metrics: use buildpack instead of Dockerfiles

[trivikr]

Is your feature request related to a problem? Please describe.

The metrics code run on Google Cloud Run is managed using Dockerfile.

• https://github.com/nodejs/build/blob/main/ansible/roles/metrics/files/summaries/Dockerfile
• https://github.com/nodejs/build/blob/main/ansible/roles/metrics/files/index-generator/Dockerfile
• https://github.com/nodejs/build/blob/main/ansible/roles/metrics/files/process-cloudflare/Dockerfile

These Dockerfiles need to be managed while upgrading Node.js, or making any other changes in application.
For example, here is a PR which upgrades Node.js versions from 14 to 20 #3767

Describe the solution you'd like

Use buildpack instead of Dockerfiles
https://cloud.google.com/docs/buildpacks/build-application#node.js

[targos]

I'm not sure it's an advantage tbh

[trivikr]

The only advantage would be the absence of Dockerfiles in the source code.
The Node.js version is only required to be defined in package.json, and buildpack will handle managing the version.

[targos]

The only advantage would be the absence of Dockerfiles in the source code.

That's what I don't see as an advantage. Cloud run works with Docker containers, and for the majority of developers, containers are built using Dockerfiles, not some obscure (to me at least) Google tool.

[trivikr]

I agree. It's better to stick with Dockerfiles since:

• It's a standard for building containers in the industry. If the setup is moved to another container solution on GCP or some other cloud, it'll be easy to migrate Dockerfiles.
• Using a Dockerfile is the first recommendation for building containers in GCP documentation (before buildpack)