dYdX event log signature hash

Question

dYdX has an event called LogDeposit(address indexed accountOwner, uint256 accountNumber, uint256 market, BalanceUpdate update, address from) within their SoloMargin contract. I am trying to get the signature hash for this using the following code:

from Crypto.Hash import keccak
keccak_hash = keccak.new(digest_bits=256)
keccak_hash.update(b'LogDeposit(address,uint256,uint256,BalanceUpdate,address)')
print(keccak_hash.hexdigest())

This produces the following signature hash: ad66b490ac5d24d41e7e33a2a9ac6645bf66b577553f31d1e2917df2f83f15a6. However, I do not think it is right. When I search for this topic in etherscan nothing is returned.

I am wondering if it has to do with the BalanceUpdate parameter. I am used to searching for the other types such as address and uint256, but this one I haven't seen and do not know if I am doing this right.

Answer 1

When calculating the signature of an event that uses structs, each struct is represented as a tuple of the types of the variables it contains. To create the tuple for your question, we need to look at the source of SoloMargin.

Based on the source published to Etherscan, I extracted the code needed to create the event:

pragma solidity 0.5.7;
pragma experimental ABIEncoderV2;

contract SoloMiningLogEvent {

    struct Wei {
        bool sign;
        uint256 value;
    }

    struct Par {
        bool sign;
        uint128 value;
    }

    struct BalanceUpdate {
        Wei deltaWei;
        Par newPar;
    }

    event LogDeposit(
        address indexed accountOwner,
        uint256 accountNumber,
        uint256 market,
        BalanceUpdate update,
        address from
    );

}

We can see that BalanceUpdate is composed of two structs:

• Wei, a tuple of (bool,uint256)
• Par, a tuple of (bool,uint128)

So our tuple representation for BalanceUpdate is:

((bool,uint256),(bool,uint128))

Thus the entire signature to generate the hash is written as:

LogDeposit(address,uint256,uint256,((bool,uint256),(bool,uint128)),address)

which results in a hash of:

0x2bad8bc95088af2c247b30fa2b2e6a0886f88625e0945cd3051008e0e270198f

Answer 2

This event's signature is:

0x2bad8bc95088af2c247b30fa2b2e6a0886f88625e0945cd3051008e0e270198f

This is keccak256 hash of the following string:

LogDeposit(address,uint256,uint256,((bool,uint256),(bool,uint128)),address)