go module usage
go module was launched after go 1.14 version
1. Introduction to go module usage
go module
is the version management tool officially launched after Go1.11 version, and starting from Go1.13 version, go module
will be the default dependency management tool of Go language.
1.1 GO111MODULE
To enable go module
support, you must first set the environment variable GO111MODULE
, through which you can turn on or off module support. It has three Optional values: off
, on
, auto
, the default value is auto
.
GO111MODULE=off
Disables module support and will look for packages from theGOPATH
andvendor
folders when compiling.GO111MODULE=on
Enable module support, theGOPATH
andvendor
folders will be ignored when compiling, only based ongo.mod
Download dependencies to the%GOPATH%/pkg/mod/
directory.GO111MODULE=auto
, when the project is outside$GOPATH/src
and the project root directory hasgo.mod
file, enable module support.
Simply put, after setting GO111MODULE=on
, you can use go module
. There is no need to create projects in GOPATH in the future. , and can also well manage the third-party package information that the project depends on.
After using go module to manage dependencies, two files go.mod
and go.sum
will be generated in the project root directory.
1.2 Republican /proxy.golang.org
is inaccessible in China, so it is highly recommended that you set up GOPROXY. Here I recommend using goproxy.cn.export GOPROXY=https://goproxy.cn1.3 go mod command
Commonly used
go modcommands are as follows:
go env -w GOPROXY=https://goproxy.cn,direct1.4 go.modgo.mod The file records all the dependency information of the project, and its structure is roughly as follows:
go mod download 下载依赖的module到本地cache(默认为$GOPATH/pkg/mod目录) go mod edit 编辑go.mod文件 go mod graph 打印模块依赖图 go mod init 初始化当前文件夹, 创建go.mod文件 go mod tidy 增加缺少的module,删除无用的module go mod vendor 将依赖复制到vendor下 go mod verify 校验依赖 go mod why 解释为什么需要依赖
Among them,
moduleis used to define the package name
require
- Used to define dependent packages and versions
-
indirect
Indicates indirect reference -
1.4.1 Dependent version
- go mod supports semantic version numbers, such as
go get foo@v1.2.3
, or it can be followed by git branches or tags, such as go get foo@master
go get foo@e3702bed2
. Regarding dependent versions, the following formats are supported:module github.com/Q1mi/studygo/blogger go 1.12 require ( github.com/DeanThompson/ginpprof v0.0.0-20190408063150-3be636683586 github.com/gin-gonic/gin v1.4.0 github.com/go-sql-driver/mysql v1.4.1 github.com/jmoiron/sqlx v1.2.0 github.com/satori/go.uuid v1.2.0 google.golang.org/appengine v1.6.1 // indirect )
1.4.2 replace
Each package accessing golang.org/x in China needs to bypass the firewall. You can go.mod Use replace to replace it with the corresponding library on github.
gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 gopkg.in/vmihailenco/msgpack.v2 v2.9.1 gopkg.in/yaml.v2 <=v2.2.1 github.com/tatsushid/go-fastping v0.0.0-20160109021039-d7bb493dee3e latest
1.5 go get
Execute the go get
command in the project to download the dependency package, and you can also specify the downloaded version.Run
go get -u will upgrade to the latest minor version or revision (x.y.z, z is the revision number, y is the minor version number)Run
- will be upgraded to the latest revision
Run
go get package@version will be upgraded to the specified version No. versionIf you download all dependencies, you can use the
go mod download- command.
1.6 Organizing dependencies
go.mod file. In this case, we can use the
go mod tidy
go.mod
.1.7 go mod edit
Formatting
Because we can manually modify the go.mod file, sometimes we need to format the file. Go provides the following commands:
replace ( golang.org/x/crypto v0.0.0-20180820150726-614d502a4dac => github.com/golang/crypto v0.0.0-20180820150726-614d502a4dac golang.org/x/net v0.0.0-20180821023952-922f4815f713 => github.com/golang/net v0.0.0-20180826012351-8a410e7b638d golang.org/x/text v0.3.0 => github.com/golang/text v0.3.0 )Add dependencies
go mod edit -fmt
Remove dependenciesIf you just want to modify the contents of the go.mod
file , then you can rungo mod edit -droprequire=package path
. For example, if you want to remove thegolang.org/x/text
package ingo.mod, you can Use the following command:
go mod edit -require=golang.org/x/text
More usage of
go mod edit can be viewed through
go help mod edit.
1.8 Using go module in the project1.8.1 Existing project
If you need to enable
go module
Execute
go mod init in the project directory to generate a go.mod
file.
- Execute
- go get
to find and record the dependencies of the current project, and generate a
go.sumto record the version and hash value of each dependent library.
- 1.8.2 New Project
For a newly created project, we can follow the following steps under the project folder:
<ol> <li>执行<code>go mod init 项目名
命令,在当前项目文件夹下创建一个go.mod
文件。 - 手动编辑
go.mod
中的require依赖项或执行go get
自动发现、维护依赖。
二、包和调用文件在同一项目下
例如:
moduledemo ├── go.mod ├── main.go └── mypackage └── mypackage.go // package mp 定义包名为 mp
步骤:
1.在项目下创建一个 go.mod 文件,文件名只能为这个。
2.在 go.mod 文件中添加以下代码
module moduledemo // 设定 moduledemo 为包根目录名,可以随意改变该名字,只需要导入时一致就好 go 1.14 // 表明版本
3.导入想要的包文件
import "moduledemo/mypackage" // 这里是导入包目录下的包文件名
4.使用包文件
mp.MyPackage() // 使用包中的 MyPackage() 函数
三、包和被调用文件不在同一个项目下
例如:
├── moduledemo │ ├── go.mod │ └── main.go └── mypackage ├── go.mod └── mypackage.go // package mp 定义包名为 mp
步骤
1.在 mypackage 下面创建 go.mod 文件,并添加以下代码
module mypackage go 1.14
2.在 moduledemo 下面创建 go.mod 文件,并添加以下代码
module moduledemo go 1.14 require mypackage v0.0.0 // 这个会在你执行 go build 之后自动在该文件添加 replace mypackage => ../mypackage // 指定需要的包目录去后面这个路径中寻找
3.导入和使用
import "mypackage" // 因为该包目录本身就是包文件所以无需添加下一级路径 mp.MyPackage() // 使用包中的 MyPackage() 函数