verdi status: distinguish database schema version incompatible (#4319)

If `verdi status` was called for a profile whose database schema version
is incompatible with the current code, a generic error was thrown that
no connection could be made to PostgreSQL. The connection is often fine,
it is just that AiiDA prohibits it until the database is made
compatible. Often one simply has to migrate the database after
installing a newer version of the code. This case is no caught
separately and the user is pointed to `verdi database migrate`.

aiida/cmdline/commands/cmd_status.py

@@ -8,14 +8,15 @@
 # For further information please visit http://www.aiida.net               #
 ###########################################################################
 """`verdi status` command."""
+import enum
 import sys
 
-import enum
 import click
 
 from aiida.cmdline.commands.cmd_verdi import verdi
 from aiida.cmdline.utils import echo
 from aiida.common.log import override_log_level
+from aiida.common.exceptions import IncompatibleDatabaseSchema
 from ..utils.echo import ExitCode
 
 
@@ -51,7 +52,7 @@ class ServiceStatus(enum.IntEnum):
 @click.option('--no-rmq', is_flag=True, help='Do not check RabbitMQ status')
 def verdi_status(no_rmq):
     """Print status of AiiDA services."""
-    # pylint: disable=broad-except,too-many-statements
+    # pylint: disable=broad-except,too-many-statements,too-many-branches
     from aiida.cmdline.utils.daemon import get_daemon_status, delete_stale_pid_file
     from aiida.common.utils import Capturing
     from aiida.manage.external.rmq import get_rmq_url
@@ -93,8 +94,13 @@ def verdi_status(no_rmq):
         with override_log_level():  # temporarily suppress noisy logging
             backend = manager.get_backend()
             backend.cursor()
-    except Exception:
-        print_status(ServiceStatus.DOWN, 'postgres', 'Unable to connect as {}@{}:{}'.format(*database_data))
+    except IncompatibleDatabaseSchema:
+        message = 'Database schema version is incompatible with the code: run `verdi database migrate`.'
+        print_status(ServiceStatus.DOWN, 'postgres', message)
+        exit_code = ExitCode.CRITICAL
+    except Exception as exc:
+        message = 'Unable to connect as {}@{}:{}'.format(*database_data)
+        print_status(ServiceStatus.DOWN, 'postgres', message, exception=exc)
         exit_code = ExitCode.CRITICAL
     else:
         print_status(ServiceStatus.UP, 'postgres', 'Connected as {}@{}:{}'.format(*database_data))
@@ -123,7 +129,6 @@ def verdi_status(no_rmq):
             print_status(ServiceStatus.UP, 'daemon', daemon_status)
         else:
             print_status(ServiceStatus.WARNING, 'daemon', daemon_status)
-            exit_code = ExitCode.SUCCESS  # A daemon that is not running is not a failure
 
     except Exception as exc:
         print_status(ServiceStatus.ERROR, 'daemon', 'Error getting daemon status', exception=exc)

tests/cmdline/commands/test_status.py

@@ -45,3 +45,18 @@ def test_status_no_rmq(run_cli_command):
 
     for string in ['config', 'profile', 'postgres', 'daemon']:
         assert string in result.output
+
+
+def test_database_incompatible(run_cli_command, monkeypatch):
+    """Test `verdi status` when database schema version is incompatible with that of the code."""
+    from aiida.manage.manager import get_manager
+
+    def get_backend():
+        from aiida.common.exceptions import IncompatibleDatabaseSchema
+        raise IncompatibleDatabaseSchema()
+
+    monkeypatch.setattr(get_manager(), 'get_backend', get_backend)
+
+    result = run_cli_command(cmd_status.verdi_status, raises=True)
+    assert 'Database schema version is incompatible with the code: run `verdi database migrate`.' in result.output
+    assert result.exit_code is ExitCode.CRITICAL