Get matrix values from an env variable (or an external source such as a file)

[pantelis-karamolegkos]

I want to set up a GitHub action workflow that uses a matrix strategy.

I would to be able to set the input values of such a matrix either from an env variable or (ideally) from a file.

jobs:
  example_matrix:
    strategy:
      matrix:
        version: [10, 12, 14]

Is it possible for the workflow to read version: [10, 12, 14] from another source?

[airtower-luna]

Yes, I've seen people use the fromJSON() for that. Usually the approach is that one job creates a job output containing JSON, and a second one uses that as its input. The documentation even has an example of that.