CancelledKeyException when trying to connect to a local regtest net

[Dmitrii Pisarenko]

Hi!

I want to write a piece of code that will observe a particular address. I am using a local testnet, therefore the first step is to connect to it.

The testnet is created using docker-compose.yml:

version: '3'

services:

  node:

    image: ulamlabs/bitcoind-custom-regtest:latest

    ports:

      - "19001:19001"

      - "19000:19000"

      - "28332:28332"

Full docker-compose.yml file: https://github.com/mentiflectax/minimal-crypto-exchange/blob/i16/docker-compose.yml

I wrote this:

final WalletAppKit kit = new WalletAppKit(netParams, new File("."), "_minimalCryptoExchangeBtcWallet");

kit.connectToLocalHost();

kit.setAutoSave(true);

kit.startAsync();

kit.awaitRunning();

Full source code: https://github.com/mentiflectax/minimal-crypto-exchange/blob/i16/process-engine/src/main/java/com/dpisarenko/minimalcryptoexchange/logic/btc/WalletObserver.java

After kit.awaitRunning(); I am getting the error

java.nio.channels.CancelledKeyException: null

    at java.base/sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:71)

    at java.base/sun.nio.ch.SelectionKeyImpl.readyOps(SelectionKeyImpl.java:130)

    at java.base/java.nio.channels.SelectionKey.isWritable(SelectionKey.java:377)

    at org.bitcoinj.net.ConnectionHandler.handleKey(ConnectionHandler.java:244)

    at org.bitcoinj.net.NioClientManager.handleKey(NioClientManager.java:86)

    at org.bitcoinj.net.NioClientManager.run(NioClientManager.java:122)

    at com.google.common.util.concurrent.AbstractExecutionThreadService$1$2.run(AbstractExecutionThreadService.java:66)

    at com.google.common.util.concurrent.Callables$4.run(Callables.java:119)

    at org.bitcoinj.utils.ContextPropagatingThreadFactory$1.run(ContextPropagatingThreadFactory.java:51)

at java.base/java.lang.Thread.run(Thread.java:830)

Entire log output is available here: https://gist.github.com/mentiflectax/189713b44041047145f006b695948c9d

How can I fix this?

Thanks in advance

Dmitrii Pisarenko

P. S.: This question is also available on StackOverflow:

https://stackoverflow.com/questions/69764709/how-can-i-get-notified-when-money-has-been-sent-to-a-particular-bitcoin-address

[Andreas Schildbach]

The CancelledKeyException isn't a bad sign. It just happens if some peer
remotely disconnects. PeerGroup will connect the next peer in place.

I don't see the code that actually observes the address. Can you show it?

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[Dmitrii Pisarenko]

Hello, Andreas!

Thanks for your answer.

> The CancelledKeyException isn't a bad sign. It just happens if some peer 

> remotely disconnects.

This code is supposed to connect to a locally running regtest network. If that network disconnects regularly, this is probably an error in the configuration of the test network, isn't it?

Below (and at https://github.com/ulamlabs/bitcoind-custom-regtest/blob/master/bitcoin.conf ) you can find the bitcoin.conf file being used. Do you see anything there that may make the peer inside this network disconnect all the time (and lead to CancelledKeyException)?

# testnet-box functionality

regtest=1

dnsseed=0

upnp=0

# always run a server, even with bitcoin-qt

server=1

rpcallowip=0.0.0.0/0

zmqpubrawtx=tcp://0.0.0.0:28332

zmqpubhashblock=tcp://0.0.0.0:28332

whitelist=0.0.0.0/0

txindex=1

addressindex=1

timestampindex=1

spentindex=1

uacomment=bitcore

rpcworkqueue=128

dbcache=16384

rpcuser=test

rpcpassword=test

# listen on different ports than default testnet

[regtest]

rpcbind=0.0.0.0

port=19000

rpcport=19001

> I don't see the code that actually observes the address. Can you show it? 

Sure, here it is:

https://github.com/mentiflectax/minimal-crypto-exchange/blob/i16/process-engine/src/main/java/com/dpisarenko/minimalcryptoexchange/logic/btc/WalletObserver.java

public void init() {

        BriefLogFormatter.init();

        final LocalTestNetParams netParams = new LocalTestNetParams();

        netParams.setPort(CUR_PORT);

        try {

            final WalletAppKit kit = new WalletAppKit(netParams, new File("."), "_minimalCryptoExchangeBtcWallet");

            kit.connectToLocalHost();

            kit.setAutoSave(false);

            kit.startAsync();

            kit.awaitRunning();

            System.out.println("Port works");

            kit.peerGroup().addPeerDiscovery(new DnsDiscovery(netParams));

            kit.wallet().addWatchedAddress(Address.fromString(netParams, "2N23tWAFEtBtTgxNjBNmnwzsiPdLcNek181"));

            kit.wallet().addCoinsReceivedEventListener(new WalletCoinsReceivedEventListener() {

                @Override

                public void onCoinsReceived(final Wallet wallet, final Transaction transaction, final Coin prevBalance, final Coin newBalance) {

                    System.out.println("Heyo!");

                }

            });

        }

        catch (Exception exception) {

            exception.printStackTrace();

        }

    }

The method that is supposed to be called whenever money has been sent to 2N23tWAFEtBtTgxNjBNmnwzsiPdLcNek181 is onCoinsReceived.

Please note that until now I never got past kit.awaitRunning(). I terminated the application after that message. So I haven't tested the code after kit.awaitRunning() yet.

Feedback regarding errors in this code is highly appreciated as I never worked with Bitcoin/BitcoinJ before.

Thanks!

Dmitrii