fix(grpc): camelCase methods can be double patched

packages/opentelemetry-plugin-grpc/src/grpc.ts

@@ -329,17 +329,19 @@ export class GrpcPlugin extends BasePlugin<grpc> {
     client: typeof grpcTypes.Client,
     methods: { [key: string]: { originalName?: string } }
   ): string[] {
-    const methodsToWrap = [
-      ...Object.keys(methods),
-      ...(Object.keys(methods)
-        .map(methodName => methods[methodName].originalName)
-        .filter(
-          originalName =>
-            // eslint-disable-next-line no-prototype-builtins
-            !!originalName && client.prototype.hasOwnProperty(originalName)
-        ) as string[]),
-    ];
-    return methodsToWrap;
+    const methodSet = new Set<string>(); // use set to remove duplicates caused by "camelCase"
+
+    // For a method defined in .proto as "UnaryMethod"
+    Object.entries(methods).forEach(([name, { originalName }]) => {
+      methodSet.add(name); // adds camel case method name: "unaryMethod"
+      // eslint-disable-next-line no-prototype-builtins
+      if (originalName && client.prototype.hasOwnProperty(originalName)) {
+        // adds original method name: "UnaryMethod",
+        methodSet.add(originalName);
+      }
+    });
+
+    return Array.from(methodSet);
   }
 
   private _getPatchedClientMethods() {

packages/opentelemetry-plugin-grpc/test/fixtures/grpc-test.proto

@@ -4,6 +4,7 @@ package pkg_test;
 
 service GrpcTester {
   rpc UnaryMethod (TestRequest) returns (TestReply) {}
+  rpc camelCaseMethod (TestRequest) returns (TestReply) {}
   rpc ClientStreamMethod (stream TestRequest) returns (TestReply) {}
   rpc ServerStreamMethod (TestRequest) returns (stream TestReply) {}
   rpc BidiStreamMethod (stream TestRequest) returns (stream TestReply) {}

packages/opentelemetry-plugin-grpc/test/grpc.test.ts

@@ -49,6 +49,7 @@ interface TestRequestResponse {
 type TestGrpcClient = grpc.Client & {
   unaryMethod: any;
   UnaryMethod: any;
+  camelCaseMethod: any;
   clientStreamMethod: any;
   serverStreamMethod: any;
   bidiStreamMethod: any;
@@ -93,6 +94,24 @@ const grpcClient = {
     });
   },
 
+  camelCaseMethod: (
+    client: TestGrpcClient,
+    request: TestRequestResponse
+  ): Promise<TestRequestResponse> => {
+    return new Promise((resolve, reject) => {
+      return client.camelCaseMethod(
+        request,
+        (err: grpc.ServiceError, response: TestRequestResponse) => {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(response);
+          }
+        }
+      );
+    });
+  },
+
   UnaryMethod: (
     client: TestGrpcClient,
     request: TestRequestResponse
@@ -220,6 +239,16 @@ function startServer(grpc: GrpcModule, proto: any) {
         : callback(null, { num: call.request.num });
     },
 
+    // This method returns the request
+    camelCaseMethod(
+      call: grpc.ServerUnaryCall<any>,
+      callback: SendUnaryDataCallback
+    ) {
+      call.request.num <= MAX_ERROR_STATUS
+        ? callback(getError('Unary Method Error', call.request.num))
+        : callback(null, { num: call.request.num });
+    },
+
     // This method sum the requests
     clientStreamMethod(
       call: grpc.ServerReadableStream<any>,
@@ -345,6 +374,13 @@ describe('GrpcPlugin', () => {
       request: requestList[0],
       result: requestList[0],
     },
+    {
+      description: 'camelCase unary call',
+      methodName: 'camelCaseMethod',
+      method: grpcClient.camelCaseMethod,
+      request: requestList[0],
+      result: requestList[0],
+    },
     {
       description: 'Unary call',
       methodName: 'UnaryMethod',