API Call in solidity: gas required exceeds allowance (8000029) or always failing transaction

Question

I'm trying to make an API call in solidity.

pragma solidity ^0.6.0;

import "github.com/smartcontractkit/chainlink/evm-contracts/src/v0.6/ChainlinkClient.sol";

contract GetData is ChainlinkClient {
  uint256 public currentPrice;
  address public owner;

  address ORACLE = 0x83F00b902cbf06E316C95F51cbEeD9D2572a349a;
  string constant JOB = "c179a8180e034cf5a341488406c32827";
  uint256 constant private ORACLE_PAYMENT = 1 * LINK;

  constructor() public {
    setPublicChainlinkToken();
    owner = msg.sender;
  }

  function requestEthereumPrice() 
    public
    onlyOwner
  {
    Chainlink.Request memory req = buildChainlinkRequest(stringToBytes32(JOB), address(this), this.fulfill.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 fulfill(bytes32 _requestId, uint256 _price)
    public
    recordChainlinkFulfillment(_requestId)
  {
    currentPrice = _price;
  }

  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  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))
    }
  }
}

When I run the requestEthereum function, I get the following error in my remix IDE.

gas required exceeds allowance (8000029) or always failing transaction

Did you fund the contract with LINK? And could you provide the rest of the contract? There could be a few things going on. — Patrick Collins, May 09 '20 at 23:25

score 1 · Accepted Answer · answered May 09 '20 at 23:40

You need to fund your contract with LINK.

After you deploy, take the contract address and send that address a small amount of LINK.

Just so we are clear, technically you are not making an API call, but pulling from an oracle. See here for more information.

API Call in solidity: gas required exceeds allowance (8000029) or always failing transaction

1 Answers1