feat(opentelemetry-node): improved ESM instrumentation support

.gitignore

@@ -4,3 +4,4 @@ build
 .DS_Store
 tmp
 /packages/mockotlpserver/db
+/openai.env

examples/openai-chat.mjs

@@ -0,0 +1,33 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+// An ES Modules (ESM) version of "openai-chat.js".
+//
+// Usage:
+//  OPENAI_API_KEY=sk-... \
+//      node --import @elastic/opentelemetry-node openai-chat.mjs
+
+import {OpenAI} from 'openai';
+
+const openai = new OpenAI();
+const result = await openai.chat.completions.create({
+    model: 'gpt-4o-mini',
+    messages: [{role: 'user', content: 'Why is the sky blue? Answer briefly.'}],
+});
+console.log(result.choices[0]?.message?.content);

packages/opentelemetry-node/import.mjs

@@ -20,52 +20,31 @@
 // Register ESM hook and start the SDK.
 // This is called for `--import @elastic/opentelemetry-node`.
 
-import * as module from 'node:module';
+import {register} from 'node:module';
 import {isMainThread} from 'node:worker_threads';
 
+// TODO: @opentelemetry/instrumentation should re-export this IITM method.
+// XXX add explicit IITM dep?
+// XXX can we have a guard that there is only one install of IITM in play?
+import {createAddHookMessageChannel} from 'import-in-the-middle';
+
 import {log} from './lib/logging.js';
 
-/**
- * Return true iff it looks like the `@elastic/opentelemetry-node/hook.mjs`
- * was loaded via node's `--experimental-loader` option.
- *
- * Dev Note: keep this in sync with "require.js".
- */
-function haveHookFromExperimentalLoader() {
-    const USED_LOADER_OPT =
-        /--(experimental-)?loader(\s+|=)@elastic\/opentelemetry-node\/hook.mjs/;
-    for (let i = 0; i < process.execArgv.length; i++) {
-        const arg = process.execArgv[i];
-        const nextArg = process.execArgv[i + 1];
-        if (
-            (arg === '--loader' || arg === '--experimental-loader') &&
-            nextArg === '@elastic/opentelemetry-node/hook.mjs'
-        ) {
-            log.trace('bootstrap-import: --loader hook args used');
-            return true;
-        } else if (USED_LOADER_OPT.test(arg)) {
-            log.trace('bootstrap-import: --loader hook arg used');
-            return true;
-        }
-    }
-    if (
-        process.env.NODE_OPTIONS &&
-        USED_LOADER_OPT.test(process.env.NODE_OPTIONS)
-    ) {
-        log.trace('bootstrap-import: --loader arg used in NODE_OPTIONS');
-        return true;
-    }
-    return false;
-}
+// Note: If there are *multiple* installations of import-in-the-middle, then
+// only those instrumentations using this same one will be hooked.
+const {registerOptions, waitForAllMessagesAcknowledged} =
+    createAddHookMessageChannel();
 
 if (isMainThread) {
-    if (
-        typeof module.register === 'function' &&
-        !haveHookFromExperimentalLoader()
-    ) {
-        log.trace('bootstrap-import: registering module hook');
-        module.register('./hook.mjs', import.meta.url);
-    }
+    log.trace('bootstrap-import: registering module hook');
+    // XXX module.register('./hook.mjs', import.meta.url);
+    // TODO: `@opentelemetry/instrumentation/hook.mjs` needs to re-export initialize
+    // register('@opentelemetry/instrumentation/hook.mjs', import.meta.url, registerOptions);
+    register('import-in-the-middle/hook.mjs', import.meta.url, registerOptions);
 
     await import('./lib/start.js');
+
+    // Ensure that the loader has acknowledged all the modules before we allow
+    // execution to continue.
+    await waitForAllMessagesAcknowledged();
 }