使用Python和Flask编写Prometheus监控

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Installation

pip install flaskpip install prometheus_python

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_clientfrom prometheus_client import Counterfrom prometheus_client.core import CollectorRegistryfrom flask import Response, Flaskapp = 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 counterrequest_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 randomimport prometheus_clientfrom prometheus_client import Gaugefrom flask import Response, Flaskapp = 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 gaugerandom_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 Counterc = 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, Gaugefrom prometheus_client.core import CollectorRegistryREGISTRY = 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

Example

kafka-logsize-exporter
一个使用Prometheus监控Kafka logsize的练手案例