Refactor Lambda Layer bundling

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

@@ -22,9 +22,7 @@
   "repository": "aws-observability/aws-otel-js-instrumentation",
   "scripts": {
     "clean": "rimraf build/*",
-    "compile:tsc": "tsc -p .",
-    "compile:webpack": "webpack",
-    "compile": "npm run compile:webpack",
+    "compile": "tsc -p .",
     "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",
@@ -95,11 +93,8 @@
     "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",
-    "webpack": "^5.98.0",
-    "webpack-cli": "^6.0.1"
+    "typescript": "4.4.4"
   },
   "dependencies": {
     "@opentelemetry/api": "1.9.0",
@@ -115,7 +110,6 @@
     "@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",
@@ -127,7 +121,6 @@
     "build/src/**/*.js",
     "build/src/**/*.js.map",
     "build/src/**/*.d.ts",
-    "build/src/**/*.d.ts.map",
     "build/src/**/*.json"
   ]
 }

lambda-layer/packages/layer/install-externals.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+set -euf -o pipefail
+
+# Space separated list of external NPM packages
+EXTERNAL_PACKAGES=( "import-in-the-middle" )
+
+for EXTERNAL_PACKAGE in "${EXTERNAL_PACKAGES[@]}"
+do
+  echo "Installing external package $EXTERNAL_PACKAGE ..."
+
+  PACKAGE_VERSION=$(npm query "#$EXTERNAL_PACKAGE" \
+    | grep version \
+    | head -1 \
+    | awk -F: '{ print $2 }' \
+    | sed 's/[",]//g')
+
+  echo "Resolved version of the external package $EXTERNAL_PACKAGE: $PACKAGE_VERSION"
+
+  npm install "$EXTERNAL_PACKAGE@$PACKAGE_VERSION" --prefix ./build/workspace/nodejs --production --ignore-scripts
+
+  echo "Installed external package $EXTERNAL_PACKAGE"
+done

lambda-layer/packages/layer/package.json

@@ -20,8 +20,8 @@
     "lint": "eslint . --ext .ts",
     "lint:fix": "eslint . --ext .ts --fix",
     "prepare": "npm run compile",
-    "compile": "tsc -p .",
-    "postcompile": "copyfiles -F 'node_modules/**' build/workspace/nodejs && copyfiles -f 'scripts/*' build/workspace && copyfiles -f 'build/src/*' build/workspace && cd build/workspace && bestzip ../layer.zip *"
+    "compile": "webpack && ./install-externals.sh",
+    "postcompile": "copyfiles -f 'src/**/*.mjs' build/workspace && copyfiles -f 'scripts/*' build/workspace && copyfiles -f 'build/src/*' build/workspace && cd build/workspace && bestzip ../layer.zip *"
   },
   "keywords": [
     "awsdistroopentelemetry",
@@ -34,5 +34,10 @@
   ],
   "dependencies": {
     "@aws/aws-distro-opentelemetry-node-autoinstrumentation": "file:../../../aws-distro-opentelemetry-node-autoinstrumentation/aws-aws-distro-opentelemetry-node-autoinstrumentation-0.5.0-dev0.tgz"
+  },
+  "devDependencies": {
+    "ts-loader": "^9.5.2",
+    "webpack": "^5.98.0",
+    "webpack-cli": "^6.0.1"
   }
 }

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

@@ -1,39 +1,6 @@
 #!/bin/bash
-_is_esm_handler() {
-  # Lambda function root directory
-  TASK_DIR="/var/task"
 
-  # Flag variables to track conditions
-  local found_mjs=false
-  local is_module=false
-
-  # Check for any files ending with `.mjs`
-  if ls "$TASK_DIR"/*.mjs &>/dev/null; then
-      found_mjs=true
-    fi
-
-  # Check if `package.json` exists and if it contains `"type": "module"`
-  if [ -f "$TASK_DIR/package.json" ]; then
-    # Check for the `"type": "module"` attribute in `package.json`
-    if grep -q '"type": *"module"' "$TASK_DIR/package.json"; then
-      is_module=true
-    fi
-  fi
-
-  # Return true if both conditions are met
-  if $found_mjs || $is_module; then
-    return 0  # 0 in bash means true
-  else
-    return 1  # 1 in bash means false
-  fi
-}
-
-if _is_esm_handler || [[ ${HANDLER_IS_ESM} == true ]]; then
-  export NODE_OPTIONS="${NODE_OPTIONS} --import @aws/aws-distro-opentelemetry-node-autoinstrumentation/register --experimental-loader=@opentelemetry/instrumentation/hook.mjs"
-  export HANDLER_IS_ESM=true
-else
-  export NODE_OPTIONS="${NODE_OPTIONS} --require /opt/wrapper.js"
-fi
+export NODE_OPTIONS="${NODE_OPTIONS} --import /opt/init.mjs"
 
 export LAMBDA_RESOURCE_ATTRIBUTES="cloud.region=$AWS_REGION,cloud.provider=aws,faas.name=$AWS_LAMBDA_FUNCTION_NAME,faas.version=$AWS_LAMBDA_FUNCTION_VERSION,faas.instance=$AWS_LAMBDA_LOG_STREAM_NAME,aws.log.group.names=$AWS_LAMBDA_LOG_GROUP_NAME";
 

lambda-layer/packages/layer/src/init.mjs

@@ -0,0 +1,7 @@
+const WRAPPER_INIT_START_TIME = Date.now();
+await import('./wrapper.js');
+console.log('OpenTelemetry wrapper init completed in', Date.now() - WRAPPER_INIT_START_TIME, 'ms');
+
+const LOADER_INIT_START_TIME = Date.now();
+await import('./loader.mjs');
+console.log('OpenTelemetry loader init completed in', Date.now() - LOADER_INIT_START_TIME, 'ms');

lambda-layer/packages/layer/src/loader.mjs

@@ -0,0 +1,91 @@
+import { register } from 'module';
+import * as path from 'path';
+import * as fs from 'fs';
+
+function _hasFolderPackageJsonTypeModule(folder) {
+  if (folder.endsWith('/node_modules')) {
+    return false;
+  }
+  let pj = path.join(folder, '/package.json');
+  if (fs.existsSync(pj)) {
+    try {
+      let pkg = JSON.parse(fs.readFileSync(pj).toString());
+      if (pkg) {
+        if (pkg.type === 'module') {
+          return true;
+        } else {
+          return false;
+        }
+      }
+    } catch (e) {
+      console.warn(`${pj} cannot be read, it will be ignored for ES module detection purposes.`, e);
+      return false;
+    }
+  }
+  if (folder === '/') {
+    return false;
+  }
+  return _hasFolderPackageJsonTypeModule(path.resolve(folder, '..'));
+}
+
+function _hasPackageJsonTypeModule(file) {
+  let jsPath = file + '.js';
+  if (fs.existsSync(jsPath)) {
+    return _hasFolderPackageJsonTypeModule(path.resolve(path.dirname(jsPath)));
+  }
+  return false;
+}
+
+function _resolveHandlerFileName() {
+  const taskRoot = process.env.LAMBDA_TASK_ROOT;
+  const handlerDef = process.env._HANDLER;
+  if (!taskRoot || !handlerDef) {
+    return null;
+  }
+  const handler = path.basename(handlerDef);
+  const moduleRoot = handlerDef.substr(0, handlerDef.length - handler.length);
+  const [module, _] = handler.split('.', 2);
+  return path.resolve(taskRoot, moduleRoot, module);
+}
+
+function _isHandlerAnESModule() {
+  try {
+    const handlerFileName = _resolveHandlerFileName();
+    if (!handlerFileName) {
+      return false;
+    }
+    if (fs.existsSync(handlerFileName + '.mjs')) {
+      return true;
+    } else if (fs.existsSync(handlerFileName + '.cjs')) {
+      return false;
+    } else {
+      return _hasPackageJsonTypeModule(handlerFileName);
+    }
+  } catch (e) {
+    console.error('Unknown error occurred while checking whether handler is an ES module', e);
+    return false;
+  }
+}
+
+let registered = false;
+
+export function registerLoader() {
+  if (!registered) {
+    register('import-in-the-middle/hook.mjs', import.meta.url);
+    registered = true;
+  }
+}
+
+if (_isHandlerAnESModule()) {
+  /*
+  We could activate ESM loader hook of the "import-in-the-middle" library,
+  - by "--loader=import-in-the-middle/hook.mjs" Node CLI option, but "--loader" option has been deprecated
+  - or by "--import=import-in-the-middle/hook.mjs" Node CLI option, but in this case,
+    there will always be "import-in-the-middle" hook initialization overhead even for non-ESM (CommonJS) modules
+
+  Hence, instead, we initialize "import-in-the-middle" hook only for ES (EcmaScript) based user handlers
+  to prevent redundant "import-in-the-middle" hook initialization overhead during coldstart
+  of the CommonJS based user handlers.
+   */
+  registerLoader();
+}

lambda-layer/packages/layer/tsconfig.webpack.json

@@ -0,0 +1,11 @@
+{
+  "extends": "../../tsconfig.esm",
+  "compilerOptions": {
+    "rootDir": ".",
+    "outDir": "build",
+  },
+  "include": [
+  "src/**/*.ts",
+  "test/**/*.ts"
+  ]
+}

aws-distro-opentelemetry-node-autoinstrumentation/webpack.config.js → lambda-layer/packages/layer/webpack.config.js

@@ -1,19 +1,23 @@
 const path = require('path');
 
 module.exports = {
-  entry: './src/register.ts',
+  entry: './src/wrapper.ts',
   target: 'node',
   mode: 'production',
   externalsPresets: { node: true },
+  externals: [
+    'import-in-the-middle',
+    '@aws-sdk',
+  ],
   output: {
     path: path.resolve('./build/src'),
-    filename: 'register.js',
+    filename: 'wrapper.js',
     library: {
         type: 'commonjs2',
     }
   },
   resolve: {
-    extensions: ['.ts', '.js'],
+    extensions: ['.ts', '.js', '.mjs'],
     modules: [
         path.resolve('./src'),
         'node_modules',

lambda-layer/tsconfig.esm.json

@@ -0,0 +1,27 @@
+{
+    "compilerOptions": {
+      "moduleResolution": "node",
+      "module": "es2020",
+      "target": "es2020",
+      "allowUnreachableCode": false,
+      "allowUnusedLabels": false,
+      "declaration": true,
+      "declarationMap": true,
+      "esModuleInterop": true,
+      "forceConsistentCasingInFileNames": true,
+      "noEmitOnError": true,
+      "noFallthroughCasesInSwitch": true,
+      "noImplicitReturns": true,
+      "noUnusedLocals": true,
+      "pretty": true,
+      "sourceMap": true,
+      "strict": true,
+      "strictNullChecks": true,
+      "incremental": true,
+      "newLine": "LF"
+    },
+    "exclude": [
+      "node_modules"
+    ]
+  }
+