Multi-Agent Transactions
Multi-agent transactions allow multiple accounts to participate in the logic of a Move contract.
This can be used to require multiple parties agree to a transaction before executing or to use resources from multiple accounts.
Writing Multi-Agent Transactions
Creating and executing a multi-agent transaction follows a similar flow to the regular transaction flow, but with several notable differences.
Instead of client.BuildTransaction, multi-agent and sponsored transactions
use client.BuildTransactionMultiAgent.
Build the transaction by including aptos.AdditionalSigners with a list of each additional signers.
Make sure to replace the Function field below with your entry function
that requires multiple agents to sign.
transaction, err := client.BuildTransactionMultiAgent(alice.AccountAddress(), aptos.TransactionPayload{
Payload: &aptos.EntryFunction{
// Replace module and function with your multi-agent function
Module: aptos.ModuleId{
Address: aptos.AccountOne,
Name: "aptos_account",
},
Function: "transfer",
ArgTypes: []aptos.TypeTag{},
Args: [][]byte{
accountBytes,
amountBytes,
},
},
AdditionalSigners: []aptos.AccountAddress{bob.AccountAddress()},
})Sign once for each signer.
You will combine these signatures in the next step.
aliceAuth, err := rawTxn.Sign(alice)
if err != nil {
panic("Failed to sign transaction as sender:" + err.Error())
}
bobAuth, err := rawTxn.Sign(bob)
if err != nil {
panic("Failed to sign transaction as second signer:" + err.Error())
}Combine the signatures with the raw transaction to create a multi-agent signed transaction.
signedTxn, ok := rawTxn.ToMultiAgentSignedTransaction(aliceAuth, []crypto.AccountAuthenticator{bobAuth})Submit the transaction by combining all agent signatures via the aptos.AdditionalSigners parameter.
submitResponse, err := client.SubmitTransaction(signedTxn)Lastly, wait for the transaction to resolve.
txnResult, err := client.WaitForTransaction(submitResponse.Hash)Common Errors
NUMBER_OF_SIGNER_ARGUMENTS_MISMATCH - This happens when you are attempting to
do multi-agent signing for a function which does not require that number of
accounts. For example, if you try using multiple signatures for a
0x1::aptos_account::transfer function - it only expects one address, and so
produces an error when more than one is provided.