installers/charm/ng-ui/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"); 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 import logging
  24 from typing import Any, Dict, NoReturn
  25 from pydantic import ValidationError
  26
  27 from ops.charm import CharmBase, CharmEvents
  28 from ops.framework import EventBase, EventSource, StoredState
  29 from ops.main import main
  30 from ops.model import ActiveStatus, BlockedStatus, MaintenanceStatus
  31 from oci_image import OCIImageResource, OCIImageResourceError
  32
  33 from pod_spec import make_pod_spec
  34
  35 logger = logging.getLogger(__name__)
  36
  37 NGUI_PORT = 80
  38
  39
  40 class ConfigurePodEvent(EventBase):
  41     """Configure Pod event"""
  42
  43     pass
  44
  45
  46 class NgUiEvents(CharmEvents):
  47     """NGUI Events"""
  48
  49     configure_pod = EventSource(ConfigurePodEvent)
  50
  51
  52 class NgUiCharm(CharmBase):
  53     """NGUI Charm."""
  54
  55     state = StoredState()
  56     on = NgUiEvents()
  57
  58     def __init__(self, *args) -> NoReturn:
  59         """NGUI Charm constructor."""
  60         super().__init__(*args)
  61
  62         # Internal state initialization
  63         self.state.set_default(pod_spec=None)
  64
  65         # North bound interface initialization
  66         self.state.set_default(nbi_host=None)
  67         self.state.set_default(nbi_port=None)
  68
  69         self.http_port = NGUI_PORT
  70         self.image = OCIImageResource(self, "image")
  71
  72         # Registering regular events
  73         self.framework.observe(self.on.start, self.configure_pod)
  74         self.framework.observe(self.on.config_changed, self.configure_pod)
  75         # self.framework.observe(self.on.upgrade_charm, self.configure_pod)
  76
  77         # Registering custom internal events
  78         self.framework.observe(self.on.configure_pod, self.configure_pod)
  79
  80         # Registering required relation changed events
  81         self.framework.observe(
  82             self.on.nbi_relation_changed, self._on_nbi_relation_changed
  83         )
  84
  85         # Registering required relation departed events
  86         self.framework.observe(
  87             self.on.nbi_relation_departed, self._on_nbi_relation_departed
  88         )
  89
  90     def _on_nbi_relation_changed(self, event: EventBase) -> NoReturn:
  91         """Reads information about the nbi relation.
  92
  93         Args:
  94             event (EventBase): NBI relation event.
  95         """
  96         data_loc = event.unit if event.unit else event.app
  97         logger.error(dict(event.relation.data))
  98         nbi_host = event.relation.data[data_loc].get("host")
  99         nbi_port = event.relation.data[data_loc].get("port")
 100
 101         if (
 102             nbi_host
 103             and nbi_port
 104             and (self.state.nbi_host != nbi_host or self.state.nbi_port != nbi_port)
 105         ):
 106             self.state.nbi_host = nbi_host
 107             self.state.nbi_port = nbi_port
 108             self.on.configure_pod.emit()
 109
 110     def _on_nbi_relation_departed(self, event: EventBase) -> NoReturn:
 111         """Clears data from nbi relation.
 112
 113         Args:
 114             event (EventBase): NBI relation event.
 115         """
 116         self.state.nbi_host = None
 117         self.state.nbi_port = None
 118         self.on.configure_pod.emit()
 119
 120     def _missing_relations(self) -> str:
 121         """Checks if there missing relations.
 122
 123         Returns:
 124             str: string with missing relations
 125         """
 126         data_status = {
 127             "nbi": self.state.nbi_host,
 128         }
 129
 130         missing_relations = [k for k, v in data_status.items() if not v]
 131
 132         return ", ".join(missing_relations)
 133
 134     @property
 135     def relation_state(self) -> Dict[str, Any]:
 136         """Collects relation state configuration for pod spec assembly.
 137
 138         Returns:
 139             Dict[str, Any]: relation state information.
 140         """
 141         relation_state = {
 142             "nbi_host": self.state.nbi_host,
 143             "nbi_port": self.state.nbi_port,
 144         }
 145         return relation_state
 146
 147     def configure_pod(self, event: EventBase) -> NoReturn:
 148         """Assemble the pod spec and apply it, if possible.
 149
 150         Args:
 151             event (EventBase): Hook or Relation event that started the
 152                                function.
 153         """
 154         if missing := self._missing_relations():
 155             self.unit.status = BlockedStatus(
 156                 f"Waiting for {missing} relation{'s' if ',' in missing else ''}"
 157             )
 158             return
 159
 160         if not self.unit.is_leader():
 161             self.unit.status = ActiveStatus("ready")
 162             return
 163
 164         self.unit.status = MaintenanceStatus("Assembling pod spec")
 165
 166         # Fetch image information
 167         try:
 168             self.unit.status = MaintenanceStatus("Fetching image information")
 169             image_info = self.image.fetch()
 170         except OCIImageResourceError:
 171             self.unit.status = BlockedStatus("Error fetching image information")
 172             return
 173
 174         try:
 175             pod_spec = make_pod_spec(
 176                 image_info,
 177                 self.config,
 178                 self.relation_state,
 179                 self.model.app.name,
 180             )
 181         except ValidationError as exc:
 182             logger.exception("Config/Relation data validation error")
 183             self.unit.status = BlockedStatus(str(exc))
 184             return
 185
 186         if self.state.pod_spec != pod_spec:
 187             self.model.pod.set_spec(pod_spec)
 188             self.state.pod_spec = pod_spec
 189
 190         self.unit.status = ActiveStatus("ready")
 191
 192
 193 if __name__ == "__main__":
 194     main(NgUiCharm)