Mesh lib

lib/charms/istio_beacon_k8s/v0/service_mesh.py

@@ -0,0 +1,151 @@
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+"""#Service Mesh Library.
+
+The service mesh library is used to facilitate adding you charmed application to a service mesh.
+The library leverages the `service_mesh` interface and the `cross_model_mesh` interface
+
+To add service mesh support to your charm, instantiate a ServiceMeshConsumer object in the
+`__init__` method of your charm:
+
+```
+from charms.istio_beacon_k8s.v0.service_mesh import Policy, ServiceMeshConsumer
+
+...
+try:
+    self._mesh = ServiceMeshConsumer(
+        self,
+        policies=[
+            Policy(relation="logging", endpoints=[f"*:{HTTP_LISTEN_PORT}"]),
+        ],
+    )
+except ops.TooManyRelatedAppsError as e:
+    self.unit.status = BlockedStatus(e)
+```
+"""
+
+import enum
+import json
+import logging
+import re
+from typing import List, Optional
+
+import pydantic
+from ops import CharmBase, Object
+
+LIBID = "3f40cb7e3569454a92ac2541c5ca0a0c"  # Never change this
+LIBAPI = 0
+LIBPATCH = 1
+
+PYDEPS = ["pydantic"]
+
+logger = logging.getLogger(__name__)
+
+
+class Method(str, enum.Enum):
+    """HTTP method."""
+
+    connect = "CONNECT"
+    delete = "DELETE"
+    get = "GET"
+    head = "HEAD"
+    options = "OPTIONS"
+    patch = "PATCH"
+    post = "POST"
+    put = "PUT"
+    trace = "TRACE"
+
+
+class Endpoint(pydantic.BaseModel):
+    """Data type for a policy endpoint."""
+
+    hosts: List[str]
+    ports: List[int]
+    methods: List[Method]
+    paths: List[str]
+
+
+class Policy(pydantic.BaseModel):
+    """Data type for holding a service mesh policy."""
+
+    relation: str
+    endpoints: List[Endpoint]
+    service: Optional[str]
+
+
+class ServiceMeshConsumer(Object):
+    """Class used for joining a service mesh."""
+
+    def __init__(
+        self,
+        charm: CharmBase,
+        mesh_relation_name: str = "service-mesh",
+        policies: Optional[List[Policy]] = None,
+    ):
+        """Class used for joining a service mesh.
+
+        Args:
+            charm: The charm instantiating this object.
+            mesh_relation_name: The relation name as defined in metadata.yaml or charmcraft.yaml
+                for the relation which used the service_mesh interface.
+            policies: List of access policies this charm supports.
+        """
+        super().__init__(charm, mesh_relation_name)
+        self._charm = charm
+        self._relation = self._charm.model.get_relation(mesh_relation_name)
+        self._policies = policies or []
+        self.framework.observe(
+            self._charm.on[mesh_relation_name].relation_created, self._relations_changed
+        )
+        self.framework.observe(self._charm.on.upgrade_charm, self._relations_changed)
+        for policy in self._policies:
+            self.framework.observe(
+                self._charm.on[policy.relation].relation_created, self._relations_changed
+            )
+            self.framework.observe(
+                self._charm.on[policy.relation].relation_broken, self._relations_changed
+            )
+
+    def _relations_changed(self, _event):
+        self.update_service_mesh()
+
+    def update_service_mesh(self):
+        """Update the service mesh.
+
+        Gathers information from all relations of the charm and updates the mesh appropriately to
+        allow communication.
+        """
+        if self._relation is None:
+            return
+        logger.debug("Updating service mesh policies.")
+        policies = []
+        cmr_matcher = re.compile(r"remote\-[a-f0-9]+")
+        for policy in self._policies:
+            for relation in self._charm.model.relations[policy.relation]:
+                if cmr_matcher.fullmatch(relation.app.name):
+                    logger.debug(
+                        f"Cross model relation found: {relation.name}. Currently not implemented. Skipping."
+                    )
+                else:
+                    logger.debug(f"Found relation: {relation.name}. Creating policy.")
+                    policies.append(
+                        {
+                            "app_name": relation.app.name,
+                            "namespace": self._my_namespace(),
+                            "endpoints": [endpoint.model_dump() for endpoint in policy.endpoints],
+                            "service": policy.service,
+                        }
+                    )
+        mesh_rel_data = {
+            "app_name": self._charm.app.name,
+            "model": self._my_namespace(),
+            "policies": policies,
+        }
+        self._relation.data[self._charm.app]["mesh_data"] = json.dumps(mesh_rel_data)
+
+    def _my_namespace(self):
+        """Return the namespace of the running charm."""
+        # This method currently assumes the namespace is the same as the model name. We
+        # should consider if there is a better way to do this.
+        return self._charm.model.name

pyproject.toml

@@ -38,6 +38,7 @@ extend-ignore = [
     "D408",
     "D409",
     "D413",
+    "N805",
 ]
 ignore = ["E501", "D107"]
 per-file-ignores = {"tests/*" = ["D100","D101","D102","D103","D104"]}

src/charm.py

@@ -35,8 +35,8 @@ def update_mesh(self):
         manifest.
         """
         for relation in self.model.relations["service-mesh"]:
+            logger.error(relation.data[relation.app])
             # Update the mesh
-            pass
         self.unit.status = ops.ActiveStatus()
 
 

tox.ini

@@ -4,14 +4,14 @@
 [tox]
 no_package = True
 skip_missing_interpreters = True
-env_list = lint, static, unit, scenario
+env_list = lint, static-charm, static-lib, unit, scenario
 min_version = 4.0.0
 
 [vars]
 src_path = {tox_root}/src
 tests_path = {tox_root}/tests
-;lib_path = {tox_root}/lib/charms/operator_name_with_underscores
-all_path = {[vars]src_path} {[vars]tests_path}
+lib_path = {tox_root}/lib/charms/istio_beacon_k8s
+all_path = {[vars]src_path} {[vars]tests_path} {[vars]lib_path}
 
 [testenv]
 set_env =
@@ -27,10 +27,8 @@ pass_env =
 description = Apply coding style standards to code
 deps =
     black
-    ruff
 commands =
     black {[vars]all_path}
-    ruff check --fix {[vars]all_path}
 
 [testenv:lint]
 description = Check code against coding style standards
@@ -39,10 +37,8 @@ deps =
     ruff
     codespell
 commands =
-    # if this charm owns a lib, uncomment "lib_path" variable
-    # and uncomment the following line
-    # codespell {[vars]lib_path}
-    codespell {tox_root}
+    codespell {[vars]src_path}
+    codespell {[vars]lib_path}
     ruff check {[vars]all_path}
     black --check --diff {[vars]all_path}
 
@@ -72,10 +68,11 @@ commands =
 description = Run static type checks
 deps =
     pyright
+    lib: pydantic
     -r {tox_root}/requirements.txt
 commands =
     charm: pyright {posargs} {[vars]src_path}
-    lib:
+    lib: pyright {posargs} {[vars]lib_path}
 
 [testenv:integration]
 description = Run integration tests