build: replace django-pglocks with django-pgware - #728

SUMMARY

Replaces django-pglocks with django-pgware, which provides the advisory locks awx/main/utils/pglock.py wraps and the task manager and dispatcher take to serialise work across nodes.

This started as a bump of django-pglocks from 1.0.4 to 2.1.0. @cigamit pointed out that 2.1.0 is a shim, and it is: the whole package is a DeprecationWarning and a re-export.

warnings.warn(
    "django-pglocks has been consolidated into django-pgware. "
    "Install django-pgware (it imports as django_pg_utils) and update "
    "imports to django_pg_utils.locks. "
    "This compatibility package will not receive further updates.",
    DeprecationWarning,
    stacklevel=2,
)

from django_pg_utils.locks import advisory_lock, async_advisory_lock

So the dependency moves to django-pgware and the one import site moves with it. Taking the shim would have pulled in django-pgware anyway, as the original diff here showed, plus a deprecation warning on every import.

What changed:

• requirements.in and requirements.txt: django-pglocks out, django-pgware==1.0.0 in as a direct requirement rather than something pulled in behind the shim.
• awx/main/utils/pglock.py: from django_pglocks import advisory_lock becomes from django_pg_utils.locks import advisory_lock. This is the only import site in the tree; the other fourteen call sites go through this wrapper.
• licenses/: django-pglocks.txt out, django-pgware.txt in, or test_licenses.py::test_python_and_js_licenses fails on both halves.
• six loses a consumer but stays, for isodate, kubernetes, openshift, pygerduty and pyrad. django-pgware needs nothing but Django.

shared, wait, comment and using are keyword only in django-pgware. Every call site in the tree passes the lock name positionally and wait by keyword, so all fourteen are already in the accepted form.

One thing to know before merging

The lock id derived from a string lock name changed, and this is true of the 2.1.0 shim as well, since the shim delegates the hashing:

A node on the old release and a node on the new one therefore do not exclude each other on the same lock name, for as long as a rolling upgrade has both running. It clears once every node is on the same release. Worth a line in the release notes rather than a change here, since there is no version of this move that keeps the old ids.

ISSUE TYPE

• Bug, Docs Fix or other nominal change

COMPONENT NAME

• API

ASCENDER VERSION

25.5.1

Tests

On a real PostgreSQL, because nothing else exercises it. awx/main/utils/pglock.py short circuits to yield True whenever connection.vendor is not postgresql, so a green SQLite suite says nothing about this library. The wrapper, with the new import, against the running database:

vendor: postgresql
blocking acquire -> True
try acquire (free) -> True
formatted name -> True
advisory locks still held: 0        # released on exit

And the property the callers depend on, across two connections:

conn A blocking acquire -> True
conn B try acquire while held -> False
conn B try acquire after release -> True

Same result as 1.0.4, so the semantics AWX relies on are unchanged.

The rest of the suite, on a freshly created database:

py.test --create-db -n auto --dist=loadfile \
  awx/main/tests/unit awx/main/tests/functional awx/conf/tests awx/sso/tests

  1 failed, 3816 passed, 10 skipped in 8m42s
  FAILED awx/main/tests/functional/api/test_generic.py::test_proxy_ip_allowed

That failure is not this change. test_proxy_ip_allowed patches REMOTE_HOST_HEADERS and PROXY_IP_ALLOWED_LIST on the settings singleton and intermittently sees another worker's state under -n auto; it passes solo, and it is the flake instrumented in #694.

Rebased onto current main, which drops the licenses/docutils.txt failure the earlier run here hit.