fix(otlp-exporter-base): use dynamic import instead of require in esm/esnext build

experimental/CHANGELOG.md

@@ -33,6 +33,9 @@ All notable changes to experimental packages in this project will be documented
 
 ### :bug: (Bug Fix)
 
+* fix(otlp-exporter-base): use dynamic imports over require for lazy-loading http transport utils [#5220](https://github.com/open-telemetry/opentelemetry-js/pull/5220) @pichlermarc
+  * enables bundling of Node.js HTTP exporters with rollup
+    * Limitation: if a single-file bundle is built the dynamically loaded file needs to be inlined via rollup's `inlineDynamicImports: true` setting. However, doing so may lead to `@opentelemetry/instrumentation-http` not generating telemetry.
 * fix(instrumentation-grpc): monitor error events with events.errorMonitor [#5369](https://github.com/open-telemetry/opentelemetry-js/pull/5369) @cjihrig
 * fix(exporter-metrics-otlp-http): browser OTLPMetricExporter was not passing config to OTLPMetricExporterBase super class [#5331](https://github.com/open-telemetry/opentelemetry-js/pull/5331) @trentm
 * fix(instrumentation-fetch, instrumentation-xhr): Ignore network events with zero-timings [#5332](https://github.com/open-telemetry/opentelemetry-js/pull/5332) @chancancode

experimental/packages/otlp-exporter-base/src/transport/http-exporter-transport.ts

@@ -37,7 +37,7 @@
   constructor(private _parameters: HttpRequestParameters) {}
 
   async send(data: Uint8Array, timeoutMillis: number): Promise<ExportResponse> {
-    const { agent, send } = this._loadUtils();
+    const { agent, send } = await this._loadUtils();
 
     return new Promise<ExportResponse>(resolve => {
       send(
@@ -56,16 +56,18 @@
     // intentionally left empty, nothing to do.
   }
 
-  private _loadUtils(): Utils {
+  private async _loadUtils(): Utils {
     let utils = this._utils;
 
     if (utils === null) {
+      const { sendWithHttp, createHttpAgent } = 
       // Lazy require to ensure that http/https is not required before instrumentations can wrap it.
       const {
         sendWithHttp,
         createHttpAgent,
-        // eslint-disable-next-line @typescript-eslint/no-var-requires
-      } = require('./http-transport-utils');
+      } = await import(
+        './http-transport-utils'
+      );
 
       utils = this._utils = {
         agent: createHttpAgent(

experimental/packages/otlp-exporter-base/tsconfig.esm.json

@@ -3,7 +3,8 @@
   "compilerOptions": {
     "outDir": "build/esm",
     "rootDir": "src",
-    "tsBuildInfoFile": "build/esm/tsconfig.esm.tsbuildinfo"
+    "tsBuildInfoFile": "build/esm/tsconfig.esm.tsbuildinfo",
+    "module": "es2020"
   },
   "include": [
     "src/**/*.ts"