installers/charm/prometheus/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 Optional, NoReturn
  27 from ipaddress import ip_network
  28
  29 from ops.framework import EventBase
  30 from ops.main import main
  31
  32 from opslib.osm.charm import CharmedOsmBase
  33
  34 from opslib.osm.pod import (
  35     IngressResourceV3Builder,
  36     FilesV3Builder,
  37     ContainerV3Builder,
  38     PodSpecV3Builder,
  39 )
  40
  41
  42 from opslib.osm.validator import (
  43     ModelValidator,
  44     validator,
  45 )
  46
  47 from opslib.osm.interfaces.prometheus import PrometheusServer
  48 from urllib.parse import urlparse
  49
  50 logger = logging.getLogger(__name__)
  51
  52 PORT = 9090
  53
  54
  55 class ConfigModel(ModelValidator):
  56     web_subpath: str
  57     default_target: str
  58     max_file_size: int
  59     site_url: Optional[str]
  60     ingress_whitelist_source_range: Optional[str]
  61     tls_secret_name: Optional[str]
  62     enable_web_admin_api: bool
  63
  64     @validator("web_subpath")
  65     def validate_web_subpath(cls, v):
  66         if len(v) < 1:
  67             raise ValueError("web-subpath must be a non-empty string")
  68         return v
  69
  70     @validator("max_file_size")
  71     def validate_max_file_size(cls, v):
  72         if v < 0:
  73             raise ValueError("value must be equal or greater than 0")
  74         return v
  75
  76     @validator("site_url")
  77     def validate_site_url(cls, v):
  78         if v:
  79             parsed = urlparse(v)
  80             if not parsed.scheme.startswith("http"):
  81                 raise ValueError("value must start with http")
  82         return v
  83
  84     @validator("ingress_whitelist_source_range")
  85     def validate_ingress_whitelist_source_range(cls, v):
  86         if v:
  87             ip_network(v)
  88         return v
  89
  90
  91 class PrometheusCharm(CharmedOsmBase):
  92
  93     """Prometheus Charm."""
  94
  95     def __init__(self, *args) -> NoReturn:
  96         """Prometheus Charm constructor."""
  97         super().__init__(*args, oci_image="image")
  98
  99         # Registering provided relation events
 100         self.prometheus = PrometheusServer(self, "prometheus")
 101         self.framework.observe(
 102             self.on.prometheus_relation_joined,  # pylint: disable=E1101
 103             self._publish_prometheus_info,
 104         )
 105
 106     def _publish_prometheus_info(self, event: EventBase) -> NoReturn:
 107         self.prometheus.publish_info(self.app.name, PORT)
 108
 109     def _build_files(self, config: ConfigModel):
 110         files_builder = FilesV3Builder()
 111         files_builder.add_file(
 112             "prometheus.yml",
 113             (
 114                 "global:\n"
 115                 "  scrape_interval: 15s\n"
 116                 "  evaluation_interval: 15s\n"
 117                 "alerting:\n"
 118                 "  alertmanagers:\n"
 119                 "    - static_configs:\n"
 120                 "        - targets:\n"
 121                 "rule_files:\n"
 122                 "scrape_configs:\n"
 123                 "  - job_name: 'prometheus'\n"
 124                 "    static_configs:\n"
 125                 f"      - targets: [{config.default_target}]\n"
 126             ),
 127         )
 128         return files_builder.build()
 129
 130     def build_pod_spec(self, image_info):
 131         # Validate config
 132         config = ConfigModel(**dict(self.config))
 133         # Create Builder for the PodSpec
 134         pod_spec_builder = PodSpecV3Builder()
 135         # Build Container
 136         container_builder = ContainerV3Builder(self.app.name, image_info)
 137         container_builder.add_port(name=self.app.name, port=PORT)
 138         container_builder.add_http_readiness_probe(
 139             "/-/ready",
 140             PORT,
 141             initial_delay_seconds=10,
 142             timeout_seconds=30,
 143         )
 144         container_builder.add_http_liveness_probe(
 145             "/-/healthy",
 146             PORT,
 147             initial_delay_seconds=30,
 148             period_seconds=30,
 149         )
 150         command = [
 151             "/bin/prometheus",
 152             "--config.file=/etc/prometheus/prometheus.yml",
 153             "--storage.tsdb.path=/prometheus",
 154             "--web.console.libraries=/usr/share/prometheus/console_libraries",
 155             "--web.console.templates=/usr/share/prometheus/consoles",
 156             f"--web.route-prefix={config.web_subpath}",
 157             f"--web.external-url=http://localhost:{PORT}{config.web_subpath}",
 158         ]
 159         if config.enable_web_admin_api:
 160             command.append("--web.enable-admin-api")
 161         container_builder.add_command(command)
 162         container_builder.add_volume_config(
 163             "config", "/etc/prometheus", self._build_files(config)
 164         )
 165         container = container_builder.build()
 166         # Add container to pod spec
 167         pod_spec_builder.add_container(container)
 168         # Add ingress resources to pod spec if site url exists
 169         if config.site_url:
 170             parsed = urlparse(config.site_url)
 171             annotations = {
 172                 "nginx.ingress.kubernetes.io/proxy-body-size": "{}".format(
 173                     str(config.max_file_size) + "m"
 174                     if config.max_file_size > 0
 175                     else config.max_file_size
 176                 ),
 177             }
 178             ingress_resource_builder = IngressResourceV3Builder(
 179                 f"{self.app.name}-ingress", annotations
 180             )
 181
 182             if config.ingress_whitelist_source_range:
 183                 annotations[
 184                     "nginx.ingress.kubernetes.io/whitelist-source-range"
 185                 ] = config.ingress_whitelist_source_range
 186
 187             if parsed.scheme == "https":
 188                 ingress_resource_builder.add_tls(
 189                     [parsed.hostname], config.tls_secret_name
 190                 )
 191             else:
 192                 annotations["nginx.ingress.kubernetes.io/ssl-redirect"] = "false"
 193
 194             ingress_resource_builder.add_rule(parsed.hostname, self.app.name, PORT)
 195             ingress_resource = ingress_resource_builder.build()
 196             pod_spec_builder.add_ingress_resource(ingress_resource)
 197         return pod_spec_builder.build()
 198
 199
 200 if __name__ == "__main__":
 201     main(PrometheusCharm)