How to create a dynamic instrumentation agent in Node.js?

Node.js / October 1, 2022 / sumitsuthar94 / 0

Creating a dynamic instrumentation agent in Node.js involves using the @opentelemetry/instrumentation package and customizing it to fit your specific use case. In this blog, we will walk you through the steps for creating a basic dynamic instrumentation agent in Node.js.

Step 1: Install Required Dependencies
The first step is to install the necessary dependencies. For our dynamic instrumentation agent, we will be using the following packages:

• @opentelemetry/api: A package that provides the OpenTelemetry API for instrumenting Node.js applications.
• @opentelemetry/core: A package that provides the core functionality for the OpenTelemetry SDK.
• @opentelemetry/instrumentation: A package that provides the framework for instrumenting Node.js applications.
• @opentelemetry/exporter-zipkin: A package that provides an exporter for sending telemetry data to a Zipkin server.

To install these packages, run the following command in your terminal:

npm install @opentelemetry/api @opentelemetry/core @opentelemetry/instrumentation @opentelemetry/exporter-zipkin

Step 2: Set Up Your Agent
Once you have installed the necessary dependencies, you can begin setting up your agent. First, create a new file called agent.js and add the following code:

const { NodeTracerProvider } = require('@opentelemetry/node');
const { ConsoleSpanExporter, SimpleSpanProcessor } = require('@opentelemetry/tracing');
const { registerInstrumentations } = require('@opentelemetry/instrumentation');
const { ZipkinExporter } = require('@opentelemetry/exporter-zipkin');
const { HttpInstrumentation } = require('@opentelemetry/instrumentation-http');

const provider = new NodeTracerProvider();

provider.addSpanProcessor(new SimpleSpanProcessor(new ConsoleSpanExporter())) // Export spans to console
provider.addSpanProcessor(new SimpleSpanProcessor(new ZipkinExporter({ serviceName: 'my-service', url: 'http://localhost:9411/api/v2/spans' }))) // Export spans to Zipkin

registerInstrumentations({
  instrumentations: [
    new HttpInstrumentation()
  ],
  tracerProvider: provider
});

provider.register();

This code sets up an OpenTelemetry Node.js tracer provider that exports telemetry data to both the console and a Zipkin server. It also registers the HttpInstrumentation instrumentation to instrument HTTP requests.

Step 3: Instrument Your Application
To instrument your application with your agent, add the following code to the beginning of your application entry file:

require('./agent');

This code requires your agent.js file and sets up your agent to instrument your application.

Conclusion
In this blog, we have walked you through the steps for creating a basic dynamic instrumentation agent in Node.js using the OpenTelemetry API and packages. By using the @opentelemetry/instrumentation package and customizing it to fit your specific use case, you can instrument your Node.js application to collect telemetry data and export it to a variety of destinations. With this foundation, you can extend your dynamic instrumentation agent to include features like custom instrumentation, additional exporters, and more.

instrumentation, javascript, node.js, opentelemetry