Build failure with recent new phoenix app

[febeling]

There are two problems when deploying an app generated with a recent Phoenix version (1.7.7):

1. The buildpack assumes there is a assets/package.json and fails when installing deps from it. The most recent phoenix 1.7 doesn't place this file there. This is the log tail (deployment to Dokku).

-----> Installing binaries
       /cache/node-v18.18.0-linux-x64.tar.gz: OK
       Using cached node 18.18.0...
       Installing Node 18.18.0...
       Downloading and installing npm 10.2.0 (replacing version 9.8.1)...
       
-----> Building dependencies
       Installing node modules
       
       up to date in 517ms
       npm ERR! code ENOENT
       npm ERR! syscall open
       npm ERR! path /tmp/build/assets/package.json
       npm ERR! errno -2
       npm ERR! enoent ENOENT: no such file or directory, open '/tmp/build/assets/package.json'
       npm ERR! enoent This is related to npm not being able to find a file.
       npm ERR! enoent
       
       npm ERR! A complete log of this run can be found in: /app/.npm/_logs/2023-10-11T11_41_08_245Z-debug-0.log
remote:  !     Failure during app build
remote:  !     Retagging old image 2e974a41ab58 as dokku/testapp-ex:latest
remote:  !     App build failed

2. The build command is now mix assets.deploy instead of the previous mix $phoenix.digest. This is an alias from mix.exs, which still runs phx.digest, but after tailwind and esbuild.

[febeling]

PR #3 addresses the part with mix assets.deploy too, among other things. - https://github.com/gigalixir/gigalixir-buildpack-phoenix-static/pull/3/files#diff-eba8dcd606bd0014b899e3624e527598796eee3446de65af0fb4274ff8a4792fR14

[febeling]

Workaround/Solution

Place an empty package.json into assets/ and override the compile command.

The package.json can look like this:

{
  "name": "myapp",
  "version": "0.0.1",
  "description": "placeholder package.json to pacify static buildpack",
  "main": "js/app.js"
}

The compile can be overridden by placing a file compile in the project root directory with this content:

cd $phoenix_dir
mix assets.deploy