"VM Exception while processing transaction: revert"，当运行链链节点并尝试部署 TestnetConsumer 合约时？

Question

该场景是通过Remix在mathchain上部署ATestnetConsumer.sol时，按照官方教程在mathcain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，并成功地在mathchain上运行了节点，但当尝试部署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合同如下所示：

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

问题位于构造函数：

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

当您在公共链上运行一个节点，并部署一个全新的LINKToken合约作为transferAndCall(由您自己的节点提供的服务(的方式时，请记住将行：setPublicChainlinkToken()替换为：

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

那你应该可以走了。请记住，在调用函数从Chainlink节点获取服务之前，您应该存放一些LINK令牌！