-browser-flake">Zen
|
||||
Browser flake</a> I’ve been
|
||||
maintaining. Keeping them up to date is a hassle though, since you have to
|
||||
update the Subresource Integrity (SRI) hashes that Nix uses to ensure
|
||||
reproducibility.</p>
|
||||
<p>Here’s a neat method I’ve been using to cleanly handle automatic hash updates.
|
||||
I use <a href="https://www.nushell.sh/">Nushell</a> to easily work with data, prefetch
|
||||
some hashes, and put it all in a JSON file that can be read by Nix at build
|
||||
time.</p>
|
||||
<p>First, let’s create a file called <code>update.nu</code>. At the top, place this shebang:</p>
|
||||
<pre class="nu"><code>#!/usr/bin/env -S nix shell nixpkgs#nushell --command nu</code></pre>
|
||||
<p>This will execute the script in a Nushell environment, which is fetched by Nix.</p>
|
||||
<h2 id="get-the-up-to-date-urls">Get the up to date URLs</h2>
|
||||
<p>We need to obtain the latest version of whatever software we want to update.
|
||||
In this case, I’ll use GitHub releases as my source of truth.</p>
|
||||
<p>You can use the GitHub API to fetch metadata about all the releases of a repository.</p>
|
||||
<pre><code>https://api.github.com/repos/($repo)/releases</code></pre>
|
||||
<p>Roughly speaking, the raw JSON returned by the GitHub releases API looks something like:</p>
|
||||
<pre><code>[
|
||||
{tag_name: "foo", prerelease: false, ...},
|
||||
{tag_name: "bar", prerelease: true, ...},
|
||||
{tag_name: "foobar", prerelease: false, ...},
|
||||
]
|
||||
</code></pre>
|
||||
<p>Note that the ordering of the objects in the array is chronological.</p>
|
||||
<blockquote>
|
||||
<p>Even if you aren’t using GitHub releases, as long as there is a reliable way to
|
||||
programmatically fetch the latest download URLs of whatever software you’re
|
||||
packaging, you can adapt this approach for your specific case.</p>
|
||||
</blockquote>
|
||||
<p>We use Nushell’s <code>http get</code> to make a network request. Nushell will
|
||||
automatically detect and parse the JSON reponse into a Nushell table.</p>
|
||||
<p>In my case, Zen Browser frequently publishes prerelease “twilight” builds which
|
||||
we don’t want to update to. So, we ignore any releases tagged “twilight” or
|
||||
marked “prerelease” by filtering them out with the <code>where</code> selector.</p>
|
||||
<p>Finally, we retrieve the tag name of the item at the first index, which would
|
||||
be the latest release (since the JSON array was chronologically sorted).</p>
|
||||
<pre class="nu"><code>#!/usr/bin/env -S nix shell nixpkgs#nushell --command nu
|
||||
|
||||
# get the latest tag of the latest release that isn't a prerelease
|
||||
def get_latest_release [repo: string] {
|
||||
try {
|
||||
http get $"https://api.github.com/repos/($repo)/releases"
|
||||
| where prerelease == false
|
||||
| where tag_name != "twilight"
|
||||
| get tag_name
|
||||
| get 0
|
||||
} catch { |err| $"Failed to fetch latest release, aborting: ($err.msg)" }
|
||||
}</code></pre>
|
||||
<h2 id="prefetching-sri-hashes">Prefetching SRI hashes</h2>
|
||||
<p>Now that we have the latest tags, we can easily obtain the latest download URLs, which are of the form:</p>
|
||||
<pre><code>https://github.com/zen-browser/desktop/releases/download/$tag/zen.linux-x86_64.tar.bz2
|
||||
https://github.com/zen-browser/desktop/releases/download/$tag/zen.aarch64-x86_64.tar.bz2</code></pre>
|
||||
<p>However, we still need the corresponding SRI hashes to pass to Nix.</p>
|
||||
<div class="sourceCode" id="cb6"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a>src = fetchurl <span class="op">{</span></span>
|
||||
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span> <span class="op">=</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-x86_64.tar.bz2"</span><span class="op">;</span></span>
|
||||
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span> <span class="op">=</span> <span class="st">"sha256-00000000000000000000000000000000000000000000"</span><span class="op">;</span></span>
|
||||
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a><span class="op">}</span>;</span></code></pre></div>
|
||||
<p>The easiest way to obtain these new hashes is to update the URL and then set
|
||||
the hash property to an empty string (<code>""</code>). Nix will spit out an hash mismatch
|
||||
error with the correct hash. However, this is inconvenient for automated
|
||||
command line scripting.</p>
|
||||
<p>The Nix documentation mentions
|
||||
<a href="https://nix.dev/manual/nix/2.18/command-ref/nix-prefetch-url">nix-prefetch-url</a>
|
||||
as a way to obtain these hashes, but as usual, it doesn’t work quite right and
|
||||
has also been replaced by a more powerful but underdocumented experimental
|
||||
feature instead.</p>
|
||||
<p>The <a href="https://nix.dev/manual/nix/2.18/command-ref/new-cli/nix3-store-prefetch-file">nix store
|
||||
prefetch-file</a>
|
||||
command does what <code>nix-prefetch-url</code> is supposed to do, but handles the caveats
|
||||
that lead to the wrong hash being produced automatically.</p>
|
||||
<p>Let’s write a Nushell function that outputs the SRI hash of the given URL. We
|
||||
tell <code>prefetch-file</code> to output structured JSON that we can parse.</p>
|
||||
<p>Since Nushell <em>is</em> a shell, we can directly invoke shell commands like usual,
|
||||
and then process their output with pipes.</p>
|
||||
<pre class="nu"><code>def get_nix_hash [url: string] {
|
||||
nix store prefetch-file --hash-type sha256 --json $url | from json | get hash
|
||||
}</code></pre>
|
||||
<p>Cool! Now <code>get_nix_hash</code> can give us SRI hashes that look like this:</p>
|
||||
<pre><code>sha256-K3zTCLdvg/VYQNsfeohw65Ghk8FAjhOl8hXU6REO4/s=</code></pre>
|
||||
<h2 id="putting-it-all-together">Putting it all together</h2>
|
||||
<p>Now that we’re able to fetch the latest release, obtain the download URLs, and
|
||||
compute their SRI hashes, we have all the information we need to make an
|
||||
automated update. However, these URLs are typically hardcoded in our Nix
|
||||
expressions. The question remains as to how to update these values.</p>
|
||||
<p>A common way I’ve seen updates performed is using something like <code>sed</code> to
|
||||
modify the Nix expressions in place. However, there’s actually a more
|
||||
maintainable and easy to understand approach.</p>
|
||||
<p>Let’s have our Nushell script generate the URLs and hashes and place them in a
|
||||
JSON file! Then, we’ll be able to read the JSON file from Nix and obtain the
|
||||
URL and hash.</p>
|
||||
<pre class="nu"><code>def generate_sources [] {
|
||||
let tag = get_latest_release "zen-browser/desktop"
|
||||
let prev_sources = open ./sources.json
|
||||
|
||||
if $tag == $prev_sources.version {
|
||||
# everything up to date
|
||||
return $tag
|
||||
}
|
||||
|
||||
# generate the download URLs with the new tag
|
||||
let x86_64_url = $"https://github.com/zen-browser/desktop/releases/download/($tag)/zen.linux-x86_64.tar.bz2"
|
||||
let aarch64_url = $"https://github.com/zen-browser/desktop/releases/download/($tag)/zen.linux-aarch64.tar.bz2"
|
||||
|
||||
# create a Nushell record that maps cleanly to JSON
|
||||
let sources = {
|
||||
# add a version field as well for convenience
|
||||
version: $tag
|
||||
|
||||
x86_64-linux: {
|
||||
url: $x86_64_url
|
||||
hash: (get_nix_hash $x86_64_url)
|
||||
}
|
||||
aarch64-linux: {
|
||||
url: $aarch64_url
|
||||
hash: (get_nix_hash $aarch64_url)
|
||||
}
|
||||
}
|
||||
|
||||
echo $sources | save --force "sources.json"
|
||||
|
||||
return $tag
|
||||
}</code></pre>
|
||||
<p>Running this script with</p>
|
||||
<div class="sourceCode" id="cb10"><pre class="sourceCode bash"><code class="sourceCode bash"><span id="cb10-1"><a href="#cb10-1" aria-hidden="true" tabindex="-1"></a><span class="fu">chmod</span> +x ./update.nu</span>
|
||||
<span id="cb10-2"><a href="#cb10-2" aria-hidden="true" tabindex="-1"></a><span class="ex">./update.nu</span></span></code></pre></div>
|
||||
<p>gives us the file <code>sources.json</code>:</p>
|
||||
<div class="sourceCode" id="cb11"><pre class="sourceCode json"><code class="sourceCode json"><span id="cb11-1"><a href="#cb11-1" aria-hidden="true" tabindex="-1"></a><span class="fu">{</span></span>
|
||||
<span id="cb11-2"><a href="#cb11-2" aria-hidden="true" tabindex="-1"></a> <span class="dt">"version"</span><span class="fu">:</span> <span class="st">"1.0.2-b.5"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-3"><a href="#cb11-3" aria-hidden="true" tabindex="-1"></a> <span class="dt">"x86_64-linux"</span><span class="fu">:</span> <span class="fu">{</span></span>
|
||||
<span id="cb11-4"><a href="#cb11-4" aria-hidden="true" tabindex="-1"></a> <span class="dt">"url"</span><span class="fu">:</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-x86_64.tar.bz2"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-5"><a href="#cb11-5" aria-hidden="true" tabindex="-1"></a> <span class="dt">"hash"</span><span class="fu">:</span> <span class="st">"sha256-K3zTCLdvg/VYQNsfeohw65Ghk8FAjhOl8hXU6REO4/s="</span></span>
|
||||
<span id="cb11-6"><a href="#cb11-6" aria-hidden="true" tabindex="-1"></a> <span class="fu">},</span></span>
|
||||
<span id="cb11-7"><a href="#cb11-7" aria-hidden="true" tabindex="-1"></a> <span class="dt">"aarch64-linux"</span><span class="fu">:</span> <span class="fu">{</span></span>
|
||||
<span id="cb11-8"><a href="#cb11-8" aria-hidden="true" tabindex="-1"></a> <span class="dt">"url"</span><span class="fu">:</span> <span class="st">"https://github.com/zen-browser/desktop/releases/download/1.0.2-b.5/zen.linux-aarch64.tar.bz2"</span><span class="fu">,</span></span>
|
||||
<span id="cb11-9"><a href="#cb11-9" aria-hidden="true" tabindex="-1"></a> <span class="dt">"hash"</span><span class="fu">:</span> <span class="st">"sha256-NwIYylGal2QoWhWKtMhMkAAJQ6iNHfQOBZaxTXgvxAk="</span></span>
|
||||
<span id="cb11-10"><a href="#cb11-10" aria-hidden="true" tabindex="-1"></a> <span class="fu">}</span></span>
|
||||
<span id="cb11-11"><a href="#cb11-11" aria-hidden="true" tabindex="-1"></a><span class="fu">}</span></span></code></pre></div>
|
||||
<p>Now, let’s read this from Nix. My file organization looks like the following:</p>
|
||||
<pre><code>./
|
||||
| flake.nix
|
||||
| zen-browser-unwrapped.nix
|
||||
| ...other files...</code></pre>
|
||||
<p><code>zen-browser-unwrapped.nix</code> contains the derivation for Zen Browser. Let’s add
|
||||
<code>version</code>, <code>url</code>, and <code>hash</code> to its inputs:</p>
|
||||
<div class="sourceCode" id="cb13"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb13-1"><a href="#cb13-1" aria-hidden="true" tabindex="-1"></a><span class="op">{</span></span>
|
||||
<span id="cb13-2"><a href="#cb13-2" aria-hidden="true" tabindex="-1"></a> <span class="va">stdenv</span><span class="op">,</span></span>
|
||||
<span id="cb13-3"><a href="#cb13-3" aria-hidden="true" tabindex="-1"></a> <span class="va">fetchurl</span><span class="op">,</span></span>
|
||||
<span id="cb13-4"><a href="#cb13-4" aria-hidden="true" tabindex="-1"></a> <span class="co"># add these below</span></span>
|
||||
<span id="cb13-5"><a href="#cb13-5" aria-hidden="true" tabindex="-1"></a> <span class="va">version</span><span class="op">,</span></span>
|
||||
<span id="cb13-6"><a href="#cb13-6" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span><span class="op">,</span></span>
|
||||
<span id="cb13-7"><a href="#cb13-7" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span><span class="op">,</span></span>
|
||||
<span id="cb13-8"><a href="#cb13-8" aria-hidden="true" tabindex="-1"></a> <span class="op">...</span></span>
|
||||
<span id="cb13-9"><a href="#cb13-9" aria-hidden="true" tabindex="-1"></a><span class="op">}</span>:</span>
|
||||
<span id="cb13-10"><a href="#cb13-10" aria-hidden="true" tabindex="-1"></a>stdenv.mkDerivation <span class="op">{</span></span>
|
||||
<span id="cb13-11"><a href="#cb13-11" aria-hidden="true" tabindex="-1"></a> <span class="co"># inherit version from inputs</span></span>
|
||||
<span id="cb13-12"><a href="#cb13-12" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> version<span class="op">;</span></span>
|
||||
<span id="cb13-13"><a href="#cb13-13" aria-hidden="true" tabindex="-1"></a> <span class="va">pname</span> <span class="op">=</span> <span class="st">"zen-browser-unwrapped"</span><span class="op">;</span></span>
|
||||
<span id="cb13-14"><a href="#cb13-14" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb13-15"><a href="#cb13-15" aria-hidden="true" tabindex="-1"></a> <span class="va">src</span> <span class="op">=</span> fetchurl <span class="op">{</span></span>
|
||||
<span id="cb13-16"><a href="#cb13-16" aria-hidden="true" tabindex="-1"></a> <span class="co"># inherit the URL and hash we obtain from the inputs</span></span>
|
||||
<span id="cb13-17"><a href="#cb13-17" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> url hash<span class="op">;</span></span>
|
||||
<span id="cb13-18"><a href="#cb13-18" aria-hidden="true" tabindex="-1"></a> <span class="op">};</span></span>
|
||||
<span id="cb13-19"><a href="#cb13-19" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>
|
||||
<p>Then in <code>flake.nix</code>, let’s provide the derivation with the data from <code>sources.json</code>:</p>
|
||||
<div class="sourceCode" id="cb14"><pre class="sourceCode nix"><code class="sourceCode nix"><span id="cb14-1"><a href="#cb14-1" aria-hidden="true" tabindex="-1"></a><span class="kw">let</span></span>
|
||||
<span id="cb14-2"><a href="#cb14-2" aria-hidden="true" tabindex="-1"></a> <span class="va">supportedSystems</span> <span class="op">=</span> <span class="op">[</span></span>
|
||||
<span id="cb14-3"><a href="#cb14-3" aria-hidden="true" tabindex="-1"></a> <span class="st">"x86_64-linux"</span></span>
|
||||
<span id="cb14-4"><a href="#cb14-4" aria-hidden="true" tabindex="-1"></a> <span class="st">"aarch64-linux"</span></span>
|
||||
<span id="cb14-5"><a href="#cb14-5" aria-hidden="true" tabindex="-1"></a> <span class="op">];</span></span>
|
||||
<span id="cb14-6"><a href="#cb14-6" aria-hidden="true" tabindex="-1"></a> <span class="va">forAllSystems</span> <span class="op">=</span> nixpkgs.lib.genAttrs supportedSystems<span class="op">;</span></span>
|
||||
<span id="cb14-7"><a href="#cb14-7" aria-hidden="true" tabindex="-1"></a><span class="kw">in</span></span>
|
||||
<span id="cb14-8"><a href="#cb14-8" aria-hidden="true" tabindex="-1"></a><span class="op">{</span></span>
|
||||
<span id="cb14-9"><a href="#cb14-9" aria-hidden="true" tabindex="-1"></a> <span class="co"># rest of file omitted for simplicity</span></span>
|
||||
<span id="cb14-10"><a href="#cb14-10" aria-hidden="true" tabindex="-1"></a> <span class="va">packages</span> <span class="op">=</span> forAllSystems <span class="op">(</span></span>
|
||||
<span id="cb14-11"><a href="#cb14-11" aria-hidden="true" tabindex="-1"></a> <span class="va">system</span><span class="op">:</span></span>
|
||||
<span id="cb14-12"><a href="#cb14-12" aria-hidden="true" tabindex="-1"></a> <span class="kw">let</span></span>
|
||||
<span id="cb14-13"><a href="#cb14-13" aria-hidden="true" tabindex="-1"></a> <span class="va">pkgs</span> <span class="op">=</span> <span class="bu">import</span> nixpkgs <span class="op">{</span> <span class="kw">inherit</span> system<span class="op">;</span> <span class="op">};</span></span>
|
||||
<span id="cb14-14"><a href="#cb14-14" aria-hidden="true" tabindex="-1"></a> <span class="co"># parse sources.json into a Nix attrset</span></span>
|
||||
<span id="cb14-15"><a href="#cb14-15" aria-hidden="true" tabindex="-1"></a> <span class="va">sources</span> <span class="op">=</span> <span class="bu">builtins</span>.fromJSON <span class="op">(</span><span class="bu">builtins</span>.readFile <span class="ss">./sources.json</span><span class="op">);</span></span>
|
||||
<span id="cb14-16"><a href="#cb14-16" aria-hidden="true" tabindex="-1"></a> <span class="kw">in</span></span>
|
||||
<span id="cb14-17"><a href="#cb14-17" aria-hidden="true" tabindex="-1"></a> <span class="kw">rec</span> <span class="op">{</span></span>
|
||||
<span id="cb14-18"><a href="#cb14-18" aria-hidden="true" tabindex="-1"></a> <span class="va">zen-browser-unwrapped</span> <span class="op">=</span> pkgs.callPackage <span class="ss">./zen-browser-unwrapped.nix</span> <span class="op">{</span></span>
|
||||
<span id="cb14-19"><a href="#cb14-19" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> <span class="op">(</span>sources.$<span class="op">{</span><span class="va">system</span><span class="op">})</span> hash url<span class="op">;</span></span>
|
||||
<span id="cb14-20"><a href="#cb14-20" aria-hidden="true" tabindex="-1"></a> <span class="kw">inherit</span> <span class="op">(</span>sources<span class="op">)</span> version<span class="op">;</span></span>
|
||||
<span id="cb14-21"><a href="#cb14-21" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb14-22"><a href="#cb14-22" aria-hidden="true" tabindex="-1"></a> <span class="co"># if the above is difficult to understand, it is equivalent to the following:</span></span>
|
||||
<span id="cb14-23"><a href="#cb14-23" aria-hidden="true" tabindex="-1"></a> <span class="va">hash</span> <span class="op">=</span> sources.$<span class="op">{</span><span class="va">system</span><span class="op">}</span>.hash<span class="op">;</span></span>
|
||||
<span id="cb14-24"><a href="#cb14-24" aria-hidden="true" tabindex="-1"></a> <span class="va">url</span> <span class="op">=</span> sources.$<span class="op">{</span><span class="va">system</span><span class="op">}</span>.url<span class="op">;</span></span>
|
||||
<span id="cb14-25"><a href="#cb14-25" aria-hidden="true" tabindex="-1"></a> <span class="va">version</span> <span class="op">=</span> sources.version<span class="op">;</span></span>
|
||||
<span id="cb14-26"><a href="#cb14-26" aria-hidden="true" tabindex="-1"></a> <span class="op">};</span></span>
|
||||
<span id="cb14-27"><a href="#cb14-27" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>
|
||||
<p>Now, running <code>nix build .#zen-browser-unwrapped</code> will be able to use the hashes
|
||||
and URLs from <code>sources.json</code> to build the package!</p>
|
||||
<h2 id="automating-it-in-ci">Automating it in CI</h2>
|
||||
<p>We now have a script that can automatically fetch releases and generate hashes
|
||||
and URLs, as well as a way for Nix to use the outputted JSON to build
|
||||
derivations. All that’s left is to fully automate it using CI!</p>
|
||||
<p>We are going to use GitHub actions for this, as it’s free and easy and you’re
|
||||
probably already hosting on GitHub.</p>
|
||||
<p>Ensure you’ve set up actions for your repo and given it sufficient permissions.</p>
|
||||
<p>We’re gonna run it on a cron timer that checks for updates at 8 PM PST every day.</p>
|
||||
<p>We use DeterminateSystems’ actions to help set up Nix. Then, we simply run our
|
||||
update script. Since we made the script return the tag it fetched, we can store
|
||||
it in a variable and then use it in our commit message.</p>
|
||||
<pre><code>name: Update to latest version, and update flake inputs
|
||||
|
||||
on:
|
||||
schedule:
|
||||
- cron: "0 4 * * *"
|
||||
workflow_dispatch:
|
||||
|
||||
jobs:
|
||||
update:
|
||||
name: Update flake inputs and browser
|
||||
runs-on: ubuntu-latest
|
||||
steps:
|
||||
- name: Checkout Repository
|
||||
uses: actions/checkout@v4
|
||||
|
||||
- name: Check flake inputs
|
||||
uses: DeterminateSystems/flake-checker-action@v4
|
||||
|
||||
- name: Install Nix
|
||||
uses: DeterminateSystems/nix-installer-action@main
|
||||
|
||||
- name: Set up magic Nix cache
|
||||
uses: DeterminateSystems/magic-nix-cache-action@main
|
||||
|
||||
- name: Check for update and perform update
|
||||
run: |
|
||||
git config --global user.name "github-actions[bot]"
|
||||
git config --global user.email "github-actions[bot]@users.noreply.github.com"
|
||||
|
||||
chmod +x ./update.nu
|
||||
export ZEN_LATEST_VER="$(./update.nu)"
|
||||
|
||||
git add -A
|
||||
git commit -m "github-actions: update to $ZEN_LATEST_VER" || echo "Latest version is $ZEN_LATEST_VER, no updates found"
|
||||
|
||||
nix flake update --commit-lock-file
|
||||
|
||||
git push</code></pre>
|
||||
<p>Now, our repository will automatically check for and perform updates every day!</p></main>
|
||||
</article>
|
||||
]]></description>
|
||||
<pubDate>Sat, 28 Dec 2024 00:00:00 UT</pubDate>
|
||||
<guid>https://blog.youwen.dev/nix-automatic-hash-updates-made-easy.html</guid>
|
||||
<dc:creator>Youwen Wu</dc:creator>
|
||||
</item>
|
||||
<item>
|
||||
<title>a haskellian blog</title>
|
||||
<link>https://blog.youwen.dev/a-haskellian-blog.html</link>
|
||||
<description><![CDATA[<article>
|
||||
<header>
|
||||
<h1 class="text-4xl">
|
||||
<a href="./a-haskellian-blog.html">a haskellian blog</a>
|
||||
</h1>
|
||||
<p
|
||||
class="mb-1 mt-2 italic font-light text-lg text-accent-light dark:text-accent-dark"
|
||||
>
|
||||
a purely functional...blog?
|
||||
</p>
|
||||
<div class="mt-2">2024-05-25</div>
|
||||
<div class="mt-1 text-sm">
|
||||
(last updated: 2024-05-25T12:00:00Z)
|
||||
</div>
|
||||
</header>
|
||||
<main class="post mt-4"><p>Welcome! This is the first post on <em>conditional finality</em> and also one that tests all
|
||||
of the features.</p>
|
||||
<p><img
|
||||
alt="conditional finality"
|
||||
src="./images/conditional-finality.png"
|
||||
/></p>
|
||||
<blockquote>
|
||||
<p>A monad is just a monoid in the category of endofunctors, what’s the problem?</p>
|
||||
</blockquote>
|
||||
<h2 id="haskell">haskell?</h2>
|
||||
<p>This entire blog is generated with <a href="https://jaspervdj.be/hakyll/">hakyll</a>. It’s
|
||||
a library for generating static sites for Haskell, a purely functional
|
||||
programming language. It’s a <em>library</em> because it doesn’t come with as many
|
||||
batteries included as tools like Hugo or Astro. You set up most of the site
|
||||
yourself by calling the library from Haskell.</p>
|
||||
<p>Here’s a brief excerpt:</p>
|
||||
<div class="sourceCode" id="cb1"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="ot">main ::</span> <span class="dt">IO</span> ()</span>
|
||||
<span id="cb1-2"><a href="#cb1-2" aria-hidden="true" tabindex="-1"></a>main <span class="ot">=</span> hakyllWith config <span class="op">$</span> <span class="kw">do</span></span>
|
||||
<span id="cb1-3"><a href="#cb1-3" aria-hidden="true" tabindex="-1"></a> forM_</span>
|
||||
<span id="cb1-4"><a href="#cb1-4" aria-hidden="true" tabindex="-1"></a> [ <span class="st">"CNAME"</span></span>
|
||||
<span id="cb1-5"><a href="#cb1-5" aria-hidden="true" tabindex="-1"></a> , <span class="st">"favicon.ico"</span></span>
|
||||
<span id="cb1-6"><a href="#cb1-6" aria-hidden="true" tabindex="-1"></a> , <span class="st">"robots.txt"</span></span>
|
||||
<span id="cb1-7"><a href="#cb1-7" aria-hidden="true" tabindex="-1"></a> , <span class="st">"_config.yml"</span></span>
|
||||
<span id="cb1-8"><a href="#cb1-8" aria-hidden="true" tabindex="-1"></a> , <span class="st">"images/*"</span></span>
|
||||
<span id="cb1-9"><a href="#cb1-9" aria-hidden="true" tabindex="-1"></a> , <span class="st">"out/*"</span></span>
|
||||
<span id="cb1-10"><a href="#cb1-10" aria-hidden="true" tabindex="-1"></a> , <span class="st">"fonts/*"</span></span>
|
||||
<span id="cb1-11"><a href="#cb1-11" aria-hidden="true" tabindex="-1"></a> ]</span>
|
||||
<span id="cb1-12"><a href="#cb1-12" aria-hidden="true" tabindex="-1"></a> <span class="op">$</span> \f <span class="ot">-></span> match f <span class="op">$</span> <span class="kw">do</span></span>
|
||||
<span id="cb1-13"><a href="#cb1-13" aria-hidden="true" tabindex="-1"></a> route idRoute</span>
|
||||
<span id="cb1-14"><a href="#cb1-14" aria-hidden="true" tabindex="-1"></a> compile copyFileCompiler</span></code></pre></div>
|
||||
<p>The code highlighting is also generated by hakyll.</p>
|
||||
<hr />
|
||||
<h2 id="why">why?</h2>
|
||||
<p>Haskell is a purely functional language with no mutable state. Its syntax
|
||||
actually makes it pretty elegant for declaring routes and “rendering” pipelines.</p>
|
||||
<ol>
|
||||
<li>Haskell is cool.</li>
|
||||
<li>It comes with enough features that I don’t feel like I have to build
|
||||
everything from scratch.</li>
|
||||
<li>It comes with Pandoc, a Haskell library for converting between markdown
|
||||
formats. It’s probably more powerful than anything you could do in <code>nodejs</code>.
|
||||
It renders all of the markdown to HTML as well as the math.
|
||||
<ol>
|
||||
<li>It supports KaTeX as well as MathML. I’m a little disappointed with the
|
||||
KaTeX though. It doesn’t directly render it, but simply injects the KaTeX
|
||||
files and renders it client-side.</li>
|
||||
</ol></li>
|
||||
</ol>
|
||||
<h3 id="speaking-of-math">speaking of math</h3>
|
||||
<p>We can have math inline, like so:
|
||||
<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msubsup><mo>∫</mo><mrow><mo>−</mo><mi>∞</mi></mrow><mi>∞</mi></msubsup><mspace width="0.167em"></mspace><msup><mi>e</mi><mrow><mo>−</mo><msup><mi>x</mi><mn>2</mn></msup></mrow></msup><mspace width="0.167em"></mspace><mi>d</mi><mi>x</mi><mo>=</mo><msqrt><mi>π</mi></msqrt></mrow><annotation encoding="application/x-tex">\int_{-\infty}^\infty \, e^{-x^2}\,dx = \sqrt{\pi}</annotation></semantics></math>. This site ships semantic
|
||||
MathML math with its HTML, and the MathJax script to the client.</p>
|
||||
<p>It’d be nice if MathML could just be used and supported across all browsers, but
|
||||
unfortunately we still aren’t quite there yet. Firefox is the only one where
|
||||
everything looks 80% of the way to LaTeX. On Safari and Chrome, even simple
|
||||
equations like <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><msqrt><mi>π</mi></msqrt><annotation encoding="application/x-tex">\sqrt{\pi}</annotation></semantics></math> render improperly.</p>
|
||||
<p>Pros of MathML:</p>
|
||||
<ul>
|
||||
<li>A little more accessible</li>
|
||||
<li>Can be rendered without additional stylesheets. I just installed the Latin
|
||||
Modern font, but this isn’t even really necessary</li>
|
||||
<li>Built-in to most browsers (#UseThePlatform)</li>
|
||||
</ul>
|
||||
<p>Cons:</p>
|
||||
<ul>
|
||||
<li>Isn’t fully standardized. Might look different on different browsers</li>
|
||||
<li>Rendering quality isn’t as good as KaTeX</li>
|
||||
</ul>
|
||||
<p>This site has MathJax render all of the math so it looks nice and standardized
|
||||
across browsers, but the math still displays regardless (like say if MathJax
|
||||
couldn’t load due to slow network) because of MathML. Best of both worlds.</p>
|
||||
<p>Let’s try it now. Here’s a simple theorem:</p>
|
||||
<p><math display="block" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mi>a</mi><mi>n</mi></msup><mo>+</mo><msup><mi>b</mi><mi>n</mi></msup><mo>≠</mo><msup><mi>c</mi><mi>n</mi></msup><mspace width="0.167em"></mspace><mo>∀</mo><mspace width="0.167em"></mspace><mrow><mo stretchy="true" form="prefix">{</mo><mi>a</mi><mo>,</mo><mspace width="0.167em"></mspace><mi>b</mi><mo>,</mo><mspace width="0.167em"></mspace><mi>c</mi><mo stretchy="true" form="postfix">}</mo></mrow><mo>∈</mo><mstyle mathvariant="double-struck"><mi>ℤ</mi></mstyle><mo>∧</mo><mi>n</mi><mo>≥</mo><mn>3</mn></mrow><annotation encoding="application/x-tex">
|
||||
a^n + b^n \ne c^n \, \forall\,\left\{ a,\,b,\,c \right\} \in \mathbb{Z} \land n \ge 3
|
||||
</annotation></semantics></math></p>
|
||||
<p>The proof is trivial and will be left as an exercise to the reader.</p>
|
||||
<h2 id="seems-a-little-overengineered">seems a little overengineered</h2>
|
||||
<p>Probably is. Not as much as the old one, though.</p></main>
|
||||
</article>
|
||||
]]></description>
|
||||
<pubDate>Sat, 25 May 2024 00:00:00 UT</pubDate>
|
||||
<guid>https://blog.youwen.dev/a-haskellian-blog.html</guid>
|
||||
<dc:creator>Youwen Wu</dc:creator>
|
||||
</item>
|
||||
|
||||
</channel>
|
||||
</rss>
|
||||
23
sitemap.xml
Normal file
23
sitemap.xml
Normal file
|
|
@ -0,0 +1,23 @@
|
|||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:news="http://www.google.com/schemas/sitemap-news/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:mobile="http://www.google.com/schemas/sitemap-mobile/1.0" xmlns:image="http://www.google.com/schemas/sitemap-image/1.1" xmlns:video="http://www.google.com/schemas/sitemap-video/1.1">
|
||||
<url>
|
||||
<loc>https://blog.youwen.dev</loc>
|
||||
<changefreq>daily</changefreq>
|
||||
<priority>1.0</priority>
|
||||
</url>
|
||||
|
||||
<url>
|
||||
<loc>https://blog.youwen.dev/nix-automatic-hash-updates-made-easy.html</loc>
|
||||
<lastmod>2024-12-28</lastmod>
|
||||
<changefreq>weekly</changefreq>
|
||||
<priority>0.8</priority>
|
||||
</url>
|
||||
|
||||
<url>
|
||||
<loc>https://blog.youwen.dev/a-haskellian-blog.html</loc>
|
||||
<lastmod>2024-05-25T12:00:00Z</lastmod>
|
||||
<changefreq>weekly</changefreq>
|
||||
<priority>0.8</priority>
|
||||
</url>
|
||||
|
||||
</urlset>
|
||||
Loading…
Reference in a new issue