Merge branch 'main' into juju-reboot-929

.github/workflows/db-charm-tests.yaml

@@ -43,3 +43,8 @@ jobs:
 
       - name: Run the charm's unit tests
         run: tox -vve unit
+        # TODO: remove this once https://github.com/canonical/mysql-k8s-operator/pull/316 is fixed
+        env:
+          # This env var is only to indicate Juju version to "simulate" in the mysqk-k8s-operator
+          # unit tests. No libjuju is being actually used in unit testing.
+          LIBJUJU_VERSION_SPECIFIER: 3.1

ops/charm.py

@@ -52,6 +52,7 @@
         '_RelationMetaDict', {
             'interface': Required[str],
             'limit': int,
+            'optional': bool,
             'scope': _Scopes},
         total=False)
 
@@ -1300,6 +1301,14 @@ class RelationMeta:
     Will be either ``"global"`` or ``"container"``.
     """
 
+    optional: bool
+    """If True, the relation is considered optional.
+
+    This value is informational only and is not used by Juju itself (all
+    relations are optional from Juju's perspective), but it may be set in
+    ``metadata.yaml`` and used by the charm code if appropriate.
+    """
+
     VALID_SCOPES = ['global', 'container']
 
     def __init__(self, role: RelationRole, relation_name: str, raw: '_RelationMetaDict'):
@@ -1319,6 +1328,8 @@ def __init__(self, role: RelationRole, relation_name: str, raw: '_RelationMetaDi
             raise TypeError("scope should be one of {}; not '{}'".format(
                 ', '.join(f"'{s}'" for s in self.VALID_SCOPES), self.scope))
 
+        self.optional = raw.get('optional', False)
+
 
 class StorageMeta:
     """Object containing metadata about a storage definition."""

ops/model.py

@@ -2546,7 +2546,15 @@ def remove_path(self, path: Union[str, PurePath], *, recursive: bool = False):
 
         Args:
             path: Path of the file or directory to delete from the remote system.
-            recursive: If True, recursively delete path and everything under it.
+            recursive: If True, and path is a directory, recursively delete it and
+                       everything under it. If path is a file, delete the file. In
+                       either case, do nothing if the file or directory does not
+                       exist. Behaviourally similar to ``rm -rf <file|dir>``.
+
+        Raises:
+            pebble.PathError: If a relative path is provided, or if `recursive` is False
+                and the file or directory cannot be removed (it does not exist or is not empty).
+
         """
         self._pebble.remove_path(str(path), recursive=recursive)
 

ops/pebble.py

@@ -2164,10 +2164,14 @@ def remove_path(self, path: str, *, recursive: bool = False):
 
         Args:
             path: Path of the file or directory to delete from the remote system.
-            recursive: If True, and path is a directory recursively deletes it and
-                       everything under it. If the path is a file, delete the file and
-                       do nothing if the file is non-existent. Behaviourally similar
-                       to ``rm -rf <file|dir>``.
+            recursive: If True, and path is a directory, recursively delete it and
+                       everything under it. If path is a file, delete the file. In
+                       either case, do nothing if the file or directory does not
+                       exist. Behaviourally similar to ``rm -rf <file|dir>``.
+
+        Raises:
+            pebble.PathError: If a relative path is provided, or if `recursive` is False
+                and the file or directory cannot be removed (it does not exist or is not empty).
 
         """
         info: Dict[str, Any] = {'path': path}

test/test_charm.py

@@ -362,7 +362,6 @@ def on_any_pebble_ready(self, event: ops.PebbleReadyEvent):
         self.assertEqual(charm.count, 2)
 
     def test_relations_meta(self):
-
         # language=YAML
         self.meta = ops.CharmMeta.from_yaml('''
 name: my-charm
@@ -373,15 +372,18 @@ def test_relations_meta(self):
     scope: container
   metrics:
     interface: prometheus-scraping
+    optional: true
 ''')
 
         self.assertEqual(self.meta.requires['database'].interface_name, 'mongodb')
         self.assertEqual(self.meta.requires['database'].limit, 1)
         self.assertEqual(self.meta.requires['database'].scope, 'container')
+        self.assertFalse(self.meta.requires['database'].optional)
 
         self.assertEqual(self.meta.requires['metrics'].interface_name, 'prometheus-scraping')
         self.assertIsNone(self.meta.requires['metrics'].limit)
         self.assertEqual(self.meta.requires['metrics'].scope, 'global')  # Default value
+        self.assertTrue(self.meta.requires['metrics'].optional)
 
     def test_relations_meta_limit_type_validation(self):
         with self.assertRaisesRegex(TypeError, "limit should be an int, not <class 'str'>"):