feat: add autoscaler runner instance ready command option

[maxvandermeij]

Description

This adds the optional instance_ready_command parameter for the docker_autoscaler.

This feature was added in Gitlab 16.11. See gitlab documentation for the [runners.autoscaler]: https://docs.gitlab.com/runner/configuration/advanced-configuration.html#the-runnersautoscaler-section.

Example value:
instance_ready_command = "cloud-init status --wait"

Migrations required

No

Verification

Updated the runner_worker_docker_autoscaler by including the instance_ready_command

runner_worker_docker_autoscaler = {
    fleeting_plugin_version = "1.0.0"
    connector_config_user = "ec2-user"
    key_pair_name = "runner-worker-key"
    max_use_count = 100
    update_interval = "1m"
    update_interval_when_expecting = "2s"
    capacity_per_instance = var.job_capacity_per_instance
    instance_ready_command = "\"cloud-init status --wait || test $? -eq 2\""
  }

Confirmed this gets added correctly to the config.toml by enabling the var.debug_write_runner_config_to_file.

Result on the local_file.config_toml[0]:

...
[runners.autoscaler]
      plugin = "fleeting-plugin-aws"
  
      capacity_per_instance = 1
      update_interval = "1m"
      update_interval_when_expecting = "2s"
  
      max_use_count = 100
      max_instances = 1
  
      instance_ready_command = "cloud-init status --wait || test $? -eq 2"
 ....

If no value is given for the instance_ready_command the config.toml will default to

...
[runners.autoscaler]
    plugin = "fleeting-plugin-aws"

    capacity_per_instance = 1
    update_interval = "1m"
    update_interval_when_expecting = "2s"

    max_use_count = 100
    max_instances = 1
    
    instance_ready_command=""
 ...

[github-actions]

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[maxvandermeij]

Anything I can do additionally to help with the review? @npalm @kayman-mk

[kayman-mk]

Thanks for improving the module.

Did you try to start an Agent with the variable unset? Just to make sure that it works with the default value.

[maxvandermeij]

Thanks for improving the module.

Did you try to start an Agent with the variable unset? Just to make sure that it works with the default value.

Yes did indeed confirm with the new "" default workers spin up perfectly.