Refactoring Prometheus Charm to use Operator Framework
Change-Id: Ib1b33bd5e6b91d2689a7c3abdfd834de20ceed88
Signed-off-by: sousaedu <eduardo.sousa@canonical.com>
diff --git a/installers/charm/prometheus/src/charm.py b/installers/charm/prometheus/src/charm.py
new file mode 100755
index 0000000..4371d47
--- /dev/null
+++ b/installers/charm/prometheus/src/charm.py
@@ -0,0 +1,195 @@
+#!/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 typing import Dict, List, NoReturn
+
+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__)
+
+PROMETHEUS_PORT = 9090
+
+
+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 PrometheusCharm(CharmBase):
+ """Prometheus Charm."""
+
+ state = StoredState()
+
+ def __init__(self, *args) -> NoReturn:
+ """Prometheus Charm constructor."""
+ super().__init__(*args)
+
+ # Internal state initialization
+ self.state.set_default(pod_spec=None)
+
+ self.port = PROMETHEUS_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 provided relation events
+ self.framework.observe(
+ self.on.prometheus_relation_joined, self._publish_prometheus_info
+ )
+
+ def _publish_prometheus_info(self, event: EventBase) -> NoReturn:
+ """Publishes Prometheus information.
+
+ Args:
+ event (EventBase): Prometheus relation event.
+ """
+ if self.unit.is_leader():
+ rel_data = {
+ "host": self.model.app.name,
+ "port": str(PROMETHEUS_PORT),
+ }
+ for k, v in rel_data.items():
+ event.relation.data[self.app][k] = v
+
+ @property
+ def relations_requirements(self):
+ return []
+
+ 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(PrometheusCharm)
diff --git a/installers/charm/prometheus/src/pod_spec.py b/installers/charm/prometheus/src/pod_spec.py
new file mode 100644
index 0000000..3e4bc44
--- /dev/null
+++ b/installers/charm/prometheus/src/pod_spec.py
@@ -0,0 +1,378 @@
+#!/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
+##
+
+from ipaddress import ip_network
+import logging
+from typing import Any, Dict, List
+from urllib.parse import urlparse
+
+logger = logging.getLogger(__name__)
+
+
+def _validate_max_file_size(max_file_size: int, site_url: str) -> bool:
+ """Validate max_file_size.
+
+ Args:
+ max_file_size (int): maximum file size allowed.
+ site_url (str): endpoint url.
+
+ Returns:
+ bool: True if valid, false otherwise.
+ """
+ if not site_url:
+ return True
+
+ parsed = urlparse(site_url)
+
+ if not parsed.scheme.startswith("http"):
+ return True
+
+ if max_file_size is None:
+ return False
+
+ return max_file_size >= 0
+
+
+def _validate_ip_network(network: str) -> bool:
+ """Validate IP network.
+
+ Args:
+ network (str): IP network range.
+
+ Returns:
+ bool: True if valid, false otherwise.
+ """
+ if not network:
+ return True
+
+ try:
+ ip_network(network)
+ except ValueError:
+ return False
+
+ return True
+
+
+def _validate_data(config_data: Dict[str, Any], relation_data: Dict[str, Any]) -> bool:
+ """Validates passed information.
+
+ Args:
+ config_data (Dict[str, Any]): configuration information.
+ relation_data (Dict[str, Any]): relation information
+
+ Raises:
+ ValueError: when config and/or relation data is not valid.
+ """
+ config_validators = {
+ "web_subpath": lambda value, _: isinstance(value, str) and len(value) > 0,
+ "default_target": lambda value, _: isinstance(value, str),
+ "site_url": lambda value, _: isinstance(value, str)
+ if value is not None
+ else True,
+ "max_file_size": lambda value, values: _validate_max_file_size(
+ value, values.get("site_url")
+ ),
+ "ingress_whitelist_source_range": lambda value, _: _validate_ip_network(value),
+ "tls_secret_name": lambda value, _: isinstance(value, str)
+ if value is not None
+ else True,
+ }
+ relation_validators = {}
+ problems = []
+
+ for key, validator in config_validators.items():
+ valid = validator(config_data.get(key), config_data)
+
+ if not valid:
+ problems.append(key)
+
+ for key, validator in relation_validators.items():
+ valid = validator(relation_data.get(key), relation_data)
+
+ if not valid:
+ problems.append(key)
+
+ if len(problems) > 0:
+ raise ValueError("Errors found in: {}".format(", ".join(problems)))
+
+ return True
+
+
+def _make_pod_ports(port: int) -> List[Dict[str, Any]]:
+ """Generate pod ports details.
+
+ Args:
+ port (int): port to expose.
+
+ Returns:
+ List[Dict[str, Any]]: pod port details.
+ """
+ return [{"name": "prometheus", "containerPort": port, "protocol": "TCP"}]
+
+
+def _make_pod_envconfig(
+ config: Dict[str, Any], relation_state: Dict[str, Any]
+) -> Dict[str, Any]:
+ """Generate pod environment configuration.
+
+ Args:
+ config (Dict[str, Any]): configuration information.
+ relation_state (Dict[str, Any]): relation state information.
+
+ Returns:
+ Dict[str, Any]: pod environment configuration.
+ """
+ envconfig = {}
+
+ return envconfig
+
+
+def _make_pod_ingress_resources(
+ config: Dict[str, Any], app_name: str, port: int
+) -> List[Dict[str, Any]]:
+ """Generate pod ingress resources.
+
+ Args:
+ config (Dict[str, Any]): configuration information.
+ app_name (str): application name.
+ port (int): port to expose.
+
+ Returns:
+ List[Dict[str, Any]]: pod ingress resources.
+ """
+ site_url = config.get("site_url")
+
+ if not site_url:
+ return
+
+ parsed = urlparse(site_url)
+
+ if not parsed.scheme.startswith("http"):
+ return
+
+ max_file_size = config["max_file_size"]
+ ingress_whitelist_source_range = config["ingress_whitelist_source_range"]
+
+ annotations = {
+ "nginx.ingress.kubernetes.io/proxy-body-size": "{}".format(
+ str(max_file_size) + "m" if max_file_size > 0 else max_file_size
+ ),
+ }
+
+ if ingress_whitelist_source_range:
+ annotations[
+ "nginx.ingress.kubernetes.io/whitelist-source-range"
+ ] = ingress_whitelist_source_range
+
+ ingress_spec_tls = None
+
+ if parsed.scheme == "https":
+ ingress_spec_tls = [{"hosts": [parsed.hostname]}]
+ tls_secret_name = config["tls_secret_name"]
+ if tls_secret_name:
+ ingress_spec_tls[0]["secretName"] = tls_secret_name
+ else:
+ annotations["nginx.ingress.kubernetes.io/ssl-redirect"] = "false"
+
+ ingress = {
+ "name": "{}-ingress".format(app_name),
+ "annotations": annotations,
+ "spec": {
+ "rules": [
+ {
+ "host": parsed.hostname,
+ "http": {
+ "paths": [
+ {
+ "path": "/",
+ "backend": {
+ "serviceName": app_name,
+ "servicePort": port,
+ },
+ }
+ ]
+ },
+ }
+ ]
+ },
+ }
+ if ingress_spec_tls:
+ ingress["spec"]["tls"] = ingress_spec_tls
+
+ return [ingress]
+
+
+def _make_pod_files(config: Dict[str, Any]) -> List[Dict[str, Any]]:
+ """Generating ConfigMap information
+
+ Args:
+ config (Dict[str, Any]): configuration information.
+
+ Returns:
+ List[Dict[str, Any]]: ConfigMap information.
+ """
+ files = [
+ {
+ "name": "config",
+ "mountPath": "/etc/prometheus",
+ "files": [
+ {
+ "path": "prometheus.yml",
+ "content": (
+ "global:"
+ " scrape_interval: 15s"
+ " evaluation_interval: 15s"
+ "alerting:"
+ " alertmanagers:"
+ " - static_configs:"
+ " - targets:"
+ "rule_files:"
+ "scrape_configs:"
+ " - job_name: 'prometheus'"
+ " static_configs:"
+ " - targets: [{}]".format(config["default_target"])
+ ),
+ }
+ ],
+ }
+ ]
+
+ return files
+
+
+def _make_readiness_probe(port: int) -> Dict[str, Any]:
+ """Generate readiness probe.
+
+ Args:
+ port (int): service port.
+
+ Returns:
+ Dict[str, Any]: readiness probe.
+ """
+ return {
+ "httpGet": {
+ "path": "/-/ready",
+ "port": port,
+ },
+ "initialDelaySeconds": 10,
+ "timeoutSeconds": 30,
+ }
+
+
+def _make_liveness_probe(port: int) -> Dict[str, Any]:
+ """Generate liveness probe.
+
+ Args:
+ port (int): service port.
+
+ Returns:
+ Dict[str, Any]: liveness probe.
+ """
+ return {
+ "httpGet": {
+ "path": "/-/healthy",
+ "port": port,
+ },
+ "initialDelaySeconds": 30,
+ "periodSeconds": 30,
+ }
+
+
+def _make_pod_command(config: Dict[str, Any], port: int) -> List[str]:
+ """Generate the startup command.
+
+ Args:
+ config (Dict[str, Any]): Configuration information.
+ port (int): port.
+
+ Returns:
+ List[str]: command to startup the process.
+ """
+ return [
+ "sh",
+ "-c",
+ "/bin/prometheus",
+ "--config.file=/etc/prometheus/prometheus.yml",
+ "--storage.tsdb.path=/prometheus",
+ "--web.console.libraries=/usr/share/prometheus/console_libraries",
+ "--web.console.templates=/usr/share/prometheus/consoles",
+ "--web.route-prefix={}".format(config.get("web_subpath")),
+ "--web.external-url=http://localhost:{}{}".format(
+ port, config.get("web_subpath")
+ ),
+ ]
+
+
+def make_pod_spec(
+ image_info: Dict[str, str],
+ config: Dict[str, Any],
+ relation_state: Dict[str, Any],
+ app_name: str = "prometheus",
+ port: int = 9090,
+) -> Dict[str, Any]:
+ """Generate the pod spec information.
+
+ Args:
+ image_info (Dict[str, str]): Object provided by
+ OCIImageResource("image").fetch().
+ config (Dict[str, Any]): Configuration information.
+ relation_state (Dict[str, Any]): Relation state information.
+ app_name (str, optional): Application name. Defaults to "ro".
+ port (int, optional): Port for the container. Defaults to 9090.
+
+ Returns:
+ Dict[str, Any]: Pod spec dictionary for the charm.
+ """
+ if not image_info:
+ return None
+
+ _validate_data(config, relation_state)
+
+ ports = _make_pod_ports(port)
+ env_config = _make_pod_envconfig(config, relation_state)
+ files = _make_pod_files(config)
+ readiness_probe = _make_readiness_probe(port)
+ liveness_probe = _make_liveness_probe(port)
+ ingress_resources = _make_pod_ingress_resources(config, app_name, port)
+ command = _make_pod_command(config, port)
+
+ return {
+ "version": 3,
+ "containers": [
+ {
+ "name": app_name,
+ "imageDetails": image_info,
+ "imagePullPolicy": "Always",
+ "ports": ports,
+ "envConfig": env_config,
+ "volumeConfig": files,
+ "command": command,
+ "kubernetes": {
+ "readinessProbe": readiness_probe,
+ "livenessProbe": liveness_probe,
+ },
+ }
+ ],
+ "kubernetesResources": {
+ "ingressResources": ingress_resources or [],
+ },
+ }