build-args non-functional for delivering more than one k/v set

Troubleshooting

This is… odd that this has to be brought up with… well, you folks, but here goes…

Currently build-push-action@v2 key, build-args requires a string. Regardless of what getInputList() actually does, --build-arg does not configure more than a single key. This is a known… non-issue that is addressable with multiple iterations of --build-arg on the command line.

See set-build-time-variables docs

Behaviour

Steps to reproduce this issue

1. with a job step of

        -
          name: Build the Docker image
          uses: docker/build-push-action@v2

          with:
            push: true
            tags: gladiatr72/python:${{ env.PYTHON_VERSION }}
            build-args: PYTHON_VERSION=${{ env.PYTHON_VERSION}}\nBUILD_ARGS='--enable optimizations --with-lto'

or

        -
          name: Build the Docker image
          uses: docker/build-push-action@v2

          with:
            push: true
            tags: gladiatr72/python:${{ env.PYTHON_VERSION }}
            build-args:  |
              PYTHON_VERSION=${{ env.PYTHON_VERSION}}
              BUILD_ARGS='--enable optimizations --with-lto'

The above syntax does not work… was an attempt to follow the expectations of that field from the tests.

Expected behaviour

The action should correctly parse the build-arg string into an appropriate docker CLI invocation. --build-arg KEYA=VALA --build-arg KEYB=KEYB

Actual behaviour

The Docker documentation and the Internet insists trying to pass multiple arguments with a single --build-arg does not work and will never work. As claimed by the aforementioned entities, multiple key/val sets must be injected with the same number of --build-arg flags. Whatever I’ve tried to append to the initial build-args value becomes part of the initial var’s argument and predictably breaks where those vars are intended for substitutions within the Dockerfile.

Configuration

• Repository URL (if public): gladiatr72/actions-test
• Build URL (if public): https://github.com/gladiatr72/actions-test/actions/runs/611841318

name: Docker Image CI

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:

    if-you-build-it:
      env:
        PYTHON_VERSION: "3.6.13"

      runs-on: ubuntu-latest

      steps:
        -
          uses: actions/checkout@v2
        -
          name: setup buildx
          uses: docker/setup-buildx-action@v1
        -
          name: login
          uses: docker/login-action@v1
          with:
            username: ${{ secrets.DOCKER_USERNAME }}
            password: ${{ secrets.DOCKER_PASSWORD }}
        -
          name: Build the Docker image
          uses: docker/build-push-action@v2

          with:
            push: true
            tags: gladiatr72/python:${{ env.PYTHON_VERSION }}
            build-args: PYTHON_VERSION=${{ env.PYTHON_VERSION}}\nBUILD_ARGS='--enable optimizations --with-lto'

Logs

5_Build the Docker image.txt

[crazy-max]

@gladiatr72 Explained here: https://github.com/docker/build-push-action#inputs

        -
          name: Build the Docker image
          uses: docker/build-push-action@v2
          with:
            push: true
            tags: gladiatr72/python:${{ env.PYTHON_VERSION }}
            build-args: |
              PYTHON_VERSION=${{ env.PYTHON_VERSION}}
              BUILD_ARGS=--enable optimizations --with-lto

[crazy-max]

@ilyamochalov

not able to find any docs on BUILD_ARGS env var mentioning neither in BuildX

There is no such env var called BUILD_ARGS for buildx but --build-arg flag which is handled in this action by the build-args input translated like this.