installers/charm/juju-simplestreams-operator/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 """Juju simpletreams charm."""
  26
  27 import logging
  28 import subprocess
  29 from dataclasses import dataclass
  30 from pathlib import Path
  31 from typing import Any, Dict
  32
  33 from charms.nginx_ingress_integrator.v0.ingress import IngressRequires
  34 from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
  35 from charms.osm_libs.v0.utils import (
  36     CharmError,
  37     check_container_ready,
  38     check_service_active,
  39 )
  40 from lightkube.models.core_v1 import ServicePort
  41 from ops.charm import ActionEvent, CharmBase
  42 from ops.main import main
  43 from ops.model import ActiveStatus, Container
  44
  45 SERVICE_PORT = 8080
  46
  47 logger = logging.getLogger(__name__)
  48 container_name = "server"
  49
  50
  51 @dataclass
  52 class ImageMetadata:
  53     """Image Metadata."""
  54
  55     region: str
  56     auth_url: str
  57     image_id: str
  58     series: str
  59
  60
  61 class JujuSimplestreamsCharm(CharmBase):
  62     """Simplestreams Kubernetes sidecar charm."""
  63
  64     def __init__(self, *args):
  65         super().__init__(*args)
  66         self.ingress = IngressRequires(
  67             self,
  68             {
  69                 "service-hostname": self.external_hostname,
  70                 "service-name": self.app.name,
  71                 "service-port": SERVICE_PORT,
  72             },
  73         )
  74         event_handler_mapping = {
  75             # Core lifecycle events
  76             self.on["server"].pebble_ready: self._on_server_pebble_ready,
  77             self.on.update_status: self._on_update_status,
  78             self.on["peer"].relation_changed: self._push_image_metadata_from_relation,
  79             # Action events
  80             self.on["add-image-metadata"].action: self._on_add_image_metadata_action,
  81         }
  82
  83         for event, handler in event_handler_mapping.items():
  84             self.framework.observe(event, handler)
  85
  86         port = ServicePort(SERVICE_PORT, name=f"{self.app.name}")
  87         self.service_patcher = KubernetesServicePatch(self, [port])
  88         self.container: Container = self.unit.get_container(container_name)
  89         self.unit.set_workload_version(self.unit.name)
  90
  91     @property
  92     def external_hostname(self) -> str:
  93         """External hostname property.
  94
  95         Returns:
  96             str: the external hostname from config.
  97                 If not set, return the ClusterIP service name.
  98         """
  99         return self.config.get("external-hostname") or self.app.name
 100
 101     # ---------------------------------------------------------------------------
 102     #   Handlers for Charm Events
 103     # ---------------------------------------------------------------------------
 104
 105     def _on_server_pebble_ready(self, _) -> None:
 106         """Handler for the config-changed event."""
 107         try:
 108             self._push_configuration()
 109             self._configure_service()
 110             self._push_image_metadata_from_relation()
 111             # Update charm status
 112             self._on_update_status()
 113         except CharmError as e:
 114             logger.debug(e.message)
 115             self.unit.status = e.status
 116
 117     def _on_update_status(self, _=None) -> None:
 118         """Handler for the update-status event."""
 119         try:
 120             check_container_ready(self.container)
 121             check_service_active(self.container, container_name)
 122             self.unit.status = ActiveStatus()
 123         except CharmError as e:
 124             logger.debug(e.message)
 125             self.unit.status = e.status
 126
 127     def _push_image_metadata_from_relation(self, _=None):
 128         subprocess.run(["rm", "-rf", "/tmp/simplestreams"])
 129         subprocess.run(["mkdir", "-p", "/tmp/simplestreams"])
 130         image_metadata_dict = self._get_image_metadata_from_relation()
 131         for image_metadata in image_metadata_dict.values():
 132             subprocess.run(
 133                 [
 134                     "files/juju-metadata",
 135                     "generate-image",
 136                     "-d",
 137                     "/tmp/simplestreams",
 138                     "-i",
 139                     image_metadata.image_id,
 140                     "-s",
 141                     image_metadata.series,
 142                     "-r",
 143                     image_metadata.region,
 144                     "-u",
 145                     image_metadata.auth_url,
 146                 ]
 147             )
 148         subprocess.run(["chmod", "555", "-R", "/tmp/simplestreams"])
 149         self.container.push_path("/tmp/simplestreams", "/app/static")
 150
 151     def _on_add_image_metadata_action(self, event: ActionEvent):
 152         relation = self.model.get_relation("peer")
 153         try:
 154             if not relation:
 155                 raise Exception("charm has not been fully initialized. Try again later.")
 156             if not self.unit.is_leader():
 157                 raise Exception("I am not the leader!")
 158             if any(
 159                 prohibited_char in param_value
 160                 for prohibited_char in ",; "
 161                 for param_value in event.params.values()
 162             ):
 163                 event.fail("invalid params")
 164                 return
 165
 166             image_metadata_dict = self._get_image_metadata_from_relation()
 167
 168             new_image_metadata = ImageMetadata(
 169                 region=event.params["region"],
 170                 auth_url=event.params["auth-url"],
 171                 image_id=event.params["image-id"],
 172                 series=event.params["series"],
 173             )
 174
 175             image_metadata_dict[event.params["image-id"]] = new_image_metadata
 176
 177             new_relation_data = []
 178             for image_metadata in image_metadata_dict.values():
 179                 new_relation_data.append(
 180                     f"{image_metadata.image_id};{image_metadata.series};{image_metadata.region};{image_metadata.auth_url}"
 181                 )
 182             relation.data[self.app]["data"] = ",".join(new_relation_data)
 183         except Exception as e:
 184             event.fail(f"Action failed: {e}")
 185             logger.error(f"Action failed: {e}")
 186
 187     # ---------------------------------------------------------------------------
 188     #   Validation and configuration and more
 189     # ---------------------------------------------------------------------------
 190
 191     def _get_image_metadata_from_relation(self) -> Dict[str, ImageMetadata]:
 192         if not (relation := self.model.get_relation("peer")):
 193             return {}
 194
 195         image_metadata_dict: Dict[str, ImageMetadata] = {}
 196
 197         relation_data = relation.data[self.app].get("data", "")
 198         if relation_data:
 199             for image_metadata_string in relation_data.split(","):
 200                 image_id, series, region, auth_url = image_metadata_string.split(";")
 201                 image_metadata_dict[image_id] = ImageMetadata(
 202                     region=region,
 203                     auth_url=auth_url,
 204                     image_id=image_id,
 205                     series=series,
 206                 )
 207
 208         return image_metadata_dict
 209
 210     def _configure_service(self) -> None:
 211         """Add Pebble layer with the ro service."""
 212         logger.debug(f"configuring {self.app.name} service")
 213         self.container.add_layer(container_name, self._get_layer(), combine=True)
 214         self.container.replan()
 215
 216     def _push_configuration(self) -> None:
 217         """Push nginx configuration to the container."""
 218         self.container.push("/etc/nginx/nginx.conf", Path("files/nginx.conf").read_text())
 219         self.container.make_dir("/app/static", make_parents=True)
 220
 221     def _update_ingress_config(self) -> None:
 222         """Update ingress config in relation."""
 223         ingress_config = {
 224             "service-hostname": self.external_hostname,
 225             "max-body-size": self.config["max-body-size"],
 226         }
 227         if "tls-secret-name" in self.config:
 228             ingress_config["tls-secret-name"] = self.config["tls-secret-name"]
 229         logger.debug(f"updating ingress-config: {ingress_config}")
 230         self.ingress.update_config(ingress_config)
 231
 232     def _get_layer(self) -> Dict[str, Any]:
 233         """Get layer for Pebble."""
 234         return {
 235             "summary": "server layer",
 236             "description": "pebble config layer for server",
 237             "services": {
 238                 container_name: {
 239                     "override": "replace",
 240                     "summary": "server service",
 241                     "command": 'nginx -g "daemon off;"',
 242                     "startup": "enabled",
 243                 }
 244             },
 245         }
 246
 247
 248 if __name__ == "__main__":  # pragma: no cover
 249     main(JujuSimplestreamsCharm)