adding callback for dispatch

Author: Ashish Aggarwal

src/dispatchers/dispatcher.ts

@@ -18,6 +18,6 @@ import Span from '../span';
 
 export interface Dispatcher {
     name(): string;
-    dispatch(span: Span): void;
+    dispatch(span: Span, callback: (error) => void): void;
     close(callback: () => void): void;
 }

src/dispatchers/file.ts

@@ -32,9 +32,12 @@ export default class FileDispatcher implements Dispatcher {
         return 'FileDispatcher';
     }
 
-    dispatch(span: Span): void {
+    dispatch(span: Span, callback: (error) => void): void {
         this._spanFileStream.write(span.toString());
         this._spanFileStream.write('\n');
+        if (callback) {
+            callback(null);
+        }
     }
 
     close(callback: () => void): void {

src/dispatchers/in_memory.ts

@@ -28,8 +28,11 @@ export default class InMemoryDispatcher implements Dispatcher {
         return 'InMemoryDispatcher';
     }
 
-    dispatch(span: Span): void {
+    dispatch(span: Span, callback: (error) => void): void {
         this._spans.push(span);
+        if (callback) {
+            callback(null);
+        }
     }
 
     close(callback: () => void): void {

src/dispatchers/noop.ts

@@ -24,7 +24,11 @@ export default class NoopDispatcher implements Dispatcher {
         return 'NoopDispatcher';
     }
 
-    dispatch(span: Span): void { }
+    dispatch(span: Span, callback: (error) => void): void {
+        if (callback) {
+            callback(null);
+        }
+    }
 
     close(callback: () => void): void {
         if (callback) {

src/dispatchers/remote.ts

@@ -36,14 +36,20 @@ export default class RemoteDispatcher implements Dispatcher {
         return 'RemoteDispatcher';
     }
 
-    dispatch(span: Span): void {
+    dispatch(span: Span, callback: (error) => void): void {
         const proto = this._convertToProtoSpan(span);
         this._client.dispatch(proto, (err, response) => {
             if (this._logger) {
                 if (err) {
                     this._logger.error(`Fail to dispatch span to haystack-agent ${err.toString()}`);
+                    if (callback) {
+                        callback(new Error(err));
+                    }
                 } else {
                     this._logger.debug(`grpc response code from haystack-agent - ${response.getCode()}`);
+                    if (callback) {
+                        callback(null);
+                    }
                 }
             }
         });

src/span.ts

@@ -127,14 +127,14 @@ export default class Span {
         });
     }
 
-    finish(finishTime?: number): void {
+    finish(finishTime?: number, callback?: (error) => void): void {
         if (this._isFinished) {
             const spanInfo = `operation=${this.operationName},context=${this.context().toString()}`;
             throw new Error(`cant finish the same span twice - ${spanInfo}`);
         }
         const endTime = finishTime || Utils.now();
         this._duration = endTime - this._startTime;
-        this._tracer.dispatcher().dispatch(this);
+        this._tracer.dispatcher().dispatch(this, callback);
         this._isFinished = true;
     }