Use DSLR instead of postgres client

.github/workflows/ci.yml

@@ -150,8 +150,6 @@ jobs:
     env:
       DJANGO_SETTINGS_MODULE: cms.settings.functional_test
       SECRET_KEY: fake_secret_key_to_run_tests # pragma: allowlist secret
-      PG_DUMP: /home/linuxbrew/.linuxbrew/opt/postgresql@16/bin/pg_dump
-      PG_RESTORE: /home/linuxbrew/.linuxbrew/opt/postgresql@16/bin/pg_restore
       BROWSER: ${{ matrix.browser }}
       PLAYWRIGHT_TRACES_DIR: playwright_traces
       PLAYWRIGHT_TRACE: 'true'
@@ -173,11 +171,6 @@ jobs:
       - name: Playwright Install
         run: poetry run python -m playwright install --with-deps ${{ matrix.browser }}
 
-      - name: Install/Update Postgres
-        # We need pg_dump and pg_restore for the functional tests
-        # The Ubuntu runner does come with postgresql, but the wrong version, so we must acquire v16
-        run: /home/linuxbrew/.linuxbrew/bin/brew install postgresql@16
-
       - uses: actions/download-artifact@v4
         with:
           name: static

functional_tests/behave_fixtures.py

@@ -1,22 +1,15 @@
-import os
-import subprocess
-from pathlib import Path
-
 import django
 from behave import fixture
 from behave.runner import Context
 from django.conf import settings
 from django.db import close_old_connections
 from django.test.runner import DiscoverRunner
 from django.test.testcases import LiveServerTestCase
+from dslr.config import settings as dslr_settings
+from dslr.operations import create_snapshot, delete_snapshot, find_snapshot, restore_snapshot
 
 # Adapted from https://behave.readthedocs.io/en/stable/usecase_django.html#manual-integration
 
-# Allow the path to the postgres client tools we depend on to be configured from the environment,
-# as they may not always be accessible by name
-PG_DUMP = os.getenv("PG_DUMP", "/usr/local/bin/pg_dump")
-PG_RESTORE = os.getenv("PG_RESTORE", "/usr/local/bin/pg_restore")
-
 
 @fixture
 def django_test_runner(context: Context) -> None:
@@ -33,15 +26,17 @@ def django_test_runner(context: Context) -> None:
     context.old_db_config = context.test_runner.setup_databases()
 
     # At this point, the Django test runner has initialised the test database and run migrations
-    # We dump the database out to a file, to allow us to later restore the database to this clean, initial state
-    context.initial_pg_dump_file = dump_database_to_file()
+    # Initialize DSLR and take a snapshot of the clean, post migration test database
+    initialize_dslr()
+    context.clean_snapshot_name = "clean_snapshot"
+    create_snapshot(context.clean_snapshot_name)
 
     # Yield to resume the tests execution
     yield  # Everything after this point is run after the entire test run
 
     context.test_runner.teardown_databases(context.old_db_config)
     context.test_runner.teardown_test_environment()
-    context.initial_pg_dump_file.unlink(missing_ok=True)  # Delete the dump file
+    delete_snapshot(find_snapshot(context.clean_snapshot_name))
 
 
 @fixture
@@ -73,62 +68,17 @@ def django_test_case(context: Context) -> None:
     close_old_connections()
 
     context.test_case.tearDown()
-    restore_database_dump(context.initial_pg_dump_file)
+    restore_snapshot(find_snapshot(context.clean_snapshot_name))
     context.test_case_class.tearDownClass()
     del context.test_case_class
     del context.test_case
 
 
-def dump_database_to_file() -> Path:
-    """Dump the Django default database out to a file.
-    Returns the Path for the dumped file.
-    """
-    dump_file = Path("tmp_test_pg_dump.sql")
-
+def initialize_dslr() -> None:
+    """Initialize DSLR to point to the Django default database."""
     db_config = settings.DATABASES["default"]
-
-    # Use the pg_dump utility to dump the entire database out into the dump file
-    with dump_file.open("w", encoding="utf-8") as write_file:
-        subprocess.run(  # noqa: S603
-            [
-                PG_DUMP,
-                "--format=custom",  # Custom format is required to use pg_restore,
-                "-d",
-                db_config["NAME"],
-                "-h",
-                db_config["HOST"],
-                "-p",
-                str(db_config["PORT"]),
-                "-U",
-                db_config["USER"],
-            ],
-            stdout=write_file,
-            env={"PGPASSWORD": db_config["PASSWORD"]},  # The password cannot be passed on the command line
-            check=True,
-        )
-    return dump_file
-
-
-def restore_database_dump(dump_file: Path) -> None:
-    """Do a clean restore on the default Django database from a dump file."""
-    db_config = settings.DATABASES["default"]
-
-    # Use the pg_restore utility to load the database dump file
-    subprocess.run(  # noqa: S603
-        [
-            PG_RESTORE,
-            "--format=custom",
-            "--clean",  # Custom format is required to use pg_restore,
-            "-d",
-            db_config["NAME"],
-            "-h",
-            db_config["HOST"],
-            "-p",
-            str(db_config["PORT"]),
-            "-U",
-            db_config["USER"],
-            dump_file.absolute(),
-        ],
-        env={"PGPASSWORD": db_config["PASSWORD"]},  # The password cannot be passed on the command line
-        check=True,
+    db_conn_str = (
+        f"postgresql://{db_config['USER']}:{db_config['PASSWORD']}"
+        f"@{db_config['HOST']}:{db_config['PORT']}/{db_config['NAME']}"
     )
+    dslr_settings.initialize(url=db_conn_str, debug=False)

pyproject.toml

@@ -41,6 +41,7 @@ wagtail-factories = "^4.1.0"
 coverage = "^7.6.4"
 
 dslr = "^0.4.0"
+psycopg2-binary = "^2.9.10"
 django-debug-toolbar = "^4.4.6"
 pudb = "^2024.1"
 tblib = "^3.0.0"