Improve Lambda Layer cold start time #2 (#171)

*Description of changes:*
This PR is a rehash of #163 with some minor changes reverted after
several autoinstrumentation package dependencies were upgraded in #168.
The changes suggested by the unaddressed comments in the previous PR are
addressed here.

The primary change made to reduce the cold start time was to bundle the
ADOT autoinstrumentation package with webpack instead of using the TS
compiler. Using the same build targets as the upstream (see [this
PR](https://github.com/open-telemetry/opentelemetry-lambda/pull/1679/files)),
the cold start performance of the layer was improved by about 50%, from
~765ms to ~385ms.

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice.

Author: ezhang6811

aws-distro-opentelemetry-node-autoinstrumentation/package.json

@@ -22,7 +22,9 @@
   "repository": "aws-observability/aws-otel-js-instrumentation",
   "scripts": {
     "clean": "rimraf build/*",
-    "compile": "tsc -p .",
+    "compile:tsc": "tsc -p .",
+    "compile:webpack": "webpack",
+    "compile": "npm run compile:webpack",
     "lint": "eslint . --ext .ts",
     "lint:fix": "eslint . --ext .ts --fix",
     "create-version": "node -p \"'export const LIB_VERSION = ' + JSON.stringify(require('./package.json').version) + ';'\" > src/version.ts",
@@ -93,8 +95,11 @@
     "proxyquire": "^2.1.3",
     "rimraf": "5.0.5",
     "sinon": "15.2.0",
+    "ts-loader": "^9.5.2",
     "ts-mocha": "10.0.0",
-    "typescript": "4.4.4"
+    "typescript": "4.4.4",
+    "webpack": "^5.98.0",
+    "webpack-cli": "^6.0.1"
   },
   "dependencies": {
     "@opentelemetry/api": "1.9.0",
@@ -110,6 +115,7 @@
     "@opentelemetry/instrumentation-aws-sdk": "0.49.0",
     "@opentelemetry/otlp-transformer": "0.57.1",
     "@opentelemetry/propagator-aws-xray": "1.26.2",
+    "@opentelemetry/propagator-aws-xray-lambda": "^0.54.0",
     "@opentelemetry/resource-detector-aws": "1.12.0",
     "@opentelemetry/resources": "1.30.1",
     "@opentelemetry/sdk-metrics": "1.30.1",
@@ -121,6 +127,7 @@
     "build/src/**/*.js",
     "build/src/**/*.js.map",
     "build/src/**/*.d.ts",
+    "build/src/**/*.d.ts.map",
     "build/src/**/*.json"
   ]
 }

aws-distro-opentelemetry-node-autoinstrumentation/src/aws-opentelemetry-configurator.ts

@@ -75,6 +75,7 @@ const FORMAT_OTEL_UNSAMPLED_TRACES_BINARY_PREFIX = 'T1U';
 // Follow Python SDK Impl to set the max span batch size
 // which will reduce the chance of UDP package size is larger than 64KB
 const LAMBDA_SPAN_EXPORT_BATCH_SIZE = 10;
+
 /**
  * Aws Application Signals Config Provider creates a configuration object that can be provided to
  * the OTel NodeJS SDK for Auto Instrumentation with Application Signals Functionality.

aws-distro-opentelemetry-node-autoinstrumentation/src/register.ts

@@ -41,7 +41,7 @@ export function setAwsDefaultEnvironmentVariables(): void {
     process.env.OTEL_EXPORTER_OTLP_PROTOCOL = 'http/protobuf';
   }
   if (!process.env.OTEL_PROPAGATORS) {
-    process.env.OTEL_PROPAGATORS = 'xray,tracecontext,b3,b3multi';
+    process.env.OTEL_PROPAGATORS = 'xray,tracecontext';
   }
   // Disable the following instrumentations by default
   // This auto-instrumentation for the `fs` module generates many low-value spans. `dns` is similar.

aws-distro-opentelemetry-node-autoinstrumentation/test/aws-opentelemetry-configurator.test.ts

@@ -506,7 +506,7 @@ describe('AwsOpenTelemetryConfiguratorTest', () => {
   function validateConfiguratorEnviron() {
     // Set by register.ts
     expect('http/protobuf').toEqual(process.env.OTEL_EXPORTER_OTLP_PROTOCOL);
-    expect('xray,tracecontext,b3,b3multi').toEqual(process.env.OTEL_PROPAGATORS);
+    expect('xray,tracecontext').toEqual(process.env.OTEL_PROPAGATORS);
 
     // Not set
     expect(undefined).toEqual(process.env.OTEL_TRACES_SAMPLER);

aws-distro-opentelemetry-node-autoinstrumentation/test/patches/instrumentation-patch.test.ts

@@ -25,7 +25,7 @@ import { AWSXRAY_TRACE_ID_HEADER, AWSXRayPropagator } from '@opentelemetry/propa
 import { Context } from 'aws-lambda';
 import { SinonStub } from 'sinon';
 import { Lambda } from '@aws-sdk/client-lambda';
-import nock = require('nock');
+import * as nock from 'nock';
 import { ReadableSpan } from '@opentelemetry/sdk-trace-base';
 import { getTestSpans } from '@opentelemetry/contrib-test-utils';
 import { instrumentationConfigs } from '../../src/register';

aws-distro-opentelemetry-node-autoinstrumentation/test/register.test.ts

@@ -33,7 +33,7 @@ describe('Register', function () {
     it('sets AWS Default Environment Variables', () => {
       setAwsDefaultEnvironmentVariables();
       expect(process.env.OTEL_EXPORTER_OTLP_PROTOCOL).toEqual('http/protobuf');
-      expect(process.env.OTEL_PROPAGATORS).toEqual('xray,tracecontext,b3,b3multi');
+      expect(process.env.OTEL_PROPAGATORS).toEqual('xray,tracecontext');
       expect(process.env.OTEL_NODE_DISABLED_INSTRUMENTATIONS).toEqual('fs');
     });
 
@@ -79,7 +79,7 @@ describe('Register', function () {
 
     assert.ok(proc.stdout.includes('AWS Distro of OpenTelemetry automatic instrumentation started successfully'));
     assert.ok(proc.stdout.includes("Environment variable OTEL_EXPORTER_OTLP_PROTOCOL is set to 'http/protobuf'"));
-    assert.ok(proc.stdout.includes("Environment variable OTEL_PROPAGATORS is set to 'xray,tracecontext,b3,b3multi'"));
+    assert.ok(proc.stdout.includes("Environment variable OTEL_PROPAGATORS is set to 'xray,tracecontext'"));
 
     // Check a span has been generated for the GET request done in app.js
     assert.ok(proc.stdout.includes("name: 'GET'"), 'console span output in stdout - validate Span Name');

aws-distro-opentelemetry-node-autoinstrumentation/tsconfig.webpack.json

@@ -0,0 +1,11 @@
+{
+    "extends": "./tsconfig.json",
+    "compilerOptions": {
+      "module": "es2020",
+      "target": "es2020",
+      "moduleResolution": "node",
+    },
+    "exclude": [
+      "node_modules",
+    ]
+  }

aws-distro-opentelemetry-node-autoinstrumentation/webpack.config.js

@@ -0,0 +1,43 @@
+const path = require('path');
+
+module.exports = {
+  entry: './src/register.ts',
+  target: 'node',
+  mode: 'production',
+  externalsPresets: { node: true },
+  output: {
+    path: path.resolve('./build/src'),
+    filename: 'register.js',
+    library: {
+        type: 'commonjs2',
+    }
+  },
+  resolve: {
+    extensions: ['.ts', '.js'],
+    modules: [
+        path.resolve('./src'),
+        'node_modules',
+    ],
+  },
+  module: {
+    rules: [
+      {
+        test: /\.ts$/,
+        use: [
+          {
+            loader: 'ts-loader',
+            options: {
+              configFile: 'tsconfig.webpack.json'
+            },
+          }
+        ],
+        exclude: /node_modules/,
+      },
+    ],
+  },
+  optimization: {
+    minimize: true,
+    providedExports: true,
+    usedExports: true,
+  },
+};

lambda-layer/packages/layer/scripts/otel-instrument

@@ -68,7 +68,7 @@ fi
 
 # - Set the propagators
 if [[ -z "$OTEL_PROPAGATORS" ]]; then
-  export OTEL_PROPAGATORS="xray,tracecontext,baggage,b3,b3multi"
+  export OTEL_PROPAGATORS="xray,tracecontext,baggage"
 fi
 
 # - Set Application Signals configuration