[DPE-5237] implement revision check for sharding components (#331)

* update deps for revision checker

* copy over infra from vm

* adding infra for local charm revision

* update set status lib

* add integration tests

* fmt + lint

* update unit tests

* remove unused bits

* Apply suggestions from code review

Co-authored-by: Mehdi Bendriss <bendrissmehdi@gmail.com>

---------

Co-authored-by: Mehdi Bendriss <bendrissmehdi@gmail.com>

Author: MiaAltieri

.gitignore

@@ -17,3 +17,4 @@ share/
 
 /requirements.txt
 /requirements-last-build.txt
+/charm_internal_version

charmcraft.yaml

@@ -20,6 +20,11 @@ parts:
     override-build: |
       rustup default stable
       craftctl default
+  files:
+    plugin: dump
+    source: .
+    prime:
+      - charm_internal_version
 bases:
   - build-on:
       - name: "ubuntu"

lib/charms/mongodb/v0/set_status.py

@@ -7,6 +7,7 @@
 from typing import Optional, Tuple
 
 from charms.mongodb.v1.mongodb import MongoConfiguration, MongoDBConnection
+from data_platform_helpers.version_check import NoVersionError, get_charm_revision
 from ops.charm import CharmBase
 from ops.framework import Object
 from ops.model import ActiveStatus, BlockedStatus, StatusBase, WaitingStatus
@@ -22,7 +23,7 @@
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 3
+LIBPATCH = 4
 
 AUTH_FAILED_CODE = 18
 UNAUTHORISED_CODE = 13
@@ -88,7 +89,7 @@ def is_status_related_to_mismatched_revision(self, status_type: str) -> bool:
         "goal state" which processes data differently and the other via the ".status" property.
         Hence we have to be flexible to handle each.
         """
-        if not self.charm.get_cluster_mismatched_revision_status():
+        if not self.get_cluster_mismatched_revision_status():
             return False
 
         if "waiting" in status_type and self.charm.is_role(Config.Role.CONFIG_SERVER):
@@ -153,7 +154,7 @@ def is_unit_status_ready_for_upgrade(self) -> bool:
         if isinstance(current_status, ActiveStatus):
             return True
 
-        if not isinstance(current_status, WaitingStatus):
+        if not isinstance(current_status, BlockedStatus):
             return False
 
         if status_message and "is not up-to date with config-server" in status_message:
@@ -235,7 +236,49 @@ def get_invalid_integration_status(self) -> Optional[StatusBase]:
                 "Relation to s3-integrator is not supported, config role must be config-server"
             )
 
-        return self.charm.get_cluster_mismatched_revision_status()
+        return self.get_cluster_mismatched_revision_status()
+
+    def get_cluster_mismatched_revision_status(self) -> Optional[StatusBase]:
+        """Returns a Status if the cluster has mismatched revisions."""
+        # check for invalid versions in sharding integrations, i.e. a shard running on
+        # revision  88 and a config-server running on revision 110
+        current_charms_version = get_charm_revision(
+            self.charm.unit, local_version=self.charm.get_charm_internal_revision
+        )
+        local_identifier = (
+            "-locally built"
+            if self.charm.version_checker.is_local_charm(self.charm.app.name)
+            else ""
+        )
+        try:
+            if self.charm.version_checker.are_related_apps_valid():
+                return
+        except NoVersionError as e:
+            # relations to shards/config-server are expected to provide a version number. If they
+            # do not, it is because they are from an earlier charm revision, i.e. pre-revison X.
+            logger.debug(e)
+            if self.charm.is_role(Config.Role.SHARD):
+                return BlockedStatus(
+                    f"Charm revision ({current_charms_version}{local_identifier}) is not up-to date with config-server."
+                )
+
+        if self.charm.is_role(Config.Role.SHARD):
+            config_server_revision = self.charm.version_checker.get_version_of_related_app(
+                self.get_config_server_name()
+            )
+            remote_local_identifier = (
+                "-locally built"
+                if self.charm.version_checker.is_local_charm(self.get_config_server_name())
+                else ""
+            )
+            return BlockedStatus(
+                f"Charm revision ({current_charms_version}{local_identifier}) is not up-to date with config-server ({config_server_revision}{remote_local_identifier})."
+            )
+
+        if self.charm.is_role(Config.Role.CONFIG_SERVER):
+            return WaitingStatus(
+                f"Waiting for shards to upgrade/downgrade to revision {current_charms_version}{local_identifier}."
+            )
 
 
 def build_unit_status(mongodb_config: MongoConfiguration, unit_host: str) -> StatusBase:

poetry.lock

@@ -21,7 +21,7 @@ tenacity = "^8.2.3"
 pyyaml = "^6.0.1"
 jinja2 = "^3.1.3"
 poetry-core = "^1.9.0"
-data-platform-helpers = "^0.1.2"
+data-platform-helpers = "^0.1.3"
 pyOpenSSL = "^24.2.1"
 setuptools = "^72.0.0"
 
@@ -72,7 +72,7 @@ juju = "^3.5.0"
 pytest = "^8.1.1"
 pytest-asyncio = "^0.21.1"
 pytest-mock = "^3.14.0"
-pytest-operator = "^0.34.0"
+pytest-operator = "^0.36.0"
 pytest-operator-cache = {git = "https://github.com/canonical/data-platform-workflows", tag = "v21.0.0", subdirectory = "python/pytest_plugins/pytest_operator_cache"}
 pytest-operator-groups = {git = "https://github.com/canonical/data-platform-workflows", tag = "v21.0.0", subdirectory = "python/pytest_plugins/pytest_operator_groups"}
 pytest-github-secrets = {git = "https://github.com/canonical/data-platform-workflows", tag = "v21.0.0", subdirectory = "python/pytest_plugins/github_secrets"}

pyproject.toml

@@ -38,6 +38,10 @@
     OperatorUser,
 )
 from charms.prometheus_k8s.v0.prometheus_scrape import MetricsEndpointProvider
+from data_platform_helpers.version_check import (
+    CrossAppVersionChecker,
+    get_charm_revision,
+)
 from ops.charm import (
     ActionEvent,
     CharmBase,
@@ -56,7 +60,6 @@
     ModelError,
     Relation,
     RelationDataContent,
-    StatusBase,
     Unit,
     WaitingStatus,
 )
@@ -140,6 +143,15 @@ def __init__(self, *args):
         self.config_server = ShardingProvider(self)
         self.cluster = ClusterProvider(self)
 
+        self.version_checker = CrossAppVersionChecker(
+            self,
+            version=get_charm_revision(self.unit, local_version=self.get_charm_internal_revision),
+            relations_to_check=[
+                Config.Relations.SHARDING_RELATIONS_NAME,
+                Config.Relations.CONFIG_SERVER_RELATIONS_NAME,
+            ],
+        )
+
     # BEGIN: properties
 
     @property
@@ -470,16 +482,15 @@ def primary(self) -> str | None:
 
         return None
 
+    @property
+    def get_charm_internal_revision(self) -> str:
+        """Returns the contents of the get_charm_internal_revision file."""
+        with open(Config.CHARM_INTERNAL_VERSION_FILE, "r") as f:
+            return f.read().strip()
+
     # END: properties
 
     # BEGIN: generic helper methods
-    def get_cluster_mismatched_revision_status(self) -> Optional[StatusBase]:
-        """Returns a Status if the cluster has mismatched revisions.
-
-        TODO implement this method as a part of sharding upgrades.
-        """
-        return None
-
     def remote_mongos_config(self, hosts) -> MongoConfiguration:
         """Generates a MongoConfiguration object for mongos in the deployment of MongoDB."""
         # mongos that are part of the cluster have the same username and password, but different
@@ -1568,7 +1579,7 @@ def is_relation_feasible(self, rel_interface: str) -> bool:
             )
             return False
 
-        if revision_mismatch_status := self.get_cluster_mismatched_revision_status():
+        if revision_mismatch_status := self.status.get_cluster_mismatched_revision_status():
             self.status.set_and_share_status(revision_mismatch_status)
             return False
 

src/charm.py

@@ -22,6 +22,7 @@ class Config:
     MONGOD_CONF_DIR = "/etc/mongod"
     MONGODB_LOG_FILENAME = "mongodb.log"
 
+    CHARM_INTERNAL_VERSION_FILE = "charm_internal_version"
     LICENSE_PATH = "/licenses/LICENSE"
     CONTAINER_NAME = "mongod"
     SERVICE_NAME = "mongod"

src/config.py

@@ -7,40 +7,26 @@
 class MongoError(Exception):
     """Common parent for Mongo errors, allowing to catch them all at once."""
 
-    pass
-
 
 class AdminUserCreationError(MongoError):
     """Raised when a commands to create an admin user on MongoDB fail."""
 
-    pass
-
 
 class ApplicationHostNotFoundError(MongoError):
     """Raised when a queried host is not in the application peers or the current host."""
 
-    pass
-
 
 class MongoSecretError(MongoError):
     """Common parent for all Mongo Secret Exceptions."""
 
-    pass
-
 
 class SecretNotAddedError(MongoSecretError):
     """Raised when a Juju 3 secret couldn't be set or re-set."""
 
-    pass
-
 
 class MissingSecretError(MongoSecretError):
     """Could be raised when a Juju 3 mandatory secret couldn't be found."""
 
-    pass
-
 
 class SecretAlreadyExistsError(MongoSecretError):
     """A secret that we want to create already exists."""
-
-    pass

src/exceptions.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python3
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+import pytest
+from pytest_operator.plugin import OpsTest
+
+from ..helpers import METADATA, wait_for_mongodb_units_blocked
+
+MONGODB_K8S_CHARM = "mongodb-k8s"
+SHARD_REL_NAME = "sharding"
+CONFIG_SERVER_REL_NAME = "config-server"
+
+LOCAL_SHARD_APP_NAME = "local-shard"
+REMOTE_SHARD_APP_NAME = "remote-shard"
+LOCAL_CONFIG_SERVER_APP_NAME = "local-config-server"
+REMOTE_CONFIG_SERVER_APP_NAME = "remote-config-server"
+
+CLUSTER_COMPONENTS = [
+    LOCAL_SHARD_APP_NAME,
+    REMOTE_SHARD_APP_NAME,
+    LOCAL_CONFIG_SERVER_APP_NAME,
+    REMOTE_CONFIG_SERVER_APP_NAME,
+]
+
+
+@pytest.mark.group(1)
+@pytest.mark.abort_on_fail
+async def test_build_and_deploy(ops_test: OpsTest) -> None:
+    my_charm = await ops_test.build_charm(".")
+    resources = {"mongodb-image": METADATA["resources"]["mongodb-image"]["upstream-source"]}
+
+    await ops_test.model.deploy(
+        MONGODB_K8S_CHARM,
+        application_name=REMOTE_SHARD_APP_NAME,
+        config={"role": "shard"},
+        channel="edge",
+    )
+
+    await ops_test.model.deploy(
+        MONGODB_K8S_CHARM,
+        application_name=REMOTE_CONFIG_SERVER_APP_NAME,
+        config={"role": "config-server"},
+        channel="edge",
+    )
+    await ops_test.model.deploy(
+        my_charm,
+        resources=resources,
+        config={"role": "config-server"},
+        application_name=LOCAL_CONFIG_SERVER_APP_NAME,
+    )
+    await ops_test.model.deploy(
+        my_charm,
+        resources=resources,
+        config={"role": "shard"},
+        application_name=LOCAL_SHARD_APP_NAME,
+    )
+
+    await ops_test.model.wait_for_idle(apps=CLUSTER_COMPONENTS, idle_period=20)
+
+
+@pytest.mark.group(1)
+@pytest.mark.abort_on_fail
+async def test_local_config_server_reports_remote_shard(ops_test: OpsTest) -> None:
+    """Tests that the local config server reports remote shard."""
+    await ops_test.model.integrate(
+        f"{REMOTE_SHARD_APP_NAME}:{SHARD_REL_NAME}",
+        f"{LOCAL_CONFIG_SERVER_APP_NAME}:{CONFIG_SERVER_REL_NAME}",
+    )
+
+    await ops_test.model.wait_for_idle(
+        apps=[LOCAL_CONFIG_SERVER_APP_NAME],
+        status="waiting",
+        raise_on_blocked=False,
+        idle_period=20,
+    )
+
+    config_server_unit = ops_test.model.applications[LOCAL_CONFIG_SERVER_APP_NAME].units[0]
+
+    assert (
+        "Waiting for shards to upgrade/downgrade to revision"
+        in config_server_unit.workload_status_message
+    ), "Config server does not correctly report mismatch in revision"
+
+
+@pytest.mark.group(1)
+@pytest.mark.abort_on_fail
+async def test_local_shard_reports_remote_config_server(ops_test: OpsTest) -> None:
+    """Tests that the local shard reports remote config-server."""
+    await ops_test.model.integrate(
+        f"{LOCAL_SHARD_APP_NAME}:{SHARD_REL_NAME}",
+        f"{REMOTE_CONFIG_SERVER_APP_NAME}:{CONFIG_SERVER_REL_NAME}",
+    )
+
+    await wait_for_mongodb_units_blocked(
+        ops_test,
+        LOCAL_SHARD_APP_NAME,
+        timeout=300,
+    )
+
+    shard_unit = ops_test.model.applications[LOCAL_SHARD_APP_NAME].units[0]
+    assert (
+        "is not up-to date with config-server." in shard_unit.workload_status_message
+    ), "Shard does not correctly report mismatch in revision"

tests/integration/upgrades/test_revision_check.py

@@ -36,8 +36,9 @@
 
 
 class TestCharm(unittest.TestCase):
+    @patch("charm.get_charm_revision")
     @patch_network_get(private_address="1.1.1.1")
-    def setUp(self):
+    def setUp(self, *unused):
         self.maxDiff = None
         self.harness = Harness(MongoDBCharm)
         mongo_resource = {
@@ -583,9 +584,11 @@ def test_reconfigure_remove_member_failure(self, connection, defer):
             connection.return_value.__enter__.return_value.remove_replset_member.assert_called()
             defer.assert_called()
 
+    @patch("charms.mongodb.v0.set_status.get_charm_revision")
+    @patch("charm.CrossAppVersionChecker.is_local_charm")
     @patch("ops.framework.EventBase.defer")
     @patch("charm.MongoDBConnection")
-    def test_reconfigure_peer_not_ready(self, connection, defer):
+    def test_reconfigure_peer_not_ready(self, connection, defer, *unused):
         """Tests reconfigure does not proceed when the adding member is not ready.
 
         Verifies in relation joined events, that when the adding member is not ready that the event