I got the Gas Estimation failed error while using VRFConsumerBaseV2 provided by Chainlink

Question

ERROR :

ValueError: Gas estimation failed: 'execution reverted'. This transaction will likely revert. If you wish to broadcast, you must set the gas limit manually.

// SPDX-License-Identifier: MIT
// An example of a consumer contract that relies on a subscription for funding.
pragma solidity ^0.8.7;

import "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";

contract VRFv2Consumer is VRFConsumerBaseV2 {
  VRFCoordinatorV2Interface COORDINATOR;
  LinkTokenInterface LINKTOKEN;

  // Your subscription ID.
  uint64 s_subscriptionId;

  // Rinkeby coordinator. For other networks,
  // see https://docs.chain.link/docs/vrf-contracts/#configurations
  address vrfCoordinator = 0x6168499c0cFfCaCD319c818142124B7A15E857ab;

  // Rinkeby LINK token contract. For other networks,
  // see https://docs.chain.link/docs/vrf-contracts/#configurations
  address link = 0x01BE23585060835E02B77ef475b0Cc51aA1e0709;

  // The gas lane to use, which specifies the maximum gas price to bump to.
  // For a list of available gas lanes on each network,
  // see https://docs.chain.link/docs/vrf-contracts/#configurations
  bytes32 keyHash = 0xd89b2bf150e3b9e13446986e571fb9cab24b13cea0a43ea20a6049a85cc807cc;

  // Depends on the number of requested values that you want sent to the
  // fulfillRandomWords() function. Storing each word costs about 20,000 gas,
  // so 100,000 is a safe default for this example contract. Test and adjust
  // this limit based on the network that you select, the size of the request,
  // and the processing of the callback request in the fulfillRandomWords()
  // function.
  uint32 callbackGasLimit = 100000;

  // The default is 3, but you can set this higher.
  uint16 requestConfirmations = 3;

  // For this example, retrieve 2 random values in one request.
  // Cannot exceed VRFCoordinatorV2.MAX_NUM_WORDS.
  uint32 numWords =  2;

  uint256[] public s_randomWords;
  uint256 public s_requestId;
  address s_owner;

  constructor(uint64 subscriptionId) VRFConsumerBaseV2(vrfCoordinator) {
    COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);
    LINKTOKEN = LinkTokenInterface(link);
    s_owner = msg.sender;
    s_subscriptionId = subscriptionId;
  }

  // Assumes the subscription is funded sufficiently.
  function requestRandomWords() external onlyOwner {
    // Will revert if subscription is not set and funded.
    s_requestId = COORDINATOR.requestRandomWords(
      keyHash,
      s_subscriptionId,
      requestConfirmations,
      callbackGasLimit,
      numWords
    );
  }
  
  function fulfillRandomWords(
    uint256, /* requestId */
    uint256[] memory randomWords
  ) internal override {
    s_randomWords = randomWords;
  }

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

I was trying to call requestRandomWords() but it showed an error like above.

I also tried it on Remix but it was not running properly there too and showed errors like

Error: Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? execution reverted { "originalError": { "code": 3, "data": "0xf0019fe600000000000000000000000000000000000000000000000000000000000003a4000000000000000000000000771809c8d7f2d4fd3f87529bf3d6023b382ba754", "message": "execution reverted" } }

Did you create and fund a subscription for randomness as described here?: https://docs.chain.link/docs/get-a-random-number/#create-and-fund-a-subscription — Zak Ayesh, Mar 12 '22 at 00:52

score 0 · Answer 1 · answered May 23 '22 at 20:12

I ran into this error too and realized I hadn't added my newly deployed contract as a "Consumer" to my Chainlink VRF Subscription Manager.

Did you set your s_subscriptionId properly on deployment?

See https://docs.chain.link/docs/chainlink-vrf/ for more information, or specifically go to https://vrf.chain.link/ to set up a Subscription Manager.

score 0 · Answer 2 · answered Aug 25 '22 at 08:33

0

you should check your testnet,and replace the configurations about vrfCoordinator and keyHash from https://docs.chain.link/docs/vrf/v2/supported-networks/#configurations

answered Aug 25 '22 at 08:33

maggie

1

score 0 · Answer 3 · answered Sep 03 '22 at 15:23

0

If you want to deploy it to bsc testnet try this solution:

https://forum.openzeppelin.com/t/im-trying-to-deploy-a-contract-in-the-bsctestnet-but-i-never-got-the-supply-solved/22279/8

answered Sep 03 '22 at 15:23

Davoud

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I got the Gas Estimation failed error while using VRFConsumerBaseV2 provided by Chainlink

3 Answers3