How to manage packages in golang

Go is an open source programming language developed by Google. Go is fast at code writing, compilation, and execution, making it ideal for web and cloud applications. Go's package management system makes building applications very easy.

In Go, a package is the basic unit of code. If you have a set of related features, it's a good practice to put them together and create a package. Packages can be reused across your application so you can avoid refactoring your code. In this article, we will discuss how to use Go’s package management system.

Installing Go

To manage Go's packages, you need to install Go. Go to Go's official website (https://golang.org/dl/) to download the latest version of Go. The installation process is very simple, just follow the prompts.

Set GOPATH

Before using Go’s package management system, you must set GOPATH. This is the path to where you installed the package. After installing Go, add the bin path of the installation directory to the system's Path variable so that you can use the go command in the console.

$ export PATH=$PATH:/usr/local/go/bin

Then, set GOPATH to the path you want. GOPATH can contain multiple directories, using colons as separators.

$ export GOPATH=/path/to/gocode

Create Go project

When you create a Go project, you need to create a directory that will contain all the source code, Tests and dependencies. In that directory, create a file called main.go and add the following code:

package main

import (
    "fmt"
    "github.com/pkg/errors"
)

func main() {
    fmt.Println("Hello, world!")
    err := errors.Errorf("something went wrong")
    fmt.Println(err)
}

In this example, we imported the fmt and errors packages. Then, we printed "Hello, world!" in the main() function and created an error instance.

In order to resolve the dependencies of the errors package, we use the complete package import path, which is a package on github. This is how we use Go's package management system.

Use go get to install the package

In addition to importing the package in the code, you can also use the go get command to install the package. Consider the following example:

$ go get github.com/pkg/errors

This command will download and install the errors package in the $GOPATH/src/github.com/pkg directory. You can then import this package in your code.

Using the vendor folder

To ensure a stable version of your application dependencies, it is a good idea to copy these dependencies into your project for future use. This is what the vendor folder is for. You can use the go mod command to create mod files and generate vendor directories.

Run the following command in the root directory of the application:

$ go mod init

This will create a mod file that contains a list of the application's dependencies and what they are version of. Then use the following command to generate the vendor directory:

$ go mod vendor

This will read the dependency list from the mod file and copy them into the vendor directory. You can then commit them to your version control system so others can use them.

Summary

In Go, the package management system is key to building applications. From installing Go to installing packages using the go get command and generating vendor directories, package management makes building applications easy and reliable. Hopefully this article helped you better understand how to manage packages in Go.

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