Node.js Lambda Tracing and Webpack Compatibility

Overview

Datadog’s tracing libraries (dd-trace) are known to be not compatible with bundlers like webpack due to the use of conditional imports and other issues. While webpack cannot build dd-trace, your application can still use the dd-trace and datadog-lambda-js libraries provided by the prebuilt Datadog Lambda layer. Follow the instructions below.

webpack

  1. Follow the installation instructions for Node.js and ensure the Datadog Lambda layer for Node.js is added to your Lambda function.

  2. Remove datadog-lambda-js and dd-trace from your package.json and the build process.

  3. Mark datadog-lambda-js and dd-trace as externals. This tells the bundler to skip building them as dependencies, since they are already available in the Lambda runtime provided by the Datadog Lambda layer.

    webpack.config.js

    var nodeExternals = require("webpack-node-externals");

module.exports = {
  // use webpack-node-externals to exclude all node dependencies.
  // You can manually set the externals too.
  externals: [nodeExternals(), "dd-trace", "datadog-lambda-js"],
};

  4. If you are using the serverless-webpack and have the option includeModules set to any value other than false, serverless-webpack automatically packs external modules under node_modules. Therefore, you must force exclude datadog-lambda-js and dd-trace. Skip this step if you don’t use serverless-webpack or you don’t have the includeModules option in your serverless.yml.

    serverless.yml

    custom:
  webpack:
    # Note: You only need the following if you already have the includeModules option configured
    includeModules:
      # ... your existing configuration for includeModules
      forceExclude:
        - dd-trace
        - datadog-lambda-js
    packagerOptions:
      scripts:
        # optional, only needed when they are included as transitive dependencies 
        - rm -rf node_modules/datadog-lambda-js node_modules/dd-trace

esbuild

  1. Follow the installation instructions for Node.js and ensure the Datadog Lambda layer for Node.js is added to your Lambda function.

  2. Remove datadog-lambda-js and dd-trace from your package.json and the build process.

  3. Mark datadog-lambda-js and dd-trace as externals. This tells the bundler to skip building them as dependencies, since they are already available in the Lambda runtime provided by the Datadog Lambda layer.

  4. Follow the steps on the Esbuild support page to use Datadog’s Esbuild plugin. This enables instrumentation of bundled dependencies.

    esbuild.config.js (if using esbuild-config)

    {
  "external": ["dd-trace", "datadog-lambda-js"],
}

    serverless.yml (if using serverless-esbuild)

    custom:
  esbuild:
    exclude: ["dd-trace", "datadog-lambda-js", "aws-sdk"] # aws-sdk is needed because it is the default value for `exclude`

Further Reading

Additional helpful documentation, links, and articles:

Instrumenting Node.js ApplicationsDOCUMENTATION more more