installers/charm/mysqld-exporter/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 from ipaddress import ip_network
  26 import logging
  27 from pathlib import Path
  28 from typing import NoReturn, Optional
  29 from urllib.parse import urlparse
  30
  31 from ops.main import main
  32 from opslib.osm.charm import CharmedOsmBase, RelationsMissing
  33 from opslib.osm.interfaces.grafana import GrafanaDashboardTarget
  34 from opslib.osm.interfaces.mysql import MysqlClient
  35 from opslib.osm.interfaces.prometheus import PrometheusScrapeTarget
  36 from opslib.osm.pod import (
  37     ContainerV3Builder,
  38     IngressResourceV3Builder,
  39     PodRestartPolicy,
  40     PodSpecV3Builder,
  41 )
  42 from opslib.osm.validator import ModelValidator, validator
  43
  44
  45 logger = logging.getLogger(__name__)
  46
  47 PORT = 9104
  48
  49
  50 class ConfigModel(ModelValidator):
  51     site_url: Optional[str]
  52     cluster_issuer: Optional[str]
  53     ingress_class: Optional[str]
  54     ingress_whitelist_source_range: Optional[str]
  55     tls_secret_name: Optional[str]
  56     mysql_uri: Optional[str]
  57     image_pull_policy: str
  58
  59     @validator("site_url")
  60     def validate_site_url(cls, v):
  61         if v:
  62             parsed = urlparse(v)
  63             if not parsed.scheme.startswith("http"):
  64                 raise ValueError("value must start with http")
  65         return v
  66
  67     @validator("ingress_whitelist_source_range")
  68     def validate_ingress_whitelist_source_range(cls, v):
  69         if v:
  70             ip_network(v)
  71         return v
  72
  73     @validator("mysql_uri")
  74     def validate_mysql_uri(cls, v):
  75         if v and not v.startswith("mysql://"):
  76             raise ValueError("mysql_uri is not properly formed")
  77         return v
  78
  79     @validator("image_pull_policy")
  80     def validate_image_pull_policy(cls, v):
  81         values = {
  82             "always": "Always",
  83             "ifnotpresent": "IfNotPresent",
  84             "never": "Never",
  85         }
  86         v = v.lower()
  87         if v not in values.keys():
  88             raise ValueError("value must be always, ifnotpresent or never")
  89         return values[v]
  90
  91
  92 class MysqlExporterCharm(CharmedOsmBase):
  93     def __init__(self, *args) -> NoReturn:
  94         super().__init__(*args, oci_image="image")
  95
  96         # Provision Kafka relation to exchange information
  97         self.mysql_client = MysqlClient(self, "mysql")
  98         self.framework.observe(self.on["mysql"].relation_changed, self.configure_pod)
  99         self.framework.observe(self.on["mysql"].relation_broken, self.configure_pod)
 100
 101         # Register relation to provide a Scraping Target
 102         self.scrape_target = PrometheusScrapeTarget(self, "prometheus-scrape")
 103         self.framework.observe(
 104             self.on["prometheus-scrape"].relation_joined, self._publish_scrape_info
 105         )
 106
 107         # Register relation to provide a Dasboard Target
 108         self.dashboard_target = GrafanaDashboardTarget(self, "grafana-dashboard")
 109         self.framework.observe(
 110             self.on["grafana-dashboard"].relation_joined, self._publish_dashboard_info
 111         )
 112
 113     def _publish_scrape_info(self, event) -> NoReturn:
 114         """Publishes scraping information for Prometheus.
 115
 116         Args:
 117             event (EventBase): Prometheus relation event.
 118         """
 119         if self.unit.is_leader():
 120             hostname = (
 121                 urlparse(self.model.config["site_url"]).hostname
 122                 if self.model.config["site_url"]
 123                 else self.model.app.name
 124             )
 125             port = str(PORT)
 126             if self.model.config.get("site_url", "").startswith("https://"):
 127                 port = "443"
 128             elif self.model.config.get("site_url", "").startswith("http://"):
 129                 port = "80"
 130
 131             self.scrape_target.publish_info(
 132                 hostname=hostname,
 133                 port=port,
 134                 metrics_path="/metrics",
 135                 scrape_interval="30s",
 136                 scrape_timeout="15s",
 137             )
 138
 139     def _publish_dashboard_info(self, event) -> NoReturn:
 140         """Publish dashboards for Grafana.
 141
 142         Args:
 143             event (EventBase): Grafana relation event.
 144         """
 145         if self.unit.is_leader():
 146             self.dashboard_target.publish_info(
 147                 name="osm-mysql",
 148                 dashboard=Path("templates/mysql_exporter_dashboard.json").read_text(),
 149             )
 150
 151     def _check_missing_dependencies(self, config: ConfigModel):
 152         """Check if there is any relation missing.
 153
 154         Args:
 155             config (ConfigModel): object with configuration information.
 156
 157         Raises:
 158             RelationsMissing: if kafka is missing.
 159         """
 160         missing_relations = []
 161
 162         if not config.mysql_uri and self.mysql_client.is_missing_data_in_unit():
 163             missing_relations.append("mysql")
 164
 165         if missing_relations:
 166             raise RelationsMissing(missing_relations)
 167
 168     def build_pod_spec(self, image_info):
 169         """Build the PodSpec to be used.
 170
 171         Args:
 172             image_info (str): container image information.
 173
 174         Returns:
 175             Dict: PodSpec information.
 176         """
 177         # Validate config
 178         config = ConfigModel(**dict(self.config))
 179
 180         if config.mysql_uri and not self.mysql_client.is_missing_data_in_unit():
 181             raise Exception("Mysql data cannot be provided via config and relation")
 182
 183         # Check relations
 184         self._check_missing_dependencies(config)
 185
 186         data_source = (
 187             config.mysql_uri.replace("mysql://", "").split("/")[0]
 188             if config.mysql_uri
 189             else f"root:{self.mysql_client.root_password}@{self.mysql_client.host}:{self.mysql_client.port}"
 190         )
 191
 192         # Create Builder for the PodSpec
 193         pod_spec_builder = PodSpecV3Builder()
 194
 195         # Add secrets to the pod
 196         mysql_secret_name = f"{self.app.name}-mysql-secret"
 197         pod_spec_builder.add_secret(
 198             mysql_secret_name,
 199             {"data_source": data_source},
 200         )
 201
 202         # Build container
 203         container_builder = ContainerV3Builder(
 204             self.app.name, image_info, config.image_pull_policy
 205         )
 206         container_builder.add_port(name=self.app.name, port=PORT)
 207         container_builder.add_http_readiness_probe(
 208             path="/api/health",
 209             port=PORT,
 210             initial_delay_seconds=10,
 211             period_seconds=10,
 212             timeout_seconds=5,
 213             success_threshold=1,
 214             failure_threshold=3,
 215         )
 216         container_builder.add_http_liveness_probe(
 217             path="/api/health",
 218             port=PORT,
 219             initial_delay_seconds=60,
 220             timeout_seconds=30,
 221             failure_threshold=10,
 222         )
 223         container_builder.add_secret_envs(
 224             mysql_secret_name, {"DATA_SOURCE_NAME": "data_source"}
 225         )
 226
 227         container = container_builder.build()
 228
 229         # Add container to PodSpec
 230         pod_spec_builder.add_container(container)
 231
 232         # Add Pod restart policy
 233         restart_policy = PodRestartPolicy()
 234         restart_policy.add_secrets(secret_names=(mysql_secret_name))
 235         pod_spec_builder.set_restart_policy(restart_policy)
 236
 237         # Add ingress resources to PodSpec if site url exists
 238         if config.site_url:
 239             parsed = urlparse(config.site_url)
 240             annotations = {}
 241             if config.ingress_class:
 242                 annotations["kubernetes.io/ingress.class"] = config.ingress_class
 243             ingress_resource_builder = IngressResourceV3Builder(
 244                 f"{self.app.name}-ingress", annotations
 245             )
 246
 247             if config.ingress_whitelist_source_range:
 248                 annotations[
 249                     "nginx.ingress.kubernetes.io/whitelist-source-range"
 250                 ] = config.ingress_whitelist_source_range
 251
 252             if config.cluster_issuer:
 253                 annotations["cert-manager.io/cluster-issuer"] = config.cluster_issuer
 254
 255             if parsed.scheme == "https":
 256                 ingress_resource_builder.add_tls(
 257                     [parsed.hostname], config.tls_secret_name
 258                 )
 259             else:
 260                 annotations["nginx.ingress.kubernetes.io/ssl-redirect"] = "false"
 261
 262             ingress_resource_builder.add_rule(parsed.hostname, self.app.name, PORT)
 263             ingress_resource = ingress_resource_builder.build()
 264             pod_spec_builder.add_ingress_resource(ingress_resource)
 265
 266         return pod_spec_builder.build()
 267
 268
 269 if __name__ == "__main__":
 270     main(MysqlExporterCharm)