Add daemon PostgreSQL notify action

plugins/postgresql/plugin.py

@@ -380,3 +380,58 @@ def monitor(config, runtime_state):
 
     finally:
         conn.close()
+
+
+NOTIFY_FIELDS = (
+    "type",
+    "operation",
+    "promote_uname",
+    "demote_uname",
+    "promoted_uname",
+    "unpromoted_uname",
+)
+
+
+def _notify_value(parameters, field):
+    value = parameters.get(field, "")
+
+    if not isinstance(value, str):
+        raise ValueError(
+            f"notify field {field} must be a string"
+        )
+
+    if any(char in value for char in ("\n", "\r", "\x00")):
+        raise ValueError(
+            f"notify field {field} contains invalid characters"
+        )
+
+    return value.strip()
+
+
+def notify(config, runtime_state, request_parameters):
+    """
+    Record Pacemaker notification metadata in daemon runtime state.
+
+    The daemon remains the local authority for this resource instance.
+    Node-target interpretation is deliberately deferred until the state
+    persistence and demotion action are migrated together.
+    """
+    if not isinstance(request_parameters, dict):
+        raise ValueError(
+            "notify parameters must be a JSON object"
+        )
+
+    state = {
+        field: _notify_value(request_parameters, field)
+        for field in NOTIFY_FIELDS
+    }
+
+    state["received_at"] = time.time()
+
+    postgresql_state = _postgres_runtime_state(runtime_state)
+    postgresql_state["notification"] = state
+
+    return {
+        "ocf_rc": OCF_SUCCESS,
+        "state": dict(state),
+    }