Go SDK - Simulating Transactions

// transfer_coin is an example of how to make a coin transfer transaction in the simplest possible way
package main

import (
  "fmt"

  "github.com/aptos-labs/aptos-go-sdk"
  "github.com/aptos-labs/aptos-go-sdk/bcs"
)

const FundAmount = 100_000_000
const TransferAmount = 1_000

// example This example shows you how to make an APT transfer transaction in the simplest possible way
func example(networkConfig aptos.NetworkConfig) {
  // Create a client for Aptos
  client, err := aptos.NewClient(networkConfig)
  if err != nil {
    panic("Failed to create client:" + err.Error())
  }

  // Create accounts locally for alice and bob
  alice, err := aptos.NewEd25519Account()
  if err != nil {
    panic("Failed to create alice:" + err.Error())
  }
  bob, err := aptos.NewEd25519Account()
  if err != nil {
    panic("Failed to create bob:" + err.Error())
  }

  fmt.Printf("\n=== Addresses ===\n")
  fmt.Printf("Alice: %s\n", alice.Address.String())
  fmt.Printf("Bob:%s\n", bob.Address.String())

  // Fund the sender with the faucet to create it on-chain
  err = client.Fund(alice.Address, FundAmount)
  if err != nil {
    panic("Failed to fund alice:" + err.Error())
  }

  aliceBalance, err := client.AccountAPTBalance(alice.Address)
  if err != nil {
    panic("Failed to retrieve alice balance:" + err.Error())
  }
  bobBalance, err := client.AccountAPTBalance(bob.Address)
  if err != nil {
    panic("Failed to retrieve bob balance:" + err.Error())
  }
  fmt.Printf("\n=== Initial Balances ===\n")
  fmt.Printf("Alice: %d\n", aliceBalance)
  fmt.Printf("Bob:%d\n", bobBalance)

  // 1. Build transaction
  accountBytes, err := bcs.Serialize(&bob.Address)
  if err != nil {
    panic("Failed to serialize bob's address:" + err.Error())
  }

  amountBytes, err := bcs.SerializeU64(TransferAmount)
  if err != nil {
    panic("Failed to serialize transfer amount:" + err.Error())
  }
  rawTxn, err := client.BuildTransaction(alice.AccountAddress(), aptos.TransactionPayload{
    Payload: &aptos.EntryFunction{
      Module: aptos.ModuleId{
        Address: aptos.AccountOne,
        Name:    "aptos_account",
      },
      Function: "transfer",
      ArgTypes: []aptos.TypeTag{},
      Args: [][]byte{
        accountBytes,
        amountBytes,
      },
    }},
  )

  if err != nil {
    panic("Failed to build transaction:" + err.Error())
  }

  // 2. Simulate transaction
  // This is useful for understanding how much the transaction will cost
  // and to ensure that the transaction is valid before sending it to the network
  // This is optional, but recommended
  simulationResult, err := client.SimulateTransaction(rawTxn, alice)
  if err != nil {
    panic("Failed to simulate transaction:" + err.Error())
  }
  fmt.Printf("\n=== Simulation ===\n")
  fmt.Printf("Gas unit price: %d\n", simulationResult[0].GasUnitPrice)
  fmt.Printf("Gas used: %d\n", simulationResult[0].GasUsed)
  fmt.Printf("Total gas fee: %d\n", simulationResult[0].GasUsed*simulationResult[0].GasUnitPrice)
  fmt.Printf("Status: %s\n", simulationResult[0].VmStatus)
}

func main() {
  example(aptos.DevnetConfig)
}