Unable to deploy contract to private blockchain using Web3j (Java client) because of TransactionTimeoutException

Question

I am using Web3j for interacting with my private blockchain network created in Azure.

I have created contracts using Remix and Metamask and was able to view that Contract from Java.

However I was not able to deploy or create contract from Java. I followed the instructions from the link https://github.com/web3j/web3j.

I keep getting the error Transaction receipt was not generated after 600 seconds for transaction caused by org.web3j.protocol.exceptions.TransactionTimeoutException

ContractRunner.java

    public static void main(String args[]) throws InterruptedException, ExecutionException, IOException, CipherException, TransactionTimeoutException {
        Web3j web3 = Web3j.build(new HttpService("http://xxxxxxxxx.westus.cloudapp.azure.com:8545/"));  // defaults to http://localhost:8545/
        Web3ClientVersion web3ClientVersion = web3.web3ClientVersion().sendAsync().get();
        String clientVersion = web3ClientVersion.getWeb3ClientVersion();
        System.out.println(clientVersion);
        Credentials credentials = WalletUtils.loadCredentials("MyPassword", "C:\\Users\\adheep_m\\AppData\\Roaming\\Ethereum\\keystore\\UTC--2017-07-07T13-52-18.006069200Z--3b0d3fa08f0e0b3da8fe1f8ac0e05861bfdada25");
        System.out.println(credentials.getAddress());

        Token contract = Token.deploy(web3,credentials,BigInteger.valueOf(3000000),BigInteger.valueOf(3000000),BigInteger.valueOf(0)).get();
        System.out.println(contract.getContractAddress());
    }

Token.sol

pragma solidity ^0.4.0;

contract Token {
mapping (address => uint) public balances;

function Token() {
    balances[msg.sender] = 1000000;
}

function transfer(address _to, uint _amount) {
    if (balances[msg.sender] < _amount) {
        throw;
    }

    balances[msg.sender] -= _amount;
    balances[_to] += _amount;
}

}

Token.java (Generated from Web3j)

public final class Token extends Contract {
    private static final String BINARY = "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";

    private Token(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    private Token(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    public Future<Uint256> balances(Address param0) {
        Function function = new Function("balances", 
                Arrays.<Type>asList(param0), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        return executeCallSingleValueReturnAsync(function);
    }

    public Future<TransactionReceipt> transfer(Address _to, Uint256 _amount) {
        Function function = new Function("transfer", Arrays.<Type>asList(_to, _amount), Collections.<TypeReference<?>>emptyList());
        return executeTransactionAsync(function);
    }

    public static Future<Token> deploy(Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit, BigInteger initialWeiValue) {
        return deployAsync(Token.class, web3j, credentials, gasPrice, gasLimit, BINARY, "", initialWeiValue);
    }

    public static Future<Token> deploy(Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit, BigInteger initialWeiValue) {
        return deployAsync(Token.class, web3j, transactionManager, gasPrice, gasLimit, BINARY, "", initialWeiValue);
    }

    public static Token load(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        return new Token(contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    public static Token load(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        return new Token(contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }
}

I am not sure what is wrong with the code. Any help would be greatly appreciated. Thanks!

Answer 1

I am not sure about how did you configure your Blockchain on Azure, i assume that you have created a mining node(s) while you are creating your private blockchain, if so, we need to connect to that node with SSH,, to do so, lookup for the mining node address,, you can find it in :

Deployments > Microsoft-azure-blockchain.azure-multi....

Now, copy the line in front of (SSH-TO-FIRST-TX-NODE) and past it on your local machine's CMD, type yes for the yes/no question, it will than ask you for a password, use the same one you used while creating your blockchain.

After connecting to the node,, type geth attach ,, this will open the geth console for you,, once it's opened type miner.start(1) ,, where the parameter 1 is the number of the threads the miner can excute,, you can passe a bigger number.

Answer 2

I finally figured out what was wrong with my code. I debugged the Web3j codes and found that since Mining nodes were not accepting the transaction after 40 retries with Sleep duration of 15000 the TransactionTimeoutException is thrown and the TransactionReceipt is not generated. See below Web3j code from TransactionManager.java

Source of the Exception

private static final int SLEEP_DURATION = 15000;
private static final int ATTEMPTS = 40;

private TransactionReceipt getTransactionReceipt(
        String transactionHash, int sleepDuration, int attempts)
        throws IOException, InterruptedException, TransactionTimeoutException {

    Optional<TransactionReceipt> receiptOptional =
            sendTransactionReceiptRequest(transactionHash);
    for (int i = 0; i < attempts; i++) {
        if (!receiptOptional.isPresent()) {
            Thread.sleep(sleepDuration);
            receiptOptional = sendTransactionReceiptRequest(transactionHash);
        } else {
            return receiptOptional.get();
        }
    }

    throw new TransactionTimeoutException("Transaction receipt was not generated after " +
            ((sleepDuration * attempts) / 1000 +
                    " seconds for transaction: " + transactionHash));
}

Reason

After breaking my head I found out that the issues was with low GAS_PRICE and GAS_LIMIT. Because of low values the miners didn't mine my transaction

FIX

I updated my code to use the default GAS_PRICE and GAS_LIMIT from Web3j's Contract class. See updated code below

    BigInteger GAS = Contract.GAS_LIMIT;
    BigInteger GAS_PRICE = Contract.GAS_PRICE;

    Token contract = Token.deploy(web3,credentials,GAS_PRICE,GAS,ETHER);
    System.out.println("Deployed Contract at "+contract.getContractAddress());