SeqIDMaker

an IDMaker that simply generate a sequence, which is useful for local
mode.

README.md

@@ -7,7 +7,7 @@ I initiated this project after [machinery](https://github.com/RichardKnop/machin
 - Await and receive reports through channels. (_channel_ is a natural way to represent asynchronous results)
 - I want to get familiar with those concepts of #golang: **interface**, **routine**, **channel**, and a distributed task framework is a good topic for practice, :)
 
-One important concept I learned from [Celery](http://www.celeryproject.org/) and inherited in _Dingo_ is that __Caller__ and __Worker__ could share the same codebase.
+One important concept I learned from [Celery](http://www.celeryproject.org/) and inherited in __Dingo__ is that __Caller__ and __Worker__ could share the same codebase.
 > When you send a task message in Celery, that message will not contain any source code, but only the name of the task you want to execute. This works similarly to how host names work on the internet: every worker maintains a mapping of task names to their actual functions, called the task registry.
 
 Below is a quicklink to go through this README:

backend_test_suite.go

@@ -228,15 +228,6 @@ func (ts *BackendTestSuite) TestOrder() {
 	ts.Tasks = append(ts.Tasks, tasks...)
 }
 
-type testSeqID struct {
-	cur int
-}
-
-func (ts *testSeqID) NewID() (string, error) {
-	ts.cur++
-	return fmt.Sprintf("%d", ts.cur), nil
-}
-
 func (ts *BackendTestSuite) TestSameID() {
 	// different type of tasks, with the same id,
 	// backend(s) should not get mass.
@@ -256,7 +247,7 @@ func (ts *BackendTestSuite) TestSameID() {
 	// register idMaker, task
 	for i := 0; i < countOfTypes; i++ {
 		name := fmt.Sprintf("SameID.%d", i)
-		err = ts.Trans.AddIDMaker(100+i, &testSeqID{})
+		err = ts.Trans.AddIDMaker(100+i, &SeqIDMaker{})
 		if err != nil {
 			return
 		}

bench_test.go

@@ -1,8 +1,6 @@
 package dingo_test
 
 import (
-	"fmt"
-	"sync/atomic"
 	"testing"
 
 	"github.com/mission-liao/dingo"
@@ -22,14 +20,6 @@ func BenchmarkRaw(b *testing.B) {
 	}
 }
 
-type testSeqID struct {
-	i int32
-}
-
-func (me *testSeqID) NewID() (string, error) {
-	return fmt.Sprintf("%d", atomic.AddInt32(&me.i, 1)), nil
-}
-
 func BenchmarkLocal(b *testing.B) {
 	var (
 		err   error
@@ -74,7 +64,7 @@ func BenchmarkLocal(b *testing.B) {
 	}
 
 	// setup for idmaker
-	err = app.AddIDMaker(101, &testSeqID{})
+	err = app.AddIDMaker(101, &dingo.SeqIDMaker{})
 	if err != nil {
 		return
 	}

bridge_local.go

@@ -276,6 +276,10 @@ func (bdg *localBridge) Poll(t *Task) (reports <-chan *Report, err error) {
 	defer bdg.objLock.Unlock()
 
 	if chain, ok := bdg.reporters[t.Name()]; ok {
+		// a 'localReporterNode' is composed of a reporting channel and task, then sent to
+		// the linked channel, every reporter routine belongs to that task would check it,
+		// and once a reporter with the same 'ID' found, the 'localReporterNode' would settle
+		// down, and its reporting channel would be used to deliver reports.
 		chain.Send(&localStorePoller{
 			task:    t,
 			reports: reports2,

bridge_test.go

@@ -358,7 +358,7 @@ func (ts *bridgeTestSuite) TestDifferentReportsWithSameID() {
 	// register idMaker, task
 	for i := 0; i < countOfTypes; i++ {
 		name := fmt.Sprintf("DifferentReportsWithSameID.%d", i)
-		err = ts.trans.AddIDMaker(100+i, &testSeqID{})
+		err = ts.trans.AddIDMaker(100+i, &SeqIDMaker{})
 		if err != nil {
 			return
 		}

dingo_multi_test.go

@@ -220,7 +220,7 @@ func (ts *DingoMultiAppTestSuite) TestSameID() {
 		ts.register(name, fn)
 		ts.allocate(name, 2, 2)
 
-		err = v.AddIDMaker(101, &testIDMaker{})
+		err = v.AddIDMaker(101, &dingo.SeqIDMaker{})
 		if err != nil {
 			return
 		}

dingo_single_test.go

@@ -3,7 +3,6 @@ package dingo_test
 import (
 	"fmt"
 	"sync"
-	"sync/atomic"
 
 	"github.com/mission-liao/dingo"
 	"github.com/stretchr/testify/suite"
@@ -140,15 +139,6 @@ func (ts *DingoSingleAppTestSuite) TestBasic() {
 	}
 }
 
-type testIDMaker struct {
-	cur int32
-}
-
-func (idm *testIDMaker) NewID() (string, error) {
-	v := atomic.AddInt32(&idm.cur, 1)
-	return fmt.Sprintf("%d", v), nil
-}
-
 func (ts *DingoSingleAppTestSuite) TestSameID() {
 	// tasks of different name have the same IDs
 	var (
@@ -171,7 +161,7 @@ func (ts *DingoSingleAppTestSuite) TestSameID() {
 		if err != nil {
 			return
 		}
-		err = ts.app.AddIDMaker(100+i, &testIDMaker{})
+		err = ts.app.AddIDMaker(100+i, &dingo.SeqIDMaker{})
 		if err != nil {
 			return
 		}

id_maker.go

@@ -1,6 +1,10 @@
 package dingo
 
 import (
+	"errors"
+	"fmt"
+	"sync/atomic"
+
 	"github.com/satori/go.uuid"
 )
 
@@ -27,3 +31,19 @@ type uuidMaker struct{}
 func (*uuidMaker) NewID() (string, error) {
 	return uuid.NewV4().String(), nil
 }
+
+/*SeqIDMaker is an implementation of IDMaker suited for local mode.
+A sequence of number would be generated when called. Usage:
+ err := app.AddIDMaker(101, &dingo.SeqIDMaker{})
+*/
+type SeqIDMaker struct {
+	i uint64
+}
+
+func (seq *SeqIDMaker) NewID() (string, error) {
+	r := atomic.AddUint64(&seq.i, 1)
+	if r > ^uint64(0)>>1 {
+		return "", errors.New("sequential id generate failed: overflow")
+	}
+	return fmt.Sprintf("%d", r), nil
+}

id_maker_test.go

@@ -0,0 +1,41 @@
+package dingo
+
+import (
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSeqIDMaker(t *testing.T) {
+	ass := assert.New(t)
+
+	// test overflow
+	{
+		m := &SeqIDMaker{i: ^uint64(0)>>1 - 1}
+		id, err := m.NewID()
+		ass.Nil(err)
+		ass.NotEqual("", id)
+
+		id, err = m.NewID()
+		ass.NotNil(err)
+		ass.Equal("", id)
+	}
+
+	// test normal usaage
+	{
+		m := &SeqIDMaker{}
+		id1, err := m.NewID()
+		ass.Nil(err)
+
+		id2, err := m.NewID()
+		ass.Nil(err)
+
+		num1, err := strconv.Atoi(id1)
+		ass.Nil(err)
+		num2, err := strconv.Atoi(id2)
+		ass.Nil(err)
+
+		ass.Equal(1, num2-num1)
+	}
+}