fix(backup): force TCP for mariadb-dump to match '<user>'@'%' grant

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/e2e/test_e2e_mariadb_anonymous_preemption.py

@@ -0,0 +1,143 @@
+"""
+Bug-repro for: mariadb-dump fails with `ERROR 1045 Access denied for user
+'<u>'@'localhost' (using password: YES)` when only '<u>'@'%' is granted and a
+preempting ''@'localhost' user is present.
+
+The fix forces TCP loopback in baudolo.backup.db so the dump matches the
+'<u>'@'%' grant instead of the socket->localhost auth row.
+
+This file:
+- builds the exact preconditions that triggered the production failure,
+- as a NEGATIVE control, runs a socket-based mariadb-dump (== the old code path)
+  and asserts that it fails with the literal 1045 / @'localhost' error,
+- as a POSITIVE proof, calls backup_database() (where the fix lives) against
+  the same DB container and asserts the dump file is produced and contains the
+  seed data.
+
+Note: the volume-rsync stage of baudolo is intentionally NOT exercised here.
+That stage needs root on /var/lib/docker/volumes, which is provided by the
+DinD wrapper in `make test-e2e` but not by an on-host invocation. The bug we
+are verifying is in the DB-dump stage, so testing backup_database() directly
+keeps the assertion focused and the test runnable both on-host and in DinD.
+"""
+
+import os
+import tempfile
+import unittest
+
+import pandas
+
+from baudolo.backup import db as db_mod
+
+from .helpers import (
+    cleanup_docker,
+    require_docker,
+    run,
+    unique,
+    wait_for_mariadb,
+    wait_for_mariadb_sql,
+)
+
+
+class TestE2EMariaDBAnonymousPreemption(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        require_docker()
+        cls.prefix = unique("baudolo-e2e-mariadb-anon")
+        cls.db_container = f"{cls.prefix}-mariadb"
+        cls.db_volume = f"{cls.prefix}-mariadb-vol"
+        cls.containers = [cls.db_container]
+        cls.volumes = [cls.db_volume]
+
+        cls.db_name = "appdb"
+        cls.db_user = "tcponly"
+        cls.db_password = "tcponlypw"
+        cls.root_password = "rootpw"
+
+        run(["docker", "volume", "create", cls.db_volume])
+
+        # Boot WITHOUT MARIADB_USER/MARIADB_PASSWORD/MARIADB_DATABASE so the
+        # entrypoint does not auto-create '<u>'@'%'. We provision the user
+        # explicitly below to mirror the SQL path used by svc-db-mariadb.
+        run([
+            "docker", "run", "-d",
+            "--name", cls.db_container,
+            "-e", f"MARIADB_ROOT_PASSWORD={cls.root_password}",
+            "-v", f"{cls.db_volume}:/var/lib/mysql",
+            "mariadb:12.2",
+        ])
+
+        wait_for_mariadb(cls.db_container, root_password=cls.root_password, timeout_s=120)
+
+        # Provision: '<u>'@'%' (the app/backup grant) + anonymous ''@'localhost'
+        # (the preemption trigger). Mirrors the production state that produced
+        # `ERROR 1045 ... '<u>'@'localhost' (using password: YES)`.
+        bootstrap_sql = (
+            f"CREATE DATABASE {cls.db_name};"
+            f"CREATE USER '{cls.db_user}'@'%' IDENTIFIED BY '{cls.db_password}';"
+            f"GRANT ALL PRIVILEGES ON {cls.db_name}.* TO '{cls.db_user}'@'%';"
+            f"CREATE USER ''@'localhost' IDENTIFIED BY 'anonpw-not-{cls.db_password}';"
+            "FLUSH PRIVILEGES;"
+            f"CREATE TABLE {cls.db_name}.t (id INT PRIMARY KEY, v VARCHAR(50));"
+            f"INSERT INTO {cls.db_name}.t VALUES (1,'ok');"
+        )
+        run([
+            "docker", "exec", cls.db_container, "sh", "-lc",
+            f'mariadb -uroot --protocol=socket -e "{bootstrap_sql}"',
+        ])
+
+        # Sanity: '<u>' can log in over TCP (matches '%'). If THIS fails,
+        # the precondition for the fix to even apply is broken.
+        wait_for_mariadb_sql(
+            cls.db_container, user=cls.db_user, password=cls.db_password, timeout_s=60
+        )
+
+    @classmethod
+    def tearDownClass(cls) -> None:
+        cleanup_docker(containers=cls.containers, volumes=cls.volumes)
+
+    def test_negative_control_socket_dump_fails_with_1045(self) -> None:
+        # Reproduces the OLD code path (no -h/--protocol). MUST fail with 1045
+        # under the configured preemption. If this ever starts passing, either
+        # the MariaDB auth semantics changed or the anonymous-user setup did
+        # not take effect — in both cases the positive test below loses its
+        # ability to discriminate "fix works" vs "bug never reproduced".
+        p = run(
+            [
+                "docker", "exec", self.db_container, "sh", "-lc",
+                f"mariadb-dump -u{self.db_user} -p{self.db_password} {self.db_name}",
+            ],
+            capture=True,
+            check=False,
+        )
+        self.assertNotEqual(p.returncode, 0, "socket-based dump unexpectedly succeeded")
+        self.assertIn("1045", (p.stderr or "") + (p.stdout or ""))
+        self.assertIn("@'localhost'", (p.stderr or "") + (p.stdout or ""))
+
+    def test_backup_database_succeeds_with_tcp_fix(self) -> None:
+        # Drives the function where the fix lives. No rsync, no privileged
+        # paths — just the dump that the negative-control proved is failing
+        # under the same preemption setup.
+        with tempfile.TemporaryDirectory() as volume_dir:
+            df = pandas.DataFrame(
+                [(self.db_container, self.db_name, self.db_user, self.db_password)],
+                columns=["instance", "database", "username", "password"],
+            )
+            produced = db_mod.backup_database(
+                container=self.db_container,
+                volume_dir=volume_dir,
+                db_type="mariadb",
+                databases_df=df,
+                database_containers=[self.db_container],
+            )
+            self.assertTrue(produced, "backup_database did not produce a dump")
+            dump_path = os.path.join(volume_dir, "sql", f"{self.db_name}.backup.sql")
+            self.assertTrue(os.path.isfile(dump_path), f"expected dump at {dump_path}")
+            with open(dump_path, "r", encoding="utf-8", errors="replace") as f:
+                content = f.read()
+            self.assertIn("INSERT INTO", content)
+            self.assertIn("'ok'", content)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)

tests/unit/backup/test_db_mariadb_dump.py

@@ -0,0 +1,68 @@
+import tempfile
+import unittest
+from unittest.mock import patch
+
+import pandas
+
+from baudolo.backup import db as db_mod
+
+
+def _df(rows):
+    return pandas.DataFrame(
+        rows, columns=["instance", "database", "username", "password"]
+    )
+
+
+def _capture_commands(*, db_type, rows, container):
+    captured = []
+
+    def _capture(cmd):
+        captured.append(cmd)
+        return []
+
+    with tempfile.TemporaryDirectory() as td:
+        with patch.object(db_mod, "execute_shell_command", side_effect=_capture):
+            db_mod.backup_database(
+                container=container,
+                volume_dir=td,
+                db_type=db_type,
+                databases_df=_df(rows),
+                database_containers=[container],
+            )
+    return captured
+
+
+class TestMariaDBDumpUsesTCP(unittest.TestCase):
+    # Regression guard for 'Access denied for user <user>@localhost' when only
+    # '<user>'@'%' is granted: the in-container mariadb-dump MUST force TCP so
+    # the connection is auth-matched against '%' instead of socket->localhost.
+
+    def test_mariadb_dump_forces_tcp_loopback(self):
+        captured = _capture_commands(
+            db_type="mariadb",
+            rows=[("mariadb", "appdb", "appuser", "s3cret")],
+            container="mariadb",
+        )
+        dump_cmds = [c for c in captured if "mariadb-dump" in c]
+        self.assertEqual(len(dump_cmds), 1, f"expected one dump command, got: {captured}")
+
+        cmd = dump_cmds[0]
+        self.assertIn("-h 127.0.0.1", cmd)
+        self.assertIn("--protocol=tcp", cmd)
+        self.assertIn("-u appuser", cmd)
+        self.assertIn("-ps3cret", cmd)
+        self.assertIn(" appdb", cmd)
+
+    def test_postgres_dump_unaffected(self):
+        captured = _capture_commands(
+            db_type="postgres",
+            rows=[("pg", "appdb", "appuser", "s3cret")],
+            container="pg",
+        )
+        dump_cmds = [c for c in captured if "pg_dump" in c and "pg_dumpall" not in c]
+        self.assertEqual(len(dump_cmds), 1)
+        self.assertNotIn("--protocol=tcp", dump_cmds[0])
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)