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     security_context: bool
  56
  57     @validator("log_level")
  58     def validate_log_level(cls, v):
  59         if v not in {"INFO", "DEBUG"}:
  60             raise ValueError("value must be INFO or DEBUG")
  61         return v
  62
  63     @validator("image_pull_policy")
  64     def validate_image_pull_policy(cls, v):
  65         values = {
  66             "always": "Always",
  67             "ifnotpresent": "IfNotPresent",
  68             "never": "Never",
  69         }
  70         v = v.lower()
  71         if v not in values.keys():
  72             raise ValueError("value must be always, ifnotpresent or never")
  73         return values[v]
  74
  75
  76 class ZookeeperCharm(CharmedOsmBase):
  77     """Zookeeper Charm."""
  78
  79     def __init__(self, *args) -> NoReturn:
  80         """Zookeeper Charm constructor."""
  81         super().__init__(*args, oci_image="image")
  82         # Initialize Zookeeper cluster relation
  83         self.zookeeper_cluster = ZookeeperCluster(self, "cluster", CLIENT_PORT)
  84         self.framework.observe(self.on["cluster"].relation_changed, self._setup_cluster)
  85         # Initialize Zookeeper relation
  86         self.zookeeper_server = ZookeeperServer(self, "zookeeper")
  87         self.framework.observe(self.on["zookeeper"].relation_joined, self._publish_info)
  88
  89     @property
  90     def num_units(self):
  91         return self.zookeeper_cluster.num_units
  92
  93     @property
  94     def zookeeper_uri(self):
  95         return self.zookeeper_cluster.zookeeper_uri
  96
  97     def _setup_cluster(self, event: EventBase):
  98         """Publishes Zookeeper information and reconfigures the pod.
  99
 100         Args:
 101             event (EventBase): Zookeeper Cluster relation event.
 102         """
 103         self._publish_info(event)
 104         self.configure_pod()
 105
 106     def _publish_info(self, event: EventBase):
 107         """Publishes Zookeeper information.
 108
 109         Args:
 110             event (EventBase): Zookeeper relation event.
 111         """
 112         if self.unit.is_leader():
 113             zk_uri = self.zookeeper_uri
 114             if zk_uri:
 115                 self.zookeeper_server.publish_info(zk_uri)
 116             else:
 117                 event.defer()
 118
 119     def build_pod_spec(self, image_info):
 120         # Validate config
 121         config = ConfigModel(**dict(self.config))
 122
 123         # Create Builder for the PodSpec
 124         pod_spec_builder = PodSpecV3Builder(
 125             enable_security_context=config.security_context
 126         )
 127
 128         # Build Container
 129         container_builder = ContainerV3Builder(
 130             self.app.name,
 131             image_info,
 132             config.image_pull_policy,
 133             run_as_non_root=config.security_context,
 134         )
 135
 136         container_builder.add_port(name="client", port=CLIENT_PORT)
 137         container_builder.add_port(name="server", port=SERVER_PORT)
 138         container_builder.add_port(name="leader-election", port=LEADER_ELECTION_PORT)
 139         container_builder.add_tcpsocket_readiness_probe(
 140             CLIENT_PORT,
 141             initial_delay_seconds=10,
 142             timeout_seconds=5,
 143             failure_threshold=6,
 144             success_threshold=1,
 145         )
 146         container_builder.add_tcpsocket_liveness_probe(
 147             CLIENT_PORT, initial_delay_seconds=20
 148         )
 149         container_builder.add_command(
 150             [
 151                 "sh",
 152                 "-c",
 153                 " ".join(
 154                     [
 155                         "start-zookeeper",
 156                         f"--servers={self.num_units}",
 157                         "--data_dir=/var/lib/zookeeper/data",
 158                         "--data_log_dir=/var/lib/zookeeper/data/log",
 159                         "--conf_dir=/opt/zookeeper/conf",
 160                         f"--client_port={CLIENT_PORT}",
 161                         f"--election_port={LEADER_ELECTION_PORT}",
 162                         f"--server_port={SERVER_PORT}",
 163                         f"--tick_time={config.tick_time}",
 164                         f"--init_limit={config.init_limit}",
 165                         f"--sync_limit={config.sync_limit}",
 166                         f"--heap={config.heap}M",
 167                         f"--max_client_cnxns={config.max_client_cnxns}",
 168                         f"--snap_retain_count={config.snap_retain_count}",
 169                         f"--purge_interval={config.purge_interval}",
 170                         f"--max_session_timeout={config.max_session_timeout}",
 171                         f"--min_session_timeout={config.min_session_timeout}",
 172                         f"--log_level={config.log_level}",
 173                     ]
 174                 ),
 175             ]
 176         )
 177
 178         container = container_builder.build()
 179
 180         # Add container to pod spec
 181         pod_spec_builder.add_container(container)
 182
 183         return pod_spec_builder.build()
 184
 185
 186 if __name__ == "__main__":
 187     main(ZookeeperCharm)