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