OpenTelemetry Collector Metrics Exporter for web and node

Note: This is an experimental package under active development. New releases may include breaking changes.

This module provides a metrics-exporter for OTLP (http/json) using protocol version v0.20.0.

Installation

npm install --save @opentelemetry/exporter-metrics-otlp-http

Service Name

The OpenTelemetry Collector Metrics Exporter does not have a service name configuration. In order to set the service name, use the service.name resource attribute as prescribed in the OpenTelemetry Resource Semantic Conventions. To see sample code and documentation for the traces exporter, visit the Collector Trace Exporter for web and node.

Metrics in Web

The OTLPMetricExporter in Web expects the endpoint to end in /v1/metrics.

import { MeterProvider, PeriodicExportingMetricReader } from '@opentelemetry/sdk-metrics';
import { OTLPMetricExporter } from '@opentelemetry/exporter-metrics-otlp-http';

const collectorOptions = {
  url: '<opentelemetry-collector-url>', // url is optional and can be omitted - default is http://localhost:4318/v1/metrics
  headers: {}, // an optional object containing custom headers to be sent with each request
  concurrencyLimit: 1, // an optional limit on pending requests
};
const metricExporter = new OTLPMetricExporter(collectorOptions);
const meterProvider = new MeterProvider({});

meterProvider.addMetricReader(new PeriodicExportingMetricReader({
  exporter: metricExporter,
  exportIntervalMillis: 1000,
}));

// Now, start recording data
const meter = meterProvider.getMeter('example-meter');
const counter = meter.createCounter('metric_name');
counter.add(10, { 'key': 'value' });

Metrics in Node

const { MeterProvider, PeriodicExportingMetricReader } = require('@opentelemetry/sdk-metrics');
const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-http');
const collectorOptions = {
  url: '<opentelemetry-collector-url>', // url is optional and can be omitted - default is http://localhost:4318/v1/metrics
  concurrencyLimit: 1, // an optional limit on pending requests
};
const metricExporter = new OTLPMetricExporter(collectorOptions);
const meterProvider = new MeterProvider({});

meterProvider.addMetricReader(new PeriodicExportingMetricReader({
  exporter: metricExporter,
  exportIntervalMillis: 1000,
}));

// Now, start recording data
const meter = meterProvider.getMeter('example-meter');
const counter = meter.createCounter('metric_name');
counter.add(10, { 'key': 'value' });

Environment Variable Configuration

In addition to settings passed to the constructor, the exporter also supports configuration via environment variables:

Environment variable	Description
OTEL_EXPORTER_OTLP_ENDPOINT	The endpoint to send metrics to. This will also be used for the traces exporter if `OTEL_EXPORTER_OTLP_TRACES_ENDPOINT` is not configured. By default `http://localhost:4318` will be used. `/v1/metrics` will be automatically appended to configured values.
OTEL_EXPORTER_OTLP_METRICS_ENDPOINT	The endpoint to send metrics to. By default `https://localhost:4318/v1/metrics` will be used. `v1/metrics` will not be appended automatically and has to be added explicitly.
OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE	The exporters aggregation temporality preference. Valid values are `cumulative`, `delta`, and `lowmemory`. `cumulative` selects cumulative temporality for all instrument kinds. `delta` selects delta aggregation temporality for Counter, Asynchronous Counter and Histogram instrument kinds, and selects cumulative aggregation for UpDownCounter and Asynchronous UpDownCounter instrument kinds. `lowmemory` selects delta aggregation temporality for Counter and Histogram instrument kinds, and selects cumulative aggregation for UpDownCounter, Asynchronous Counter and Asynchronous UpDownCounter instrument kinds. By default `cumulative` is used.

Settings configured programmatically take precedence over environment variables. Per-signal environment variables take precedence over non-per-signal environment variables.

Running opentelemetry-collector locally to see the metrics

Go to examples/otlp-exporter-node
Follow the instructions there to observe the metrics.

Useful links

For more information on OpenTelemetry, visit: https://opentelemetry.io/
For more about OpenTelemetry JavaScript: https://github.com/open-telemetry/opentelemetry-js
For help or feedback on this project, join us in GitHub Discussions
For exporting metrics via gRPC please check exporter-metrics-otlp-grpc
For exporting metrics via protobuf please check exporter-metrics-otlp-proto