Running a compiled Deno script in a GitHub Action

user: anonymous

{
  "path": "/blog/running-a-compiled-deno-script-in-a-github-action",
  "attrs": {
    "title": "Running a compiled Deno script in a GitHub Action",
    "splash": {
      "image": "/images/first-blossoms-2021.jpg"
    },
    "date": "2021-03-14",
    "layout": "BlogPostLayout",
    "excerpt": "In this post I enhance a GitHub Action to invoke the compiled scan.js Deno script which scans for broken links in generated HTML pages.\n"
  },
  "md": "# Running a compiled Deno script in a GitHub Action\n\nThis is a quick followup to my recent post about [Getting Started with Deno](getting-started-with-deno).\n\nIn this post I will enhance a GitHub Action to do the following:\n\n- Generate HTML using a static site generator (SSG).\n- Launch a preview web server which runs in the background.\n- Download a compiled Deno script.\n- Invoke the Deno script to scan for broken links in the generated HTML.\n- Only publish the HTML if there are no broken links.\n\n## scan.js\n\nI cross-compiled [scan.js](https://github.com/jldec/deno-hello/blob/main/scan.js) using Deno v1.8.1, and uploaded the resulting binaries to a [release](https://github.com/jldec/deno-hello/releases) on GitHub.\n\nUsing the releases feature of GitHub is a convenient way to publish compiled artifacts. In this case I used the manual upload feature in GitHub, but this step could be automated as well.\n\n![Releases with compiled artifacts in Repo deno-hello](/images/deno-scan-releases.png)\n\nHere is the deno compile [command](https://github.com/jldec/deno-hello/blob/main/compile.sh#L1). The binary for Linux is called `scan-linux-x86`.\n\n```\ndeno --unstable compile \\\n  --allow-net \\\n  --lite \\\n  --target x86_64-unknown-linux-gnu \\\n  --output scan-linux-x86 \\\n  scan.js\n```\n\nThe resulting binaries are quite large (~50MB), even using [--lite](https://deno.land/manual@v1.7.4/tools/compiler#generating-smaller-binaries), but I expect that to improve.\n\n## .github/workflow/generate.yaml\n\nIn this case, I modified the [workflow](https://github.com/jldec/cloudflare-pages-test/blob/main/.github/workflows/generate.yaml) for the static site in [jldec/cloudflare-pages-test](https://github.com/jldec/cloudflare-pages-test). Here is the excerpt of the yaml for the relevant step.\n\n```yaml\n- name: generate output\n  run: |\n    ...\n    npm run generate\n    npm run preview &\n    curl -LO https://github.com/jldec/deno-hello/releases/download/v1.0.0/scan-linux-x86 && chmod +x scan-linux-x86\n    ./scan-linux-x86 http://localhost:3001/\n    ...\n```\n\n`npm run generate` invokes the static site generator.  \n\n`npm run preview &` starts the preview server on port 3001, running in the background.\n\nBoth commands are defined as scripts in [package.json](https://github.com/jldec/cloudflare-pages-test/blob/main/package.json).\n\n`curl -LO` downloads the Linux binary from the GitHub release. Running curl here gives the preview server time to start listening on port 3001, before commencing the scan.\n\n## Success\n\nWhen the `scan-linux-x86` command finds no broken links in the static site, it exits with 0, allowing the GitHub Action [workflow](https://github.com/jldec/cloudflare-pages-test/runs/2112253519?check_suite_focus=true#step:4:72) to continue.\n\n![scan success in GitHub Action log output](/images/scan-success.png)\n\nIf there are broken links the workflow will [fail](https://github.com/jldec/cloudflare-pages-test/runs/2106962300?check_suite_focus=true), and I will hear about it in my inbox :)\n\n![scan failure in GitHub Action log output](/images/scan-failure.png)\n\n> [![Deno logo](/images/deno-logo.png \".no-border\")](https://deno.land/)\n\n_To leave a comment  \nplease visit [dev.to/jldec](https://dev.to/jldec/running-a-compiled-deno-script-in-a-github-action-4ljn)_\n\n\n",
  "html": "<h1>Running a compiled Deno script in a GitHub Action</h1>\n<p>This is a quick followup to my recent post about <a href=\"getting-started-with-deno\">Getting Started with Deno</a>.</p>\n<p>In this post I will enhance a GitHub Action to do the following:</p>\n<ul>\n<li>Generate HTML using a static site generator (SSG).</li>\n<li>Launch a preview web server which runs in the background.</li>\n<li>Download a compiled Deno script.</li>\n<li>Invoke the Deno script to scan for broken links in the generated HTML.</li>\n<li>Only publish the HTML if there are no broken links.</li>\n</ul>\n<h2>scan.js</h2>\n<p>I cross-compiled <a href=\"https://github.com/jldec/deno-hello/blob/main/scan.js\">scan.js</a> using Deno v1.8.1, and uploaded the resulting binaries to a <a href=\"https://github.com/jldec/deno-hello/releases\">release</a> on GitHub.</p>\n<p>Using the releases feature of GitHub is a convenient way to publish compiled artifacts. In this case I used the manual upload feature in GitHub, but this step could be automated as well.</p>\n<p><img src=\"/images/deno-scan-releases.png\" alt=\"Releases with compiled artifacts in Repo deno-hello\"></p>\n<p>Here is the deno compile <a href=\"https://github.com/jldec/deno-hello/blob/main/compile.sh#L1\">command</a>. The binary for Linux is called <code>scan-linux-x86</code>.</p>\n<pre><code>deno --unstable compile \\\n  --allow-net \\\n  --lite \\\n  --target x86_64-unknown-linux-gnu \\\n  --output scan-linux-x86 \\\n  scan.js\n</code></pre>\n<p>The resulting binaries are quite large (~50MB), even using <a href=\"https://deno.land/manual@v1.7.4/tools/compiler#generating-smaller-binaries\">--lite</a>, but I expect that to improve.</p>\n<h2>.github/workflow/generate.yaml</h2>\n<p>In this case, I modified the <a href=\"https://github.com/jldec/cloudflare-pages-test/blob/main/.github/workflows/generate.yaml\">workflow</a> for the static site in <a href=\"https://github.com/jldec/cloudflare-pages-test\">jldec/cloudflare-pages-test</a>. Here is the excerpt of the yaml for the relevant step.</p>\n<pre><code class=\"language-yaml\">- name: generate output\n  run: |\n    ...\n    npm run generate\n    npm run preview &amp;\n    curl -LO https://github.com/jldec/deno-hello/releases/download/v1.0.0/scan-linux-x86 &amp;&amp; chmod +x scan-linux-x86\n    ./scan-linux-x86 http://localhost:3001/\n    ...\n</code></pre>\n<p><code>npm run generate</code> invokes the static site generator.</p>\n<p><code>npm run preview &amp;</code> starts the preview server on port 3001, running in the background.</p>\n<p>Both commands are defined as scripts in <a href=\"https://github.com/jldec/cloudflare-pages-test/blob/main/package.json\">package.json</a>.</p>\n<p><code>curl -LO</code> downloads the Linux binary from the GitHub release. Running curl here gives the preview server time to start listening on port 3001, before commencing the scan.</p>\n<h2>Success</h2>\n<p>When the <code>scan-linux-x86</code> command finds no broken links in the static site, it exits with 0, allowing the GitHub Action <a href=\"https://github.com/jldec/cloudflare-pages-test/runs/2112253519?check_suite_focus=true#step:4:72\">workflow</a> to continue.</p>\n<p><img src=\"/images/scan-success.png\" alt=\"scan success in GitHub Action log output\"></p>\n<p>If there are broken links the workflow will <a href=\"https://github.com/jldec/cloudflare-pages-test/runs/2106962300?check_suite_focus=true\">fail</a>, and I will hear about it in my inbox :)</p>\n<p><img src=\"/images/scan-failure.png\" alt=\"scan failure in GitHub Action log output\"></p>\n<blockquote>\n<p><a href=\"https://deno.land/\"><img src=\"/images/deno-logo.png\" alt=\"Deno logo\" title=\".no-border\"></a></p>\n</blockquote>\n<p><em>To leave a comment<br>\nplease visit <a href=\"https://dev.to/jldec/running-a-compiled-deno-script-in-a-github-action-4ljn\">dev.to/jldec</a></em></p>\n"
}