如何在Go SDK中部署以太坊智能合约

Question

I am trying to deploy ethereum smart contracts in go sdk but i am getting some error as

./inbox_test.go:20:44: not enough arguments in call to backends.NewSimulatedBackend
        have (core.GenesisAlloc)
        want (core.GenesisAlloc, uint64)

I am following step by step guide to deploy smart contract in go and i am not able to do this

func TestDeployInbox(t *testing.T) {

    //Setup simulated block chain
    key, _ := crypto.GenerateKey()
    auth := bind.NewKeyedTransactor(key)
    alloc := make(core.GenesisAlloc)
    alloc[auth.From] = core.GenesisAccount{Balance: big.NewInt(1000000000)}
    blockchain := backends.NewSimulatedBackend(alloc)

    //Deploy contract
    address, _, _, err := DeployInbox(
        auth,
        blockchain,
        "Hello World",
    )
    // commit all pending transactions
    blockchain.Commit()

    if err != nil {
        t.Fatalf("Failed to deploy the Inbox contract: %v", err)
    }

    if len(address.Bytes()) == 0 {
        t.Error("Expected a valid deployment address. Received empty address byte array instead")
    }

}

This code should deploy smart contract in go sdk

Answer 1

The method signature for NewSimulatedBackend has changed. As is:

https://github.com/ethereum/go-ethereum/blob/master/accounts/abi/bind/backends/simulated.go#L68

// NewSimulatedBackend creates a new binding backend using a simulated blockchain
// for testing purposes.
func NewSimulatedBackend(alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
    database := rawdb.NewMemoryDatabase()
    genesis := core.Genesis{Config: params.AllEthashProtocolChanges, GasLimit: gasLimit, Alloc: alloc}
    genesis.MustCommit(database)
    blockchain, _ := core.NewBlockChain(database, nil, genesis.Config, ethash.NewFaker(), vm.Config{}, nil)

    backend := &SimulatedBackend{
        database:   database,
        blockchain: blockchain,
        config:     genesis.Config,
        events:     filters.NewEventSystem(new(event.TypeMux), &filterBackend{database, blockchain}, false),
    }
    backend.rollback()
    return backend
}

You need also pass gasLimit along. Something like this:

gasPrice, err := client.SuggestGasPrice(context.Background())
if err != nil {
    log.Fatal(err)
}

key, _ := crypto.GenerateKey()
auth := bind.NewKeyedTransactor(key)

auth.GasLimit = uint64(300000) // in units
auth.GasPrice = gasPrice

alloc := make(core.GenesisAlloc)
alloc[auth.From] = core.GenesisAccount{Balance: big.NewInt(1000000000)}
blockchain := backends.NewSimulatedBackend(alloc, auth.GasLimit)