From 1acbe8f6afafb99ba9a0db9a82a33338c7a165fe Mon Sep 17 00:00:00 2001
From: Anjula <anjula@Anjulas-MacBook-Pro.local>
Date: Wed, 1 Apr 2020 02:24:59 +0530
Subject: [PATCH] Changing Batcher implementation

---
 batcher.go      | 124 +++++++++++++++++++++++++++++-------------------
 batcher_test.go |  68 ++++++++++++++++----------
 worker.go       |  22 ---------
 3 files changed, 116 insertions(+), 98 deletions(-)
 delete mode 100644 worker.go

diff --git a/batcher.go b/batcher.go
index af6c00d..320e136 100644
--- a/batcher.go
+++ b/batcher.go
@@ -6,83 +6,107 @@ import (
 	"time"
 )
 
-type Function func(workerID int, data []interface{})
+type Function func(data []interface{}) bool
 
 type BatchConfig struct {
-	size      int
-	WaitTime  time.Duration
-	Func      Function
-	items     []interface{}
-	batchChan chan []interface{}
+	MaxCapacity       int
+	WaitTime   time.Duration
+	function   Function
+	batchChan  chan interface{}
+	mutex      sync.RWMutex
 }
 
-var mutex = &sync.Mutex{}
-
 //Initialises a new instance
-func NewBatcher(size int, waitTime time.Duration, numWorkers int, funct Function) (b *BatchConfig, err error) {
-
+func NewBatcher(maxJobs int, waitTime time.Duration, f Function) (*BatchConfig, error) {
 	switch {
-	case size <= 0:
+	case maxJobs <= 0:
 		return &BatchConfig{}, errors.New("invalid size")
 	case waitTime <= 0:
 		return &BatchConfig{}, errors.New("invalid wait time")
-	case numWorkers <= 0:
-		return &BatchConfig{}, errors.New("invalid number of workers")
 	}
 
-	batch := &BatchConfig{
-		size:      size,
-		WaitTime:  waitTime,
-		Func:      funct,
-		items:     make([]interface{}, 0), //initialize empty slice
-		batchChan: make(chan []interface{}, numWorkers),
+
+	return &BatchConfig{
+		MaxCapacity:  maxJobs,
+		WaitTime: waitTime,
+		function: f,
+	}, nil
+}
+
+//This function helps to insert an item
+func (b *BatchConfig) Insert(item interface{}) (bool, error) {
+	if item == nil {
+		return false, errors.New("item inserted is null")
 	}
-	batch.worker(numWorkers)
 
-	go batch.autoDump()
+	b.mutex.Lock()
+	defer b.mutex.Unlock()
 
-	return batch, nil
+	if b.batchChan == nil {
+		b.batchChan = make(chan interface{}, b.MaxCapacity)
+		go b.dumper()
+	}
+
+	b.batchChan <- item
+
+	return true, nil
 }
 
-//This function helps to insert item to array
-func (b *BatchConfig) Insert(item interface{}) bool {
-	mutex.Lock()
-	defer mutex.Unlock()
-	if len(b.items) < b.size {
-		b.items = append(b.items, item)
-		return true
+func (b *BatchConfig) InsertItems(items []interface{}) (bool, error) {
+	if items == nil {
+		return false, errors.New("items inserted is null")
 	}
 
-	return false
-}
+	b.mutex.Lock()
+	defer b.mutex.Unlock()
 
+	batchLen := len(items)
+	// If the length of batch is larger than maxCapacity
+	if batchLen > b.MaxCapacity {
+		items = items[:b.MaxCapacity]
+	}
 
-func (b *BatchConfig) dump() {
-	copiedItems := make([]interface{},len(b.items))
-	if len(b.items) != 0 {
-		mutex.Lock()
-		copy(copiedItems,b.items)
-		b.items = b.items[:0]
-		b.batchChan <- copiedItems
-		mutex.Unlock()
+	if b.batchChan == nil {
+		b.batchChan = make(chan interface{}, b.MaxCapacity)
+		go b.dumper()
 	}
-}
 
-func (b *BatchConfig) autoDump() {
-	if len(b.items) == b.size {
-		b.dump()
-	}else {
-		b.timeout()
+	for _, item := range items {
+		b.batchChan <- item
 	}
+	return true, nil
 }
 
-//This function heps to with timeout dump
-func (b *BatchConfig) timeout() {
-	ticker := time.NewTicker(b.WaitTime)
+
+
+
+func (b *BatchConfig) dumper() {
+	var batch []interface{}
+	timer := time.NewTimer(b.WaitTime)
+
 	for {
 		select {
-		case <- ticker.C:
-				b.dump()
+		case <-timer.C:
+			b.function(batch)
+			b.close()
+			return
+		case item := <-b.batchChan:
+			batch = append(batch, item)
+			if len(batch) >= b.MaxCapacity {
+				// Callback with batch
+				b.function(batch)
+				// Init batch array
+				batch = []interface{}{}
+			}
 		}
 	}
 }
+
+func (b *BatchConfig) close() {
+	b.mutex.Lock()
+	defer b.mutex.Unlock()
+	if b.batchChan != nil {
+		close(b.batchChan)
+		b.batchChan = nil
+	}
+}
diff --git a/batcher_test.go b/batcher_test.go
index 4857eb0..b440a6f 100644
--- a/batcher_test.go
+++ b/batcher_test.go
@@ -1,16 +1,14 @@
 package batcher
 
 import (
-	"fmt"
-	"log"
 	"testing"
 	"time"
 )
 
-func DummyBatchFn1(workerID int, data []interface{}) {
-	for _,v  := range  data{
-		log.Println(fmt.Sprintf("[WokerID]: %d [data]: %d",workerID, v))
-	}
+
+
+func DummyBatchFn1(data []interface{}) bool{
+	return true
 }
 
 type batch struct {
@@ -59,34 +57,52 @@ func TestNewBatcher(t *testing.T) {
 	}
 
 	for _, tt := range newBatcherTest {
-		_, err := NewBatcher(tt.batch.size, tt.batch.waitTime, tt.batch.numWorkers, tt.batch.funct)
-
-		if err != nil {
-			response := false
-			if response != tt.response {
-				t.Error("Failed: NewBatcher Test")
-			}
-		} else {
-			response := true
-			if response != tt.response {
-				t.Error("Failed: NewBatcher Test")
+		 _,err :=NewBatcher(tt.batch.size, tt.batch.waitTime,tt.batch.funct)
+		 if err!= nil{
+		 	if tt.response != false{
+		 		t.Error("[ERROR]: NewBatcher function")
 			}
-		}
+		 }
+
 	}
 
 }
 
+func BenchmarkNewBatcher(b *testing.B) {
+	ba := batch{
+		size:       1,
+		waitTime:   15*time.Second,
+		numWorkers: 1,
+		funct:      DummyBatchFn1,
+	}
+	for i :=0; i<b.N; i++ {
+		_,err :=NewBatcher(ba.size,ba.waitTime,ba.funct)
+		if err !=nil{
+			b.Error("[ERROR]: NewBatcher function - Benchmarks")
+		}
+	}
+}
+
 func TestBatchConfig_Insert(t *testing.T) {
-	batch, err := NewBatcher(10,3,2, DummyBatchFn1)
-	if err !=nil{
-		t.Error("Failed: Insert Function Test : New Batcher")
+	batch,err := NewBatcher(60, 10*time.Millisecond, DummyBatchFn1)
+
+	if err != nil{
+		t.Error("[ERROR]: NewBatcher function - Insert")
 	}
-	for i:=1; i<=10; i++ {
-		check := batch.Insert(i)
 
-		if check != true {
-			t.Error("Failed: Insert Function Test")
+	for i:=1; i<=1000; i++ {
+		_, err :=batch.Insert(i)
+		if err != nil{
+			t.Error("[ERROR]: Insert function")
 		}
-	}
 
+	}
 }
+
+func TestBatchConfig_InsertItems(t *testing.T) {
+	_, err := NewBatcher(10, 10*time.Millisecond, DummyBatchFn1)
+
+	if err != nil{
+		t.Error("[ERROR]: NewBatcher function - Insert")
+	}
+}
\ No newline at end of file
diff --git a/worker.go b/worker.go
deleted file mode 100644
index 22c2a03..0000000
--- a/worker.go
+++ /dev/null
@@ -1,22 +0,0 @@
-package batcher
-
-import (
-	"sync"
-)
-
-var wg sync.WaitGroup
-
-func (b *BatchConfig) worker (workerCount int){
-	for i := 1; i < workerCount; i++ {
-		go func(workerID int, flushJobs <-chan []interface{}) {
-			for j := range flushJobs {
-				b.Func(workerID,j)
-			}
-		}(i, b.batchChan)
-
-	}
-}
-
-
-
-