使用Python和Flask编写Prometheus监控

Python Prometheus

Installation

pip install flask
pip install prometheus_client

Metrics

Prometheus提供4种类型Metrics：Counter, Gauge, Summary和Histogram

Counter

Counter可以增长，并且在程序重启的时候会被重设为0，常被用于任务个数，总处理时间，错误个数等只增不减的指标。

import prometheus_client
from prometheus_client import Counter
from prometheus_client.core import CollectorRegistry
from flask import Response, Flask
app = Flask(__name__)
requests_total = Counter("request_count", "Total request cout of the host")
@app.route("/metrics")
def requests_count():
    requests_total.inc()
    # requests_total.inc(2)
    return Response(prometheus_client.generate_latest(requests_total),
                    mimetype="text/plain")
@app.route('/')
def index():
    requests_total.inc()
    return "Hello World"
if __name__ == "__main__":
    app.run(host="0.0.0.0")

运行改脚本，访问youhost:5000/metrics

# HELP request_count Total request cout of the host
# TYPE request_count counter
request_count 3.0

Gauge

Gauge与Counter类似，唯一不同的是Gauge数值可以减少，常被用于温度、利用率等指标。

import random
import prometheus_client
from prometheus_client import Gauge
from flask import Response, Flask
app = Flask(__name__)
random_value = Gauge("random_value", "Random value of the request")
@app.route("/metrics")
def r_value():
    random_value.set(random.randint(0, 10))
    return Response(prometheus_client.generate_latest(random_value),
                    mimetype="text/plain")
if __name__ == "__main__":
    app.run(host="0.0.0.0")

运行改脚本，访问youhost:5000/metrics

# HELP random_value Random value of the request
# TYPE random_value gauge
random_value 3.0

Summary/Histogram

Summary/Histogram概念比较复杂，一般exporter很难用到，暂且不说。

PLUS

LABELS

使用labels来区分metric的特征

from prometheus_client import Counter
c = Counter('requests_total', 'HTTP requests total', ['method', 'clientip'])
c.labels('get', '127.0.0.1').inc()
c.labels('post', '192.168.0.1').inc(3)
c.labels(method="get", clientip="192.168.0.1").inc()

REGISTRY

from prometheus_client import Counter, Gauge
from prometheus_client.core import CollectorRegistry
REGISTRY = CollectorRegistry(auto_describe=False)
requests_total = Counter("request_count", "Total request cout of the host", registry=REGISTRY)
random_value = Gauge("random_value", "Random value of the request", registry=REGISTRY)

Reference

1. prometheus
2. client_python
3. prometheus_client_example