golang Ethereum

Golang Ethereum: How to use Go to write smart contracts

The popularity of blockchain technology has brought great changes to life and the economy, among which Ethereum is one of the open source distributed public blockchain platforms , allowing developers to implement programmable digital assets through smart contracts. Unlike other common programming languages, Golang makes smart contract development simpler and safer, while providing higher execution efficiency and concurrency. In this article, we will explore how to write smart contracts using Golang.

Introduction to Ethereum

Ethereum is a decentralized, open source, public blockchain platform with smart contract and distributed application (DApp) capabilities. Smart contracts are self-executing contracts that are written based on code and can be deployed and run on the Ethereum network. At the same time, they can realize the transfer, data storage and complex logical operations of Ethereum, making Ethereum a leader in blockchain development. important platform.

Golang is a very popular programming language also known as Go. Developed in 2009 by Robert Griesemer, Rob Pike, and Ken Thompson at Google, it is a programming language used for building high-performance networks and distributed systems. Compared with traditional programming languages, Go has higher simplicity, security and performance, and supports concurrency, so it is also widely used in the blockchain field.

Installation and configuration Golang

Before we begin, we need to install and configure the Golang environment. You can download the latest version of Golang installer from the official website and follow the instructions to install it. After completion, you can check whether the installation is successful in the terminal:

go version

If the installation is successful, the Go version will be displayed.

Writing Smart Contracts

Now we take a simple smart contract as an example to illustrate how to use Golang to write smart contracts.

First, we create a go-ethereum project, you can execute the following command in the terminal:

mkdir go-ethereum
cd go-ethereum

Then, we use go module to initialize the project:

go mod init go-ethereum

Next, We need to add dependencies to support smart contract development on Ethereum. We use the go-ethereum package here, which is a Go language implementation developed by the Ethereum team and provides rich API support for developing smart contracts.

go get github.com/ethereum/go-ethereum

In the project directory, we create a Solidity smart contract (MyContract.sol) as shown below:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract MyContract {
    uint256 value;

    function setValue(uint256 _value) public {
        value = _value;
    }

    function getValue() public view returns (uint256) {
        return value;
    }
}

At the top, we add the SPDX-License-Identifier annotation to the contract to specify the license. Next, we declare the MyContract contract and add a state variable called value. We define two public functions, setValue and getValue. The former sets the value of value to _value, and the latter returns the value of the current value.

Next, we use the following command to generate the Go binding for the Solidity smart contract in the project directory:

abigen --sol MyContract.sol --pkg bindings --out MyContract.go

The option --pkg specifies the package name of the Go code that will be generated, --out Specifies the output file name of the generated Go code. The abigen command uses the source file MyContract.sol of the Solidity smart contract to generate the Go binding code MyContract.go.

Now, we create a Go file (main.go) using the following command and add the following content in it:

package main

import (
    "context"
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/ethclient"

    "./bindings"
)

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

    contractAddress := common.HexToAddress("0x06857768a9b56c860c89effbeb8ce6c6a46940ef")
    instance, err := bindings.NewMyContract(contractAddress, client)
    if err != nil {
        panic(err)
    }

    value, err := instance.GetValue(&bind.CallOpts{})
    if err != nil {
        panic(err)
    }
    fmt.Println("Value:", value)

    tx, err := instance.SetValue(&bind.TransactOpts{
        From:     common.HexToAddress("0x8c51b77048b5A9A1bcc30158b4859Af247bAd2b0"),
        GasLimit: uint64(200000),
        GasPrice: big.NewInt(20000000000),
    }, big.NewInt(10))
    if err != nil {
        panic(err)
    }
    fmt.Println("Tx Hash:", tx.Hash().Hex())
}

At the top, we imported several dependencies, including go- The ethereum package and the MyContract package we generated using the abigen tool, as well as several standard library packages. We create a main function to start our application.

In the main function, we use the ethclient.Dial method to connect to the Ethereum network, specifying the https://mainnet.infura.io node provided by Infura. Instantiate MyContract and specify the contract address and client. We call the GetValue function to get the value of the current value and print the result to the console.

Next, we call the SetValue function to set value to 10 and specify the gas limit and gas price. Finally, we print out the transaction hash.

Now, we can compile and run our program using the following commands:

go build
./go-ethereum

The application will connect to the Ethereum network and use the MyContract contract's methods setValue and getValue to set and get The value of value.

Summary

In this article, we learned how to write Ethereum smart contracts using Golang and demonstrated how to use the abigen tool to generate Go binding code for Solidity smart contracts. We also use the go-ethereum package, which provides rich API support to make writing smart contracts easier. The combination of Golang and Ethereum brings new possibilities to the development of distributed applications, making it easier for developers to build decentralized applications and implement programmable digital assets on the Ethereum network.

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