js-metrics

Metrics is a lightweight web server that provides health status and Prometheus-compatible reports.

Installation

npm install --save @randlabs/js-metrics

Usage

const Metrics = require("@randlabs/js-metrics");

const metricsServer = await Metrics.createServer(options);

Example

const Metrics = require("@randlabs/js-metrics");
 
const metricsServer = await Metrics.createServer({
    host: "127.0.0.1",
    port: 3001,
    accessToken: "1234",
    endpoints: {
        getHealth: "/health",
        getStats: "/metrics",
    },
    getHealthCallback: () => {
        return {
            value: Math.random() * 100
        };
    },
    metricsSetupCallback: (registry) => {
        const g = new promclient.Gauge({
            name: 'test_gauge',
            help: 'Example of a gauge',
            registers: [ registry ]
        });

        g.set(Math.random() * 100);
    }
});

// do other stuff

await metricsServer.shutdown();

Create a new metrics web server with the given options.

• options - Initialization options.
• options.host - Bind address. Defaults to 127.0.0.1. Not used in cluster workers.
• options.port - Specifies the server port. Not used in cluster workers.
• options.accessToken - Protect access to endpoints with an access token. Optional. Not used in cluster workers.
• options.usingClusters - If the app runs inside a cluster environment, set this option to true.
• options.endpoints - Overrides the endpoints paths. Optional. Not used in cluster workers.
• options.endpoints.getHealth - Overrides the "/health" url path. Optional.
• options.endpoints.getStats - Overrides the "/stats" url path. Optional.
• options.getHealthCallback - Callback function called when health information is required. It must return a HealthStatus object.
• options.metricsSetupCallback - Callback function called to initialize Prometheus metrics. It receives a registry objects where collectors must be added.

License

Apache 2.0