installers/charm/osm-ng-ui/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 NG-UI charm.
  26
  27 See more: https://charmhub.io/osm
  28 """
  29
  30 import logging
  31 import re
  32 from typing import Any, Dict
  33
  34 from charms.nginx_ingress_integrator.v0.ingress import IngressRequires
  35 from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
  36 from charms.osm_libs.v0.utils import (
  37     CharmError,
  38     check_container_ready,
  39     check_service_active,
  40 )
  41 from charms.osm_nbi.v0.nbi import NbiRequires
  42 from lightkube.models.core_v1 import ServicePort
  43 from ops.charm import CharmBase
  44 from ops.framework import StoredState
  45 from ops.main import main
  46 from ops.model import ActiveStatus, Container
  47
  48 SERVICE_PORT = 80
  49
  50 logger = logging.getLogger(__name__)
  51
  52
  53 class OsmNgUiCharm(CharmBase):
  54     """OSM NG-UI Kubernetes sidecar charm."""
  55
  56     _stored = StoredState()
  57
  58     def __init__(self, *args):
  59         super().__init__(*args)
  60         self.ingress = IngressRequires(
  61             self,
  62             {
  63                 "service-hostname": self.external_hostname,
  64                 "service-name": self.app.name,
  65                 "service-port": SERVICE_PORT,
  66             },
  67         )
  68         self._observe_charm_events()
  69         self._patch_k8s_service()
  70         self._stored.set_default(default_site_patched=False)
  71         self.nbi = NbiRequires(self)
  72         self.container: Container = self.unit.get_container("ng-ui")
  73
  74     @property
  75     def external_hostname(self) -> str:
  76         """External hostname property.
  77
  78         Returns:
  79             str: the external hostname from config.
  80                 If not set, return the ClusterIP service name.
  81         """
  82         return self.config.get("external-hostname") or self.app.name
  83
  84     # ---------------------------------------------------------------------------
  85     #   Handlers for Charm Events
  86     # ---------------------------------------------------------------------------
  87
  88     def _on_config_changed(self, _) -> None:
  89         """Handler for the config-changed event."""
  90         try:
  91             self._validate_config()
  92             self._check_relations()
  93             # Check if the container is ready.
  94             # Eventually it will become ready after the first pebble-ready event.
  95             check_container_ready(self.container)
  96
  97             self._configure_service(self.container)
  98             self._update_ingress_config()
  99             # Update charm status
 100             self._on_update_status()
 101         except CharmError as e:
 102             logger.debug(e.message)
 103             self.unit.status = e.status
 104
 105     def _on_update_status(self, _=None) -> None:
 106         """Handler for the update-status event."""
 107         try:
 108             self._check_relations()
 109             check_container_ready(self.container)
 110             check_service_active(self.container, "ng-ui")
 111             self.unit.status = ActiveStatus()
 112         except CharmError as e:
 113             logger.debug(e.message)
 114             self.unit.status = e.status
 115
 116     def _on_required_relation_broken(self, _) -> None:
 117         """Handler for the kafka-broken event."""
 118         # Check Pebble has started in the container
 119         try:
 120             check_container_ready(self.container)
 121             check_service_active(self.container, "ng-ui")
 122             self.container.stop("ng-ui")
 123             self._stored.default_site_patched = False
 124         except CharmError:
 125             pass
 126         finally:
 127             self._on_update_status()
 128
 129     # ---------------------------------------------------------------------------
 130     #   Validation and configuration and more
 131     # ---------------------------------------------------------------------------
 132
 133     def _patch_k8s_service(self) -> None:
 134         port = ServicePort(SERVICE_PORT, name=f"{self.app.name}")
 135         self.service_patcher = KubernetesServicePatch(self, [port])
 136
 137     def _observe_charm_events(self) -> None:
 138         event_handler_mapping = {
 139             # Core lifecycle events
 140             self.on.ng_ui_pebble_ready: self._on_config_changed,
 141             self.on.config_changed: self._on_config_changed,
 142             self.on.update_status: self._on_update_status,
 143             # Relation events
 144             self.on["nbi"].relation_changed: self._on_config_changed,
 145             self.on["nbi"].relation_broken: self._on_required_relation_broken,
 146         }
 147         for event, handler in event_handler_mapping.items():
 148             self.framework.observe(event, handler)
 149
 150     def _validate_config(self) -> None:
 151         """Validate charm configuration.
 152
 153         Raises:
 154             CharmError: if charm configuration is invalid.
 155         """
 156         logger.debug("validating charm config")
 157
 158     def _check_relations(self) -> None:
 159         """Validate charm relations.
 160
 161         Raises:
 162             CharmError: if charm configuration is invalid.
 163         """
 164         logger.debug("check for missing relations")
 165
 166         if not self.nbi.host or not self.nbi.port:
 167             raise CharmError("need nbi relation")
 168
 169     def _update_ingress_config(self) -> None:
 170         """Update ingress config in relation."""
 171         ingress_config = {
 172             "service-hostname": self.external_hostname,
 173             "max-body-size": self.config["max-body-size"],
 174         }
 175         if "tls-secret-name" in self.config:
 176             ingress_config["tls-secret-name"] = self.config["tls-secret-name"]
 177         logger.debug(f"updating ingress-config: {ingress_config}")
 178         self.ingress.update_config(ingress_config)
 179
 180     def _configure_service(self, container: Container) -> None:
 181         """Add Pebble layer with the ng-ui service."""
 182         logger.debug(f"configuring {self.app.name} service")
 183         self._patch_default_site(container)
 184         container.add_layer("ng-ui", self._get_layer(), combine=True)
 185         container.replan()
 186
 187     def _get_layer(self) -> Dict[str, Any]:
 188         """Get layer for Pebble."""
 189         return {
 190             "summary": "ng-ui layer",
 191             "description": "pebble config layer for ng-ui",
 192             "services": {
 193                 "ng-ui": {
 194                     "override": "replace",
 195                     "summary": "ng-ui service",
 196                     "command": 'nginx -g "daemon off;"',
 197                     "startup": "enabled",
 198                 }
 199             },
 200         }
 201
 202     def _patch_default_site(self, container: Container) -> None:
 203         max_body_size = self.config.get("max-body-size")
 204         if (
 205             self._stored.default_site_patched
 206             and max_body_size == self._stored.default_site_max_body_size
 207         ):
 208             return
 209         default_site_config = container.pull("/etc/nginx/sites-available/default").read()
 210         default_site_config = re.sub(
 211             "client_max_body_size .*\n",
 212             f"client_max_body_size {max_body_size}M;\n",
 213             default_site_config,
 214         )
 215         default_site_config = re.sub(
 216             "proxy_pass .*\n",
 217             f"proxy_pass https://{self.nbi.host}:{self.nbi.port};\n",
 218             default_site_config,
 219         )
 220         container.push("/etc/nginx/sites-available/default", default_site_config)
 221         self._stored.default_site_patched = True
 222         self._stored.default_site_max_body_size = max_body_size
 223
 224
 225 if __name__ == "__main__":  # pragma: no cover
 226     main(OsmNgUiCharm)