“VM Exception while processing transaction: revert”，当运行chainlink节点并尝试部署TestnetConsumer合约时？

Question

场景是通过 Remix 在 mathchain 上部署ATestnetConsumer.sol时，按照官方教程在 mathchain 上运行一个节点，这是一个兼容 EVM 的公共链。 我完成了 Oracle 合约和 LINKToken 合约的部署，并在 mathchain 上成功运行了节点，但是在尝试部署 TestnetConsumer 合约时，它显示：

Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending?
Internal JSON-RPC error. { "code": -32603, "message": "VM Exception while processing transaction: revert", "data": "" }

有人知道为什么吗？

TestnetConsumer 合约列表如下：

pragma solidity 0.4.24;

import "https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/ChainlinkClient.sol";
import "https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/vendor/Ownable.sol";

contract ATestnetConsumer is ChainlinkClient, Ownable {
  uint256 constant private ORACLE_PAYMENT = 1 * LINK;

  uint256 public currentPrice;
  int256 public changeDay;
  bytes32 public lastMarket;

  event RequestEthereumPriceFulfilled(
    bytes32 indexed requestId,
    uint256 indexed price
  );

  event RequestEthereumChangeFulfilled(
    bytes32 indexed requestId,
    int256 indexed change
  );

  event RequestEthereumLastMarket(
    bytes32 indexed requestId,
    bytes32 indexed market
  );

  constructor() public Ownable() {
    setPublicChainlinkToken();
  }

  function requestEthereumPrice(address _oracle, string _jobId)
    public
    onlyOwner
  {
    Chainlink.Request memory req = buildChainlinkRequest(stringToBytes32(_jobId), this, this.fulfillEthereumPrice.selector);
    req.add("get", "https://min-api.cryptocompare.com/data/price?fsym=ETH&tsyms=USD");
    req.add("path", "USD");
    req.addInt("times", 100);
    sendChainlinkRequestTo(_oracle, req, ORACLE_PAYMENT);
  }

  function requestEthereumChange(address _oracle, string _jobId)
    public
    onlyOwner
  {
    Chainlink.Request memory req = buildChainlinkRequest(stringToBytes32(_jobId), this, this.fulfillEthereumChange.selector);
    req.add("get", "https://min-api.cryptocompare.com/data/pricemultifull?fsyms=ETH&tsyms=USD");
    req.add("path", "RAW.ETH.USD.CHANGEPCTDAY");
    req.addInt("times", 1000000000);
    sendChainlinkRequestTo(_oracle, req, ORACLE_PAYMENT);
  }

  function requestEthereumLastMarket(address _oracle, string _jobId)
    public
    onlyOwner
  {
    Chainlink.Request memory req = buildChainlinkRequest(stringToBytes32(_jobId), this, this.fulfillEthereumLastMarket.selector);
    req.add("get", "https://min-api.cryptocompare.com/data/pricemultifull?fsyms=ETH&tsyms=USD");
    string[] memory path = new string[](4);
    path[0] = "RAW";
    path[1] = "ETH";
    path[2] = "USD";
    path[3] = "LASTMARKET";
    req.addStringArray("path", path);
    sendChainlinkRequestTo(_oracle, req, ORACLE_PAYMENT);
  }

  function fulfillEthereumPrice(bytes32 _requestId, uint256 _price)
    public
    recordChainlinkFulfillment(_requestId)
  {
    emit RequestEthereumPriceFulfilled(_requestId, _price);
    currentPrice = _price;
  }

  function fulfillEthereumChange(bytes32 _requestId, int256 _change)
    public
    recordChainlinkFulfillment(_requestId)
  {
    emit RequestEthereumChangeFulfilled(_requestId, _change);
    changeDay = _change;
  }

  function fulfillEthereumLastMarket(bytes32 _requestId, bytes32 _market)
    public
    recordChainlinkFulfillment(_requestId)
  {
    emit RequestEthereumLastMarket(_requestId, _market);
    lastMarket = _market;
  }

  function getChainlinkToken() public view returns (address) {
    return chainlinkTokenAddress();
  }

  function withdrawLink() public onlyOwner {
    LinkTokenInterface link = LinkTokenInterface(chainlinkTokenAddress());
    require(link.transfer(msg.sender, link.balanceOf(address(this))), "Unable to transfer");
  }

  function cancelRequest(
    bytes32 _requestId,
    uint256 _payment,
    bytes4 _callbackFunctionId,
    uint256 _expiration
  )
    public
    onlyOwner
  {
    cancelChainlinkRequest(_requestId, _payment, _callbackFunctionId, _expiration);
  }

  function stringToBytes32(string memory source) private pure returns (bytes32 result) {
    bytes memory tempEmptyStringTest = bytes(source);
    if (tempEmptyStringTest.length == 0) {
      return 0x0;
    }

    assembly { // solhint-disable-line no-inline-assembly
      result := mload(add(source, 32))
    }
  }
}

Answer 1

问题出在构造函数上：

constructor() public Ownable() {
    setPublicChainlinkToken();
}

当您在公链上运行一个节点，并部署一个全新的 LINKToken 合约作为调用和调用您自己节点提供的服务的方式时，请记住将以transferAndCall ： setPublicChainlinkToken()替换为：

    // set the Oracle contract address
    setChainlinkOracle(YOUR_ORACLE_CONTRACT_ADDRESS); 
    // set LINKToken contract address
    setChainlinkToken(YOUR_LINKTOKEN_CONTRACT_ADDRESS);

那你应该对go好。 请记住，在调用 function 以从您的 Chainlink 节点获取服务之前，您应该存入一些 LINK 令牌！