proof of concept connection to ZeroMQ

README.md

@@ -26,6 +26,13 @@ CGO_LDFLAGS="-L/path/to/rocksdb -lrocksdb -lstdc++ -lm -lz -lbz2 -lsnappy -llz4
   go get github.com/tecbot/gorocksdb
 ```
 
+Install ZeroMQ: https://github.com/zeromq/libzmq
+
+Install Go interface to ZeroMQ:
+```
+go get github.com/pebbe/zmq4
+```
+
 Install blockbook:
 
 ```

bitcoin/mq.go

@@ -0,0 +1,39 @@
+package bitcoin
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"log"
+
+	zmq "github.com/pebbe/zmq4"
+)
+
+func ZeroMQ(binding string) {
+	context, err := zmq.NewContext()
+	if err != nil {
+		log.Fatal(err)
+	}
+	socket, err := context.NewSocket(zmq.SUB)
+	if err != nil {
+		log.Fatal(err)
+	}
+	socket.SetSubscribe("hashblock")
+	socket.SetSubscribe("hashtx")
+	socket.SetSubscribe("rawblock")
+	socket.SetSubscribe("rawtx")
+	socket.Connect(binding)
+	defer socket.Close()
+	for i := 0; i < 101; i++ {
+		msg, err := socket.RecvMessageBytes(0)
+		if err != nil {
+			log.Fatal(err)
+		}
+		topic := string(msg[0])
+		body := hex.EncodeToString(msg[1])
+		sequence := uint32(0)
+		if len(msg[len(msg)-1]) == 4 {
+			sequence = binary.LittleEndian.Uint32(msg[len(msg)-1])
+		}
+		log.Printf("%s-%d (%v)  %s", topic, sequence, msg[len(msg)-1], body)
+	}
+}

blockbook.go

@@ -54,12 +54,19 @@ var (
 	dryRun      = flag.Bool("dryrun", false, "do not index blocks, only download")
 	parse       = flag.Bool("parse", false, "use in-process block parsing")
 
-	httpServerBinding = flag.String("httpserver", "nil", "http server binding [address]:port, by default no http server")
+	httpServerBinding = flag.String("httpserver", "nil", "http server binding [address]:port, if missing no http server")
+
+	zeroMQBinding = flag.String("zeromq", "nil", "binding to zeromq, if missing no zeromq connection")
 )
 
 func main() {
 	flag.Parse()
 
+	if *zeroMQBinding != "nil" {
+		bitcoin.ZeroMQ(*zeroMQBinding)
+		return
+	}
+
 	if *repair {
 		if err := db.RepairRocksDB(*dbPath); err != nil {
 			log.Fatal(err)