Prometheus.md

title	Prometheus (Stats)
date	2018-07-22 14:27:35 -0700
draft	false
weight	3
class	resized-logo
aliases	/supported-exporters/java/prometheus /guides/exporters/supported-exporters/java/prometheus
logo	/img/prometheus-logo.png

• Introduction
• Creating the exporter
• Running Prometheus
• Viewing your metrics
• Project link

Introduction

Prometheus is a monitoring system that collects metrics, by scraping exposed endpoints at regular intervals, evaluating rule expressions. It can also trigger alerts if certain conditions are met.

OpenCensus Java allows exporting stats to Prometheus by means of the Prometheus package io.opencensus.exporter.stats.prometheus

{{% notice tip %}} For assistance setting up Prometheus, Click here for a guided codelab. {{% /notice %}}

Creating the exporter

To create the exporter, we'll need to:

• Import and use the Prometheus exporter package
• Define a namespace that will uniquely identify our metrics when viewed on Prometheus
• Expose a port on which we shall run a /metrics endpoint
• With the defined port, we'll need a Promethus configuration file so that Prometheus can scrape from this endpoint

Add this to your pom.xml file:

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <opencensus.version>0.17.0</opencensus.version> <!-- The OpenCensus version to use -->
    </properties>

    <dependencies>
        <dependency>
            <groupId>io.opencensus</groupId>
            <artifactId>opencensus-api</artifactId>
            <version>${opencensus.version}</version>
        </dependency>

        <dependency>
            <groupId>io.opencensus</groupId>
            <artifactId>opencensus-impl</artifactId>
            <version>${opencensus.version}</version>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>io.opencensus</groupId>
            <artifactId>opencensus-exporter-stats-prometheus</artifactId>
            <version>${opencensus.version}</version>
        </dependency>

        <dependency>
            <groupId>io.prometheus</groupId>
            <artifactId>simpleclient_httpserver</artifactId>
            <version>0.3.0</version>
        </dependency>
    </dependencies>

We also need to expose the Prometheus endpoint say on address "localhost:8888".

{{}} package io.opencensus.tutorial.prometheus;

import io.opencensus.exporter.stats.prometheus.PrometheusStatsCollector; import io.prometheus.client.exporter.HTTPServer;

public class PrometheusTutorial { public static void main(String ...args) { // Register the Prometheus exporter PrometheusStatsCollector.createAndRegister();

    // Run the server as a daemon on address "localhost:8888"
    HTTPServer server = new HTTPServer("localhost", 8888, true);
}

} {{}}

and then for our corresponding prometheus.yaml file:

global:
  scrape_interval: 10s

  external_labels:
    monitor: 'demo'

scrape_configs:
  - job_name: 'demo'

    scrape_interval: 10s

    static_configs:
      - targets: ['localhost:8888']

Running Prometheus

And then run Prometheus with your configuration

prometheus --config.file=prometheus.yaml

Viewing your metrics

Please visit http://localhost:9090

Project link

You can find out more about the Prometheus project at https://prometheus.io/