--- /dev/null
+#!/usr/bin/env python3
+# Copyright 2020 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 pydantic import ValidationError
+from typing import Any, Dict, NoReturn
+
+from ops.charm import CharmBase, CharmEvents
+from ops.framework import EventBase, EventSource, StoredState
+from ops.main import main
+from ops.model import ActiveStatus, BlockedStatus, MaintenanceStatus
+from oci_image import OCIImageResource, OCIImageResourceError
+
+from pod_spec import make_pod_spec
+
+logger = logging.getLogger(__name__)
+
+
+class ConfigurePodEvent(EventBase):
+ """Configure Pod event"""
+
+ pass
+
+
+class PolEvents(CharmEvents):
+ """POL Events"""
+
+ configure_pod = EventSource(ConfigurePodEvent)
+
+
+class PolCharm(CharmBase):
+ """POL Charm."""
+
+ state = StoredState()
+ on = PolEvents()
+
+ def __init__(self, *args) -> NoReturn:
+ """POL Charm constructor."""
+ super().__init__(*args)
+
+ # Internal state initialization
+ self.state.set_default(pod_spec=None)
+
+ # Message bus data initialization
+ self.state.set_default(message_host=None)
+ self.state.set_default(message_port=None)
+
+ # Database data initialization
+ self.state.set_default(database_uri=None)
+
+ 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)
+ self.framework.observe(self.on.upgrade_charm, self.configure_pod)
+
+ # Registering custom internal events
+ self.framework.observe(self.on.configure_pod, self.configure_pod)
+
+ # Registering required relation events
+ self.framework.observe(
+ self.on.kafka_relation_changed, self._on_kafka_relation_changed
+ )
+ self.framework.observe(
+ self.on.mongodb_relation_changed, self._on_mongodb_relation_changed
+ )
+
+ # Registering required relation departed events
+ self.framework.observe(
+ self.on.kafka_relation_departed, self._on_kafka_relation_departed
+ )
+ self.framework.observe(
+ self.on.mongodb_relation_departed, self._on_mongodb_relation_departed
+ )
+
+ def _on_kafka_relation_changed(self, event: EventBase) -> NoReturn:
+ """Reads information about the kafka relation.
+
+ Args:
+ event (EventBase): Kafka relation event.
+ """
+ data_loc = event.unit if event.unit else event.app
+
+ message_host = event.relation.data[data_loc].get("host")
+ message_port = event.relation.data[data_loc].get("port")
+
+ if (
+ message_host
+ and message_port
+ and (
+ self.state.message_host != message_host
+ or self.state.message_port != message_port
+ )
+ ):
+ self.state.message_host = message_host
+ self.state.message_port = message_port
+ self.on.configure_pod.emit()
+
+ def _on_kafka_relation_departed(self, event: EventBase) -> NoReturn:
+ """Clear kafka relation data.
+
+ Args:
+ event (EventBase): Kafka relation event.
+ """
+ self.state.message_host = None
+ self.state.message_port = None
+ self.on.configure_pod.emit()
+
+ def _on_mongodb_relation_changed(self, event: EventBase) -> NoReturn:
+ """Reads information about the DB relation.
+
+ Args:
+ event (EventBase): DB relation event.
+ """
+ data_loc = event.unit if event.unit else event.app
+
+ database_uri = event.relation.data[data_loc].get("connection_string")
+
+ if database_uri and self.state.database_uri != database_uri:
+ self.state.database_uri = database_uri
+ self.on.configure_pod.emit()
+
+ def _on_mongodb_relation_departed(self, event: EventBase) -> NoReturn:
+ """Clear mongodb relation data.
+
+ Args:
+ event (EventBase): DB relation event.
+ """
+ self.state.database_uri = None
+ self.on.configure_pod.emit()
+
+ def _missing_relations(self) -> str:
+ """Checks if there missing relations.
+
+ Returns:
+ str: string with missing relations
+ """
+ data_status = {
+ "kafka": self.state.message_host,
+ "mongodb": self.state.database_uri,
+ }
+
+ missing_relations = [k for k, v in data_status.items() if not v]
+
+ return ", ".join(missing_relations)
+
+ @property
+ def relation_state(self) -> Dict[str, Any]:
+ """Collects relation state configuration for pod spec assembly.
+
+ Returns:
+ Dict[str, Any]: relation state information.
+ """
+ relation_state = {
+ "message_host": self.state.message_host,
+ "message_port": self.state.message_port,
+ "database_uri": self.state.database_uri,
+ }
+
+ return relation_state
+
+ def configure_pod(self, event: EventBase) -> NoReturn:
+ """Assemble the pod spec and apply it, if possible.
+
+ Args:
+ event (EventBase): Hook or Relation event that started the
+ function.
+ """
+ if missing := self._missing_relations():
+ self.unit.status = BlockedStatus(
+ "Waiting for {0} relation{1}".format(
+ missing, "s" if "," in missing else ""
+ )
+ )
+ return
+
+ if not self.unit.is_leader():
+ self.unit.status = ActiveStatus("ready")
+ 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,
+ self.relation_state,
+ self.model.app.name,
+ )
+ except ValidationError 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(PolCharm)
projects / osm / devops.git / blobdiff