X-Git-Url: https://osm.etsi.org/gitweb/?a=blobdiff_plain;f=installers%2Fcharm%2Fmysqld-exporter%2Fsrc%2Fcharm.py;fp=installers%2Fcharm%2Fmysqld-exporter%2Fsrc%2Fcharm.py;h=1f42dc76fbcf89db7b0ec6d210b3aa8c6165f943;hb=90d10f5dc85d577c7cec2d608b19a23120df1281;hp=0000000000000000000000000000000000000000;hpb=b025f3082689234268b79adc91f7d47ac61ca924;p=osm%2Fdevops.git diff --git a/installers/charm/mysqld-exporter/src/charm.py b/installers/charm/mysqld-exporter/src/charm.py new file mode 100755 index 00000000..1f42dc76 --- /dev/null +++ b/installers/charm/mysqld-exporter/src/charm.py @@ -0,0 +1,229 @@ +#!/usr/bin/env python3 +# Copyright 2021 Canonical Ltd. +# +# Licensed under the Apache License, Version 2.0 (the "License"); you may +# not use this file except in compliance with the License. You may obtain +# a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +# License for the specific language governing permissions and limitations +# under the License. +# +# For those usages not covered by the Apache License, Version 2.0 please +# contact: legal@canonical.com +# +# To get in touch with the maintainers, please contact: +# osm-charmers@lists.launchpad.net +## + +import logging +from pathlib import Path +from typing import Dict, List, NoReturn +from urllib.parse import urlparse + +from ops.charm import CharmBase +from ops.framework import EventBase, StoredState +from ops.main import main +from ops.model import ActiveStatus, Application, BlockedStatus, MaintenanceStatus, Unit +from oci_image import OCIImageResource, OCIImageResourceError + +from pod_spec import make_pod_spec + +logger = logging.getLogger(__name__) + +MYSQLD_EXPORTER_PORT = 9104 + + +class RelationsMissing(Exception): + def __init__(self, missing_relations: List): + self.message = "" + if missing_relations and isinstance(missing_relations, list): + self.message += f'Waiting for {", ".join(missing_relations)} relation' + if "," in self.message: + self.message += "s" + + +class RelationDefinition: + def __init__(self, relation_name: str, keys: List, source_type): + if source_type != Application and source_type != Unit: + raise TypeError( + "source_type should be ops.model.Application or ops.model.Unit" + ) + self.relation_name = relation_name + self.keys = keys + self.source_type = source_type + + +def check_missing_relation_data( + data: Dict, + expected_relations_data: List[RelationDefinition], +): + missing_relations = [] + for relation_data in expected_relations_data: + if not all( + f"{relation_data.relation_name}_{k}" in data for k in relation_data.keys + ): + missing_relations.append(relation_data.relation_name) + if missing_relations: + raise RelationsMissing(missing_relations) + + +def get_relation_data( + charm: CharmBase, + relation_data: RelationDefinition, +) -> Dict: + data = {} + relation = charm.model.get_relation(relation_data.relation_name) + if relation: + self_app_unit = ( + charm.app if relation_data.source_type == Application else charm.unit + ) + expected_type = relation_data.source_type + for app_unit in relation.data: + if app_unit != self_app_unit and isinstance(app_unit, expected_type): + if all(k in relation.data[app_unit] for k in relation_data.keys): + for k in relation_data.keys: + data[f"{relation_data.relation_name}_{k}"] = relation.data[ + app_unit + ].get(k) + break + return data + + +class MysqldExporterCharm(CharmBase): + """Mysqld Exporter Charm.""" + + state = StoredState() + + def __init__(self, *args) -> NoReturn: + """Mysqld Exporter Charm constructor.""" + super().__init__(*args) + + # Internal state initialization + self.state.set_default(pod_spec=None) + + self.port = MYSQLD_EXPORTER_PORT + self.image = OCIImageResource(self, "image") + + # Registering regular events + self.framework.observe(self.on.start, self.configure_pod) + self.framework.observe(self.on.config_changed, self.configure_pod) + + # Registering required relation events + self.framework.observe(self.on.mysql_relation_changed, self.configure_pod) + + # Registering required relation departed events + self.framework.observe(self.on.mysql_relation_departed, self.configure_pod) + + # Registering provided relation events + self.framework.observe( + self.on.prometheus_scrape_relation_joined, self._publish_scrape_info + ) + self.framework.observe( + self.on.grafana_dashboard_relation_joined, self._publish_dashboard_info + ) + + def _publish_scrape_info(self, event: EventBase) -> NoReturn: + """Publishes scrape information. + + Args: + event (EventBase): Exporter relation event. + """ + rel_data = { + "hostname": urlparse(self.model.config["site_url"]).hostname + if self.model.config["site_url"] + else self.model.app.name, + "port": "80" + if self.model.config["site_url"] + else str(MYSQLD_EXPORTER_PORT), + "metrics_path": "/metrics", + "scrape_interval": "30s", + "scrape_timeout": "15s", + } + for k, v in rel_data.items(): + event.relation.data[self.unit][k] = v + + def _publish_dashboard_info(self, event: EventBase) -> NoReturn: + """Publishes dashboard information. + + Args: + event (EventBase): Exporter relation event. + """ + rel_data = { + "name": "osm-mysql", + "dashboard": Path("files/mysql_exporter_dashboard.json").read_text(), + } + for k, v in rel_data.items(): + event.relation.data[self.unit][k] = v + + @property + def relations_requirements(self): + return [ + RelationDefinition( + "mysql", ["host", "port", "user", "password", "root_password"], Unit + ) + ] + + def get_relation_state(self): + relation_state = {} + for relation_requirements in self.relations_requirements: + data = get_relation_data(self, relation_requirements) + relation_state = {**relation_state, **data} + check_missing_relation_data(relation_state, self.relations_requirements) + return relation_state + + def configure_pod(self, _=None) -> NoReturn: + """Assemble the pod spec and apply it, if possible. + + Args: + event (EventBase): Hook or Relation event that started the + function. + """ + if not self.unit.is_leader(): + self.unit.status = ActiveStatus("ready") + return + + relation_state = None + try: + relation_state = self.get_relation_state() + except RelationsMissing as exc: + logger.exception("Relation missing error") + self.unit.status = BlockedStatus(exc.message) + return + + self.unit.status = MaintenanceStatus("Assembling pod spec") + + # Fetch image information + try: + self.unit.status = MaintenanceStatus("Fetching image information") + image_info = self.image.fetch() + except OCIImageResourceError: + self.unit.status = BlockedStatus("Error fetching image information") + return + + try: + pod_spec = make_pod_spec( + image_info, + self.model.config, + relation_state, + self.model.app.name, + self.port, + ) + except ValueError as exc: + logger.exception("Config/Relation data validation error") + self.unit.status = BlockedStatus(str(exc)) + return + + if self.state.pod_spec != pod_spec: + self.model.pod.set_spec(pod_spec) + self.state.pod_spec = pod_spec + + self.unit.status = ActiveStatus("ready") + + +if __name__ == "__main__": + main(MysqldExporterCharm)