cmd, consensus/ethash, eth: miner push notifications

6 files changed, 206 insertions, 62 deletions

diff --git a/consensus/ethash/algorithm_test.go b/consensus/ethash/algorithm_test.go
index e7625f7c0..db22cccd0 100644
--- a/consensus/ethash/algorithm_test.go
+++ b/consensus/ethash/algorithm_test.go
@@ -729,7 +729,7 @@ func TestConcurrentDiskCacheGeneration(t *testing.T) {
 
 		go func(idx int) {
 			defer pend.Done()
-			ethash := New(Config{cachedir, 0, 1, "", 0, 0, ModeNormal})
+			ethash := New(Config{cachedir, 0, 1, "", 0, 0, ModeNormal}, nil)
 			defer ethash.Close()
 			if err := ethash.VerifySeal(nil, block.Header()); err != nil {
 				t.Errorf("proc %d: block verification failed: %v", idx, err)
diff --git a/consensus/ethash/consensus.go b/consensus/ethash/consensus.go
index eb0f73d98..e18a06d52 100644
--- a/consensus/ethash/consensus.go
+++ b/consensus/ethash/consensus.go
@@ -493,7 +493,7 @@ func (ethash *Ethash) VerifySeal(chain consensus.ChainReader, header *types.Head
 	if !bytes.Equal(header.MixDigest[:], digest) {
 		return errInvalidMixDigest
 	}
-	target := new(big.Int).Div(maxUint256, header.Difficulty)
+	target := new(big.Int).Div(two256, header.Difficulty)
 	if new(big.Int).SetBytes(result).Cmp(target) > 0 {
 		return errInvalidPoW
 	}
diff --git a/consensus/ethash/ethash.go b/consensus/ethash/ethash.go
index 0cb3059b9..19c94deb6 100644
--- a/consensus/ethash/ethash.go
+++ b/consensus/ethash/ethash.go
@@ -45,11 +45,11 @@ import (
 var ErrInvalidDumpMagic = errors.New("invalid dump magic")
 
 var (
-	// maxUint256 is a big integer representing 2^256-1
-	maxUint256 = new(big.Int).Exp(big.NewInt(2), big.NewInt(256), big.NewInt(0))
+	// two256 is a big integer representing 2^256
+	two256 = new(big.Int).Exp(big.NewInt(2), big.NewInt(256), big.NewInt(0))
 
 	// sharedEthash is a full instance that can be shared between multiple users.
-	sharedEthash = New(Config{"", 3, 0, "", 1, 0, ModeNormal})
+	sharedEthash = New(Config{"", 3, 0, "", 1, 0, ModeNormal}, nil)
 
 	// algorithmRevision is the data structure version used for file naming.
 	algorithmRevision = 23
@@ -447,8 +447,10 @@ type Ethash struct {
 	exitCh    chan chan error // Notification channel to exiting backend threads
 }
 
-// New creates a full sized ethash PoW scheme and starts a background thread for remote mining.
-func New(config Config) *Ethash {
+// New creates a full sized ethash PoW scheme and starts a background thread for
+// remote mining, also optionally notifying a batch of remote services of new work
+// packages.
+func New(config Config, notify []string) *Ethash {
 	if config.CachesInMem <= 0 {
 		log.Warn("One ethash cache must always be in memory", "requested", config.CachesInMem)
 		config.CachesInMem = 1
@@ -473,13 +475,13 @@ func New(config Config) *Ethash {
 		submitRateCh: make(chan *hashrate),
 		exitCh:       make(chan chan error),
 	}
-	go ethash.remote()
+	go ethash.remote(notify)
 	return ethash
 }
 
 // NewTester creates a small sized ethash PoW scheme useful only for testing
 // purposes.
-func NewTester() *Ethash {
+func NewTester(notify []string) *Ethash {
 	ethash := &Ethash{
 		config:       Config{PowMode: ModeTest},
 		caches:       newlru("cache", 1, newCache),
@@ -494,7 +496,7 @@ func NewTester() *Ethash {
 		submitRateCh: make(chan *hashrate),
 		exitCh:       make(chan chan error),
 	}
-	go ethash.remote()
+	go ethash.remote(notify)
 	return ethash
 }
 
diff --git a/consensus/ethash/ethash_test.go b/consensus/ethash/ethash_test.go
index ccdd30fb0..87ac17c2b 100644
--- a/consensus/ethash/ethash_test.go
+++ b/consensus/ethash/ethash_test.go
@@ -32,17 +32,18 @@ import (
 
 // Tests that ethash works correctly in test mode.
 func TestTestMode(t *testing.T) {
-	head := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
+	header := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
 
-	ethash := NewTester()
+	ethash := NewTester(nil)
 	defer ethash.Close()
-	block, err := ethash.Seal(nil, types.NewBlockWithHeader(head), nil)
+
+	block, err := ethash.Seal(nil, types.NewBlockWithHeader(header), nil)
 	if err != nil {
 		t.Fatalf("failed to seal block: %v", err)
 	}
-	head.Nonce = types.EncodeNonce(block.Nonce())
-	head.MixDigest = block.MixDigest()
-	if err := ethash.VerifySeal(nil, head); err != nil {
+	header.Nonce = types.EncodeNonce(block.Nonce())
+	header.MixDigest = block.MixDigest()
+	if err := ethash.VerifySeal(nil, header); err != nil {
 		t.Fatalf("unexpected verification error: %v", err)
 	}
 }
@@ -55,7 +56,7 @@ func TestCacheFileEvict(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
-	e := New(Config{CachesInMem: 3, CachesOnDisk: 10, CacheDir: tmpdir, PowMode: ModeTest})
+	e := New(Config{CachesInMem: 3, CachesOnDisk: 10, CacheDir: tmpdir, PowMode: ModeTest}, nil)
 	defer e.Close()
 
 	workers := 8
@@ -78,21 +79,21 @@ func verifyTest(wg *sync.WaitGroup, e *Ethash, workerIndex, epochs int) {
 		if block < 0 {
 			block = 0
 		}
-		head := &types.Header{Number: big.NewInt(block), Difficulty: big.NewInt(100)}
-		e.VerifySeal(nil, head)
+		header := &types.Header{Number: big.NewInt(block), Difficulty: big.NewInt(100)}
+		e.VerifySeal(nil, header)
 	}
 }
 
 func TestRemoteSealer(t *testing.T) {
-	ethash := NewTester()
+	ethash := NewTester(nil)
 	defer ethash.Close()
+
 	api := &API{ethash}
 	if _, err := api.GetWork(); err != errNoMiningWork {
 		t.Error("expect to return an error indicate there is no mining work")
 	}
-
-	head := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
-	block := types.NewBlockWithHeader(head)
+	header := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
+	block := types.NewBlockWithHeader(header)
 
 	// Push new work.
 	ethash.Seal(nil, block, nil)
@@ -108,16 +109,14 @@ func TestRemoteSealer(t *testing.T) {
 	if res := api.SubmitWork(types.BlockNonce{}, block.HashNoNonce(), common.Hash{}); res {
 		t.Error("expect to return false when submit a fake solution")
 	}
-
 	// Push new block with same block number to replace the original one.
-	head = &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(1000)}
-	block = types.NewBlockWithHeader(head)
+	header = &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(1000)}
+	block = types.NewBlockWithHeader(header)
 	ethash.Seal(nil, block, nil)
 
 	if work, err = api.GetWork(); err != nil || work[0] != block.HashNoNonce().Hex() {
 		t.Error("expect to return the latest pushed work")
 	}
-
 	// Push block with higher block number.
 	newHead := &types.Header{Number: big.NewInt(2), Difficulty: big.NewInt(100)}
 	newBlock := types.NewBlockWithHeader(newHead)
@@ -130,19 +129,18 @@ func TestRemoteSealer(t *testing.T) {
 
 func TestHashRate(t *testing.T) {
 	var (
-		ethash   = NewTester()
-		api      = &API{ethash}
 		hashrate = []hexutil.Uint64{100, 200, 300}
 		expect   uint64
 		ids      = []common.Hash{common.HexToHash("a"), common.HexToHash("b"), common.HexToHash("c")}
 	)
-
+	ethash := NewTester(nil)
 	defer ethash.Close()
 
 	if tot := ethash.Hashrate(); tot != 0 {
 		t.Error("expect the result should be zero")
 	}
 
+	api := &API{ethash}
 	for i := 0; i < len(hashrate); i += 1 {
 		if res := api.SubmitHashRate(hashrate[i], ids[i]); !res {
 			t.Error("remote miner submit hashrate failed")
@@ -155,9 +153,8 @@ func TestHashRate(t *testing.T) {
 }
 
 func TestClosedRemoteSealer(t *testing.T) {
-	ethash := NewTester()
-	// Make sure exit channel has been listened
-	time.Sleep(1 * time.Second)
+	ethash := NewTester(nil)
+	time.Sleep(1 * time.Second) // ensure exit channel is listening
 	ethash.Close()
 
 	api := &API{ethash}
diff --git a/consensus/ethash/sealer.go b/consensus/ethash/sealer.go
index a9449d406..03d848473 100644
--- a/consensus/ethash/sealer.go
+++ b/consensus/ethash/sealer.go
@@ -17,11 +17,14 @@
 package ethash
 
 import (
+	"bytes"
 	crand "crypto/rand"
+	"encoding/json"
 	"errors"
 	"math"
 	"math/big"
 	"math/rand"
+	"net/http"
 	"runtime"
 	"sync"
 	"time"
@@ -109,7 +112,7 @@ func (ethash *Ethash) mine(block *types.Block, id int, seed uint64, abort chan s
 	var (
 		header  = block.Header()
 		hash    = header.HashNoNonce().Bytes()
-		target  = new(big.Int).Div(maxUint256, header.Difficulty)
+		target  = new(big.Int).Div(two256, header.Difficulty)
 		number  = header.Number.Uint64()
 		dataset = ethash.dataset(number)
 	)
@@ -161,40 +164,65 @@ search:
 	runtime.KeepAlive(dataset)
 }
 
-// remote starts a standalone goroutine to handle remote mining related stuff.
-func (ethash *Ethash) remote() {
+// remote is a standalone goroutine to handle remote mining related stuff.
+func (ethash *Ethash) remote(notify []string) {
 	var (
-		works       = make(map[common.Hash]*types.Block)
-		rates       = make(map[common.Hash]hashrate)
-		currentWork *types.Block
+		works = make(map[common.Hash]*types.Block)
+		rates = make(map[common.Hash]hashrate)
+
+		currentBlock *types.Block
+		currentWork  [3]string
+
+		notifyTransport = &http.Transport{}
+		notifyClient    = &http.Client{
+			Transport: notifyTransport,
+			Timeout:   time.Second,
+		}
+		notifyReqs = make([]*http.Request, len(notify))
 	)
+	// notifyWork notifies all the specified mining endpoints of the availability of
+	// new work to be processed.
+	notifyWork := func() {
+		work := currentWork
+		blob, _ := json.Marshal(work)
 
-	// getWork returns a work package for external miner.
+		for i, url := range notify {
+			// Terminate any previously pending request and create the new work
+			if notifyReqs[i] != nil {
+				notifyTransport.CancelRequest(notifyReqs[i])
+			}
+			notifyReqs[i], _ = http.NewRequest("POST", url, bytes.NewReader(blob))
+			notifyReqs[i].Header.Set("Content-Type", "application/json")
+
+			// Push the new work concurrently to all the remote nodes
+			go func(req *http.Request, url string) {
+				res, err := notifyClient.Do(req)
+				if err != nil {
+					log.Warn("Failed to notify remote miner", "err", err)
+				} else {
+					log.Trace("Notified remote miner", "miner", url, "hash", log.Lazy{Fn: func() common.Hash { return common.HexToHash(work[0]) }}, "target", work[2])
+					res.Body.Close()
+				}
+			}(notifyReqs[i], url)
+		}
+	}
+	// makeWork creates a work package for external miner.
 	//
 	// The work package consists of 3 strings:
 	//   result[0], 32 bytes hex encoded current block header pow-hash
 	//   result[1], 32 bytes hex encoded seed hash used for DAG
 	//   result[2], 32 bytes hex encoded boundary condition ("target"), 2^256/difficulty
-	getWork := func() ([3]string, error) {
-		var res [3]string
-		if currentWork == nil {
-			return res, errNoMiningWork
-		}
-		res[0] = currentWork.HashNoNonce().Hex()
-		res[1] = common.BytesToHash(SeedHash(currentWork.NumberU64())).Hex()
+	makeWork := func(block *types.Block) {
+		hash := block.HashNoNonce()
 
-		// Calculate the "target" to be returned to the external sealer.
-		n := big.NewInt(1)
-		n.Lsh(n, 255)
-		n.Div(n, currentWork.Difficulty())
-		n.Lsh(n, 1)
-		res[2] = common.BytesToHash(n.Bytes()).Hex()
+		currentWork[0] = hash.Hex()
+		currentWork[1] = common.BytesToHash(SeedHash(block.NumberU64())).Hex()
+		currentWork[2] = common.BytesToHash(new(big.Int).Div(two256, block.Difficulty()).Bytes()).Hex()
 
 		// Trace the seal work fetched by remote sealer.
-		works[currentWork.HashNoNonce()] = currentWork
-		return res, nil
+		currentBlock = block
+		works[hash] = block
 	}
-
 	// submitWork verifies the submitted pow solution, returning
 	// whether the solution was accepted or not (not can be both a bad pow as well as
 	// any other error, like no pending work or stale mining result).
@@ -238,21 +266,23 @@ func (ethash *Ethash) remote() {
 	for {
 		select {
 		case block := <-ethash.workCh:
-			if currentWork != nil && block.ParentHash() != currentWork.ParentHash() {
+			if currentBlock != nil && block.ParentHash() != currentBlock.ParentHash() {
 				// Start new round mining, throw out all previous work.
 				works = make(map[common.Hash]*types.Block)
 			}
 			// Update current work with new received block.
 			// Note same work can be past twice, happens when changing CPU threads.
-			currentWork = block
+			makeWork(block)
+
+			// Notify and requested URLs of the new work availability
+			notifyWork()
 
 		case work := <-ethash.fetchWorkCh:
 			// Return current mining work to remote miner.
-			miningWork, err := getWork()
-			if err != nil {
-				work.errc <- err
+			if currentBlock == nil {
+				work.errc <- errNoMiningWork
 			} else {
-				work.res <- miningWork
+				work.res <- currentWork
 			}
 
 		case result := <-ethash.submitWorkCh:
diff --git a/consensus/ethash/sealer_test.go b/consensus/ethash/sealer_test.go
new file mode 100644
index 000000000..6d8a77049
--- /dev/null
+++ b/consensus/ethash/sealer_test.go
@@ -0,0 +1,115 @@
+package ethash
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"math/big"
+	"net"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+// Tests whether remote HTTP servers are correctly notified of new work.
+func TestRemoteNotify(t *testing.T) {
+	// Start a simple webserver to capture notifications
+	sink := make(chan [3]string)
+
+	server := &http.Server{
+		Handler: http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+			blob, err := ioutil.ReadAll(req.Body)
+			if err != nil {
+				t.Fatalf("failed to read miner notification: %v", err)
+			}
+			var work [3]string
+			if err := json.Unmarshal(blob, &work); err != nil {
+				t.Fatalf("failed to unmarshal miner notification: %v", err)
+			}
+			sink <- work
+		}),
+	}
+	// Open a custom listener to extract its local address
+	listener, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatalf("failed to open notification server: %v", err)
+	}
+	defer listener.Close()
+
+	go server.Serve(listener)
+
+	// Create the custom ethash engine
+	ethash := NewTester([]string{"http://" + listener.Addr().String()})
+	defer ethash.Close()
+
+	// Stream a work task and ensure the notification bubbles out
+	header := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
+	block := types.NewBlockWithHeader(header)
+
+	ethash.Seal(nil, block, nil)
+	select {
+	case work := <-sink:
+		if want := header.HashNoNonce().Hex(); work[0] != want {
+			t.Errorf("work packet hash mismatch: have %s, want %s", work[0], want)
+		}
+		if want := common.BytesToHash(SeedHash(header.Number.Uint64())).Hex(); work[1] != want {
+			t.Errorf("work packet seed mismatch: have %s, want %s", work[1], want)
+		}
+		target := new(big.Int).Div(new(big.Int).Lsh(big.NewInt(1), 256), header.Difficulty)
+		if want := common.BytesToHash(target.Bytes()).Hex(); work[2] != want {
+			t.Errorf("work packet target mismatch: have %s, want %s", work[2], want)
+		}
+	case <-time.After(time.Second):
+		t.Fatalf("notification timed out")
+	}
+}
+
+// Tests that pushing work packages fast to the miner doesn't cause any daa race
+// issues in the notifications.
+func TestRemoteMultiNotify(t *testing.T) {
+	// Start a simple webserver to capture notifications
+	sink := make(chan [3]string, 1024)
+
+	server := &http.Server{
+		Handler: http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+			blob, err := ioutil.ReadAll(req.Body)
+			if err != nil {
+				t.Fatalf("failed to read miner notification: %v", err)
+			}
+			var work [3]string
+			if err := json.Unmarshal(blob, &work); err != nil {
+				t.Fatalf("failed to unmarshal miner notification: %v", err)
+			}
+			sink <- work
+		}),
+	}
+	// Open a custom listener to extract its local address
+	listener, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatalf("failed to open notification server: %v", err)
+	}
+	defer listener.Close()
+
+	go server.Serve(listener)
+
+	// Create the custom ethash engine
+	ethash := NewTester([]string{"http://" + listener.Addr().String()})
+	defer ethash.Close()
+
+	// Stream a lot of work task and ensure all the notifications bubble out
+	for i := 0; i < cap(sink); i++ {
+		header := &types.Header{Number: big.NewInt(int64(i)), Difficulty: big.NewInt(100)}
+		block := types.NewBlockWithHeader(header)
+
+		ethash.Seal(nil, block, nil)
+	}
+	for i := 0; i < cap(sink); i++ {
+		select {
+		case <-sink:
+		case <-time.After(250 * time.Millisecond):
+			t.Fatalf("notification %d timed out", i)
+		}
+	}
+}