chore: added warning

Author: aryamohanan

packages/aws-fargate/esm-loader.mjs

@@ -5,6 +5,8 @@
 'use strict';
 
 /**
+ * IMPORTANT: This file is deprecated, no longer supported, and will be removed in the next major release (v6).
+ * 
  * IMPORTANT NOTE: From Node.js version 18.19 and above, the ESM loaders operate off-thread.
  * Consequently, ESM instrumentation using '--experimental-loader' becomes deprecated.
  * Instead, we are using '--import' for loading instrumentation and relocated the Instana collector

packages/azure-container-services/esm-loader.mjs

@@ -5,6 +5,8 @@
 'use strict';
 
 /**
+ * IMPORTANT: This file is deprecated, no longer supported, and will be removed in the next major release (v6).
+ *
  * IMPORTANT NOTE: From Node.js version 18.19 and above, the ESM loaders operate off-thread.
  * Consequently, ESM instrumentation using '--experimental-loader' becomes deprecated.
  * Instead, we are using '--import' for loading instrumentation and relocated the Instana collector

packages/collector/esm-loader.mjs

@@ -5,6 +5,8 @@
 'use strict';
 
 /**
+ * IMPORTANT: This file is deprecated, no longer supported, and will be removed in the next major release (v6).
+ *
  * IMPORTANT NOTE: From Node.js version 18.19 and above, the ESM loaders operate off-thread.
  * Consequently, ESM instrumentation using '--experimental-loader' becomes deprecated.
  * Instead, we are using '--import' for loading instrumentation and relocated the Instana collector

packages/core/src/tracing/index.js

@@ -183,7 +183,8 @@ exports.init = function init(_config, downstreamConnection, _processIdentityProv
     console.debug(`The App is using the following preload flags: ${preloadFlags}`);
   }
 
-  // Consider removing this in the next major release of the @instana package.
+  // v18.19 and above usage of --experimental-loader flag no longer supported
+  // TODO: Remove warnings in the next major release(v6)
   if (coreUtil.esm.hasExperimentalLoaderFlag()) {
     // eslint-disable-next-line no-console
     console.warn(
@@ -194,6 +195,20 @@ exports.init = function init(_config, downstreamConnection, _processIdentityProv
         'https://www.ibm.com/docs/en/instana-observability/current?topic=nodejs-collector-installation.'
     );
   }
+
+  //  Warning for usage of the legacy 'esm-loader.mjs' file.
+  //  This loader worked with '--experimental-loader' in Node.js versions below 18.19.
+  //  TODO: Remove 'esm-loader.mjs' file and this warning in the next major release (v6).
+  if (coreUtil.esm.hasEsmLoaderFile()) {
+    // eslint-disable-next-line no-console
+    console.warn(
+      "Detected use of 'esm-loader.mjs'. This file is no longer supported and will be removed in next major release. " +
+        "To ensure tracing by Instana, please use the 'esm-register.mjs' file instead. For more information, " +
+        'refer to the Instana documentation: ' +
+        'https://www.ibm.com/docs/en/instana-observability/current?topic=nodejs-collector-installation.'
+    );
+  }
+
   config = _config;
   processIdentityProvider = _processIdentityProvider;
 

packages/core/src/util/esm.js

@@ -16,6 +16,17 @@ exports.hasExperimentalLoaderFlag = function hasExperimentalLoaderFlag() {
   );
 };
 
+/**
+ * Check if esm-loader.mjs is being used.
+ * @returns {boolean} - True if esm-loader.mjs is present in Node options or execArgv, false otherwise.
+ */
+exports.hasEsmLoaderFile = function hasEsmLoaderFile() {
+  return (
+    (process.env.NODE_OPTIONS && process.env.NODE_OPTIONS.includes('esm-loader.mjs')) ||
+    process.execArgv.some(arg => arg.includes('esm-loader.mjs'))
+  );
+};
+
 /**
  * Checks if the application is an ECMAScript Modules (ESM) app by inspecting
  * the presence of flags like --experimental-loader and --import in the environment.

packages/google-cloud-run/esm-loader.mjs

@@ -5,6 +5,8 @@
 'use strict';
 
 /**
+ * IMPORTANT: This file is deprecated, no longer supported, and will be removed in the next major release (v6).
+ *
  * IMPORTANT NOTE: From Node.js version 18.19 and above, the ESM loaders operate off-thread.
  * Consequently, ESM instrumentation using '--experimental-loader' becomes deprecated.
  * Instead, we are using '--import' for loading instrumentation and relocated the Instana collector

packages/serverless-collector/esm-loader.mjs

@@ -5,6 +5,8 @@
 'use strict';
 
 /**
+ * IMPORTANT: This file is deprecated, no longer supported, and will be removed in the next major release (v6).
+ *
  * IMPORTANT NOTE: From Node.js version 18.19 and above, the ESM loaders operate off-thread.
  * Consequently, ESM instrumentation using '--experimental-loader' becomes deprecated.
  * Instead, we are using '--import' for loading instrumentation and relocated the Instana collector