DDTrace NodeJS

Install Dependencies¶

To install the DDTrace extension for NodeJS, follow the complete APM integration steps in the Datadog NodeJS Integration Documentation.

NodeJS v12+¶

npm install dd-trace --save

NodeJS v10 v8¶

npm install dd-trace@latest-node10

Note: You must import and initialize the DDTrace library before any NodeJS code or any Module is loaded. If the DDTrace library is not properly initialized, it may not receive trace data.

Example¶

In an environment that only runs JavaScript:

// This line must come before importing any instrumented module.
const tracer = require("dd-trace").init();

For environments that use TypeScript and bundlers and support ECMAScript Module syntax, you need to initialize DDTrace in a different file:

//
// server.ts
//
import "./tracer"; // must come before importing any instrumented module.

//
// tracer.ts
//
import tracer from "dd-trace";
tracer.init(); // initialized in a different file to avoid hoisting.
export default tracer;

Additionally, if the default configuration is sufficient or DDTrace is successfully configured via environment variables, you can directly import the module in your code:

import "dd-trace/init";

Run¶

Run Node Code

DD_AGENT_HOST=localhost DD_TRACE_AGENT_PORT=9529 node server

Environment Variable Support¶

The following lists common ENV support. For a complete list of ENV support, see Datadog Documentation.

• DD_ENV

  Sets the environment variable for the service.

• DD_VERSION

  The version number of the APP.

• DD_SERVICE

  Used to set the application's service name, defaults to the name field in package.json.

• DD_SERVICE_MAPPING

  Defines service name mappings for renaming services in Tracing.

• DD_TAGS

  Adds default Tags to each Span.

• DD_TRACE_AGENT_HOSTNAME

  The hostname where Datakit is listening, default is localhost.

• DD_TRACE_AGENT_PORT

  The port number where Datakit is listening, default is 9529.

• DD_TRACE_SAMPLE_RATE

  Sets the sampling rate from 0.0 (0%) to 1.0 (100%).