Could not find Chrome

[blegat]

I'm trying to use PlutoPDF in github actions for https://github.com/blegat/LINMA2710
As you can see in the logs, I'm getting the error

[ Info: Running notebook...
[ Info: Generating pdf...
┌ Info: PlutoPDF: Running npm install in scratch space...
│   npm_version =
│    10.5.0
└    

up to date in 294ms
[ Info: PlutoPDF: Finished npm install.
file:///home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/build_dir4/node_modules/puppeteer-core/lib/esm/puppeteer/node/BrowserLauncher.js:262
                    throw new Error(`Could not find Chrome (ver. ${this.puppeteer.browserVersion}). This can occur if either\n` +
                          ^

Error: Could not find Chrome (ver. 132.0.6834.110). This can occur if either
 1. you did not perform an installation before running the script (e.g. `npx puppeteer browsers install chrome`) or
 2. your cache path is incorrectly configured (which is: /home/runner/.cache/puppeteer).
For (2), check out our guide on configuring puppeteer at https://pptr.dev/guides/configuration.
    at ChromeLauncher.resolveExecutablePath (file:///home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/build_dir4/node_modules/puppeteer-core/lib/esm/puppeteer/node/BrowserLauncher.js:262:27)
    at ChromeLauncher.computeLaunchArguments (file:///home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/build_dir4/node_modules/puppeteer-core/lib/esm/puppeteer/node/ChromeLauncher.js:85:24)
    at async ChromeLauncher.launch (file:///home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/build_dir4/node_modules/puppeteer-core/lib/esm/puppeteer/node/BrowserLauncher.js:48:28)
    at async pdf (file:///home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/build_dir4/export.js:14:21)
    at async file:///home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/build_dir4/bin.js:16:1

Node.js v20.12.2

The solution seems to be puppeteer/puppeteer#10388 (comment) but I haven't tested.
This is a follow-up from #18 (comment)

[fonsp]

Hm strange!

I think a good first step is to use Manifest.toml, this makes everything more reproducible (so I can help) and reliable.

My suggestion is to:

• Make sure that you, the GHA and the students all use the same Julia version
• Include the Manifest.toml in https://github.com/blegat/LINMA2710/tree/main/Lectures
• Create a new directory in your repo, called pluto-slider-server-environment, and in this directory have the Project.toml and Manifest.toml that you will use in your GitHub Actions. So this env should have PlutoSliderServer and PlutoPDF. Remove all Pkg.add statements from the .yaml files.

Instead of Pkg.precompile, always just use Pkg.instatiate. PlutoPDF might need a Pkg.build after the instatiate.

[fonsp]

Note that the GHA in this repository works (it worked for your PR). You can check out the workflow here https://github.com/JuliaPluto/PlutoPDF.jl/blob/main/.github/workflows/Test.yml and see what's different

[blegat]

Thanks for the recommendation. I was actually checking out the Manifest.toml but I just removed it because Google Colab was using Julia v1.10 not not Julia v1.11 ^^
I've set up the pluto-slider-server directory with the Manifest.toml checked out but I get the same issue: https://github.com/blegat/LINMA2710/actions/runs/13998318254/job/39198805567
What I find quite surprising is that the first run actually worked: https://github.com/blegat/LINMA2710/actions/runs/13900510879/job/38890838243
So it could be pure coincidence or maybe something is cached somehow...

[blegat]

It was indeed caching, removing julia-actions/cache fixes the issue.

[fonsp]

Crazy! But then why does it work on our CI?

Can you try clearing your cache, and then reenabling the cache? It might be that your cache got corrupted, and it kept using the corrupted cache.

[blegat]

I just tried. I deleted all the caches and reenabled the julia-actions/cache step and it worked: https://github.com/blegat/LINMA2710/actions/runs/13999943689/job/39203939458
Then, I didn't clean the cache that was created and in the next commit it failed again with the same error: https://github.com/blegat/LINMA2710/actions/runs/14000721024/job/39206308081
So it seems it wasn't just one unlucky corrected cache, it seems it will be an issue everytime.

[blegat]

But then why does it work on our CI?

I don't see julia-actions/cache in your CI

[fonsp]

Does cache-scratchspaces: false fix it? I wonder why

[blegat]

Yes it seems to fix it 🎉 I have updated JuliaPluto/static-export-template#28 accordingly

[fonsp]

Nice, thats helpful info! I would still like to see a fix instead of a workaround.

From the original error message, the issue seems to be that the Julia cache persists the npm install directory:

/home/runner/.julia/scratchspaces/6eb38059-8c05-41f7-8871-5e7e2697ace6/

But Chrome is stored somewhere else:

/home/runner/.cache/puppeteer

On GHA only the first directory is persisted, and somehow puppeteer does not handle this case correctly.

I think some solutions are:

• Run npx puppeteer browsers install chrome during PlutoPDF.build_node like the error hint suggests.
• Ask puppeteer to use a directory inside Julia scratch instead of /home/runner/.cache/puppeteer for the chrome installation.

[Technici4n]

Indeed, adding cache-scratchspaces: false was also the fix I used: https://github.com/epfl-matmat/numerical-analysis/pull/13/files#diff-48fcdbcf3daed39707fb9303956fadcb00bf92c3c24e569291cc777977aaf8c8R36

[blegat]

According to https://pptr.dev/troubleshooting#could-not-find-expected-browser-locally, we could use PUPPETEER_CACHE_DIR