Support defining group ID in environment

[relwell]

Previously, we could define a runner group's name, but not its ID. This creates some challenges around specifying multiple runner groups and being able to retrieve information about them through GitHub's API. This allows us to set the group's ID using the same RUNNERS environment variable that allows us to set its name.

This change updates the README with the necessary information as well.

It's worth noting that per our existing README file, all configuration parameters can be set via the documented environment variables at runtime, or with a .env document made available in the working directory at runtime.

Closes #32
Closes #33
Closes #34
Closes #35

[cjflan]

If we are going to keep the architecture of one runner type per controller, does it make more sense to make this a part of the runners variable or split it out into its own env variable?

Alternative here

[relwell]

If we are going to keep the architecture of one runner type per controller, does it make more sense to make this a part of the runners variable or split it out into its own env variable?

Alternative here

I thought of that originally, too, but we're already instructing users to populate the environment variable with JSON, and so it makes sense to stay idiomatic there. I think that may come from ARC.

[cjflan]

Sounds good, defining the runner name and ID together makes sense as well. We should update the error message on a failed parse to include a reference to the ID then too.

orka-github-actions-integration/pkg/env/env.go

Line 199 in ad3afd2

return nil, fmt.Errorf(`unable to parse the %s environment variable as a JSON array of runners. Make sure the variable is correctly set with a valid JSON array, for example, '[{"name":"my-test-runner"}]'`, RunnersEnvName)

[relwell]

Sounds good, defining the runner name and ID together makes sense as well. We should update the error message on a failed parse to include a reference to the ID then too.

orka-github-actions-integration/pkg/env/env.go

Line 199 in ad3afd2

return nil, fmt.Errorf(`unable to parse the %s environment variable as a JSON array of runners. Make sure the variable is correctly set with a valid JSON array, for example, '[{"name":"my-test-runner"}]'`, RunnersEnvName)

Will do, but it's worth keeping in mind that the ID should remain optional.

See:

[cjflan]

The ID should stay (and is) optional. I was thinking of making sure that it referenced the ID in case someone set the runner like [{"name": "baz", "id": "2"}] and the parsing error would come from the ID part of the unmarshal, but that may be more hand holding than necessary.

[cjflan]

LGTM

[cjflan]

We should also add the documentation from the .env file to the README in this section

https://github.com/macstadium/orka-github-actions-integration?tab=readme-ov-file#environment-variables

[relwell]

@cjflan not sure we want to add it to the .env file, because most customers will only run a single runner group, and therefore can omit the field. I would put the cognitive burden on the more complex use case, if that makes sense.