Docker container action with parametric Dockerfile filename

[uraimo]

I was playing around with the creation of a docker container action and I’ve noticed that I can’t select a specific Dockerfile (I have a few of them, each one in a different directory, more on this later) using some input variable provided by the user of the Action as shown below:

# action.yml
name: 'para_docker'
description: 'test'
inputs:
  type: # id of input
  description: 'type of the docker container'
  required: true
  default: 'default'
runs:
  using: 'docker'
  image: '${{ inputs.type }}/Dockerfile' <<<<<<<<<<<<<<<<<
  args:
    - ${{ inputs.type }}

I get an error here: “image:’${{ inputs.type }}/Dockerfile’”, because at that point (when the docker image is created before it’s launched) “inputs” does not exist.

I’m using the [path]/Dockerfile format because it seems to be the only one available, no custom Dockerfile names.

From this it seems that input variables can only be passed to args: and not much else, or at least they can’t be used for that specific parameter of the docker action type.

Is this correct and will this always stay like this?

And, can the name of the dockerfile be made parametric and dependent on some input parameter chosen by the user of the action in some other way?

[AndreaGriffiths11]

Hi @uraimo,

Thanks for being here and our apologies for the delay. Currently, it is not possible to specify a value in that image field in the way that you’ve configured.

The only supported formats are documented here:

https://help.github.com/en/actions/automating-your-workflow-with-github-actions/metadata-syntax-for-github-actions#image

I’ve taken your suggestion and passed it along to the appropriate teams. Thanks again for reaching out 😀

[uraimo]

Thanks Andrea, being able to use variables in more places would be great!

In this case, I’ve worked around it launching Docker manually with a minimal Javascript action that boots the container with the Dockerfile I want.

[mosteo]

Hi @uraimo , could you elaborate a bit on how you do this? I’m trying to write an action that somehow takes the Docker image in which it has to run, but I’m stuck. Thanks!

[uraimo]

Hey @mosteo, you can take a look at this: https://github.com/uraimo/run-on-arch-action/tree/master/src
My workaround uses that js launcher to execute the bash script where most of the logic is contained(setup the host, launch docker with the params obtained from the launcher), you could use the same approach.

Another thing that you’ll probably need is retrieving some data from inside your docker, remember that , unexpectedly, you will still be able to call things like ’echo ::set-output name=Name::Value‘ like you would inside the standard action container!

[mosteo]

Very cool. This certainly gives me several ideas to try. Thanks a lot!