@opentelemetry/exporter-metrics-otlp-http

What is @opentelemetry/exporter-metrics-otlp-http?

@opentelemetry/exporter-metrics-otlp-http is an npm package that allows you to export OpenTelemetry metrics data using the OTLP (OpenTelemetry Protocol) over HTTP. This package is part of the OpenTelemetry project, which provides a set of APIs, libraries, agents, and instrumentation to enable observability in your applications.

What are @opentelemetry/exporter-metrics-otlp-http's main functionalities?

Export Metrics

This feature allows you to export metrics data to an OTLP endpoint over HTTP. The code sample demonstrates how to set up a MeterProvider with an OTLPMetricExporter and create a counter metric that is incremented every second.

const { MeterProvider } = require('@opentelemetry/sdk-metrics-base');
const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-http');

const exporter = new OTLPMetricExporter({
  url: 'http://localhost:4318/v1/metrics',
});

const meterProvider = new MeterProvider({
  exporter,
  interval: 2000,
});

const meter = meterProvider.getMeter('example-meter');
const counter = meter.createCounter('example_counter');

setInterval(() => {
  counter.add(1, { key: 'value' });
}, 1000);

Other packages similar to @opentelemetry/exporter-metrics-otlp-http

@opentelemetry/exporter-collector

@opentelemetry/exporter-collector is a more general exporter that can send both traces and metrics to the OpenTelemetry Collector using the OTLP protocol. It supports both gRPC and HTTP transports, making it more versatile compared to @opentelemetry/exporter-metrics-otlp-http, which is focused solely on metrics over HTTP.

@opentelemetry/exporter-zipkin

@opentelemetry/exporter-zipkin is an exporter that sends OpenTelemetry trace data to a Zipkin backend. While it focuses on trace data rather than metrics, it provides a similar function of exporting observability data to a backend system. It uses the Zipkin format over HTTP.

README

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

1. Go to examples/otlp-exporter-node
2. 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

License

Apache 2.0 - See LICENSE for more information.