[DPE-1993] Patroni COS (canonical#261)

* Add Patroni COS integration

* Bump libs

* Unit tests

* Scrape IP instead of localhost

* Fix unit tests

* Increase upgrade timout

* Bump libs

* Revert data_interfaces

lib/charms/data_platform_libs/v0/upgrade.py

@@ -263,7 +263,7 @@ def restart(self, event) -> None:
 import json
 import logging
 from abc import ABC, abstractmethod
-from typing import List, Literal, Optional, Set, Tuple
+from typing import Dict, List, Literal, Optional, Set, Tuple
 
 import poetry.core.constraints.version as poetry_version
 from ops.charm import (
@@ -285,7 +285,7 @@ def restart(self, event) -> None:
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 14
+LIBPATCH = 15
 
 PYDEPS = ["pydantic>=1.10,<2", "poetry-core"]
 
@@ -346,7 +346,7 @@ class KafkaDependenciesModel(BaseModel):
         print(model.dict())  # exporting back validated deps
     """
 
-    dependencies: dict[str, str]
+    dependencies: Dict[str, str]
     name: str
     upgrade_supported: str
     version: str

src/charm.py

@@ -144,12 +144,27 @@ def __init__(self, *args):
         self._observer.start_observer()
         self._grafana_agent = COSAgentProvider(
             self,
-            metrics_endpoints=[
-                {"path": "/metrics", "port": METRICS_PORT},
+            metrics_endpoints=[{"path": "/metrics", "port": METRICS_PORT}],
+            scrape_configs=self.patroni_scrape_config,
+            refresh_events=[
+                self.on[PEER].relation_changed,
+                self.on.secret_changed,
+                self.on.secret_remove,
             ],
             log_slots=[f"{POSTGRESQL_SNAP_NAME}:logs"],
         )
 
+    def patroni_scrape_config(self) -> List[Dict]:
+        """Generates scrape config for the Patroni metrics endpoint."""
+        return [
+            {
+                "metrics_path": "/metrics",
+                "static_configs": [{"targets": [f"{self._unit_ip}:8008"]}],
+                "tls_config": {"insecure_skip_verify": True},
+                "scheme": "https" if self.is_tls_enabled else "http",
+            }
+        ]
+
     @property
     def app_units(self) -> set[Unit]:
         """The peer-related units in the application."""