dockstat/dockstat.py
2023-01-12 09:15:33 +00:00

212 lines
6.1 KiB
Python

#!/usr/bin/env python3
"""
Module to act as a Prometheus Exporter for Docker containers with a
healthcheck configured
"""
import argparse
import os
import os.path
import sys
from http.server import HTTPServer
from typing import Any
import docker # type: ignore[import]
import docker.errors # type: ignore[import]
import numpy
from docker.models.containers import Container # type: ignore[import]
from prometheus_client import CollectorRegistry # type: ignore[import]
from prometheus_client import Gauge, MetricsHandler, generate_latest
LISTEN_PORT = int(os.environ.get("DOCKSTAT_LISTEN_PORT", 8080))
HEALTHY_STR = "healthy"
class HTTPHandler(MetricsHandler): # type: ignore[misc]
"""
Class to encompass the requirements of a Prometheus Exporter
for Docker containers with a healthcheck configured
"""
def __init__(self, *args: Any, **kwargs: Any):
self.docker_api: docker.APIClient = docker.APIClient()
self.docker_client = docker.from_env()
super().__init__(*args, **kwargs)
# Override built-in method
def do_GET(self) -> None:
"""
Handle GET requests
"""
if self.path == "/metrics":
try:
self._metrics()
except docker.errors.NotFound:
pass
if self.path == "/healthcheck":
if not healthy():
print("ERROR: Check requirements")
self._respond(500, "ERR")
self._respond(200, "OK")
def _respond(self, status: int, message: str) -> None:
"""
Output a simple HTTP status and string to the client
e.g. 200 OK
Args:
status (int): HTTP status to output
message (str): String to output
"""
self.send_response(int(status) or 500)
self.end_headers()
try:
self.wfile.write(bytes(str(message).encode()))
except BrokenPipeError:
pass
def _metrics(self) -> None:
"""
Handle the request for metrics
"""
if not healthy:
print("ERROR: Check requirements")
self._respond(500, "Server not configured correctly")
return
registry = CollectorRegistry()
health_gauge = Gauge(
"container_inspect_state_health_status",
"Container's healthcheck value (binary)",
labelnames=["id", "name", "value"],
registry=registry,
)
status_gauge = Gauge(
"container_inspect_state_running",
"Container's running state (binary)",
labelnames=["id", "name"],
registry=registry,
)
started_at_gauge = Gauge(
"container_inspect_state_started_at",
"Container's start time (int)",
labelnames=["id", "name"],
registry=registry,
)
exit_code_gauge = Gauge(
"container_inspect_state_exit_code",
"Container's exit code (int)",
labelnames=["id", "name"],
registry=registry,
)
alert_threshold_gauge = Gauge(
"container_inspect_downtime_alert_threshold",
"Container's downtime alert threshold in seconds (int)",
labelnames=["id", "name"],
registry=registry,
)
container: Container
for container in self.docker_client.containers.list(all=True): # type: ignore
try:
data = self.docker_api.inspect_container(container.id)
except docker.errors.NotFound:
print(f"WARNING: Container {container.id} does not exist. Skipping.")
continue
running = bool(data["State"]["Running"])
started_at = data["State"]["StartedAt"]
exit_code = int(data["State"]["ExitCode"])
alert_threshold = int(
data["Config"]["Labels"].get("io.prometheus.alert.downtime", 3600)
)
starttime = numpy.datetime64(started_at, "s").astype("long")
status_gauge.labels(
container.id,
container.name,
).set(int(running))
started_at_gauge.labels(
container.id,
container.name,
).set(starttime)
exit_code_gauge.labels(
container.id,
container.name,
).set(int(exit_code))
alert_threshold_gauge.labels(
container.id,
container.name,
).set(alert_threshold)
try:
health_str = data["State"]["Health"]["Status"]
health_gauge.labels(
container.id,
container.name,
health_str,
).set(int(health_str == HEALTHY_STR))
except KeyError:
pass
self._respond(200, generate_latest(registry).decode())
def healthy() -> bool:
"""
Simple funtion to return if all the requirements are met
Returns:
bool: True if healthy or False if unhealthy
"""
return all(
[
os.path.exists("/var/run/docker.sock"),
]
)
if __name__ == "__main__":
def cli_parse() -> argparse.Namespace:
"""
Parse the CLI
Returns:
argparse.Namespace: Arguments from the CLI
"""
parser = argparse.ArgumentParser()
parser.add_argument(
"-H",
"--healthcheck",
action="store_true",
help="Simply exit with 0 for healthy or 1 when unhealthy",
)
return parser.parse_args()
def main() -> int:
"""
main()
"""
args: argparse.Namespace = cli_parse()
if args.healthcheck:
# Invert the sense of 'healthy' for Unix CLI usage
return not healthy()
print(f"Starting web server on port {LISTEN_PORT}")
try:
HTTPServer(("", LISTEN_PORT), HTTPHandler).serve_forever()
except KeyboardInterrupt:
print("Exiting")
return 0
sys.exit(main())