Use relation_created instead of relation_joined

The handler is supposed to run when the relation is created, not when a unit joins the relation

See canonical/mysql-router-k8s-operator#101

lib/charms/opensearch/v0/opensearch_tls.py

@@ -31,7 +31,7 @@
     generate_csr,
     generate_private_key,
 )
-from ops.charm import ActionEvent, RelationBrokenEvent, RelationJoinedEvent
+from ops.charm import ActionEvent, RelationBrokenEvent, RelationCreatedEvent
 from ops.framework import Object
 
 # The unique Charmhub library identifier, never change it
@@ -62,7 +62,7 @@ def __init__(self, charm, peer_relation: str):
         )
 
         self.framework.observe(
-            self.charm.on[TLS_RELATION].relation_joined, self._on_tls_relation_joined
+            self.charm.on[TLS_RELATION].relation_created, self._on_tls_relation_created
         )
         self.framework.observe(
             self.charm.on[TLS_RELATION].relation_broken, self._on_tls_relation_broken
@@ -108,12 +108,11 @@ def request_new_unit_certificates(self) -> None:
             secrets = self.charm.secrets.get_object(Scope.UNIT, cert_type.val)
             self._request_certificate_renewal(Scope.UNIT, cert_type, secrets)
 
-    def _on_tls_relation_joined(self, event: RelationJoinedEvent) -> None:
-        """Request certificate when TLS relation joined."""
+    def _on_tls_relation_created(self, event: RelationCreatedEvent) -> None:
+        """Request certificate when TLS relation created."""
         if not (deployment_desc := self.charm.opensearch_peer_cm.deployment_desc()):
             event.defer()
             return
-
         admin_cert = self.charm.secrets.get_object(Scope.APP, CertType.APP_ADMIN.val)
         if (
             self.charm.unit.is_leader()

tests/unit/lib/test_opensearch_tls.py

@@ -102,10 +102,10 @@ def test_find_secret(self):
     @patch("charms.opensearch.v0.opensearch_tls.OpenSearchTLS._request_certificate")
     @patch("charm.OpenSearchOperatorCharm._put_admin_user")
     @patch("charm.OpenSearchOperatorCharm._purge_users")
-    def test_on_relation_joined_admin(
+    def test_on_relation_created_admin(
         self, _, _put_admin_user, _request_certificate, deployment_desc
     ):
-        """Test on certificate relation joined event."""
+        """Test on certificate relation created event."""
         deployment_desc.return_value = DeploymentDescription(
             config=PeerClusterConfig(cluster_name="", init_hold=False, roles=[]),
             start=StartMode.WITH_GENERATED_ROLES,
@@ -114,11 +114,10 @@ def test_on_relation_joined_admin(
             app=self.charm.app.name,
             state=DeploymentState(value=State.ACTIVE),
         )
-
         event_mock = MagicMock()
 
         self.harness.set_leader(is_leader=True)
-        self.charm.tls._on_tls_relation_joined(event_mock)
+        self.charm.tls._on_tls_relation_created(event_mock)
         self.assertEqual(
             _request_certificate.mock_calls,
             [
@@ -134,10 +133,10 @@ def test_on_relation_joined_admin(
     @patch("charms.opensearch.v0.opensearch_tls.OpenSearchTLS._request_certificate")
     @patch("charm.OpenSearchOperatorCharm._put_admin_user")
     @patch("charm.OpenSearchOperatorCharm._purge_users")
-    def test_on_relation_joined_non_admin(
+    def test_on_relation_created_non_admin(
         self, _, _put_admin_user, _request_certificate, deployment_desc
     ):
-        """Test on certificate relation joined event."""
+        """Test on certificate relation created event."""
         deployment_desc.return_value = DeploymentDescription(
             config=PeerClusterConfig(cluster_name="", init_hold=False, roles=[]),
             start=StartMode.WITH_GENERATED_ROLES,
@@ -146,11 +145,10 @@ def test_on_relation_joined_non_admin(
             app=self.charm.app.name,
             state=DeploymentState(value=State.ACTIVE),
         )
-
         event_mock = MagicMock()
 
         self.harness.set_leader(is_leader=False)
-        self.charm.tls._on_tls_relation_joined(event_mock)
+        self.charm.tls._on_tls_relation_created(event_mock)
         self.assertEqual(
             _request_certificate.mock_calls,
             [