[DPE-5965] - Set private key with juju secrets

.gitignore

@@ -7,3 +7,8 @@ __pycache__/
 *.py[cod]
 .idea
 .vscode/
+etcd-v3.4.35-linux-amd64*
+last_written_value
+client.pem
+client.key
+client_ca.pem

config.yaml

@@ -8,4 +8,14 @@ options:
       Configure the internal system user and it's password. The password will
       be auto-generated if this option is not set. It is for internal use only
       and SHOULD NOT be used by applications. This needs to be a Juju Secret URI pointing
-      to a secret that contains the following content: `root: <password>`.
+      to a secret that contains the following content: `root: <password>`.
+
+  tls-peer-private-key:
+    type: secret
+    description: |
+      A Juju secret URI of a secret containing the private key for peer-to-peer TLS certificates.
+
+  tls-client-private-key:
+    type: secret
+    description: |
+      A Juju secret URI of a secret containing the private key for server-to-client TLS certificates.

lib/charms/data_platform_libs/v0/data_interfaces.py

@@ -331,7 +331,7 @@ def _on_topic_requested(self, event: TopicRequestedEvent):
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 40
+LIBPATCH = 41
 
 PYDEPS = ["ops>=2.0.0"]
 
@@ -609,7 +609,7 @@ def get_group(self, group: str) -> Optional[SecretGroup]:
 class CachedSecret:
     """Locally cache a secret.
 
-    The data structure is precisely re-using/simulating as in the actual Secret Storage
+    The data structure is precisely reusing/simulating as in the actual Secret Storage
     """
 
     KNOWN_MODEL_ERRORS = [MODEL_ERRORS["no_label_and_uri"], MODEL_ERRORS["owner_no_refresh"]]
@@ -2363,7 +2363,6 @@ def _update_relation_data(self, relation: Relation, data: Dict[str, str]) -> Non
     def _delete_relation_data(self, relation: Relation, fields: List[str]) -> None:
         """Delete data available (directily or indirectly -- i.e. secrets) from the relation for owner/this_app."""
         if self.secret_fields and self.deleted_label:
-
             _, normal_fields = self._process_secret_fields(
                 relation,
                 self.secret_fields,