installers/charm/zookeeper/src/charm.py

   1 #!/usr/bin/env python3
   2 # Copyright 2021 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 # pylint: disable=E0213
  24
  25 import logging
  26 from typing import NoReturn
  27
  28
  29 from ops.framework import EventBase
  30 from ops.main import main
  31 from opslib.osm.charm import CharmedOsmBase
  32 from opslib.osm.interfaces.zookeeper import ZookeeperCluster, ZookeeperServer
  33 from opslib.osm.pod import ContainerV3Builder, PodSpecV3Builder
  34 from opslib.osm.validator import ModelValidator, validator
  35
  36 logger = logging.getLogger(__name__)
  37
  38 CLIENT_PORT = 2181
  39 SERVER_PORT = 2888
  40 LEADER_ELECTION_PORT = 3888
  41
  42
  43 class ConfigModel(ModelValidator):
  44     log_level: str
  45     image_pull_policy: str
  46     min_session_timeout: int
  47     max_session_timeout: int
  48     purge_interval: int
  49     snap_retain_count: int
  50     max_client_cnxns: int
  51     heap: int
  52     sync_limit: int
  53     init_limit: int
  54     tick_time: int
  55
  56     @validator("log_level")
  57     def validate_log_level(cls, v):
  58         if v not in {"INFO", "DEBUG"}:
  59             raise ValueError("value must be INFO or DEBUG")
  60         return v
  61
  62     @validator("image_pull_policy")
  63     def validate_image_pull_policy(cls, v):
  64         values = {
  65             "always": "Always",
  66             "ifnotpresent": "IfNotPresent",
  67             "never": "Never",
  68         }
  69         v = v.lower()
  70         if v not in values.keys():
  71             raise ValueError("value must be always, ifnotpresent or never")
  72         return values[v]
  73
  74
  75 class ZookeeperCharm(CharmedOsmBase):
  76     """Zookeeper Charm."""
  77
  78     def __init__(self, *args) -> NoReturn:
  79         """Zookeeper Charm constructor."""
  80         super().__init__(*args, oci_image="image")
  81         # Initialize Zookeeper cluster relation
  82         self.zookeeper_cluster = ZookeeperCluster(self, "cluster", CLIENT_PORT)
  83         self.framework.observe(self.on["cluster"].relation_changed, self._setup_cluster)
  84         # Initialize Zookeeper relation
  85         self.zookeeper_server = ZookeeperServer(self, "zookeeper")
  86         self.framework.observe(self.on["zookeeper"].relation_joined, self._publish_info)
  87
  88     @property
  89     def num_units(self):
  90         return self.zookeeper_cluster.num_units
  91
  92     @property
  93     def zookeeper_uri(self):
  94         return self.zookeeper_cluster.zookeeper_uri
  95
  96     def _setup_cluster(self, event: EventBase):
  97         """Publishes Zookeeper information and reconfigures the pod.
  98
  99         Args:
 100             event (EventBase): Zookeeper Cluster relation event.
 101         """
 102         self._publish_zookeeper_info(event)
 103         self.configure_pod()
 104
 105     def _publish_info(self, event: EventBase):
 106         """Publishes Zookeeper information.
 107
 108         Args:
 109             event (EventBase): Zookeeper relation event.
 110         """
 111         if self.unit.is_leader():
 112             zk_uri = self.zookeeper_uri
 113             if zk_uri:
 114                 self.zookeeper_server.publish_info(zk_uri)
 115             else:
 116                 event.defer()
 117
 118     def build_pod_spec(self, image_info):
 119         # Validate config
 120         config = ConfigModel(**dict(self.config))
 121
 122         # Create Builder for the PodSpec
 123         pod_spec_builder = PodSpecV3Builder()
 124
 125         # Build Container
 126         container_builder = ContainerV3Builder(
 127             self.app.name, image_info, config.image_pull_policy
 128         )
 129
 130         container_builder.add_port(name="client", port=CLIENT_PORT)
 131         container_builder.add_port(name="server", port=SERVER_PORT)
 132         container_builder.add_port(name="leader-election", port=LEADER_ELECTION_PORT)
 133         container_builder.add_tcpsocket_readiness_probe(
 134             CLIENT_PORT,
 135             initial_delay_seconds=10,
 136             timeout_seconds=5,
 137             failure_threshold=6,
 138             success_threshold=1,
 139         )
 140         container_builder.add_tcpsocket_liveness_probe(
 141             CLIENT_PORT, initial_delay_seconds=20
 142         )
 143         container_builder.add_command(
 144             [
 145                 "sh",
 146                 "-c",
 147                 " ".join(
 148                     [
 149                         "start-zookeeper",
 150                         f"--servers={self.num_units}",
 151                         "--data_dir=/var/lib/zookeeper/data",
 152                         "--data_log_dir=/var/lib/zookeeper/data/log",
 153                         "--conf_dir=/opt/zookeeper/conf",
 154                         f"--client_port={CLIENT_PORT}",
 155                         f"--election_port={LEADER_ELECTION_PORT}",
 156                         f"--server_port={SERVER_PORT}",
 157                         f"--tick_time={config.tick_time}",
 158                         f"--init_limit={config.init_limit}",
 159                         f"--sync_limit={config.sync_limit}",
 160                         f"--heap={config.heap}M",
 161                         f"--max_client_cnxns={config.max_client_cnxns}",
 162                         f"--snap_retain_count={config.snap_retain_count}",
 163                         f"--purge_interval={config.purge_interval}",
 164                         f"--max_session_timeout={config.max_session_timeout}",
 165                         f"--min_session_timeout={config.min_session_timeout}",
 166                         f"--log_level={config.log_level}",
 167                     ]
 168                 ),
 169             ]
 170         )
 171
 172         container = container_builder.build()
 173
 174         # Add container to pod spec
 175         pod_spec_builder.add_container(container)
 176
 177         return pod_spec_builder.build()
 178
 179
 180 if __name__ == "__main__":
 181     main(ZookeeperCharm)