installers/charm/grafana/src/charm.py

#!/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
##

# pylint: disable=E0213

import logging
from typing import Optional, NoReturn
from ipaddress import ip_network

from ops.main import main

from opslib.osm.charm import CharmedOsmBase, RelationsMissing

from opslib.osm.pod import (
    IngressResourceV3Builder,
    FilesV3Builder,
    ContainerV3Builder,
    PodSpecV3Builder,
)


from opslib.osm.validator import (
    ModelValidator,
    validator,
)

from opslib.osm.interfaces.prometheus import PrometheusClient

from urllib.parse import urlparse
from string import Template
from pathlib import Path

logger = logging.getLogger(__name__)

PORT = 3000


class ConfigModel(ModelValidator):
    max_file_size: int
    osm_dashboards: bool
    site_url: Optional[str]
    ingress_whitelist_source_range: Optional[str]
    tls_secret_name: Optional[str]

    @validator("max_file_size")
    def validate_max_file_size(cls, v):
        if v < 0:
            raise ValueError("value must be equal or greater than 0")
        return v

    @validator("site_url")
    def validate_site_url(cls, v):
        if v:
            parsed = urlparse(v)
            if not parsed.scheme.startswith("http"):
                raise ValueError("value must start with http")
        return v

    @validator("ingress_whitelist_source_range")
    def validate_ingress_whitelist_source_range(cls, v):
        if v:
            ip_network(v)
        return v


class GrafanaCharm(CharmedOsmBase):
    """GrafanaCharm Charm."""

    def __init__(self, *args) -> NoReturn:
        """Prometheus Charm constructor."""
        super().__init__(*args, oci_image="image")

        self.prometheus_client = PrometheusClient(self, "prometheus")
        self.framework.observe(self.on["prometheus"].relation_changed, self.configure_pod)
        self.framework.observe(self.on["prometheus"].relation_broken, self.configure_pod)

    def _build_dashboard_files(self, config: ConfigModel):
        files_builder = FilesV3Builder()
        files_builder.add_file(
            "dashboard_osm.yaml",
            Path("files/default_dashboards.yaml").read_text(),
        )
        if config.osm_dashboards:
            osm_dashboards_mapping = {
                "kafka_exporter_dashboard.yaml": "files/kafka_exporter_dashboard.yaml",
                "mongodb_exporter_dashboard.yaml": "files/mongodb_exporter_dashboard.yaml",
                "mysql_exporter_dashboard.yaml": "files/mysql_exporter_dashboard.yaml",
                "nodes_exporter_dashboard.yaml": "files/nodes_exporter_dashboard.yaml",
                "summary_dashboard.yaml": "files/summary_dashboard.yaml",
            }
            for file_name, path in osm_dashboards_mapping.items():
                files_builder.add_file(file_name, Path(path).read_text())
        return files_builder.build()

    def _build_datasources_files(self):
        files_builder = FilesV3Builder()
        files_builder.add_file(
            "datasource_prometheus.yaml",
            Template(Path("files/default_datasources.yaml").read_text()).substitute(
                prometheus_host=self.prometheus_client.hostname,
                prometheus_port=self.prometheus_client.port,
            ),
        )
        return files_builder.build()

    def _check_missing_dependencies(self):
        missing_relations = []

        if self.prometheus_client.is_missing_data_in_app():
            missing_relations.append("prometheus")

        if missing_relations:
            raise RelationsMissing(missing_relations)

    def build_pod_spec(self, image_info):
        # Validate config
        config = ConfigModel(**dict(self.config))
        # Check relations
        self._check_missing_dependencies()
        # Create Builder for the PodSpec
        pod_spec_builder = PodSpecV3Builder()
        # Build Container
        container_builder = ContainerV3Builder(self.app.name, image_info)
        container_builder.add_port(name=self.app.name, port=PORT)
        container_builder.add_http_readiness_probe(
            "/api/health",
            PORT,
            initial_delay_seconds=10,
            period_seconds=10,
            timeout_seconds=5,
            failure_threshold=3,
        )
        container_builder.add_http_liveness_probe(
            "/api/health",
            PORT,
            initial_delay_seconds=60,
            timeout_seconds=30,
            failure_threshold=10,
        )
        container_builder.add_volume_config(
            "dashboards",
            "/etc/grafana/provisioning/dashboards/",
            self._build_dashboard_files(config),
        )
        container_builder.add_volume_config(
            "datasources",
            "/etc/grafana/provisioning/datasources/",
            self._build_datasources_files(),
        )
        container = container_builder.build()
        # Add container to pod spec
        pod_spec_builder.add_container(container)
        # Add ingress resources to pod spec if site url exists
        if config.site_url:
            parsed = urlparse(config.site_url)
            annotations = {
                "nginx.ingress.kubernetes.io/proxy-body-size": "{}".format(
                    str(config.max_file_size) + "m"
                    if config.max_file_size > 0
                    else config.max_file_size
                ),
            }
            ingress_resource_builder = IngressResourceV3Builder(
                f"{self.app.name}-ingress", annotations
            )

            if config.ingress_whitelist_source_range:
                annotations[
                    "nginx.ingress.kubernetes.io/whitelist-source-range"
                ] = config.ingress_whitelist_source_range

            if parsed.scheme == "https":
                ingress_resource_builder.add_tls(
                    [parsed.hostname], config.tls_secret_name
                )
            else:
                annotations["nginx.ingress.kubernetes.io/ssl-redirect"] = "false"

            ingress_resource_builder.add_rule(parsed.hostname, self.app.name, PORT)
            ingress_resource = ingress_resource_builder.build()
            pod_spec_builder.add_ingress_resource(ingress_resource)
        return pod_spec_builder.build()


if __name__ == "__main__":
    main(GrafanaCharm)