Unable to run a nodejs project as yarn is not present in path

[anoop2811]

What happened?

I have an application which requires yarn to start at run time but yarn is not present in the path in the run image.

• What were you attempting to do?
  Run application called backstage (backstage.io)

• What did you expect to happen?
  Expected it to run using the yarn start

• What was the actual behavior? Please provide log output, if possible.
  bash: yarn: command not found

Build Configuration

• What platform (pack, kpack, tekton buildpacks plugin, etc.) are you
  using? Please include a version.
  pack build backstage-buildpack --path . --builder paketobuildpacks/builder:full

• What buildpacks are you using? Please include versions.
  Was using the packeto nodejs buildpack

• What builder are you using? If custom, can you provide the output from pack inspect-builder <builder>?
  paketobuildpacks/builder:full

• Can you provide a sample app or relevant configuration (buildpack.yml,
  nginx.conf, etc.)?
  package copy.json.txt

Checklist

• [x ] I have included log output.
• [x ] The log output includes an error message.
• [x ] I have included steps for reproduction.

[arjun024]

Hi @anoop2811, thanks for the report. I have a couple of questions for you.

(1) Do you have a yarn.lock at the root of your application? This is how the nodejs composite buildpack determines if package manager to use is yarn or npm. npm is the default package manager for all node.js applications unless a yarn.lock is present at the root. See sample app https://github.com/paketo-buildpacks/samples/tree/main/nodejs/yarn

(2) Are you expecting to use yarn2? If yes, paketo does not have yarn2 support yet. Please see the discussion here (paketo-buildpacks/yarn#19)

[anoop2811]

Hi @arjun024 , yes, I do have a yarn.lock file at the root of the application and I am not using yarn2.

[arjun024]

Could you provide the build logs and a sample app if possible?

[anoop2811]

Hi @arjun024,
Please find the sample project here: https://github.com/anoop2811/backstage
Build logs attached:
build.log.txt
Run error:

docker run -p 3000:3000 -it  backstage-buildpack
bash: yarn: command not found

[arjun024]

Thanks for the sample and logs. As of now, the yarn-start buildpack only makes yarn available to the build stage and not in the final built application image. I think it's reasonable for the nodejs buildpack to support a case where the start command is of the syntax yarn workspace <workspace_name> <command>. I'll work on a change to get yarn available at launch and try to get it released soon.

In the meantime, you can make use of the build-plan buildpack. You need a plan.toml at the root of the application asking yarn to be available at launch time i.e. the final application image. See e.g. here

[anoop2811]

Thanks @arjun024 .
I tried addind the following plan.toml
plan.toml.txt
and tried again using the following command:
pack build backstage-buildpack --path . --builder paketobuildpacks/builder:full -b paketo-buildpacks/[email protected] -b paketo-community/[email protected]

but I still get the same error

[arjun024]

@anoop2811 With v0.9.0 of the nodejs buildpack, you should be able to have yarn available on the application image. See example app. Feel free to reopen the issue if the problem persists.