ethstats: implement block history retrievals

Author: karalabe

ethstats/ethstats.go

@@ -42,6 +42,10 @@ import (
 	"golang.org/x/net/websocket"
 )
 
+// historyUpdateRange is the number of blocks a node should report upon login or
+// history request.
+const historyUpdateRange = 50
+
 // Service implements an Ethereum netstats reporting daemon that pushes local
 // chain statistics up to a monitoring server.
 type Service struct {
@@ -54,6 +58,9 @@ type Service struct {
 	node string // Name of the node to display on the monitoring page
 	pass string // Password to authorize access to the monitoring page
 	host string // Remote address of the monitoring service
+
+	pongCh chan struct{} // Pong notifications are fed into this channel
+	histCh chan []uint64 // History request block numbers are fed into this channel
 }
 
 // New returns a monitoring service ready for stats reporting.
@@ -66,11 +73,13 @@ func New(url string, ethServ *eth.Ethereum, lesServ *les.LightEthereum) (*Servic
 	}
 	// Assemble and return the stats service
 	return &Service{
-		eth:  ethServ,
-		les:  lesServ,
-		node: parts[1],
-		pass: parts[3],
-		host: parts[4],
+		eth:    ethServ,
+		les:    lesServ,
+		node:   parts[1],
+		pass:   parts[3],
+		host:   parts[4],
+		pongCh: make(chan struct{}),
+		histCh: make(chan []uint64, 1),
 	}, nil
 }
 
@@ -135,22 +144,34 @@ func (s *Service) loop() {
 			time.Sleep(10 * time.Second)
 			continue
 		}
-		if err = s.report(in, out); err != nil {
+		go s.readLoop(conn, in)
+
+		// Send the initial stats so our node looks decent from the get go
+		if err = s.report(out); err != nil {
 			glog.V(logger.Warn).Infof("Initial stats report failed: %v", err)
 			conn.Close()
 			continue
 		}
+		if err = s.reportHistory(out, nil); err != nil {
+			glog.V(logger.Warn).Infof("History report failed: %v", err)
+			conn.Close()
+			continue
+		}
 		// Keep sending status updates until the connection breaks
 		fullReport := time.NewTicker(15 * time.Second)
 
 		for err == nil {
 			select {
 			case <-fullReport.C:
-				if err = s.report(in, out); err != nil {
+				if err = s.report(out); err != nil {
 					glog.V(logger.Warn).Infof("Full stats report failed: %v", err)
 				}
-			case head := <-headSub.Chan():
-				if head == nil { // node stopped
+			case list := <-s.histCh:
+				if err = s.reportHistory(out, list); err != nil {
+					glog.V(logger.Warn).Infof("Block history report failed: %v", err)
+				}
+			case head, ok := <-headSub.Chan():
+				if !ok { // node stopped
 					conn.Close()
 					return
 				}
@@ -160,8 +181,8 @@ func (s *Service) loop() {
 				if err = s.reportPending(out); err != nil {
 					glog.V(logger.Warn).Infof("Post-block transaction stats report failed: %v", err)
 				}
-			case ev := <-txSub.Chan():
-				if ev == nil { // node stopped
+			case _, ok := <-txSub.Chan():
+				if !ok { // node stopped
 					conn.Close()
 					return
 				}
@@ -183,6 +204,76 @@ func (s *Service) loop() {
 	}
 }
 
+// readLoop loops as long as the connection is alive and retrieves data packets
+// from the network socket. If any of them match an active request, it forwards
+// it, if they themselves are requests it initiates a reply, and lastly it drops
+// unknown packets.
+func (s *Service) readLoop(conn *websocket.Conn, in *json.Decoder) {
+	// If the read loop exists, close the connection
+	defer conn.Close()
+
+	for {
+		// Retrieve the next generic network packet and bail out on error
+		var msg map[string][]interface{}
+		if err := in.Decode(&msg); err != nil {
+			glog.V(logger.Warn).Infof("Failed to decode stats server message: %v", err)
+			return
+		}
+		if len(msg["emit"]) == 0 {
+			glog.V(logger.Warn).Infof("Stats server sent non-broadcast: %v", msg)
+			return
+		}
+		command, ok := msg["emit"][0].(string)
+		if !ok {
+			glog.V(logger.Warn).Infof("Invalid stats server message type: %v", msg["emit"][0])
+			return
+		}
+		// If the message is a ping reply, deliver (someone must be listening!)
+		if len(msg["emit"]) == 2 && command == "node-pong" {
+			select {
+			case s.pongCh <- struct{}{}:
+				// Pong delivered, continue listening
+				continue
+			default:
+				// Ping routine dead, abort
+				glog.V(logger.Warn).Infof("Stats server pinger seems to have died")
+				return
+			}
+		}
+		// If the message is a history request, forward to the event processor
+		if len(msg["emit"]) == 2 && command == "history" {
+			// Make sure the request is valid and doesn't crash us
+			request, ok := msg["emit"][1].(map[string]interface{})
+			if !ok {
+				glog.V(logger.Warn).Infof("Invalid history request: %v", msg["emit"][1])
+				return
+			}
+			list, ok := request["list"].([]interface{})
+			if !ok {
+				glog.V(logger.Warn).Infof("Invalid history block list: %v", request["list"])
+				return
+			}
+			// Convert the block number list to an integer list
+			numbers := make([]uint64, len(list))
+			for i, num := range list {
+				n, ok := num.(float64)
+				if !ok {
+					glog.V(logger.Warn).Infof("Invalid history block number: %v", num)
+					return
+				}
+				numbers[i] = uint64(n)
+			}
+			select {
+			case s.histCh <- numbers:
+				continue
+			default:
+			}
+		}
+		// Report anything else and continue
+		glog.V(logger.Info).Infof("Unknown stats message: %v", msg)
+	}
+}
+
 // nodeInfo is the collection of metainformation about a node that is displayed
 // on the monitoring page.
 type nodeInfo struct {
@@ -195,6 +286,7 @@ type nodeInfo struct {
 	Os       string `json:"os"`
 	OsVer    string `json:"os_v"`
 	Client   string `json:"client"`
+	History  bool   `json:"canUpdateHistory"`
 }
 
 // authMsg is the authentication infos needed to login to a monitoring server.
@@ -229,6 +321,7 @@ func (s *Service) login(in *json.Decoder, out *json.Encoder) error {
 			Os:       runtime.GOOS,
 			OsVer:    runtime.GOARCH,
 			Client:   "0.1.1",
+			History:  true,
 		},
 		Secret: s.pass,
 	}
@@ -249,8 +342,8 @@ func (s *Service) login(in *json.Decoder, out *json.Encoder) error {
 // report collects all possible data to report and send it to the stats server.
 // This should only be used on reconnects or rarely to avoid overloading the
 // server. Use the individual methods for reporting subscribed events.
-func (s *Service) report(in *json.Decoder, out *json.Encoder) error {
-	if err := s.reportLatency(in, out); err != nil {
+func (s *Service) report(out *json.Encoder) error {
+	if err := s.reportLatency(out); err != nil {
 		return err
 	}
 	if err := s.reportBlock(out, nil); err != nil {
@@ -267,7 +360,7 @@ func (s *Service) report(in *json.Decoder, out *json.Encoder) error {
 
 // reportLatency sends a ping request to the server, measures the RTT time and
 // finally sends a latency update.
-func (s *Service) reportLatency(in *json.Decoder, out *json.Encoder) error {
+func (s *Service) reportLatency(out *json.Encoder) error {
 	// Send the current time to the ethstats server
 	start := time.Now()
 
@@ -281,9 +374,12 @@ func (s *Service) reportLatency(in *json.Decoder, out *json.Encoder) error {
 		return err
 	}
 	// Wait for the pong request to arrive back
-	var pong map[string][]interface{}
-	if err := in.Decode(&pong); err != nil || len(pong["emit"]) != 2 || pong["emit"][0].(string) != "node-pong" {
-		return errors.New("unexpected ping reply")
+	select {
+	case <-s.pongCh:
+		// Pong delivered, report the latency
+	case <-time.After(3 * time.Second):
+		// Ping timeout, abort
+		return errors.New("ping timed out")
 	}
 	// Send back the measured latency
 	latency := map[string][]interface{}{
@@ -336,9 +432,26 @@ func (s uncleStats) MarshalJSON() ([]byte, error) {
 
 // reportBlock retrieves the current chain head and repors it to the stats server.
 func (s *Service) reportBlock(out *json.Encoder, block *types.Block) error {
-	// Gather the head block infos from the local blockchain
+	// Assemble the block stats report and send it to the server
+	stats := map[string]interface{}{
+		"id":    s.node,
+		"block": s.assembleBlockStats(block),
+	}
+	report := map[string][]interface{}{
+		"emit": []interface{}{"block", stats},
+	}
+	if err := out.Encode(report); err != nil {
+		return err
+	}
+	return nil
+}
+
+// assembleBlockStats retrieves any required metadata to report a single block
+// and assembles the block stats. If block is nil, the current head is processed.
+func (s *Service) assembleBlockStats(block *types.Block) *blockStats {
+	// Gather the block infos from the local blockchain
 	var (
-		head   *types.Header
+		header *types.Header
 		td     *big.Int
 		txs    []*types.Transaction
 		uncles []*types.Header
@@ -348,38 +461,77 @@ func (s *Service) reportBlock(out *json.Encoder, block *types.Block) error {
 		if block == nil {
 			block = s.eth.BlockChain().CurrentBlock()
 		}
-		head = block.Header()
-		td = s.eth.BlockChain().GetTd(head.Hash(), head.Number.Uint64())
+		header = block.Header()
+		td = s.eth.BlockChain().GetTd(header.Hash(), header.Number.Uint64())
 
 		txs = block.Transactions()
 		uncles = block.Uncles()
 	} else {
 		// Light nodes would need on-demand lookups for transactions/uncles, skip
 		if block != nil {
-			head = block.Header()
+			header = block.Header()
+		} else {
+			header = s.les.BlockChain().CurrentHeader()
+		}
+		td = s.les.BlockChain().GetTd(header.Hash(), header.Number.Uint64())
+	}
+	// Assemble and return the block stats
+	return &blockStats{
+		Number:    header.Number,
+		Hash:      header.Hash(),
+		Timestamp: header.Time,
+		Miner:     header.Coinbase,
+		GasUsed:   new(big.Int).Set(header.GasUsed),
+		GasLimit:  new(big.Int).Set(header.GasLimit),
+		Diff:      header.Difficulty.String(),
+		TotalDiff: td.String(),
+		Txs:       txs,
+		Uncles:    uncles,
+	}
+}
+
+// reportHistory retrieves the most recent batch of blocks and reports it to the
+// stats server.
+func (s *Service) reportHistory(out *json.Encoder, list []uint64) error {
+	// Figure out the indexes that need reporting
+	indexes := make([]uint64, 0, historyUpdateRange)
+	if len(list) > 0 {
+		// Specific indexes requested, send them back in particular
+		for _, idx := range list {
+			indexes = append(indexes, idx)
+		}
+	} else {
+		// No indexes requested, send back the top ones
+		var head *types.Header
+		if s.eth != nil {
+			head = s.eth.BlockChain().CurrentHeader()
 		} else {
 			head = s.les.BlockChain().CurrentHeader()
 		}
-		td = s.les.BlockChain().GetTd(head.Hash(), head.Number.Uint64())
+		start := head.Number.Int64() - historyUpdateRange
+		if start < 0 {
+			start = 0
+		}
+		for i := uint64(start); i <= head.Number.Uint64(); i++ {
+			indexes = append(indexes, i)
+		}
 	}
-	// Assemble the block stats report and send it to the server
+	// Gather the batch of blocks to report
+	history := make([]*blockStats, len(indexes))
+	for i, number := range indexes {
+		if s.eth != nil {
+			history[i] = s.assembleBlockStats(s.eth.BlockChain().GetBlockByNumber(number))
+		} else {
+			history[i] = s.assembleBlockStats(types.NewBlockWithHeader(s.les.BlockChain().GetHeaderByNumber(number)))
+		}
+	}
+	// Assemble the history report and send it to the server
 	stats := map[string]interface{}{
-		"id": s.node,
-		"block": &blockStats{
-			Number:    head.Number,
-			Hash:      head.Hash(),
-			Timestamp: head.Time,
-			Miner:     head.Coinbase,
-			GasUsed:   new(big.Int).Set(head.GasUsed),
-			GasLimit:  new(big.Int).Set(head.GasLimit),
-			Diff:      head.Difficulty.String(),
-			TotalDiff: td.String(),
-			Txs:       txs,
-			Uncles:    uncles,
-		},
+		"id":      s.node,
+		"history": history,
 	}
 	report := map[string][]interface{}{
-		"emit": []interface{}{"block", stats},
+		"emit": []interface{}{"history", stats},
 	}
 	if err := out.Encode(report); err != nil {
 		return err