Add StackdriverRemoteLogIO.from_config and register stackdriver scheme

[jason810496]

Part of #70265 (related: #67056).

Why

#67056 decoupled remote logging from the hardcoded branches in airflow_local_settings.py: core and
the Task SDK now resolve the handler via ProvidersManager dispatch on the
[logging] remote_base_log_folder URL scheme, instantiating the provider class through a no-arg
from_config() classmethod. This issue migrates the stackdriver scheme.

What

• Add StackdriverRemoteLogIO.from_config() in
  providers/google/src/airflow/providers/google/cloud/log/stackdriver_task_handler.py,
  mirroring the legacy branch:
  

  airflow/airflow-core/src/airflow/config_templates/airflow_local_settings.py

  Lines 250 to 268 in 104ad12

  	elif remote_base_log_folder.startswith("stackdriver://"):
  	from airflow.providers.google.cloud.log.stackdriver_task_handler import StackdriverRemoteLogIO
  	key_path = conf.get_mandatory_value("logging", "GOOGLE_KEY_PATH", fallback=None)
  	# stackdriver:///airflow-tasks => airflow-tasks
  	log_name = urlsplit(remote_base_log_folder).path[1:]
  	REMOTE_TASK_LOG = StackdriverRemoteLogIO(
  	**cast(
  	"dict[str, Any]",
  	{
  	"base_log_folder": BASE_LOG_FOLDER,
  	"gcp_log_name": log_name,
  	"gcp_key_path": key_path,
  	"delete_local_copy": delete_local_copy,
  	}
  	| _io_kwargs,
  	)
  	)

  
  — including the [logging] remote_task_handler_kwargs IO-kwargs merge and expanduser on
  base_log_folder, so behavior is unchanged for existing configs.
• Register the stackdriver scheme under a remote-logging: section in
  providers/google/provider.yaml and mirror it in
  providers/google/src/airflow/providers/google/get_provider_info.py.
• Add tests mirroring TestS3RemoteLogIOFromConfig in
  providers/amazon/tests/unit/amazon/aws/log/test_s3_task_handler.py.
• Verify end to end with a real system test: set up the actual backend yourself (a real
  service or a local equivalent), run a task with remote logging enabled, and confirm logs are
  uploaded and read back through the new dispatch path. Include the setup and verification
  results in the PR description.

Notes

• The legacy branch parses the log name from the URL path: stackdriver:///airflow-tasks →
  gcp_log_name="airflow-tasks" (urlsplit(...).path[1:]). Mirror this in from_config, with a
  clear ValueError when no log name can be derived (see how Add CloudWatchRemoteLogIO.from_config and register cloudwatch scheme #69816 handles log_group_arn
  parsing for cloudwatch).
• It also reads [logging] google_key_path (fallback None) into gcp_key_path, and passes no
  remote_base — unlike the other object-storage backends.

Reference

Merged examples to follow: #69817 (s3), #69816 (cloudwatch). If from_config raises on a bad
config, the shared factory falls back to the legacy path, so this is not a breaking change.

[aaron-y-chen]

I can work on it, I have a GCP account that I can use for e2e verification. Thanks!

[fat-catTW]

Hello.
nailo2c said he would let me help with this issue.
I will work on it. Thanks.