installers/charm/pla/src/charm.py

   1 #!/usr/bin/env python3
   2 #   Copyright 2020 Canonical Ltd.
   3 #
   4 #   Licensed under the Apache License, Version 2.0 (the "License");
   5 #   you may not use this file except in compliance with the License.
   6 #   You may obtain 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,
  12 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 #   See the License for the specific language governing permissions and
  14 #   limitations under the License.
  15
  16 import sys
  17 import logging
  18
  19 sys.path.append("lib")
  20
  21 from ops.charm import CharmBase
  22 from ops.framework import StoredState, Object
  23 from ops.main import main
  24 from ops.model import (
  25     ActiveStatus,
  26     MaintenanceStatus,
  27     WaitingStatus,
  28 )
  29
  30 from glob import glob
  31 from pathlib import Path
  32 from string import Template
  33
  34 logger = logging.getLogger(__name__)
  35
  36
  37 class PLACharm(CharmBase):
  38     state = StoredState()
  39
  40     def __init__(self, framework, key):
  41         super().__init__(framework, key)
  42         self.state.set_default(spec=None)
  43         self.state.set_default(kafka_host=None)
  44         self.state.set_default(kafka_port=None)
  45         self.state.set_default(mongodb_uri=None)
  46
  47         # Observe Charm related events
  48         self.framework.observe(self.on.config_changed, self.on_config_changed)
  49         self.framework.observe(self.on.start, self.on_start)
  50         self.framework.observe(self.on.upgrade_charm, self.on_upgrade_charm)
  51
  52         # Relations
  53         self.framework.observe(
  54             self.on.kafka_relation_changed, self.on_kafka_relation_changed
  55         )
  56         self.framework.observe(
  57             self.on.mongo_relation_changed, self.on_mongo_relation_changed
  58         )
  59
  60     def _apply_spec(self):
  61         # Only apply the spec if this unit is a leader.
  62         unit = self.model.unit
  63         if not unit.is_leader():
  64             unit.status = ActiveStatus("Ready")
  65             return
  66         if not self.state.kafka_host or not self.state.kafka_port:
  67             unit.status = WaitingStatus("Waiting for Kafka")
  68             return
  69         if not self.state.mongodb_uri:
  70             unit.status = WaitingStatus("Waiting for MongoDB")
  71             return
  72
  73         unit.status = MaintenanceStatus("Applying new pod spec")
  74
  75         new_spec = self.make_pod_spec()
  76         if new_spec == self.state.spec:
  77             unit.status = ActiveStatus("Ready")
  78             return
  79         self.framework.model.pod.set_spec(new_spec)
  80         self.state.spec = new_spec
  81         unit.status = ActiveStatus("Ready")
  82
  83     def make_pod_spec(self):
  84         config = self.framework.model.config
  85
  86         ports = [
  87             {"name": "port", "containerPort": config["port"], "protocol": "TCP",},
  88         ]
  89
  90         config_spec = {
  91             "OSMPLA_MESSAGE_DRIVER": "kafka",
  92             "OSMPLA_MESSAGE_HOST": self.state.kafka_host,
  93             "OSMPLA_MESSAGE_PORT": self.state.kafka_port,
  94             "OSMPLA_DATABASE_DRIVER": "mongo",
  95             "OSMPLA_DATABASE_URI": self.state.mongodb_uri,
  96             "OSMPLA_GLOBAL_LOG_LEVEL": config["log_level"],
  97             "OSMPLA_DATABASE_COMMONKEY": config["database_common_key"],
  98         }
  99
 100         spec = {
 101             "version": 2,
 102             "containers": [
 103                 {
 104                     "name": self.framework.model.app.name,
 105                     "image": config["image"],
 106                     "ports": ports,
 107                     "config": config_spec,
 108                 }
 109             ],
 110         }
 111
 112         return spec
 113
 114     def on_config_changed(self, event):
 115         """Handle changes in configuration"""
 116         self._apply_spec()
 117
 118     def on_start(self, event):
 119         """Called when the charm is being installed"""
 120         self._apply_spec()
 121
 122     def on_upgrade_charm(self, event):
 123         """Upgrade the charm."""
 124         unit = self.model.unit
 125         unit.status = MaintenanceStatus("Upgrading charm")
 126         self.on_start(event)
 127
 128     def on_kafka_relation_changed(self, event):
 129         unit = self.model.unit
 130         if not unit.is_leader():
 131             return
 132         self.state.kafka_host = event.relation.data[event.unit].get("host")
 133         self.state.kafka_port = event.relation.data[event.unit].get("port")
 134         self._apply_spec()
 135
 136     def on_mongo_relation_changed(self, event):
 137         unit = self.model.unit
 138         if not unit.is_leader():
 139             return
 140         self.state.mongodb_uri = event.relation.data[event.unit].get(
 141             "connection_string"
 142         )
 143         self._apply_spec()
 144
 145
 146 if __name__ == "__main__":
 147     main(PLACharm)