fix: set telemetry config value, patch service, update tests (#185)

lib/charms/observability_libs/v0/kubernetes_service_patch.py → lib/charms/observability_libs/v1/kubernetes_service_patch.py

@@ -9,21 +9,20 @@
 default contains a "placeholder" port, which is 65536/TCP.
 
 When modifying the default set of resources managed by Juju, one must consider the lifecycle of the
-charm. In this case, any modifications to the default service (created during deployment), will
-be overwritten during a charm upgrade.
+charm. In this case, any modifications to the default service (created during deployment), will be
+overwritten during a charm upgrade.
 
 When initialised, this library binds a handler to the parent charm's `install` and `upgrade_charm`
 events which applies the patch to the cluster. This should ensure that the service ports are
 correct throughout the charm's life.
 
-The constructor simply takes a reference to the parent charm, and a list of tuples that each define
-a port for the service, where each tuple contains:
+The constructor simply takes a reference to the parent charm, and a list of
+[`lightkube`](https://github.com/gtsystem/lightkube) ServicePorts that each define a port for the
+service. For information regarding the `lightkube` `ServicePort` model, please visit the
+`lightkube` [docs](https://gtsystem.github.io/lightkube-models/1.23/models/core_v1/#serviceport).
 
-- a name for the port
-- port for the service to listen on
-- optionally: a targetPort for the service (the port in the container!)
-- optionally: a nodePort for the service (for NodePort or LoadBalancer services only!)
-- optionally: a name of the service (in case service name needs to be patched as well)
+Optionally, a name of the service (in case service name needs to be patched as well), labels,
+selectors, and annotations can be provided as keyword arguments.
 
 ## Getting Started
 
@@ -32,37 +31,80 @@
 
 ```shell
 cd some-charm
-charmcraft fetch-lib charms.observability_libs.v0.kubernetes_service_patch
-echo <<-EOF >> requirements.txt
+charmcraft fetch-lib charms.observability_libs.v1.kubernetes_service_patch
+cat << EOF >> requirements.txt
 lightkube
 lightkube-models
 EOF
 ```
 
 Then, to initialise the library:
 
-For ClusterIP services:
+For `ClusterIP` services:
+
 ```python
 # ...
-from charms.observability_libs.v0.kubernetes_service_patch import KubernetesServicePatch
+from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
+from lightkube.models.core_v1 import ServicePort
 
 class SomeCharm(CharmBase):
   def __init__(self, *args):
     # ...
-    self.service_patcher = KubernetesServicePatch(self, [(f"{self.app.name}", 8080)])
+    port = ServicePort(443, name=f"{self.app.name}")
+    self.service_patcher = KubernetesServicePatch(self, [port])
     # ...
 ```
 
-For LoadBalancer/NodePort services:
+For `LoadBalancer`/`NodePort` services:
+
 ```python
 # ...
-from charms.observability_libs.v0.kubernetes_service_patch import KubernetesServicePatch
+from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
+from lightkube.models.core_v1 import ServicePort
 
 class SomeCharm(CharmBase):
   def __init__(self, *args):
     # ...
+    port = ServicePort(443, name=f"{self.app.name}", targetPort=443, nodePort=30666)
     self.service_patcher = KubernetesServicePatch(
-        self, [(f"{self.app.name}", 443, 443, 30666)], "LoadBalancer"
+        self, [port], "LoadBalancer"
+    )
+    # ...
+```
+
+Port protocols can also be specified. Valid protocols are `"TCP"`, `"UDP"`, and `"SCTP"`
+
+```python
+# ...
+from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
+from lightkube.models.core_v1 import ServicePort
+
+class SomeCharm(CharmBase):
+  def __init__(self, *args):
+    # ...
+    tcp = ServicePort(443, name=f"{self.app.name}-tcp", protocol="TCP")
+    udp = ServicePort(443, name=f"{self.app.name}-udp", protocol="UDP")
+    sctp = ServicePort(443, name=f"{self.app.name}-sctp", protocol="SCTP")
+    self.service_patcher = KubernetesServicePatch(self, [tcp, udp, sctp])
+    # ...
+```
+
+Bound with custom events by providing `refresh_event` argument:
+For example, you would like to have a configurable port in your charm and want to apply
+service patch every time charm config is changed.
+
+```python
+from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
+from lightkube.models.core_v1 import ServicePort
+
+class SomeCharm(CharmBase):
+  def __init__(self, *args):
+    # ...
+    port = ServicePort(int(self.config["charm-config-port"]), name=f"{self.app.name}")
+    self.service_patcher = KubernetesServicePatch(
+        self,
+        [port],
+        refresh_event=self.on.config_changed
     )
     # ...
 ```
@@ -83,29 +125,29 @@ def setUp(self, *unused):
 
 import logging
 from types import MethodType
-from typing import Literal, Sequence, Tuple, Union
+from typing import List, Literal, Optional, Union
 
-from lightkube import ApiError, Client
+from lightkube import ApiError, Client  # pyright: ignore
+from lightkube.core import exceptions
 from lightkube.models.core_v1 import ServicePort, ServiceSpec
 from lightkube.models.meta_v1 import ObjectMeta
 from lightkube.resources.core_v1 import Service
 from lightkube.types import PatchType
 from ops.charm import CharmBase
-from ops.framework import Object
+from ops.framework import BoundEvent, Object
 
 logger = logging.getLogger(__name__)
 
 # The unique Charmhub library identifier, never change it
 LIBID = "0042f86d0a874435adef581806cddbbb"
 
 # Increment this major API version when introducing breaking changes
-LIBAPI = 0
+LIBAPI = 1
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 6
+LIBPATCH = 9
 
-PortDefinition = Union[Tuple[str, int], Tuple[str, int, int], Tuple[str, int, int, int]]
 ServiceType = Literal["ClusterIP", "LoadBalancer"]
 
 
@@ -115,18 +157,20 @@ class KubernetesServicePatch(Object):
     def __init__(
         self,
         charm: CharmBase,
-        ports: Sequence[PortDefinition],
-        service_name: str = None,
+        ports: List[ServicePort],
+        service_name: Optional[str] = None,
         service_type: ServiceType = "ClusterIP",
-        additional_labels: dict = None,
-        additional_selectors: dict = None,
-        additional_annotations: dict = None,
+        additional_labels: Optional[dict] = None,
+        additional_selectors: Optional[dict] = None,
+        additional_annotations: Optional[dict] = None,
+        *,
+        refresh_event: Optional[Union[BoundEvent, List[BoundEvent]]] = None,
     ):
         """Constructor for KubernetesServicePatch.
 
         Args:
             charm: the charm that is instantiating the library.
-            ports: a list of tuples (name, port, targetPort, nodePort) for every service port.
+            ports: a list of ServicePorts
             service_name: allows setting custom name to the patched service. If none given,
                 application name will be used.
             service_type: desired type of K8s service. Default value is in line with ServiceSpec's
@@ -136,6 +180,9 @@ def __init__(
             additional_selectors: Selectors to be added to the kubernetes service (by default only
                 "app.kubernetes.io/name" is set to the service name)
             additional_annotations: Annotations to be added to the kubernetes service.
+            refresh_event: an optional bound event or list of bound events which
+                will be observed to re-apply the patch (e.g. on port change).
+                The `install` and `upgrade-charm` events would be observed regardless.
         """
         super().__init__(charm, "kubernetes-service-patch")
         self.charm = charm
@@ -154,23 +201,29 @@ def __init__(
         # Ensure this patch is applied during the 'install' and 'upgrade-charm' events
         self.framework.observe(charm.on.install, self._patch)
         self.framework.observe(charm.on.upgrade_charm, self._patch)
+        self.framework.observe(charm.on.update_status, self._patch)
+
+        # apply user defined events
+        if refresh_event:
+            if not isinstance(refresh_event, list):
+                refresh_event = [refresh_event]
+
+            for evt in refresh_event:
+                self.framework.observe(evt, self._patch)
 
     def _service_object(
         self,
-        ports: Sequence[PortDefinition],
-        service_name: str = None,
+        ports: List[ServicePort],
+        service_name: Optional[str] = None,
         service_type: ServiceType = "ClusterIP",
-        additional_labels: dict = None,
-        additional_selectors: dict = None,
-        additional_annotations: dict = None,
+        additional_labels: Optional[dict] = None,
+        additional_selectors: Optional[dict] = None,
+        additional_annotations: Optional[dict] = None,
     ) -> Service:
         """Creates a valid Service representation.
 
         Args:
-            ports: a list of tuples of the form (name, port) or (name, port, targetPort)
-                or (name, port, targetPort, nodePort) for every service port. If the 'targetPort'
-                is omitted, it is assumed to be equal to 'port', with the exception of NodePort
-                and LoadBalancer services, where all port numbers have to be specified.
+            ports: a list of ServicePorts
             service_name: allows setting custom name to the patched service. If none given,
                 application name will be used.
             service_type: desired type of K8s service. Default value is in line with ServiceSpec's
@@ -203,15 +256,7 @@ def _service_object(
             ),
             spec=ServiceSpec(
                 selector=selector,
-                ports=[
-                    ServicePort(
-                        name=p[0],
-                        port=p[1],
-                        targetPort=p[2] if len(p) > 2 else p[1],  # type: ignore[misc]
-                        nodePort=p[3] if len(p) > 3 else None,  # type: ignore[arg-type, misc]
-                    )
-                    for p in ports
-                ],
+                ports=ports,
                 type=service_type,
             ),
         )
@@ -222,11 +267,15 @@ def _patch(self, _) -> None:
         Raises:
             PatchFailed: if patching fails due to lack of permissions, or otherwise.
         """
-        if not self.charm.unit.is_leader():
+        try:
+            client = Client()  # pyright: ignore
+        except exceptions.ConfigError as e:
+            logger.warning("Error creating k8s client: %s", e)
             return
 
-        client = Client()
         try:
+            if self._is_patched(client):
+                return
             if self.service_name != self._app:
                 self._delete_and_create_service(client)
             client.patch(Service, self.service_name, self.service, patch_type=PatchType.MERGE)
@@ -251,13 +300,25 @@ def is_patched(self) -> bool:
         Returns:
             bool: A boolean indicating if the service patch has been applied.
         """
-        client = Client()
+        client = Client()  # pyright: ignore
+        return self._is_patched(client)
+
+    def _is_patched(self, client: Client) -> bool:
         # Get the relevant service from the cluster
-        service = client.get(Service, name=self.service_name, namespace=self._namespace)
+        try:
+            service = client.get(Service, name=self.service_name, namespace=self._namespace)
+        except ApiError as e:
+            if e.status.code == 404 and self.service_name != self._app:
+                return False
+            logger.error("Kubernetes service get failed: %s", str(e))
+            raise
+
         # Construct a list of expected ports, should the patch be applied
-        expected_ports = [(p.port, p.targetPort) for p in self.service.spec.ports]
+        expected_ports = [(p.port, p.targetPort) for p in self.service.spec.ports]  # type: ignore[attr-defined]
         # Construct a list in the same manner, using the fetched service
-        fetched_ports = [(p.port, p.targetPort) for p in service.spec.ports]  # type: ignore[attr-defined]  # noqa: E501
+        fetched_ports = [
+            (p.port, p.targetPort) for p in service.spec.ports  # type: ignore[attr-defined]
+        ]  # noqa: E501
         return expected_ports == fetched_ports
 
     @property

src/charm.py

@@ -11,8 +11,9 @@
 import yaml
 from charmed_kubeflow_chisme.exceptions import ErrorWithStatus
 from charms.grafana_k8s.v0.grafana_dashboard import GrafanaDashboardProvider
-from charms.observability_libs.v0.kubernetes_service_patch import KubernetesServicePatch
+from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
 from charms.prometheus_k8s.v0.prometheus_scrape import MetricsEndpointProvider
+from lightkube.models.core_v1 import ServicePort
 from ops.charm import CharmBase
 from ops.framework import StoredState
 from ops.main import main
@@ -32,6 +33,16 @@ def __init__(self, *args):
 
         self.logger: logging.Logger = logging.getLogger(__name__)
 
+        # Patch the service to correctly expose the ports to be used
+        dex_port = ServicePort(int(self.model.config["port"]), name="dex")
+        metrics_port = ServicePort(int(METRICS_PORT), name="metrics-port")
+
+        self.service_patcher = KubernetesServicePatch(
+            self,
+            [dex_port, metrics_port],
+            service_name=f"{self.model.app.name}",
+        )
+
         self.prometheus_provider = MetricsEndpointProvider(
             charm=self,
             relation_name="metrics-endpoint",
@@ -51,10 +62,6 @@ def __init__(self, *args):
         self._entrypoint = "/usr/local/bin/docker-entrypoint"
         self._dex_config_path = "/etc/dex/config.docker.yaml"
 
-        self.service_patcher = KubernetesServicePatch(
-            self, [(self._container_name, self.model.config["port"])]
-        )
-
         for event in [
             self.on.install,
             self.on.leader_elected,
@@ -222,6 +229,7 @@ def _generate_dex_auth_config(self) -> str:
                 "issuer": f"{public_url}/dex",
                 "storage": {"type": "kubernetes", "config": {"inCluster": True}},
                 "web": {"http": f"0.0.0.0:{port}"},
+                "telemetry": {"http": "0.0.0.0:5558"},
                 "logger": {"level": "debug", "format": "text"},
                 "oauth2": {"skipApprovalScreen": True},
                 "staticClients": oidc_client_info,

tests/integration/test_charm.py

@@ -241,6 +241,12 @@ async def test_prometheus_grafana_integration(ops_test: OpsTest):
             assert response_metric["juju_application"] == APP_NAME
             assert response_metric["juju_model"] == ops_test.model_name
 
+            # Assert the unit is available by checking the query result
+            # The data is presented as a list [1707357912.349, '1'], where the
+            # first value is a timestamp and the second value is the state of the unit
+            # 1 means available, 0 means unavailable
+            assert response["data"]["result"][0]["value"][1] == "1"
+
 
 # Helper to retry calling a function over 30 seconds or 5 attempts
 retry_for_5_attempts = Retrying(