Before: SPARK_EXECUTOR_DATA_DIR, SPARK_EXECUTOR_JOBS_DIR, and
YARN_RESOURCE_MANAGER_URL were each read directly via os.environ.get()
inside the module that used them. Log level was hardcoded DEBUG in
common/logging.py. There was no single file showing what the full set
of env vars the app reads is.
After: common/config.py defines a single Settings dataclass that
reads all env vars at import time and exposes them as fields on a
module-level singleton. App code uses "from common.config import
settings; settings.data_dir" etc. New SPARK_EXECUTOR_LOG_LEVEL env
var controls stderr + info file verbosity (debug file always gets full
DEBUG).
Improvements:
- One file lists every env var the app reads (was: grep the codebase)
- Tests can monkeypatch fields on the settings singleton directly
instead of monkeypatching the env + reloading
- Adding a new env var means adding one field in config.py, not
editing 3+ call sites
- settings.reload() method for tests that prefer env-var style
Out of scope (kept where they are):
- GUNICORN_* env vars live in gunicorn.conf.py (gunicorn concept)
- PYTHONUNBUFFERED in Dockerfile (Python runtime flag)
- SPARK_SUBMIT_OPTS not in config (JVM flag, not Python)
Test changes:
- test_job_writer.py: settings.jobs_dir instead of monkeypatching
SPARK_EXECUTOR_JOBS_DIR
- test_yarn_client.py: settings.yarn_resource_manager_url instead of
monkeypatching YARN_RESOURCE_MANAGER_URL
- test_generate_tool.py: same as job_writer
- Each test file gets an autouse fixture that snapshots+restores
settings so one test mutation does not leak into the next
116/116 still pass. Live verified: SPARK_EXECUTOR_LOG_LEVEL=INFO
suppresses DEBUG loguru output as expected.
yarn_client.py no longer invokes the 'yarn' binary via subprocess; it uses
httpx against /ws/v1/cluster/apps/* endpoints. This means the runtime image
no longer needs the Hadoop client installation — the only YARN-side
dependency left in the container is the config dir consumed by
spark-submit itself.
New model field:
- Job.yarn_rm_url: str | None
- PendingSubmission.yarn_rm_url: str | None (snapshotted at prepare)
prepare_submit_job snapshots Connection.yarn_rm_url into the pending
record (consistent with the existing master/deploy_mode/spark_conf
snapshot pattern); confirm_submit_job copies it onto the Job so
status/logs/kill can use it without re-looking-up the connection.
Resolution order for the RM URL at runtime:
1. Job.yarn_rm_url (preferred — survives connection edits/deletes)
2. Connection.yarn_rm_url fallback (if a future tool is added that
doesn't go through a Job)
3. YARN_RESOURCE_MANAGER_URL env var
Errors:
- YarnConfigError (HTTP 4xx semantics) when URL is missing/malformed
- YarnError for HTTP 4xx/5xx from the RM, network failures, missing
state field, or unparseable log responses
10 new tests in test_yarn_client.py cover the REST surface:
success, 404, 5xx, missing state field, env-var fallback, malformed
URL, log 404 with log-aggregation hint, kill PUT body shape, and
httpx connection-error wrapping.
Claude