installers/charm/osm-keystone/src/cluster.py

   1 # Copyright 2021 Canonical Ltd.
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License"); you may
   4 # not use this file except in compliance with the License. You may obtain
   5 # a copy of the License at
   6 #
   7 #         http://www.apache.org/licenses/LICENSE-2.0
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   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  11 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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  15 # For those usages not covered by the Apache License, Version 2.0 please
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  18 # To get in touch with the maintainers, please contact:
  19 # osm-charmers@lists.launchpad.net
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  21 #
  22 # This file populates the Actions tab on Charmhub.
  23 # See https://juju.is/docs/some-url-to-be-determined/ for a checklist and guidance.
  24
  25 """Keystone cluster library.
  26
  27 This library allows the integration with Apache Guacd charm. Is is published as part of the
  28 [davigar15-apache-guacd]((https://charmhub.io/davigar15-apache-guacd) charm.
  29
  30 The charm that requires guacd should include the following content in its metadata.yaml:
  31
  32 ```yaml
  33 # ...
  34 peers:
  35     cluster:
  36         interface: cluster
  37 # ...
  38 ```
  39
  40 A typical example of including this library might be:
  41
  42 ```python
  43 # ...
  44 from ops.framework import StoredState
  45 from charms.keystone.v0 import cluster
  46
  47 class SomeApplication(CharmBase):
  48   on = cluster.ClusterEvents()
  49
  50   def __init__(self, *args):
  51     # ...
  52     self.cluster = cluster.Cluster(self)
  53     self.framework.observe(self.on.cluster_keys_changed, self._cluster_keys_changed)
  54     # ...
  55
  56   def _cluster_keys_changed(self, _):
  57     fernet_keys = self.cluster.fernet_keys
  58     credential_keys = self.cluster.credential_keys
  59     # ...
  60 ```
  61 """
  62
  63
  64 import json
  65 import logging
  66 from typing import Any, Dict, List
  67
  68 from ops.charm import CharmEvents
  69 from ops.framework import EventBase, EventSource, Object
  70 from ops.model import Relation
  71
  72 # Number of keys need might need to be adjusted in the future
  73 NUMBER_FERNET_KEYS = 2
  74 NUMBER_CREDENTIAL_KEYS = 2
  75
  76 logger = logging.getLogger(__name__)
  77
  78
  79 class ClusterKeysChangedEvent(EventBase):
  80     """Event to announce a change in the Guacd service."""
  81
  82
  83 class ClusterEvents(CharmEvents):
  84     """Cluster Events."""
  85
  86     cluster_keys_changed = EventSource(ClusterKeysChangedEvent)
  87
  88
  89 class Cluster(Object):
  90     """Peer relation."""
  91
  92     def __init__(self, charm):
  93         super().__init__(charm, "cluster")
  94         self.charm = charm
  95
  96     @property
  97     def fernet_keys(self) -> List[str]:
  98         """Fernet keys."""
  99         relation: Relation = self.model.get_relation("cluster")
 100         application_data = relation.data[self.model.app]
 101         return json.loads(application_data.get("keys-fernet", "[]"))
 102
 103     @property
 104     def credential_keys(self) -> List[str]:
 105         """Credential keys."""
 106         relation: Relation = self.model.get_relation("cluster")
 107         application_data = relation.data[self.model.app]
 108         return json.loads(application_data.get("keys-credential", "[]"))
 109
 110     def save_keys(self, keys: Dict[str, Any]) -> None:
 111         """Generate fernet and credential keys.
 112
 113         This method will generate new keys and fire the cluster_keys_changed event.
 114         """
 115         logger.debug("Saving keys...")
 116         relation: Relation = self.model.get_relation("cluster")
 117         data = relation.data[self.model.app]
 118         current_keys_str = data.get("key_repository", "{}")
 119         current_keys = json.loads(current_keys_str)
 120         if current_keys != keys:
 121             data["key_repository"] = json.dumps(keys)
 122             self.charm.on.cluster_keys_changed.emit()
 123         logger.info("Keys saved!")
 124
 125     def get_keys(self) -> Dict[str, Any]:
 126         """Get keys from the relation.
 127
 128         Returns:
 129             Dict[str, Any]: Dictionary with the keys.
 130         """
 131         relation: Relation = self.model.get_relation("cluster")
 132         data = relation.data[self.model.app]
 133         current_keys_str = data.get("key_repository", "{}")
 134         current_keys = json.loads(current_keys_str)
 135         return current_keys