[DPE-2731] Secret labels (6/edge) (#270)

.github/workflows/ci.yaml

@@ -106,6 +106,13 @@ jobs:
         uses: actions/download-artifact@v3
         with:
           name: ${{ needs.build.outputs.artifact-name }}
+      - name: Free up disk space
+        run: |
+          # From https://github.com/actions/runner-images/issues/2840#issuecomment-790492173                                                                                                                    
+          sudo rm -rf /usr/share/dotnet
+          sudo rm -rf /opt/ghc
+          sudo rm -rf /usr/local/share/boost
+          sudo rm -rf "$AGENT_TOOLSDIRECTORY"
       - name: Select tests
         id: select-tests
         run: |

lib/charms/mongodb/v0/mongodb_secrets.py

@@ -0,0 +1,137 @@
+"""Secrets related helper classes/functions."""
+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+from typing import Dict, Optional
+
+from ops import Secret, SecretInfo
+from ops.charm import CharmBase
+from ops.model import SecretNotFoundError
+
+from config import Config
+from exceptions import SecretAlreadyExistsError
+
+# The unique Charmhub library identifier, never change it
+
+# The unique Charmhub library identifier, never change it
+LIBID = "87456e41c7594240b92b783a648592b5"
+
+# Increment this major API version when introducing breaking changes
+LIBAPI = 0
+
+# Increment this PATCH version before using `charmcraft publish-lib` or reset
+# to 0 if you are raising the major API version
+LIBPATCH = 1
+
+APP_SCOPE = Config.Relations.APP_SCOPE
+UNIT_SCOPE = Config.Relations.UNIT_SCOPE
+Scopes = Config.Relations.Scopes
+
+
+def generate_secret_label(charm: CharmBase, scope: Scopes) -> str:
+    """Generate unique group_mappings for secrets within a relation context.
+
+    Defined as a standalone function, as the choice on secret labels definition belongs to the
+    Application Logic. To be kept separate from classes below, which are simply to provide a
+    (smart) abstraction layer above Juju Secrets.
+    """
+    members = [charm.app.name, scope]
+    return f"{'.'.join(members)}"
+
+
+# Secret cache
+
+
+class CachedSecret:
+    """Abstraction layer above direct Juju access with caching.
+
+    The data structure is precisely re-using/simulating Juju Secrets behavior, while
+    also making sure not to fetch a secret multiple times within the same event scope.
+    """
+
+    def __init__(self, charm: CharmBase, label: str, secret_uri: Optional[str] = None):
+        self._secret_meta = None
+        self._secret_content = {}
+        self._secret_uri = secret_uri
+        self.label = label
+        self.charm = charm
+
+    def add_secret(self, content: Dict[str, str], scope: Scopes) -> Secret:
+        """Create a new secret."""
+        if self._secret_uri:
+            raise SecretAlreadyExistsError(
+                "Secret is already defined with uri %s", self._secret_uri
+            )
+
+        if scope == Config.Relations.APP_SCOPE:
+            secret = self.charm.app.add_secret(content, label=self.label)
+        else:
+            secret = self.charm.unit.add_secret(content, label=self.label)
+        self._secret_uri = secret.id
+        self._secret_meta = secret
+        return self._secret_meta
+
+    @property
+    def meta(self) -> Optional[Secret]:
+        """Getting cached secret meta-information."""
+        if self._secret_meta:
+            return self._secret_meta
+
+        if not (self._secret_uri or self.label):
+            return
+
+        try:
+            self._secret_meta = self.charm.model.get_secret(label=self.label)
+        except SecretNotFoundError:
+            if self._secret_uri:
+                self._secret_meta = self.charm.model.get_secret(
+                    id=self._secret_uri, label=self.label
+                )
+        return self._secret_meta
+
+    def get_content(self) -> Dict[str, str]:
+        """Getting cached secret content."""
+        if not self._secret_content:
+            if self.meta:
+                self._secret_content = self.meta.get_content()
+        return self._secret_content
+
+    def set_content(self, content: Dict[str, str]) -> None:
+        """Setting cached secret content."""
+        if self.meta:
+            self.meta.set_content(content)
+            self._secret_content = content
+
+    def get_info(self) -> Optional[SecretInfo]:
+        """Wrapper function for get the corresponding call on the Secret object if any."""
+        if self.meta:
+            return self.meta.get_info()
+
+
+class SecretCache:
+    """A data structure storing CachedSecret objects."""
+
+    def __init__(self, charm):
+        self.charm = charm
+        self._secrets: Dict[str, CachedSecret] = {}
+
+    def get(self, label: str, uri: Optional[str] = None) -> Optional[CachedSecret]:
+        """Getting a secret from Juju Secret store or cache."""
+        if not self._secrets.get(label):
+            secret = CachedSecret(self.charm, label, uri)
+            if secret.meta:
+                self._secrets[label] = secret
+        return self._secrets.get(label)
+
+    def add(self, label: str, content: Dict[str, str], scope: Scopes) -> CachedSecret:
+        """Adding a secret to Juju Secret."""
+        if self._secrets.get(label):
+            raise SecretAlreadyExistsError(f"Secret {label} already exists")
+
+        secret = CachedSecret(self.charm, label)
+        secret.add_secret(content, scope)
+        self._secrets[label] = secret
+        return self._secrets[label]
+
+
+# END: Secret cache

lib/charms/mongodb/v1/mongodb_backups.py

@@ -523,7 +523,7 @@ def _try_to_restore(self, backup_id: str) -> None:
                         restore_cmd = restore_cmd + remapping_args.split(" ")
                     self.charm.run_pbm_command(restore_cmd)
                 except (subprocess.CalledProcessError, ExecError) as e:
-                    if type(e) is subprocess.CalledProcessError:
+                    if isinstance(e, subprocess.CalledProcessError):
                         error_message = e.output.decode("utf-8")
                     else:
                         error_message = str(e.stderr)
@@ -560,7 +560,7 @@ def _try_to_backup(self):
                     )
                     return backup_id_match.group("backup_id") if backup_id_match else "N/A"
                 except (subprocess.CalledProcessError, ExecError) as e:
-                    if type(e) is subprocess.CalledProcessError:
+                    if isinstance(e, subprocess.CalledProcessError):
                         error_message = e.output.decode("utf-8")
                     else:
                         error_message = str(e.stderr)
@@ -642,7 +642,7 @@ def _get_backup_restore_operation_result(self, current_pbm_status, previous_pbm_
             return f"Operation is still in progress: '{current_pbm_status.message}'"
 
         if (
-            type(previous_pbm_status) is MaintenanceStatus
+            isinstance(previous_pbm_status, MaintenanceStatus)
             and "backup id:" in previous_pbm_status.message
         ):
             backup_id = previous_pbm_status.message.split("backup id:")[-1].strip()

requirements.txt

@@ -15,4 +15,5 @@ pyrsistent==0.19.3
 pyyaml==6.0.1
 zipp==3.11.0
 pyOpenSSL==22.1.0
-typing-extensions==4.5.0 
+typing-extensions==4.5.0 
+parameterized==0.9.0