Using output from a run command in a future step

[nodesocket]

I have a complex command ./dockebuild.sh that runs a bunch of things in a bash script, and at the end outputs the built Docker image tag.

jobs:
  ecs:
    name: ecs
    runs-on: ubuntu-latest
    steps:
        - name: Checkout
          uses: actions/checkout@v1
        - name: Docker build
          run: ./dockerbuild.sh
        - name: Render ECS task definition
          uses: aws-actions/amazon-ecs-render-task-definition@v1
          with:
            task-definition: task-definition.json
            container-name: stage-web
            image: <a value from the output of ./dockerbuild.sh here>

How can I grab just what I need from the output of ./dockerbuild.sh and use it in Render ECS task definition?   Note: there is tons of output from ./dockebuild.shbut I need to search for a specific regular expression and use that.

[nodesocket]

I just tried:

export GA_DOCKER_IMAGE="repo-here:tag-here"

Inside of the script dockerbuild.sh and updating the run command to:

. dockerbuild.sh

Then using the exported ENVAR like:

- name: Render new ECS task definition
  uses: aws-actions/amazon-ecs-render-task-definition@v1
  with:
    task-definition: task-definition.json
    container-name: stage-web
    image: ${{ env.GA_DOCKER_IMAGE }}

But ${{ env.GA_DOCKER_IMAGE }} is empty. Any ideas?

[rbellamy]

Try:

echo "::set-env name=GA_DOCKER_IMAGE::repo-here:tag-here"

https://help.github.com/en/actions/reference/development-tools-for-github-actions#set-an-environment-variable-set-env

[weide-zhou]

Hi @nodesocket ,

You need to filter the output result of the dockebuild.sh file, eg: use ‘grep’.

For instance, two outputs in sh file:

echo tag1=v1
echo tag2=v2

Then in workflow yaml file:

- name: get output value
        id: getimage
        run: |
          echo "::set-output name=tag::$(sh dockerbuild.sh | grep tag2)"
      - name: check the value
        run: |
          echo ${${{ steps.getimage.outputs.tag }}} # this will show 'v2', is the expected tag.

Or directly use ‘set-env’ in dockebuild.sh file:

echo "::set-env name=GA_DOCKER_IMAGE::repo-here:tag2"

then you can invoke it in yaml file with ‘$GA_DOCKER_IMAGE’ and used as action parameters.

- name: get the value from env
        run: |
          echo $GA_DOCKER_IMAGE

Hope it helps!

[nodesocket]

Thanks @weide-zhou and @rbellamy:

I will try this. What is this syntax? Is it specific to running inside of a GitHub action bash script?

echo "::set-env name=GA_DOCKER_IMAGE::repo-here:tag2"

[weide-zhou]

Please check the link for more details about ‘set-env’. Actually it’s a wrapped github action function which described here, it’s only used in Github actions. Thanks.