What is a module? Let’s talk about how to use Golang to implement modules

In recent years, Golang has been attracting everyone's attention. In addition to its excellent concurrency processing capabilities, it also has many other features and usage scenarios. Among them, module is a new feature after Golang version 1.11. It manages Golang packages in the form of module and can be shared and used in different projects. This article will introduce how to use Golang to implement modules to help readers better understand and use this feature.

1. What is a module

Golang’s module (Module) is a collection of packages (Package), which is generally used to solve version conflicts of different packages. Modules can be understood as highly independent code libraries, which are different from the idea of ​​a single workspace under the GOPATH directory. Modules depend on external packages, and these external packages are introduced in the form of module. This allows different versions of packages to be used in the same project and avoids problems caused by package version conflicts.

2. How to use modules

In versions after Golang 1.11, it is very simple to use Golang’s module mechanism. If you are using Golang modules for the first time, you first need to create a new folder in the GOPATH root directory, such as "go-main" .

The steps are as follows:

1. Create the go.mod file

Go to the "go-main" directory you just created and execute the following in the terminal (or command line) Command:

go mod init go-main

After executing this command, a go.mod file will be generated in the "go-main" directory. This file is still empty. It will record the external packages used by the project.

2. Add dependencies in the go.mod file

In the go.mod file, you can use require to tell the external packages required by the Golang project, such as:

require (
    github.com/gorilla/mux v1.7.3
    github.com/spf13/viper v1.4.0
)

Here we specify two external packages based on Github, which are github.com/gorilla/mux and github.com/spf13/viper.

It should be noted that the version number here is more important. A project can contain multiple external packages, and each package can have its own version. Using the specified version can ensure good cooperation of the code.

3. Install dependencies

After defining external packages in the go.mod file, you need to install them in the project. In the terminal, execute the following command:

go mod tidy

This command will download all packages and create a vendor directory required for the project. This directory will save the source code of all these external packages.

4. Use dependencies

After installing external packages, you can use them normally in Golang. For example, in your project code, you can reference Gorilla Mux like this:

import "github.com/gorilla/mux"

In the above code, we referenced the "github.com/gorilla/mux" package through import and used it immediately .

5. Handling of special cases

If your project uses special packages or requires special parameters, then you can create vendor packages for them under the vendor folder in the root directory of GOPATH. .

It should be noted that this method is to ensure the normal operation of the project in the event of some failures or dependencies being removed. If you can avoid using vendor packages, it's better not to use them as they will increase maintenance time and cost.

3. Summary

This article starts with what a Golang module is, then gives the complete process of using the Golang module, and finally talks about some matters that need to be paid attention to under special circumstances.

The use of Golang modules is a very convenient thing. It can avoid version conflicts between packages and make project development and maintenance more healthy and efficient. The Golang module is still being continuously improved and developed. I believe there will be better improvements and optimizations in the future, and there will definitely be a better user experience.

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