Merge pull request #33 from ethersphere/feature/ethutil-refactor

ethreact - Feature/ethutil refactor

ethchain/dagger.go

@@ -3,6 +3,7 @@ package ethchain
 import (
 	"github.com/ethereum/eth-go/ethcrypto"
 	"github.com/ethereum/eth-go/ethlog"
+	"github.com/ethereum/eth-go/ethreact"
 	"github.com/ethereum/eth-go/ethutil"
 	"github.com/obscuren/sha3"
 	"hash"
@@ -14,7 +15,7 @@ import (
 var powlogger = ethlog.NewLogger("POW")
 
 type PoW interface {
-	Search(block *Block, reactChan chan ethutil.React) []byte
+	Search(block *Block, reactChan chan ethreact.Event) []byte
 	Verify(hash []byte, diff *big.Int, nonce []byte) bool
 }
 
@@ -22,7 +23,7 @@ type EasyPow struct {
 	hash *big.Int
 }
 
-func (pow *EasyPow) Search(block *Block, reactChan chan ethutil.React) []byte {
+func (pow *EasyPow) Search(block *Block, reactChan chan ethreact.Event) []byte {
 	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 	hash := block.HashNoNonce()
 	diff := block.Difficulty

ethchain/state_manager.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"github.com/ethereum/eth-go/ethcrypto"
 	"github.com/ethereum/eth-go/ethlog"
+	"github.com/ethereum/eth-go/ethreact"
 	"github.com/ethereum/eth-go/ethtrie"
 	"github.com/ethereum/eth-go/ethutil"
 	"github.com/ethereum/eth-go/ethwire"
@@ -36,7 +37,7 @@ type EthManager interface {
 	BlockChain() *BlockChain
 	TxPool() *TxPool
 	Broadcast(msgType ethwire.MsgType, data []interface{})
-	Reactor() *ethutil.ReactorEngine
+	Reactor() *ethreact.ReactorEngine
 	PeerCount() int
 	IsMining() bool
 	IsListening() bool

ethereum.go

@@ -6,6 +6,7 @@ import (
 	"github.com/ethereum/eth-go/ethchain"
 	"github.com/ethereum/eth-go/ethcrypto"
 	"github.com/ethereum/eth-go/ethlog"
+	"github.com/ethereum/eth-go/ethreact"
 	"github.com/ethereum/eth-go/ethrpc"
 	"github.com/ethereum/eth-go/ethutil"
 	"github.com/ethereum/eth-go/ethwire"
@@ -71,7 +72,7 @@ type Ethereum struct {
 
 	listening bool
 
-	reactor *ethutil.ReactorEngine
+	reactor *ethreact.ReactorEngine
 
 	RpcServer *ethrpc.JsonRpcServer
 
@@ -106,7 +107,7 @@ func New(db ethutil.Database, clientIdentity ethwire.ClientIdentity, keyManager
 		keyManager:     keyManager,
 		clientIdentity: clientIdentity,
 	}
-	ethereum.reactor = ethutil.NewReactorEngine()
+	ethereum.reactor = ethreact.New()
 
 	ethereum.txPool = ethchain.NewTxPool(ethereum)
 	ethereum.blockChain = ethchain.NewBlockChain(ethereum)
@@ -118,7 +119,7 @@ func New(db ethutil.Database, clientIdentity ethwire.ClientIdentity, keyManager
 	return ethereum, nil
 }
 
-func (s *Ethereum) Reactor() *ethutil.ReactorEngine {
+func (s *Ethereum) Reactor() *ethreact.ReactorEngine {
 	return s.reactor
 }
 
@@ -350,6 +351,7 @@ func (s *Ethereum) ReapDeadPeerHandler() {
 
 // Start the ethereum
 func (s *Ethereum) Start(seed bool) {
+	s.reactor.Start()
 	// Bind to addr and port
 	ln, err := net.Listen("tcp", ":"+s.Port)
 	if err != nil {
@@ -461,6 +463,9 @@ func (s *Ethereum) Stop() {
 	s.txPool.Stop()
 	s.stateManager.Stop()
 
+	s.reactor.Flush()
+	s.reactor.Stop()
+
 	ethlogger.Infoln("Server stopped")
 	close(s.shutdownChan)
 }

ethlog/loggers.go

@@ -40,6 +40,9 @@ func (msg *logMessage) send(logger LogSystem) {
 var logMessages chan (*logMessage)
 var logSystems []LogSystem
 var quit chan bool
+var drained chan bool
+var shutdown chan bool
+var mutex = sync.Mutex{}
 
 type LogLevel uint8
 
@@ -57,29 +60,41 @@ func start() {
 out:
 	for {
 		select {
+		case <-quit:
+			break out
 		case msg := <-logMessages:
 			for _, logSystem := range logSystems {
 				if logSystem.GetLogLevel() >= msg.LogLevel {
 					msg.send(logSystem)
 				}
 			}
-		case <-quit:
+		case drained <- true:
-			break out
+		default:
+			drained <- true // this blocks until a message is sent to the queu
 		}
 	}
+	close(shutdown)
+}
+
+func Reset() {
+	mutex.Lock()
+	defer mutex.Unlock()
+	if logSystems != nil {
+		quit <- true
+		select {
+		case <-drained:
+		}
+		<-shutdown
+	}
+	logSystems = nil
 }
 
 // waits until log messages are drained (dispatched to log writers)
 func Flush() {
-	quit <- true
+	mutex.Lock()
-
+	defer mutex.Unlock()
-done:
+	if logSystems != nil {
-	for {
+		<-drained
-		select {
-		case <-logMessages:
-		default:
-			break done
-		}
 	}
 }
 
@@ -92,28 +107,34 @@ func NewLogger(tag string) *Logger {
 }
 
 func AddLogSystem(logSystem LogSystem) {
-	var mutex = &sync.Mutex{}
 	mutex.Lock()
 	defer mutex.Unlock()
 	if logSystems == nil {
 		logMessages = make(chan *logMessage)
 		quit = make(chan bool)
+		drained = make(chan bool, 1)
+		shutdown = make(chan bool, 1)
 		go start()
 	}
 	logSystems = append(logSystems, logSystem)
 }
 
-func (logger *Logger) sendln(level LogLevel, v ...interface{}) {
+func send(msg *logMessage) {
-	if logMessages != nil {
+	select {
-		msg := newPrintlnLogMessage(level, logger.tag, v...)
+	case <-drained:
+	}
 	logMessages <- msg
+}
+
+func (logger *Logger) sendln(level LogLevel, v ...interface{}) {
+	if logSystems != nil {
+		send(newPrintlnLogMessage(level, logger.tag, v...))
 	}
 }
 
 func (logger *Logger) sendf(level LogLevel, format string, v ...interface{}) {
-	if logMessages != nil {
+	if logSystems != nil {
-		msg := newPrintfLogMessage(level, logger.tag, format, v...)
+		send(newPrintfLogMessage(level, logger.tag, format, v...))
-		logMessages <- msg
 	}
 }
 

ethlog/loggers_test.go

@@ -28,10 +28,6 @@ func (t *TestLogSystem) GetLogLevel() LogLevel {
 	return t.level
 }
 
-func quote(s string) string {
-	return fmt.Sprintf("'%s'", s)
-}
-
 func TestLoggerPrintln(t *testing.T) {
 	logger := NewLogger("TEST")
 	testLogSystem := &TestLogSystem{level: WarnLevel}
@@ -41,10 +37,10 @@ func TestLoggerPrintln(t *testing.T) {
 	logger.Infoln("info")
 	logger.Debugln("debug")
 	Flush()
+	Reset()
 	output := testLogSystem.Output
-	fmt.Println(quote(output))
 	if output != "[TEST] error\n[TEST] warn\n" {
-		t.Error("Expected logger output '[TEST] error\\n[TEST] warn\\n', got ", quote(testLogSystem.Output))
+		t.Error("Expected logger output '[TEST] error\\n[TEST] warn\\n', got ", testLogSystem.Output)
 	}
 }
 
@@ -57,10 +53,10 @@ func TestLoggerPrintf(t *testing.T) {
 	logger.Infof("info")
 	logger.Debugf("debug")
 	Flush()
+	Reset()
 	output := testLogSystem.Output
-	fmt.Println(quote(output))
 	if output != "[TEST] error to { 2}\n[TEST] warn" {
-		t.Error("Expected logger output '[TEST] error to { 2}\\n[TEST] warn', got ", quote(testLogSystem.Output))
+		t.Error("Expected logger output '[TEST] error to { 2}\\n[TEST] warn', got ", testLogSystem.Output)
 	}
 }
 
@@ -73,13 +69,14 @@ func TestMultipleLogSystems(t *testing.T) {
 	logger.Errorln("error")
 	logger.Warnln("warn")
 	Flush()
+	Reset()
 	output0 := testLogSystem0.Output
 	output1 := testLogSystem1.Output
 	if output0 != "[TEST] error\n" {
-		t.Error("Expected logger 0 output '[TEST] error\\n', got ", quote(testLogSystem0.Output))
+		t.Error("Expected logger 0 output '[TEST] error\\n', got ", testLogSystem0.Output)
 	}
 	if output1 != "[TEST] error\n[TEST] warn\n" {
-		t.Error("Expected logger 1 output '[TEST] error\\n[TEST] warn\\n', got ", quote(testLogSystem1.Output))
+		t.Error("Expected logger 1 output '[TEST] error\\n[TEST] warn\\n', got ", testLogSystem1.Output)
 	}
 }
 
@@ -92,11 +89,11 @@ func TestFileLogSystem(t *testing.T) {
 	logger.Errorf("error to %s\n", filename)
 	logger.Warnln("warn")
 	Flush()
+	Reset()
 	contents, _ := ioutil.ReadFile(filename)
 	output := string(contents)
-	fmt.Println(quote(output))
 	if output != "[TEST] error to test.log\n[TEST] warn\n" {
-		t.Error("Expected contents of file 'test.log': '[TEST] error to test.log\\n[TEST] warn\\n', got ", quote(output))
+		t.Error("Expected contents of file 'test.log': '[TEST] error to test.log\\n[TEST] warn\\n', got ", output)
 	} else {
 		os.Remove(filename)
 	}
@@ -105,5 +102,7 @@ func TestFileLogSystem(t *testing.T) {
 func TestNoLogSystem(t *testing.T) {
 	logger := NewLogger("TEST")
 	logger.Warnln("warn")
+	fmt.Println("1")
 	Flush()
+	Reset()
 }

ethminer/miner.go

@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"github.com/ethereum/eth-go/ethchain"
 	"github.com/ethereum/eth-go/ethlog"
-	"github.com/ethereum/eth-go/ethutil"
+	"github.com/ethereum/eth-go/ethreact"
 	"github.com/ethereum/eth-go/ethwire"
 	"sort"
 )
@@ -15,19 +15,19 @@ type Miner struct {
 	pow         ethchain.PoW
 	ethereum    ethchain.EthManager
 	coinbase    []byte
-	reactChan   chan ethutil.React
+	reactChan   chan ethreact.Event
 	txs         ethchain.Transactions
 	uncles      []*ethchain.Block
 	block       *ethchain.Block
 	powChan     chan []byte
-	powQuitChan chan ethutil.React
+	powQuitChan chan ethreact.Event
 	quitChan    chan bool
 }
 
 func NewDefaultMiner(coinbase []byte, ethereum ethchain.EthManager) Miner {
-	reactChan := make(chan ethutil.React, 1)   // This is the channel that receives 'updates' when ever a new transaction or block comes in
+	reactChan := make(chan ethreact.Event, 1)   // This is the channel that receives 'updates' when ever a new transaction or block comes in
 	powChan := make(chan []byte, 1)             // This is the channel that receives valid sha hases for a given block
-	powQuitChan := make(chan ethutil.React, 1) // This is the channel that can exit the miner thread
+	powQuitChan := make(chan ethreact.Event, 1) // This is the channel that can exit the miner thread
 	quitChan := make(chan bool, 1)
 
 	ethereum.Reactor().Subscribe("newBlock", reactChan)

ethreact/README.md

@@ -0,0 +1,40 @@
+# ethreact
+
+ethereum event reactor. Component of the ethereum stack.
+various events like state change on an account or new block found are broadcast to subscribers.
+Broadcasting to subscribers is running on its own routine and globally order preserving.
+
+## Clients
+### subscribe
+
+    eventChannel := make(chan ethreact.Event)
+    reactor.Subscribe(event, eventChannel)
+
+The same channel can be subscribed to multiple events but only once for each event. In order to allow order of events to be preserved, broadcast of events is synchronous within the main broadcast loop. Therefore any blocking subscriber channels will be skipped, i.e. missing broadcasting events while they are blocked.
+
+### unsubscribe
+
+    reactor.Unsubscribe(event, eventChannel)
+
+### Processing events
+
+event.Resource is of type interface{}. The actual type of event.Resource depends on event.Name and may need to be cast for processing.
+
+    var event ethreact.Event
+    for {
+        select {
+        case event = <-eventChannel:
+            processTransaction(event.Resource.(Transaction))
+        }
+    }
+
+## Broadcast 
+
+    reactor := ethreact.New()
+    reactor.Start()
+    reactor.Post(name, resource)
+    reactor.Flush() // wait till all broadcast messages are dispatched
+    reactor.Stop() // stop the main broadcast loop immediately (even if there are unbroadcast events left)
+
+
+

ethreact/reactor.go

@@ -0,0 +1,181 @@
+package ethreact
+
+import (
+	"github.com/ethereum/eth-go/ethlog"
+	"sync"
+)
+
+var logger = ethlog.NewLogger("REACTOR")
+
+type EventHandler struct {
+	lock  sync.RWMutex
+	name  string
+	chans []chan Event
+}
+
+// Post the Event with the reactor resource on the channels
+// currently subscribed to the event
+func (e *EventHandler) Post(event Event) {
+	e.lock.RLock()
+	defer e.lock.RUnlock()
+
+	// if we want to preserve order pushing to subscibed channels
+	// dispatching should be syncrounous
+	// this means if subscribed event channel is blocked (closed or has fixed capacity)
+	// the reactor dispatch will be blocked, so we need to mitigate by skipping
+	// rogue blocking subscribers
+	for i, ch := range e.chans {
+		select {
+		case ch <- event:
+		default:
+			logger.Warnf("subscribing channel %d to event %s blocked. skipping\n", i, event.Name)
+		}
+	}
+}
+
+// Add a subscriber to this event
+func (e *EventHandler) Add(ch chan Event) {
+	e.lock.Lock()
+	defer e.lock.Unlock()
+
+	e.chans = append(e.chans, ch)
+}
+
+// Remove a subscriber
+func (e *EventHandler) Remove(ch chan Event) int {
+	e.lock.Lock()
+	defer e.lock.Unlock()
+
+	for i, c := range e.chans {
+		if c == ch {
+			e.chans = append(e.chans[:i], e.chans[i+1:]...)
+		}
+	}
+	return len(e.chans)
+}
+
+// Basic reactor resource
+type Event struct {
+	Resource interface{}
+	Name     string
+}
+
+// The reactor basic engine. Acts as bridge
+// between the events and the subscribers/posters
+type ReactorEngine struct {
+	lock            sync.RWMutex
+	eventChannel    chan Event
+	eventHandlers   map[string]*EventHandler
+	quit            chan bool
+	shutdownChannel chan bool
+	running         bool
+	drained         chan bool
+}
+
+func New() *ReactorEngine {
+	return &ReactorEngine{
+		eventHandlers:   make(map[string]*EventHandler),
+		eventChannel:    make(chan Event),
+		quit:            make(chan bool, 1),
+		drained:         make(chan bool, 1),
+		shutdownChannel: make(chan bool, 1),
+	}
+}
+
+func (reactor *ReactorEngine) Start() {
+	reactor.lock.Lock()
+	defer reactor.lock.Unlock()
+	if !reactor.running {
+		go func() {
+		out:
+			for {
+				select {
+				case <-reactor.quit:
+					break out
+				case event := <-reactor.eventChannel:
+					// needs to be called syncronously to keep order of events
+					reactor.dispatch(event)
+				case reactor.drained <- true:
+				default:
+					reactor.drained <- true // blocking till message is coming in
+				}
+			}
+			reactor.lock.Lock()
+			defer reactor.lock.Unlock()
+			reactor.running = false
+			logger.Infoln("stopped")
+			close(reactor.shutdownChannel)
+		}()
+		reactor.running = true
+		logger.Infoln("started")
+	}
+}
+
+func (reactor *ReactorEngine) Stop() {
+	reactor.lock.RLock()
+	if reactor.running {
+		reactor.quit <- true
+		select {
+		case <-reactor.drained:
+		}
+	}
+	reactor.lock.RUnlock()
+	<-reactor.shutdownChannel
+}
+
+func (reactor *ReactorEngine) Flush() {
+	<-reactor.drained
+}
+
+// Subscribe a channel to the specified event
+func (reactor *ReactorEngine) Subscribe(event string, eventChannel chan Event) {
+	reactor.lock.Lock()
+	defer reactor.lock.Unlock()
+
+	eventHandler := reactor.eventHandlers[event]
+	// Create a new event handler if one isn't available
+	if eventHandler == nil {
+		eventHandler = &EventHandler{name: event}
+		reactor.eventHandlers[event] = eventHandler
+	}
+	// Add the events channel to reactor event handler
+	eventHandler.Add(eventChannel)
+	logger.Debugf("added new subscription to %s", event)
+}
+
+func (reactor *ReactorEngine) Unsubscribe(event string, eventChannel chan Event) {
+	reactor.lock.Lock()
+	defer reactor.lock.Unlock()
+
+	eventHandler := reactor.eventHandlers[event]
+	if eventHandler != nil {
+		len := eventHandler.Remove(eventChannel)
+		if len == 0 {
+			reactor.eventHandlers[event] = nil
+		}
+		logger.Debugf("removed subscription to %s", event)
+	}
+}
+
+func (reactor *ReactorEngine) Post(event string, resource interface{}) {
+	reactor.lock.Lock()
+	defer reactor.lock.Unlock()
+
+	if reactor.running {
+		reactor.eventChannel <- Event{Resource: resource, Name: event}
+		select {
+		case <-reactor.drained:
+		}
+	}
+}
+
+func (reactor *ReactorEngine) dispatch(event Event) {
+	name := event.Name
+	eventHandler := reactor.eventHandlers[name]
+	// if no subscriptions to this event type - no event handler created
+	// then noone to notify
+	if eventHandler != nil {
+		// needs to be called syncronously
+		eventHandler.Post(event)
+	}
+}

ethreact/reactor_test.go

@@ -0,0 +1,63 @@
+package ethreact
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestReactorAdd(t *testing.T) {
+	reactor := New()
+	ch := make(chan Event)
+	reactor.Subscribe("test", ch)
+	if reactor.eventHandlers["test"] == nil {
+		t.Error("Expected new eventHandler to be created")
+	}
+	reactor.Unsubscribe("test", ch)
+	if reactor.eventHandlers["test"] != nil {
+		t.Error("Expected eventHandler to be removed")
+	}
+}
+
+func TestReactorEvent(t *testing.T) {
+	var name string
+	reactor := New()
+	// Buffer the channel, so it doesn't block for this test
+	cap := 20
+	ch := make(chan Event, cap)
+	reactor.Subscribe("even", ch)
+	reactor.Subscribe("odd", ch)
+	reactor.Post("even", "disappears") // should not broadcast if engine not started
+	reactor.Start()
+	for i := 0; i < cap; i++ {
+		if i%2 == 0 {
+			name = "even"
+		} else {
+			name = "odd"
+		}
+		reactor.Post(name, i)
+	}
+	reactor.Post("test", cap) // this should not block
+	i := 0
+	reactor.Flush()
+	close(ch)
+	for event := range ch {
+		fmt.Printf("%d: %v", i, event)
+		if i%2 == 0 {
+			name = "even"
+		} else {
+			name = "odd"
+		}
+		if val, ok := event.Resource.(int); ok {
+			if i != val || event.Name != name {
+				t.Error("Expected event %d to be of type %s and resource %d, got ", i, name, i, val)
+			}
+		} else {
+			t.Error("Unable to cast")
+		}
+		i++
+	}
+	if i != cap {
+		t.Error("excpected exactly %d events, got ", i)
+	}
+	reactor.Stop()
+}

ethutil/reactor.go

@@ -1,87 +0,0 @@
-package ethutil
-
-import (
-	"sync"
-)
-
-type ReactorEvent struct {
-	mut   sync.Mutex
-	event string
-	chans []chan React
-}
-
-// Post the specified reactor resource on the channels
-// currently subscribed
-func (e *ReactorEvent) Post(react React) {
-	e.mut.Lock()
-	defer e.mut.Unlock()
-
-	for _, ch := range e.chans {
-		go func(ch chan React) {
-			ch <- react
-		}(ch)
-	}
-}
-
-// Add a subscriber to this event
-func (e *ReactorEvent) Add(ch chan React) {
-	e.mut.Lock()
-	defer e.mut.Unlock()
-
-	e.chans = append(e.chans, ch)
-}
-
-// Remove a subscriber
-func (e *ReactorEvent) Remove(ch chan React) {
-	e.mut.Lock()
-	defer e.mut.Unlock()
-
-	for i, c := range e.chans {
-		if c == ch {
-			e.chans = append(e.chans[:i], e.chans[i+1:]...)
-		}
-	}
-}
-
-// Basic reactor resource
-type React struct {
-	Resource interface{}
-	Event    string
-}
-
-// The reactor basic engine. Acts as bridge
-// between the events and the subscribers/posters
-type ReactorEngine struct {
-	patterns map[string]*ReactorEvent
-}
-
-func NewReactorEngine() *ReactorEngine {
-	return &ReactorEngine{patterns: make(map[string]*ReactorEvent)}
-}
-
-// Subscribe a channel to the specified event
-func (reactor *ReactorEngine) Subscribe(event string, ch chan React) {
-	ev := reactor.patterns[event]
-	// Create a new event if one isn't available
-	if ev == nil {
-		ev = &ReactorEvent{event: event}
-		reactor.patterns[event] = ev
-	}
-
-	// Add the channel to reactor event handler
-	ev.Add(ch)
-}
-
-func (reactor *ReactorEngine) Unsubscribe(event string, ch chan React) {
-	ev := reactor.patterns[event]
-	if ev != nil {
-		ev.Remove(ch)
-	}
-}
-
-func (reactor *ReactorEngine) Post(event string, resource interface{}) {
-	ev := reactor.patterns[event]
-	if ev != nil {
-		ev.Post(React{Resource: resource, Event: event})
-	}
-}

ethutil/reactor_test.go

@@ -1,30 +0,0 @@
-package ethutil
-
-import "testing"
-
-func TestReactorAdd(t *testing.T) {
-	engine := NewReactorEngine()
-	ch := make(chan React)
-	engine.Subscribe("test", ch)
-	if len(engine.patterns) != 1 {
-		t.Error("Expected patterns to be 1, got", len(engine.patterns))
-	}
-}
-
-func TestReactorEvent(t *testing.T) {
-	engine := NewReactorEngine()
-
-	// Buffer 1, so it doesn't block for this test
-	ch := make(chan React, 1)
-	engine.Subscribe("test", ch)
-	engine.Post("test", "hello")
-
-	value := <-ch
-	if val, ok := value.Resource.(string); ok {
-		if val != "hello" {
-			t.Error("Expected Resource to be 'hello', got", val)
-		}
-	} else {
-		t.Error("Unable to cast")
-	}
-}