fix(reconciler): Support default value for RUNNER_NAME_PREFIX from my…

[sklirg]

…oung34-derivate

Fixes not-in-sync errors between GitHub API and running Pods when the default value for RUNNER_NAME_PREFIX is used (and likely also if RUNNER_NAME_PREFIX is set).

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If the environment variable RUNNER_NAME_PREFIX is not set, then the default value of github-runner will be used as a prefix.

This shows up in GitHub Runners as such:

The code would originally try to match the runner name by using the name from the custom resource as a prefix, which would be incorrect in the case a RUNNER_NAME_PREFIX is not provided (or is the empty string) and the name of the CR is not "github-runner-runner-pool". Furthermore, if this variable is provided as non-empty, the same thing would occur as far as I can see.

Example configuration which triggers this is

apiVersion: garo.tietoevry.com/v1alpha1
kind: GithubActionRunner
metadata:
  namespace: github-actions-runner-operator
  name: runner-pool

With the pod template containers spec from sample, namely no env: name for RUNNER_NAME_PREFIX.

A workaround is to set the CR name to the same as RUNNER_NAME_PREFIX, e.g. both github-runner-runner-pool, but this duplicates the name and the prefix (because the pod name is templated from CR.name, like "${RUNNER_NAME_PREFIX}-${cr.Name}-${SUFFIX}") so you end up with names like "Runners / github-runner-runner-pool-github-runner-runner-pool-pod-wxvvc"