changed method of restricting number of segments

src/agent/Buffer.ts

@@ -18,16 +18,13 @@
  */
 
 import { createLogger } from '../logging';
-import config from '../config/AgentConfig';
 
 const logger = createLogger(__filename);
 
 export default class Buffer<T> {
-  private readonly maxSize: number;
   private readonly buffer: T[];
 
   constructor() {
-    this.maxSize = config.maxBufferSize;
     this.buffer = [];
   }
 
@@ -36,10 +33,6 @@ export default class Buffer<T> {
   }
 
   put(element: T): boolean {
-    if (this.length > this.maxSize) {
-      logger.warn('Drop the data because of the buffer is oversize');
-      return false;
-    }
     this.buffer.push(element);
 
     return true;

src/agent/protocol/grpc/clients/TraceReportClient.ts

@@ -56,6 +56,8 @@ export default class TraceReportClient implements Client {
 
   start() {
     const reportFunction = () => {
+      emitter.emit('segments-sent');  // reset limiter in SpanContext
+
       try {
         if (this.buffer.length === 0) {
           return;

src/lib/EventEmitter.ts

@@ -24,6 +24,7 @@ import Segment from '../trace/context/Segment';
 
 declare interface SkyWalkingEventEmitter {
   on(event: 'segment-finished', listener: (segment: Segment) => void): this;
+  on(event: 'segments-sent', listener: () => void): this;
 }
 
 class SkyWalkingEventEmitter extends EventEmitter {

src/trace/context/ContextManager.ts

@@ -17,9 +17,11 @@
  *
  */
 
+import config from '../../config/AgentConfig';
 import Context from '../../trace/context/Context';
 import Span from '../../trace/span/Span';
 import SpanContext from '../../trace/context/SpanContext';
+import DummyContext from '../../trace/context/DummyContext';
 
 import async_hooks from 'async_hooks';
 
@@ -81,7 +83,13 @@ class ContextManager {
   get current(): Context {
     const asyncState = this.asyncState;
 
-    return !asyncState.spans.length ? new SpanContext() : asyncState.spans[asyncState.spans.length - 1].context;
+    if (asyncState.spans.length)
+      return asyncState.spans[asyncState.spans.length - 1].context;
+
+    if (SpanContext.nActiveSegments < config.maxBufferSize)
+      return new SpanContext();
+
+    return new DummyContext();
   }
 
   get spans(): Span[] {

src/trace/context/SpanContext.ts

@@ -35,7 +35,12 @@ import { emitter } from '../../lib/EventEmitter';
 
 const logger = createLogger(__filename);
 
+emitter.on('segments-sent', () => {
+  SpanContext.nActiveSegments = 0;  // reset limiter
+});
+
 export default class SpanContext implements Context {
+  static nActiveSegments = 0;  // counter to allow only config.maxBufferSize active (non-dummy) segments per reporting frame
   spanId = 0;
   nSpans = 0;
   finished = false;
@@ -166,7 +171,8 @@ export default class SpanContext implements Context {
       nSpans: this.nSpans,
     });
 
-    this.nSpans += 1;
+    if (!this.nSpans++)
+      SpanContext.nActiveSegments += 1;
 
     if (ContextManager.spans.indexOf(span) === -1)
       ContextManager.spans.push(span);