Adding and Removing dependency in Go modules

Adding dependency is made easy with go get command. Specify the package needed and Go will add it to the module as a dependency. Before we get to that part let's look at how to initialize module in Go.

Topics Covered

Initialize module

Adding dependency

Removing dependency

Initialize module

We can initialize the module first to create go.mod file. This will contain details about our module

Name of the module

Version of Go used in the module

Dependencies of the module

After creating a new folder for your module, run the go mod init {modulename} command to initialize your module

go mod init helloworld

The above command creates go.mod file with the module name "helloworld"

Adding dependency

go get command is the standard way of adding dependencies to your modules.

Download and install particular package using the go get {package_name}

go get github.com/gofiber/fiber/v2

The above command will install the fiber package (This is just an example and don't worry if you are not familiar with fiber)

After adding the dependency, just import it into your go file and you can start using the installed package

package main

import "github.com/gofiber/fiber/v2"

func main() {
    // Staring a server
    app := fiber.New()

    app.Get("/", func(c *fiber.Ctx) error {
        return c.SendString("Hello from fiber")
    })

    app.Listen(":3000")
}

For more info about go get command and its arguments, check this link

Removing dependency

When you want to remove any dependency, you need to perform a couple of steps

Remove all the imports and code related to the package

Run go mod tidy -v command to remove any unused package

From the above example, we need to remove all the places where we are using fiber.

package main

func main() {
    // Staring a server
}

We just have an empty main function in our example but you get the point :)

go mod tidy -v

Output:
unused github.com/gofiber/fiber

The above command is used to remove any unused dependencies from the module. Since we have removed any reference to the installed package, it will assume that that package is not needed anymore and remove it from the dependency.

go.mod will also be updated to remove the dependency.

Summary

Initialize a module using go mod init {packagename}

Add dependency using go get {packagename}

Remove dependency by deleting the import references and running go mod tidy -v command

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