Add osism get mariadb-backup-host

osism/commands/get.py

@@ -2,6 +2,7 @@
 
 from datetime import datetime
 import pprint
+import re
 import subprocess
 import json
 
@@ -263,6 +264,83 @@ def take_action(self, parsed_args):
         return
 
 
+# Printed once by kolla-mariadb-backup-host.yml: the host the backup runs on
+# (empty if none) and the host each shard resolved.
+BACKUP_HOST_PATTERN = re.compile(r"mariadb_backup_host=([^\s\"]*) resolved=([^\s\"]*)")
+
+
+class MariadbBackupHost(Command):
+    """Show the host that 'osism apply mariadb-backup' writes archives to.
+
+    The value is resolved by the mariadb role itself, in a read-only play on
+    the kolla-ansible worker, because its default, the shard grouping it
+    depends on and the usual override are all outside the inventory.
+    """
+
+    def get_parser(self, prog_name):
+        parser = super(MariadbBackupHost, self).get_parser(prog_name)
+        parser.add_argument(
+            "--format",
+            default="table",
+            choices=["table", "script"],
+            help="Output type; script prints the bare host name",
+        )
+        parser.add_argument(
+            "--timeout",
+            default=300,
+            type=int,
+            help="Seconds to wait for the play",
+        )
+        return parser
+
+    def take_action(self, parsed_args):
+        from celery.exceptions import TimeoutError as CeleryTimeoutError
+
+        from osism.tasks import AnsibleFailure, kolla
+
+        utils.check_task_lock_and_exit()
+
+        t = kolla.run.delay("kolla", "mariadb-backup-host", [], publish=False)
+        try:
+            output = t.get(timeout=parsed_args.timeout)
+        except AnsibleFailure as exc:
+            logger.error(
+                f"{exc}. 'osism apply -e kolla mariadb-backup-host' shows "
+                "the full output."
+            )
+            return 1
+        except CeleryTimeoutError:
+            logger.error(f"Timeout while waiting for task {t.task_id}.")
+            # Unsubscribe now; left pending, the result is released during
+            # interpreter shutdown and Celery prints a traceback.
+            t.forget()
+            return 1
+
+        match = BACKUP_HOST_PATTERN.search(output)
+        if not match:
+            logger.error("The play did not report a backup host.")
+            return 1
+
+        hosts = [host for host in match.group(1).split(",") if host]
+        if not hosts:
+            # kolla skips the backup silently in this case.
+            resolved = match.group(2).replace(",", ", ")
+            logger.error(
+                f"No backup would be taken: no resolved backup host "
+                f"({resolved}) is in the default MariaDB shard."
+            )
+            return 1
+
+        if parsed_args.format == "script":
+            print("\n".join(hosts))
+        else:
+            print(
+                tabulate([[host] for host in hosts], headers=["Host"], tablefmt="psql")
+            )
+
+        return
+
+
 class States(Command):
     def get_parser(self, prog_name):
         parser = super(States, self).get_parser(prog_name)

setup.cfg

@@ -63,6 +63,7 @@ osism.commands:
     get facts = osism.commands.get:Facts
     get hosts = osism.commands.get:Hosts
     get hostvars = osism.commands.get:Hostvars
+    get mariadb-backup-host = osism.commands.get:MariadbBackupHost
     get logs ansible = osism.commands.log:Ansible
     get logs container = osism.commands.log:Container
     get logs file = osism.commands.log:File

tests/unit/commands/test_get.py

@@ -420,3 +420,105 @@ def test_states_prints_nothing_without_cache_entry(monkeypatch, capsys):
     cmd.take_action(parsed_args)
 
     assert capsys.readouterr().out == ""
+
+
+# --- MariadbBackupHost.take_action ---
+
+
+def _backup_line(selected, resolved):
+    return (
+        "ok: [testbed-node-0] => {\n"
+        f'    "msg": "mariadb_backup_host={selected} resolved={resolved}"\n'
+        "}\n"
+    )
+
+
+def _run_backup_host(args, output=None, side_effect=None):
+    cmd = _make(get.MariadbBackupHost)
+    parsed_args = cmd.get_parser("test").parse_args(args)
+
+    task = MagicMock()
+    if side_effect is not None:
+        task.get.side_effect = side_effect
+    else:
+        task.get.return_value = output
+
+    with patch("osism.commands.get.utils.check_task_lock_and_exit"), patch(
+        "osism.tasks.kolla.run"
+    ) as mock_run:
+        mock_run.delay.return_value = task
+        result = cmd.take_action(parsed_args)
+
+    return result, mock_run
+
+
+def test_mariadb_backup_host_runs_the_play_without_publishing(capsys):
+    result, mock_run = _run_backup_host(
+        [], output=_backup_line("testbed-node-0", "testbed-node-0")
+    )
+
+    assert not result
+    mock_run.delay.assert_called_once_with(
+        "kolla", "mariadb-backup-host", [], publish=False
+    )
+    assert "testbed-node-0" in capsys.readouterr().out
+
+
+def test_mariadb_backup_host_script_format_prints_bare_host(capsys):
+    # Colour codes as the worker emits them must not leak into the host name.
+    output = "\x1b[0;32m" + _backup_line("testbed-node-1", "testbed-node-1") + "\x1b[0m"
+
+    result, _ = _run_backup_host(["--format", "script"], output=output)
+
+    assert not result
+    assert capsys.readouterr().out == "testbed-node-1\n"
+
+
+def test_mariadb_backup_host_ignores_other_shards(capsys):
+    # Every shard resolves a host; only the default shard's is backed up.
+    output = _backup_line("db-0", "db-0,db-shard1-0")
+
+    result, _ = _run_backup_host(["--format", "script"], output=output)
+
+    assert not result
+    assert capsys.readouterr().out == "db-0\n"
+
+
+def test_mariadb_backup_host_fails_when_no_backup_would_be_taken(loguru_logs, capsys):
+    result, _ = _run_backup_host([], output=_backup_line("", "db-shard1-0"))
+
+    assert result == 1
+    assert capsys.readouterr().out == ""
+    assert any(
+        r["level"] == "ERROR" and "db-shard1-0" in r["message"] for r in loguru_logs
+    )
+
+
+def test_mariadb_backup_host_fails_without_a_report(loguru_logs):
+    result, _ = _run_backup_host([], output="PLAY RECAP\n")
+
+    assert result == 1
+    assert any("did not report a backup host" in r["message"] for r in loguru_logs)
+
+
+def test_mariadb_backup_host_fails_when_the_play_fails(loguru_logs):
+    from osism.tasks import AnsibleFailure
+
+    result, _ = _run_backup_host(
+        [], side_effect=AnsibleFailure("kolla-ansible play failed with rc 1")
+    )
+
+    assert result == 1
+    assert any("osism apply -e kolla" in r["message"] for r in loguru_logs)
+
+
+def test_mariadb_backup_host_fails_on_timeout(loguru_logs):
+    from celery.exceptions import TimeoutError as CeleryTimeoutError
+
+    result, mock_run = _run_backup_host(
+        ["--timeout", "5"], side_effect=CeleryTimeoutError()
+    )
+
+    assert result == 1
+    assert any("Timeout" in r["message"] for r in loguru_logs)
+    mock_run.delay.return_value.forget.assert_called_once_with()