Deploying a Smart Contract

If you haven't already, check out the section on smart contract compiation since this lesson requires knowledge on compiling a solidity smart contract to a Go contract file.

Assuming you've imported the newly created Go package file generated from abigen, and set the ethclient, loaded your private key, the next step is to create a keyed transactor. First import the accounts/abi/bind package from go-ethereum and then invoke NewKeyedTransactor passing in the private key. Afterwards set the usual properties such as the nonce, gas price, gas limit, and ETH value.

auth := bind.NewKeyedTransactor(privateKey)
auth.Nonce = big.NewInt(int64(nonce))
auth.Value = big.NewInt(0)     // in wei
auth.GasLimit = uint64(300000) // in units
auth.GasPrice = gasPrice

If you recall in the previous section, we created a very simpile Store contract that sets and stores key/value pairs. The generated Go contract file provides a deploy method. The deploy method name always starts with the word Deploy followed by the contract name, in this case it's Store.

The deploy function takes in the keyed transactor, the ethclient, and any input arguments that the smart contract constructor might takes in. We've set our smart contract to take in a string argument for the version. This function will return the Ethereum address of the newly deployed contract, the transaction object, the contract instance so that we can start interacting with, and the error if any.

input := "1.0"
address, tx, instance, err := store.DeployStore(auth, client, input)
if err != nil {
  log.Fatal(err)
}

fmt.Println(address.Hex())   // 0x147B8eb97fD247D06C4006D269c90C1908Fb5D54
fmt.Println(tx.Hash().Hex()) // 0xdae8ba5444eefdc99f4d45cd0c4f24056cba6a02cefbf78066ef9f4188ff7dc0

_ = instance // will be using the instance in the next section

Yes it's that simply. You can take the transaction hash and see the deployment status on Etherscan: https://rinkeby.etherscan.io/tx/0xdae8ba5444eefdc99f4d45cd0c4f24056cba6a02cefbf78066ef9f4188ff7dc0


Full code

Commands

solc --abi Store.sol
solc --bin Store.sol
abigen --bin=Store_sol_Store.bin --abi=Store_sol_Store.abi --pkg=store --out=Store.go

Store.sol

pragma solidity ^0.4.24;

contract Store {
  event ItemSet(bytes32 key, bytes32 value);

  string public version;
  mapping (bytes32 => bytes32) public items;

  constructor(string _version) public {
    version = _version;
  }

  function setItem(bytes32 key, bytes32 value) external {
    items[key] = value;
    emit ItemSet(key, value);
  }
}

contract_deploy.go

package main

import (
    "context"
    "crypto/ecdsa"
    "fmt"
    "log"
    "math/big"

    "github.com/ethereum/go-ethereum/accounts/abi/bind"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethclient"

    store "./contracts" // for demo
)

func main() {
    client, err := ethclient.Dial("https://rinkeby.infura.io")
    if err != nil {
        log.Fatal(err)
    }

    privateKey, err := crypto.HexToECDSA("fad9c8855b740a0b7ed4c221dbad0f33a83a49cad6b3fe8d5817ac83d38b6a19")
    if err != nil {
        log.Fatal(err)
    }

    publicKey := privateKey.Public()
    publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
    if !ok {
        log.Fatal("cannot assert type: publicKey is not of type *ecdsa.PublicKey")
    }

    fromAddress := crypto.PubkeyToAddress(*publicKeyECDSA)
    nonce, err := client.PendingNonceAt(context.Background(), fromAddress)
    if err != nil {
        log.Fatal(err)
    }

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

    auth := bind.NewKeyedTransactor(privateKey)
    auth.Nonce = big.NewInt(int64(nonce))
    auth.Value = big.NewInt(0)     // in wei
    auth.GasLimit = uint64(300000) // in units
    auth.GasPrice = gasPrice

    input := "1.0"
    address, tx, instance, err := store.DeployStore(auth, client, input)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(address.Hex())   // 0x147B8eb97fD247D06C4006D269c90C1908Fb5D54
    fmt.Println(tx.Hash().Hex()) // 0xdae8ba5444eefdc99f4d45cd0c4f24056cba6a02cefbf78066ef9f4188ff7dc0

    _ = instance
}

solc version used for these examples

$ solc --version
0.4.24+commit.e67f0147.Emscripten.clang

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