fix(ioredis): fix instrumentation of ESM-imported ioredis

- With an ESM import the top-level object is a Module Namespace Object
  (https://tc39.es/ecma262/#sec-module-namespace-objects) that has no
  prototype. For compat, Node.js assigns the usual CommonJS
  module.exports to `<module>.default`, so use that when this is
  an ESM module.
- Also, TypeScript translates class properties to assignments in the
  constructor after the super() call. Because super() can call init()
  and enable() synchronously, it calls back into
  'IORedisInstrumentation' before 'traceSendCommand' was defined.
  Defining it as a method fixes that issue.

Fixes: open-telemetry#1692

plugins/node/opentelemetry-instrumentation-ioredis/src/instrumentation.ts

@@ -49,7 +49,10 @@ export class IORedisInstrumentation extends InstrumentationBase<any> {
       new InstrumentationNodeModuleDefinition<any>(
         'ioredis',
         ['>1', '<6'],
-        (moduleExports, moduleVersion?: string) => {
+        (module, moduleVersion?: string) => {
+          const moduleExports = (module[Symbol.toStringTag] === "Module"
+            ? module.default // ESM
+            : module); // CommonJS
           diag.debug('Applying patch for ioredis');
           if (isWrapped(moduleExports.prototype.sendCommand)) {
             this._unwrap(moduleExports.prototype, 'sendCommand');
@@ -67,10 +70,13 @@ export class IORedisInstrumentation extends InstrumentationBase<any> {
             'connect',
             this._patchConnection()
           );
-          return moduleExports;
+          return module;
         },
-        moduleExports => {
-          if (moduleExports === undefined) return;
+        module => {
+          if (module === undefined) return;
+          const moduleExports = (module[Symbol.toStringTag] === "Module"
+            ? module.default // ESM
+            : module); // CommonJS
           diag.debug('Removing patch for ioredis');
           this._unwrap(moduleExports.prototype, 'sendCommand');
           this._unwrap(moduleExports.prototype, 'connect');
@@ -84,17 +90,17 @@ export class IORedisInstrumentation extends InstrumentationBase<any> {
    */
   private _patchSendCommand(moduleVersion?: string) {
     return (original: Function) => {
-      return this.traceSendCommand(original, moduleVersion);
+      return this._traceSendCommand(original, moduleVersion);
     };
   }
 
   private _patchConnection() {
     return (original: Function) => {
-      return this.traceConnection(original);
+      return this._traceConnection(original);
     };
   }
 
-  private traceSendCommand = (original: Function, moduleVersion?: string) => {
+  private _traceSendCommand(original: Function, moduleVersion?: string) {
     const instrumentation = this;
     return function (this: RedisInterface, cmd?: IORedisCommand) {
       if (arguments.length < 1 || typeof cmd !== 'object') {
@@ -178,9 +184,9 @@ export class IORedisInstrumentation extends InstrumentationBase<any> {
         throw error;
       }
     };
-  };
+  }
 
-  private traceConnection = (original: Function) => {
+  private _traceConnection(original: Function) {
     const instrumentation = this;
     return function (this: RedisInterface) {
       const config =
@@ -213,5 +219,5 @@ export class IORedisInstrumentation extends InstrumentationBase<any> {
         throw error;
       }
     };
-  };
+  }
 }