Add sampler

Author: eldreygalindo

packages/opencensus-core/src/trace/model/root-span.ts

@@ -19,7 +19,8 @@ import { Clock } from '../../internal/clock'
 import * as uuid from 'uuid';
 import { debug } from '../../internal/util'
 import { SpanBaseModel, TraceContext, OnEndSpanEventListener } from '../types/tracetypes'
-import { Tracer } from './tracer';
+import { Tracer } from './tracer'
+import { Sampler } from './sampler'
 
 export class RootSpan extends SpanBaseModel implements OnEndSpanEventListener {
 
@@ -73,12 +74,18 @@ export class RootSpan extends SpanBaseModel implements OnEndSpanEventListener {
     }
 
     public startSpan(name: string, type: string) {
-        let newSpan = new Span(this);
-        newSpan.name = name
-        newSpan.type = type
-        newSpan.start();
-        this._spans.push(newSpan);
-        return newSpan;
+        if(!this.sampler == null || this.sampler.continue(this._traceId)){
+            let newSpan = new Span(this);
+            newSpan.name = name
+            newSpan.type = type
+            newSpan.start();
+            this._spans.push(newSpan);
+            return newSpan;
+        }else{
+            //TODO
+            debug("ELDREY -> RootSpan return startSpan null")
+            return
+        }
     }
 
 }

packages/opencensus-core/src/trace/model/tracer.ts

@@ -22,8 +22,9 @@ import { Stackdriver } from '../../exporters/stackdriver/stackdriver'
 import { StackdriverOptions } from '../../exporters/stackdriver/options'
 import { Exporter } from '../../exporters/exporter'
 import { TraceContext, OnEndSpanEventListener } from '../types/tracetypes';
-import { TracerConfig, defaultConfig } from '../tracing';
+import { TracerConfig, defaultConfig } from '../tracing'
 import { Buffer } from '../../exporters/buffer'
+import { Sampler } from './sampler'
 
 export type Func<T> = (...args: any[]) => T;
 
@@ -38,7 +39,7 @@ export class Tracer implements OnEndSpanEventListener {
     private config: TracerConfig;
 
     //TODO: simple solution - to be rewied in future
-    private eventListeners: OnEndSpanEventListener[] = [];
+    private eventListeners: OnEndSpanEventListener[] = [];   
     //TODO: temp solution 
     private endedTraces: RootSpan[] = [];
 
@@ -73,9 +74,16 @@ export class Tracer implements OnEndSpanEventListener {
         return this._active;
     }
 
-    public startRootSpan(context?: TraceContext): RootSpan {
+    public startRootSpan(context?: TraceContext, sampler?: Sampler): RootSpan {
         let newTrace = new RootSpan(this, context);
+        debug("tracer startRootSpan ")
         this.setCurrentRootSpan(newTrace);
+        if(sampler == null){
+            sampler = new Sampler(newTrace.traceId);
+            sampler.always();
+        }
+        debug("tracer startRootSpan ")
+        newTrace.sampler = sampler;
         newTrace.start();
         return newTrace;
     }
@@ -86,7 +94,7 @@ export class Tracer implements OnEndSpanEventListener {
             return debug('cannot end trace - no active trace found')
         }
         if (this.currentRootSpan != root) {
-            return debug('currentRootSpan != root on notifyEnd. Possbile implementation bug.')
+            return debug('currentRootSpan != root on notifyEnd. Possbile implementation bug.') 
         }
         this.notifyEndSpan(this.currentRootSpan);
         //this.clearCurrentTrace();
@@ -96,16 +104,11 @@ export class Tracer implements OnEndSpanEventListener {
     public runInContex<T>(fn: Func<T>): T {
         return this.contextManager.runAndReturn(fn)
     }
-
+    
     public registerEndSpanListener(listener: OnEndSpanEventListener) {
         this.eventListeners.push(listener);
         //this.buffer.registerExporter(exporter)
     }
-    
-    /*public registerExporter(exporter: Exporter) {
-        //this.eventListeners.push(listner);
-        this.buffer.registerExporter(exporter)
-    }*/
 
     private notifyEndSpan(root: RootSpan) {
         if (this.active) {

packages/opencensus-core/src/trace/sampler/sampler.ts

@@ -0,0 +1,86 @@
+/**
+ * Copyright 2018 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { debug, randomSpanId } from '../../internal/util'
+
+
+const minNumber = 1e-4;
+const maxNumber = 1;
+
+export class Sampler{
+     traceId:       string;
+     spanId:        string;
+     isRemote:      boolean;
+     idUpperBound:  number;
+
+     /**
+      * 
+      * @param traceId 
+      * @param spanId 
+      * @param isRemote 
+      */
+     constructor(traceId?:string, spanId?:string, isRemote?:boolean){
+         debug('Samplre constructor')
+         if(traceId){ 
+             this.traceId   = traceId;
+         }
+         if(spanId){
+            this.spanId    = spanId;
+         }
+        this.isRemote  = isRemote || false;
+
+     }
+
+     public always():Sampler{
+         this.idUpperBound = maxNumber;
+         return this;
+     }
+
+     public never():Sampler{
+         this.idUpperBound = minNumber;
+         return this;
+     }
+
+     public probability(probability:number):Sampler{
+        if(probability < minNumber){
+            return this.never();
+
+        } else if (probability > maxNumber){
+            return this.always();
+
+        }
+
+        this.idUpperBound = probability * maxNumber;
+        return this;
+     }
+
+     public continue (traceId:string):boolean{
+        debug('Samplre continue')
+        let lower_bytes = traceId.substring(traceId.length - 4)
+        let j;
+        let lower_long: number
+        for(j = 0; j < lower_bytes.length; j++) {
+            lower_long =  lower_bytes.charCodeAt(j);
+        }
+
+        if(lower_long <= this.idUpperBound){
+            return true
+        }else{
+            return false;
+        }
+     }
+
+ }

packages/opencensus-core/src/trace/types/tracetypes.ts

@@ -16,6 +16,7 @@
 
 import { Clock } from '../../internal/clock'
 import { debug, randomSpanId } from '../../internal/util'
+import { Sampler } from '../model/sampler'
 
 
 export interface MapLabels { [propName: string]: string; }
@@ -49,6 +50,7 @@ export abstract class SpanBaseModel {
     //links
     //TODO truncated 
     private _truncated: boolean;
+    private _sampler: Sampler;
 
     constructor() {
         this._className = this.constructor.name;
@@ -141,6 +143,16 @@ export abstract class SpanBaseModel {
         this.annotations[key] = value;
     }
 
+    public get sampler(){
+        debug('tracetypes get sampler()')
+        return this._sampler;
+    }
+
+    public set sampler(sampler:Sampler){
+        debug('tracetypes set sempler(sampler)')
+        this._sampler = sampler;
+    }
+
     public start() {
         if (this.started) {
             debug('calling %s.start() on already started %s %o',