installers/charm/osm-pol/src/charm.py

   1 #!/usr/bin/env python3
   2 # Copyright 2022 Canonical Ltd.
   3 #
   4 # Licensed under the Apache License, Version 2.0 (the "License"); you may
   5 # not use this file except in compliance with the License. You may obtain
   6 # a copy of the License at
   7 #
   8 #         http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  12 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  13 # License for the specific language governing permissions and limitations
  14 # under the License.
  15 #
  16 # For those usages not covered by the Apache License, Version 2.0 please
  17 # contact: legal@canonical.com
  18 #
  19 # To get in touch with the maintainers, please contact:
  20 # osm-charmers@lists.launchpad.net
  21 #
  22 #
  23 # Learn more at: https://juju.is/docs/sdk
  24
  25 """OSM POL charm.
  26
  27 See more: https://charmhub.io/osm
  28 """
  29
  30 import logging
  31 from typing import Any, Dict
  32
  33 from charms.kafka_k8s.v0.kafka import KafkaEvents, KafkaRequires
  34 from charms.osm_libs.v0.utils import (
  35     CharmError,
  36     DebugMode,
  37     HostPath,
  38     check_container_ready,
  39     check_service_active,
  40 )
  41 from ops.charm import ActionEvent, CharmBase
  42 from ops.framework import StoredState
  43 from ops.main import main
  44 from ops.model import ActiveStatus, Container
  45
  46 from legacy_interfaces import MongoClient, MysqlClient
  47
  48 HOSTPATHS = [
  49     HostPath(
  50         config="pol-hostpath",
  51         container_path="/usr/lib/python3/dist-packages/osm_policy_module",
  52     ),
  53     HostPath(
  54         config="common-hostpath",
  55         container_path="/usr/lib/python3/dist-packages/osm_common",
  56     ),
  57 ]
  58
  59 logger = logging.getLogger(__name__)
  60
  61
  62 class OsmPolCharm(CharmBase):
  63     """OSM POL Kubernetes sidecar charm."""
  64
  65     on = KafkaEvents()
  66     _stored = StoredState()
  67     container_name = "pol"
  68     service_name = "pol"
  69
  70     def __init__(self, *args):
  71         super().__init__(*args)
  72
  73         self.kafka = KafkaRequires(self)
  74         self.mongodb_client = MongoClient(self, "mongodb")
  75         self.mysql_client = MysqlClient(self, "mysql")
  76         self._observe_charm_events()
  77         self.container: Container = self.unit.get_container(self.container_name)
  78         self.debug_mode = DebugMode(self, self._stored, self.container, HOSTPATHS)
  79
  80     # ---------------------------------------------------------------------------
  81     #   Handlers for Charm Events
  82     # ---------------------------------------------------------------------------
  83
  84     def _on_config_changed(self, _) -> None:
  85         """Handler for the config-changed event."""
  86         try:
  87             self._validate_config()
  88             self._check_relations()
  89             # Check if the container is ready.
  90             # Eventually it will become ready after the first pebble-ready event.
  91             check_container_ready(self.container)
  92
  93             self._configure_service(self.container)
  94             # Update charm status
  95             self._on_update_status()
  96         except CharmError as e:
  97             logger.debug(e.message)
  98             self.unit.status = e.status
  99
 100     def _on_update_status(self, _=None) -> None:
 101         """Handler for the update-status event."""
 102         try:
 103             self._validate_config()
 104             self._check_relations()
 105             check_container_ready(self.container)
 106             if self.debug_mode.started:
 107                 return
 108             check_service_active(self.container, self.service_name)
 109             self.unit.status = ActiveStatus()
 110         except CharmError as e:
 111             logger.debug(e.message)
 112             self.unit.status = e.status
 113
 114     def _on_required_relation_broken(self, _) -> None:
 115         """Handler for the kafka-broken event."""
 116         # Check Pebble has started in the container
 117         try:
 118             check_container_ready(self.container)
 119             check_service_active(self.container, self.service_name)
 120             self.container.stop(self.container_name)
 121         except CharmError:
 122             pass
 123         self._on_update_status()
 124
 125     def _on_get_debug_mode_information_action(self, event: ActionEvent) -> None:
 126         """Handler for the get-debug-mode-information action event."""
 127         if not self.debug_mode.started:
 128             event.fail("debug-mode has not started. Hint: juju config pol debug-mode=true")
 129             return
 130
 131         debug_info = {"command": self.debug_mode.command, "password": self.debug_mode.password}
 132         event.set_results(debug_info)
 133
 134     # ---------------------------------------------------------------------------
 135     #   Validation and configuration and more
 136     # ---------------------------------------------------------------------------
 137
 138     def _observe_charm_events(self) -> None:
 139         event_handler_mapping = {
 140             # Core lifecycle events
 141             self.on.pol_pebble_ready: self._on_config_changed,
 142             self.on.config_changed: self._on_config_changed,
 143             self.on.update_status: self._on_update_status,
 144             # Relation events
 145             self.on.kafka_available: self._on_config_changed,
 146             self.on["kafka"].relation_broken: self._on_required_relation_broken,
 147             # Action events
 148             self.on.get_debug_mode_information_action: self._on_get_debug_mode_information_action,
 149         }
 150         for relation in [self.on[rel_name] for rel_name in ["mongodb", "mysql"]]:
 151             event_handler_mapping[relation.relation_changed] = self._on_config_changed
 152             event_handler_mapping[relation.relation_broken] = self._on_required_relation_broken
 153
 154         for event, handler in event_handler_mapping.items():
 155             self.framework.observe(event, handler)
 156
 157     def _validate_config(self) -> None:
 158         """Validate charm configuration.
 159
 160         Raises:
 161             CharmError: if charm configuration is invalid.
 162         """
 163         logger.debug("validating charm config")
 164
 165     def _check_relations(self) -> None:
 166         """Validate charm relations.
 167
 168         Raises:
 169             CharmError: if charm configuration is invalid.
 170         """
 171         logger.debug("check for missing relations")
 172         missing_relations = []
 173
 174         if not self.kafka.host or not self.kafka.port:
 175             missing_relations.append("kafka")
 176         if self.mongodb_client.is_missing_data_in_unit():
 177             missing_relations.append("mongodb")
 178         if not self.config.get("mysql-uri") and self.mysql_client.is_missing_data_in_unit():
 179             missing_relations.append("mysql")
 180
 181         if missing_relations:
 182             relations_str = ", ".join(missing_relations)
 183             one_relation_missing = len(missing_relations) == 1
 184             error_msg = f'need {relations_str} relation{"" if one_relation_missing else "s"}'
 185             logger.warning(error_msg)
 186             raise CharmError(error_msg)
 187
 188     def _configure_service(self, container: Container) -> None:
 189         """Add Pebble layer with the pol service."""
 190         logger.debug(f"configuring {self.app.name} service")
 191         container.add_layer("pol", self._get_layer(), combine=True)
 192         container.replan()
 193
 194     def _get_layer(self) -> Dict[str, Any]:
 195         """Get layer for Pebble."""
 196         return {
 197             "summary": "pol layer",
 198             "description": "pebble config layer for pol",
 199             "services": {
 200                 self.service_name: {
 201                     "override": "replace",
 202                     "summary": "pol service",
 203                     "command": "/bin/bash scripts/start.sh",
 204                     "startup": "enabled",
 205                     "user": "appuser",
 206                     "group": "appuser",
 207                     "environment": {
 208                         # General configuration
 209                         "OSMPOL_GLOBAL_LOGLEVEL": self.config["log-level"],
 210                         # Kafka configuration
 211                         "OSMPOL_MESSAGE_HOST": self.kafka.host,
 212                         "OSMPOL_MESSAGE_PORT": self.kafka.port,
 213                         "OSMPOL_MESSAGE_DRIVER": "kafka",
 214                         # Database Mongodb configuration
 215                         "OSMPOL_DATABASE_DRIVER": "mongo",
 216                         "OSMPOL_DATABASE_URI": self.mongodb_client.connection_string,
 217                         # Database MySQL configuration
 218                         "OSMPOL_SQL_DATABASE_URI": self._get_mysql_uri(),
 219                     },
 220                 }
 221             },
 222         }
 223
 224     def _get_mysql_uri(self):
 225         return self.config.get("mysql-uri") or self.mysql_client.get_root_uri("pol")
 226
 227
 228 if __name__ == "__main__":  # pragma: no cover
 229     main(OsmPolCharm)