+++ /dev/null
-#!/usr/bin/env python3
-# Copyright 2021 Canonical Ltd.
-#
-# Licensed under the Apache License, Version 2.0 (the "License"); you may
-# not use this file except in compliance with the License. You may obtain
-# a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-# License for the specific language governing permissions and limitations
-# under the License.
-#
-# For those usages not covered by the Apache License, Version 2.0 please
-# contact: legal@canonical.com
-#
-# To get in touch with the maintainers, please contact:
-# osm-charmers@lists.launchpad.net
-##
-
-import logging
-from pathlib import Path
-from typing import Dict, List, NoReturn
-
-from ops.charm import CharmBase
-from ops.framework import EventBase, StoredState
-from ops.main import main
-from ops.model import ActiveStatus, Application, BlockedStatus, MaintenanceStatus, Unit
-from oci_image import OCIImageResource, OCIImageResourceError
-
-from pod_spec import make_pod_spec
-
-logger = logging.getLogger(__name__)
-
-PROMETHEUS_KAFKA_EXPORTER_PORT = 9308
-
-
-class RelationsMissing(Exception):
- def __init__(self, missing_relations: List):
- self.message = ""
- if missing_relations and isinstance(missing_relations, list):
- self.message += f'Waiting for {", ".join(missing_relations)} relation'
- if "," in self.message:
- self.message += "s"
-
-
-class RelationDefinition:
- def __init__(self, relation_name: str, keys: List, source_type):
- if source_type != Application and source_type != Unit:
- raise TypeError(
- "source_type should be ops.model.Application or ops.model.Unit"
- )
- self.relation_name = relation_name
- self.keys = keys
- self.source_type = source_type
-
-
-def check_missing_relation_data(
- data: Dict,
- expected_relations_data: List[RelationDefinition],
-):
- missing_relations = []
- for relation_data in expected_relations_data:
- if not all(
- f"{relation_data.relation_name}_{k}" in data for k in relation_data.keys
- ):
- missing_relations.append(relation_data.relation_name)
- if missing_relations:
- raise RelationsMissing(missing_relations)
-
-
-def get_relation_data(
- charm: CharmBase,
- relation_data: RelationDefinition,
-) -> Dict:
- data = {}
- relation = charm.model.get_relation(relation_data.relation_name)
- if relation:
- self_app_unit = (
- charm.app if relation_data.source_type == Application else charm.unit
- )
- expected_type = relation_data.source_type
- for app_unit in relation.data:
- if app_unit != self_app_unit and isinstance(app_unit, expected_type):
- if all(k in relation.data[app_unit] for k in relation_data.keys):
- for k in relation_data.keys:
- data[f"{relation_data.relation_name}_{k}"] = relation.data[
- app_unit
- ].get(k)
- break
- return data
-
-
-class PrometheusKafkaExporterCharm(CharmBase):
- """Prometheus Kafka Exporter Charm."""
-
- state = StoredState()
-
- def __init__(self, *args) -> NoReturn:
- """Prometheus Kafka Exporter Charm constructor."""
- super().__init__(*args)
-
- # Internal state initialization
- self.state.set_default(pod_spec=None)
-
- self.port = PROMETHEUS_KAFKA_EXPORTER_PORT
- self.image = OCIImageResource(self, "image")
-
- # Registering regular events
- self.framework.observe(self.on.start, self.configure_pod)
- self.framework.observe(self.on.config_changed, self.configure_pod)
-
- # Registering required relation events
- self.framework.observe(self.on.kafka_relation_changed, self.configure_pod)
-
- # Registering required relation departed events
- self.framework.observe(self.on.kafka_relation_departed, self.configure_pod)
-
- # Registering provided relation events
- self.framework.observe(
- self.on.prometheus_target_relation_joined, self._publish_target_info
- )
- self.framework.observe(
- self.on.grafana_dashboard_relation_joined, self._publish_dashboard_info
- )
-
- def _publish_target_info(self, event: EventBase) -> NoReturn:
- """Publishes target information.
-
- Args:
- event (EventBase): Exporter relation event.
- """
- rel_data = {
- "hostname": self.model.app.name,
- "port": str(PROMETHEUS_KAFKA_EXPORTER_PORT),
- }
- for k, v in rel_data.items():
- event.relation.data[self.unit][k] = v
-
- def _publish_dashboard_info(self, event: EventBase) -> NoReturn:
- """Publishes dashboard information.
-
- Args:
- event (EventBase): Exporter relation event.
- """
- rel_data = {
- "dashboard": Path("files/kafka_exporter_dashboard.yaml").read_text(),
- }
- for k, v in rel_data.items():
- event.relation.data[self.unit][k] = v
-
- @property
- def relations_requirements(self):
- return [RelationDefinition("kafka", ["host", "port"], Unit)]
-
- def get_relation_state(self):
- relation_state = {}
- for relation_requirements in self.relations_requirements:
- data = get_relation_data(self, relation_requirements)
- relation_state = {**relation_state, **data}
- check_missing_relation_data(relation_state, self.relations_requirements)
- return relation_state
-
- def configure_pod(self, _=None) -> NoReturn:
- """Assemble the pod spec and apply it, if possible.
-
- Args:
- event (EventBase): Hook or Relation event that started the
- function.
- """
- if not self.unit.is_leader():
- self.unit.status = ActiveStatus("ready")
- return
-
- relation_state = None
- try:
- relation_state = self.get_relation_state()
- except RelationsMissing as exc:
- logger.exception("Relation missing error")
- self.unit.status = BlockedStatus(exc.message)
- return
-
- self.unit.status = MaintenanceStatus("Assembling pod spec")
-
- # Fetch image information
- try:
- self.unit.status = MaintenanceStatus("Fetching image information")
- image_info = self.image.fetch()
- except OCIImageResourceError:
- self.unit.status = BlockedStatus("Error fetching image information")
- return
-
- try:
- pod_spec = make_pod_spec(
- image_info,
- self.model.config,
- relation_state,
- self.model.app.name,
- self.port,
- )
- except ValueError as exc:
- logger.exception("Config/Relation data validation error")
- self.unit.status = BlockedStatus(str(exc))
- return
-
- if self.state.pod_spec != pod_spec:
- self.model.pod.set_spec(pod_spec)
- self.state.pod_spec = pod_spec
-
- self.unit.status = ActiveStatus("ready")
-
-
-if __name__ == "__main__":
- main(PrometheusKafkaExporterCharm)
projects / osm / devops.git / blobdiff