Moleculer-prometheus NPM

moleculer-prometheus

Moleculer metrics module for Prometheus.

Grafana screenshot

Features

collect default Node.js metrics.
measure service calls.
support custom metrics.
Grafana dashboard example.

Install

$ npm install moleculer-prometheus

Usage

// services/metrics.prometheus.service.js

const PromService = require("moleculer-prometheus");

module.exports = {
    mixins: [PromService],
    settings: {
        port: 3030,
        collectDefaultMetrics: true,
        timeout: 5 * 1000, 
    }
};

// moleculer.config.js
module.exports = {
    // ...
    metrics: true,
    // ...
}

Add custom metric

// services/metrics.prometheus.js
const PromService = require("moleculer-prometheus");

module.exports = {
    mixins: [PromService],
    settings: {
        metrics: {
           "custom_value": { type: "Gauge", help: "Moleculer Prometheus custom metric" } 
        } 
    }
};

Broadcast a metrics.update event to set the metric value

broker.broadcast("metrics.update", {
    name: "custom_value",
    method: "set",
    value: Math.round(Math.random() * 100)
});

Settings

Property	Type	Default	Description
`port`	`Number`	`3030`	Exposed HTTP port.
`collectDefaultMetrics`	`Boolean`	`true`	Enable to collect default metrics.
`timeout`	`Number`	`10000`	Timeout option for 'collectDefaultMetrics' in milliseconds.
`metrics`	`Object`	`{}`	Metric definitions.

Default Moleculer metrics

Name	Type	Labels	Description
`moleculer_nodes_total`	Gauge	-	Moleculer nodes count
`moleculer_services_total`	Gauge	-	Moleculer services count
`moleculer_actions_total`	Gauge	-	Moleculer actions count
`moleculer_events_total`	Gauge	-	Moleculer event subscription count
`moleculer_nodes`	Gauge	`nodeID`, `type`, `version`, `langVersion`	Moleculer node list
`moleculer_action_endpoints_total`	Gauge	`action`	Moleculer action endpoints
`moleculer_service_endpoints_total`	Gauge	`service`, `version`	Moleculer service endpoints
`moleculer_event_endpoints_total`	Gauge	`event`, `group`	Moleculer event endpoints
`moleculer_req_total`	Counter	`action`, `service`, `nodeID`	Moleculer request count
`moleculer_req_errors_total`	Counter	`action`, `service`, `nodeID`, `errorCode`, `errorName`, `errorType`	Moleculer request error count
`moleculer_req_duration_ms`	Histogram	`action`, `service`, `nodeID`	Moleculer request durations