diff --git a/contrib/zmq/zmq_sub.py b/contrib/zmq/zmq_sub.py index 06893407f5f..8b8503331d2 100755 --- a/contrib/zmq/zmq_sub.py +++ b/contrib/zmq/zmq_sub.py @@ -11,7 +11,8 @@ -zmqpubrawtx=tcp://127.0.0.1:28332 \ -zmqpubrawblock=tcp://127.0.0.1:28332 \ -zmqpubhashtx=tcp://127.0.0.1:28332 \ - -zmqpubhashblock=tcp://127.0.0.1:28332 + -zmqpubhashblock=tcp://127.0.0.1:28332 \ + -zmqpubsequence=tcp://127.0.0.1:28332 We use the asyncio library here. `self.handle()` installs itself as a future at the end of the function. Since it never returns with the event @@ -47,16 +48,14 @@ class ZMQHandler(): self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "hashtx") self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "rawblock") self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "rawtx") + self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "sequence") self.zmqSubSocket.connect("tcp://127.0.0.1:%i" % port) async def handle(self) : - msg = await self.zmqSubSocket.recv_multipart() - topic = msg[0] - body = msg[1] + topic, body, seq = await self.zmqSubSocket.recv_multipart() sequence = "Unknown" - if len(msg[-1]) == 4: - msgSequence = struct.unpack('C : Blockhash connected + <32-byte hash>D : Blockhash disconnected + <32-byte hash>R<8-byte LE uint> : Transactionhash removed from mempool for non-block inclusion reason + <32-byte hash>A<8-byte LE uint> : Transactionhash added mempool + +Where the 8-byte uints correspond to the mempool sequence number. These options can also be provided in bitcoin.conf. @@ -124,13 +134,20 @@ No authentication or authorization is done on connecting clients; it is assumed that the ZeroMQ port is exposed only to trusted entities, using other means such as firewalling. -Note that when the block chain tip changes, a reorganisation may occur -and just the tip will be notified. It is up to the subscriber to -retrieve the chain from the last known block to the new tip. Also note -that no notification occurs if the tip was in the active chain - this -is the case after calling invalidateblock RPC. +Note that for `*block` topics, when the block chain tip changes, +a reorganisation may occur and just the tip will be notified. +It is up to the subscriber to retrieve the chain from the last known +block to the new tip. Also note that no notification will occur if the tip +was in the active chain--as would be the case after calling invalidateblock RPC. +In contrast, the `sequence` topic publishes all block connections and +disconnections. There are several possibilities that ZMQ notification can get lost during transmission depending on the communication type you are using. Bitcoind appends an up-counting sequence number to each notification which allows listeners to detect lost notifications. + +The `sequence` topic refers specifically to the mempool sequence +number, which is also published along with all mempool events. This +is a different sequence value than in ZMQ itself in order to allow a total +ordering of mempool events to be constructed.