DEV Community: ssadek1976

Output value from getAmountsIn > getAmountsIn in arbitrage price difference opportunity

ssadek1976 — Sun, 30 Oct 2022 08:41:45 +0000

Hello,

For a given pair in a flashloan arbitrage operation, taking the example of uniswap and sushiswap as the selected DEX´s for executing an arbitrage opportunity, and for 1INCH/WETH token pair, sushiswap WETH price is cheaper than uniswap (despite having larger reserve volumes in comparison).

The problem lies when I execute the following two lines of code in my uniswapV2callmethod:

uint amountToRepay = UniswapV2Library.getAmountsIn(factory, _amount, path)[0];
uint amountReceived = router.swapExactTokensForTokens(
                    _amount,
                    amountToRepay, 
                    path,
                    msg.sender,
                    (block.timestamp + 300))[1];

and it returns amountToRepay > amountReceived when I was expecting the result to be other way round owing to spotted price difference opportunity under arbitrage operation.

Output console.log (from my back-end smart contract)
getAmountsIn() results.......
path[0] 0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2
path[1] 0x111111111117dc0aa78b770fa6a738034120c302
amountBorrowed 2497817866881194385864
amountToRepay 964334905750628563
getAmountsOut() results.......
path[0] 0x111111111117dc0aa78b770fa6a738034120c302
path[1] 0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2
amountReceived 950114205093874394

Output error message
Error: VM Exception while processing transaction: reverted with reason string 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
at . (0x7a250d5630b4cf539739df2c5dacb4c659f2488d)
at FlashloanerArbitrage.uniswapV2Call (contracts/FlashloanerArbitrage.sol:261)
at . (0x86f518368e0d49d5916e2bd9eb162e9952b7b04d)
at FlashloanerArbitrage.startSwap (contracts/FlashloanerArbitrage.sol:180)
at processTicksAndRejections (node:internal/process/task_queues:96:5)
at EthModule._estimateGasAction (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswapV2_hardhat\node_modules\hardhat\src\internal\hardhat-network\provider\modules\eth.ts:429:7)
at HardhatNetworkProvider._sendWithLogging (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswapV2_hardhat\node_modules\hardhat\src\internal\hardhat-network\provider\provider.ts:139:22)
at HardhatNetworkProvider.request (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswapV2_hardhat\node_modules\hardhat\src\internal\hardhat-network\provider\provider.ts:116:18)
at JsonRpcHandler._handleRequest (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswapV2_hardhat\node_modules\hardhat\src\internal\hardhat-network\jsonrpc\handler.ts:188:20)
at JsonRpcHandler._handleSingleRequest (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswapV2_hardhat\node_modules\hardhat\src\internal\hardhat-network\jsonrpc\handler.ts:167:17)
at Server.JsonRpcHandler.handleHttp (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswapV2_hardhat\node_modules\hardhat\src\internal\hardhat-network\jsonrpc\handler.ts:52:21)

Where am I going wrong here as this issue has been troubling me for several weeks now.
I have tried implementing other_ pricing oracle methods but it comes back to this very same issue.

Any help or suggestions would be greatly appreciated.

Thank you

UNPREDICTABLE_GAS_LIMIT when calling estimateGas function

ssadek1976 — Sun, 18 Sep 2022 07:41:37 +0000

Hello,

When I issue npx ts-node .ts and attempt to call out estimateGas function on sushiswap router as shown in below code snippet it triggers UNPREDICTABLE_GAS_LIMIT error (see below output error log #1).

`const gasLimit = await sushiEthDai.estimateGas.swap(
            !shouldStartEth ? DAI_TRADE : 0,
            shouldStartEth ? ETH_TRADE : 0,
            flashLoanerAddress,
            ethers.utils.toUtf8Bytes('1')
          );`

Output Error Log #1
Error: cannot estimate gas; transaction may fail or may require manual gas limit See: https://links.ethers.org/v5-errors-UNPREDICTABLE_GAS_LIMIT
at Logger.makeError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:269:28)
at Logger.throwError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:281:20)
at checkError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\src.ts\json-rpc-provider.ts:78:20)
at JsonRpcProvider. (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\src.ts\json-rpc-provider.ts:642:20)
at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\lib\json-rpc-provider.js:48:23)
at Object.throw (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\lib\json-rpc-provider.js:29:53)
at rejected (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\lib\json-rpc-provider.js:21:65)
at processTicksAndRejections (node:internal/process/task_queues:96:5) {
reason: 'execution reverted',
code: 'UNPREDICTABLE_GAS_LIMIT',
method: 'estimateGas',
transaction: {
from: 'xxxxxxxxxxxxxxxxxxxxxxxxxx',
to: '0xC3D03e4F041Fd4cD388c549Ee2A29a9E5075882f',
data: '0x022c0d9f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000a7564f968608ad09236b794836f93a5b76dfd53d000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000013100000000000000000000000000000000000000000000000000000000000000',
accessList: null
},
error: Error: processing response error (body="{\"jsonrpc\":\"2.0\",\"id\":56,\"error\":{\"code\":-32000,\"message\":\"execution reverted\"}}", error={"code":-32000}, requestBody="{\"method\":\"eth_estimateGas\",\"params\":[{\"from\":\"0x825c5e7d385f9f07e2312154b0cf3cdd06396869\",\"to\":\"0xc3d03e4f041fd4cd388c549ee2a29a9e5075882f\",\"data\":\"0x022c0d9f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000a7564f968608ad09236b794836f93a5b76dfd53d000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000013100000000000000000000000000000000000000000000000000000000000000\"}],\"id\":56,\"jsonrpc\":\"2.0\"}", requestMethod="POST", url="https://mainnet.infura.io/v3/xxxxxxxxxxxxxxxx", code=SERVER_ERROR, version=web/5.7.1)
at Logger.makeError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:269:28)
at Logger.throwError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:281:20)
at C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\src.ts\index.ts:341:28
at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:33:23)

at Object.next (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:14:53)
at fulfilled (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:5:58)

at processTicksAndRejections (node:internal/process/task_queues:96:5) {
reason: 'processing response error',
code: 'SERVER_ERROR',
body: '{"jsonrpc":"2.0","id":56,"error":{"code":-32000,"message":"execution reverted"}}',
error: Error: execution reverted
at getResult (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\src.ts\json-rpc-provider.ts:142:28)
at processJsonFunc (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\src.ts\index.ts:383:22)
at C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\src.ts\index.ts:320:42

at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:33:23)

at Object.next (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:14:53)
at fulfilled (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:5:58)
at processTicksAndRejections (node:internal/process/task_queues:96:5) {
code: -32000,
data: undefined
},
requestBody: '{"method":"eth_estimateGas","params":[{"from":"xxxxxxxxxxxxxxxxxxxxxxxx","to":"0xc3d03e4f041fd4cd388c549ee2a29a9e5075882f","data":"0x022c0d9f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000a7564f968608ad09236b794836f93a5b76dfd53d000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000013100000000000000000000000000000000000000000000000000000000000000"}],"id":56,"jsonrpc":"2.0"}',
requestMethod: 'POST',
url: 'https://mainnet.infura.io/v3/xxxxxxxxxxxxxxxxxxxxx'
}
}

I also tried overriding the gas limit when passing it as a parameter into the same function shown below but it returns this time a slightly different error Error: cannot override "gas" (see below output error log #2).

`const gasLimit = await sushiEthDai.estimateGas.swap(
            !shouldStartEth ? DAI_TRADE : 0,
            shouldStartEth ? ETH_TRADE : 0,
            flashLoanerAddress,
            ethers.utils.toUtf8Bytes('1'), {
                gas: 6721975
            }
          );`

Output Error Log #2
Error: cannot estimate gas; transaction may fail or may require manual gas limit See: https://links.ethers.org/v5-errors-UNPREDICTABLE_GAS_LIMIT
at Logger.makeError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:269:28)
at Logger.throwError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:281:20)
at checkError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\src.ts\json-rpc-provider.ts:78:20)
at JsonRpcProvider. (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\src.ts\json-rpc-provider.ts:642:20)
at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\lib\json-rpc-provider.js:48:23)
at Object.throw (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\lib\json-rpc-provider.js:29:53)
at rejected (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\lib\json-rpc-provider.js:21:65)
at processTicksAndRejections (node:internal/process/task_queues:96:5) {
reason: 'execution reverted',
code: 'UNPREDICTABLE_GAS_LIMIT',
method: 'estimateGas',
transaction: {
from: 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
to: '0xC3D03e4F041Fd4cD388c549Ee2A29a9E5075882f',
data: '0x022c0d9f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000a7564f968608ad09236b794836f93a5b76dfd53d000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000013100000000000000000000000000000000000000000000000000000000000000',
accessList: null
},
error: Error: processing response error (body="{\"jsonrpc\":\"2.0\",\"id\":56,\"error\":{\"code\":-32000,\"message\":\"execution reverted\"}}", error={"code":-32000}, requestBody="{\"method\":\"eth_estimateGas\",\"params\":[{\"from\":\"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\",\"to\":\"0xc3d03e4f041fd4cd388c549ee2a29a9e5075882f\",\"data\":\"0x022c0d9f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000a7564f968608ad09236b794836f93a5b76dfd53d000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000013100000000000000000000000000000000000000000000000000000000000000\"}],\"id\":56,\"jsonrpc\":\"2.0\"}", requestMethod="POST", url="https://mainnet.infura.io/v3/xxxxxxxxxxxxxxxxxxxxxxxxxxxxx", code=SERVER_ERROR, version=web/5.7.1)
at Logger.makeError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:269:28)
at Logger.throwError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:281:20)
at C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\src.ts\index.ts:341:28
at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:33:23)

at Object.next (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:14:53)
at fulfilled (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:5:58)

at processTicksAndRejections (node:internal/process/task_queues:96:5) {
reason: 'processing response error',
code: 'SERVER_ERROR',
body: '{"jsonrpc":"2.0","id":56,"error":{"code":-32000,"message":"execution reverted"}}',
error: Error: execution reverted
at getResult (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\providers\src.ts\json-rpc-provider.ts:142:28)
at processJsonFunc (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\src.ts\index.ts:383:22)
at C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\src.ts\index.ts:320:42

at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:33:23)

at Object.next (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:14:53)
at fulfilled (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\web\lib\index.js:5:58)
at processTicksAndRejections (node:internal/process/task_queues:96:5) {
code: -32000,
data: undefined
},
requestBody: '{"method":"eth_estimateGas","params":[{"from":"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx","to":"0xc3d03e4f041fd4cd388c549ee2a29a9e5075882f","data":"0x022c0d9f0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a000000000000000000000000a7564f968608ad09236b794836f93a5b76dfd53d000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000013100000000000000000000000000000000000000000000000000000000000000"}],"id":56,"jsonrpc":"2.0"}',
requestMethod: 'POST',
url: 'https://mainnet.infura.io/v3/xxxxxxxxxxxxxxxxxxxxxxxxxx'
}
}
Error: cannot override "gas" (operation="overrides", overrides=["gas"], code=UNSUPPORTED_OPERATION, version=contracts/5.7.0)
at Logger.makeError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:269:28)
at Logger.throwError (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\logger\src.ts\index.ts:281:20)
at C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\contracts\src.ts\index.ts:304:16

at step (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\contracts\lib\index.js:48:23)

at Object.next (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\contracts\lib\index.js:29:53)
at fulfilled (C:\Samuel\Blockchain\Flashloan-arbitrage-bot-uniswap-v2\node_modules\@ethersproject\contracts\lib\index.js:20:58)
at processTicksAndRejections (node:internal/process/task_queues:96:5) {
reason: 'cannot override "gas"',
code: 'UNSUPPORTED_OPERATION',
operation: 'overrides',
overrides: [ 'gas' ]
}

Not sure if tsnode accepts command line options for setting gas limits or directly within tsconfig.json. This last case, I have consulted the tsconfig docs but it says nothing or no mention about gas limits. So I´m stuck here.

Any help would be greatly appreciated.

Thank you,
Samuel

Ethereum contract call methods do not return any values

ssadek1976 — Thu, 15 Sep 2022 14:03:29 +0000

Hi there,

I have a problem when running the following 4 lines of code from the main JS script (see below):

await uniswapFactory.getPair(daiAddress, wethAddress)
await sushiFactory.getPair(daiAddress, wethAddress),
const uniswapReserves = await uniswapDaiEth.getReserves();
const sushiReserves = await sushiEthDai.getReserves();

For the first two, if I substituted them with hardcoded token pair addresses from Etherscan into the code it works. If I run the first two directly into Truffle console it resolves the pair addresses but strangely enough it doesn´t resolve when I execute the JS script!

For the above two .getReserves() function calls it doesn´t retrieve any of the reserve values unless if I ran them as they are under Truffle console environment then it retrieves them OK.

I appreciate your assistance here as it´s been bugging me for the full last two days and am running out of options to resolve this.

Full JS script

`require('dotenv').config();
const { INFURA_API_KEY, PRIVATE_KEY } = process.env;
const { ethers } = require('ethers');

const UniswapV2Pair = require(".././build/contracts/IUniswapV2Pair.json");
const UniswapV2Factory = require('.././build/contracts/IUniswapV2Factory.json');

const daiAddress = "0x6B175474E89094C44Da98b954EedeAC495271d0F";
const wethAddress = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";

const privateKey = process.env.PRIVATE_KEY;
const infuraProvider = new ethers.providers.InfuraProvider('mainnet', process.env.INFURA_API_KEY);
const wallet = new ethers.Wallet(privateKey, infuraProvider);

const testBasic = async () => {
const uniswapFactory = new ethers.Contract(
"0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f",
UniswapV2Factory.abi,
wallet
);

const sushiFactory = new ethers.Contract(
"0xC0AEe478e3658e2610c5F7A4A2E1777cE9e4f2Ac",
UniswapV2Factory.abi,
wallet
);

let uniswapDaiEth;
let sushiEthDai;

const loadPairs = async () => {
uniswapDaiEth = new ethers.Contract(
await uniswapFactory.getPair(daiAddress, wethAddress),
UniswapV2Pair.abi,
wallet
);
sushiEthDai = new ethers.Contract(
await sushiFactory.getPair(daiAddress, wethAddress),
UniswapV2Pair.abi,
wallet
);
};
await loadPairs();

infuraProvider.on('block', async (blockNumber) => {
try {
const uniswapReserves = await uniswapDaiEth.getReserves();
const sushiReserves = await sushiEthDai.getReserves();
} catch (err) {
console.error(err);
}
});
};

testBasic();`

Thank you very much for your help!

Best, Samuel