go mod init
- Go course
- Beginner
- Lesson 7/90
- 4 min
Learn to start a new Go module and the go.mod file.
go mod init
The go mod init command starts a new Go module. A module is a collection of related Go packages managed by a go.mod file.
To start a module, run go mod init example/hello in your project directory. This creates a go.mod file and writes the module path into it.
The module path usually looks like a URL: github.com/user/project. It provides uniqueness and is used when fetching dependencies with go get.
Contents of go.mod
The go.mod file is fairly simple. The first line holds the module path after the module keyword. The second line states the Go version after the go keyword.
As you add dependencies, require blocks appear; each dependency is listed with its path and version. The go.sum file keeps the hash of each dependency.
You rarely edit this file by hand; commands like go get and go mod tidy keep it up to date automatically.
Practice Module path
The command go mod init example.com/merhaba produces the line module example.com/merhaba. Parse this line with strings.CutPrefix and print the module path: yol, ok := strings.CutPrefix("module example.com/merhaba", "module ").
Starter code
package main
import (
"fmt"
"strings"
)
func main() {
// buraya yaz
}Sample solution
package main
import (
"fmt"
"strings"
)
func main() {
yol, ok := strings.CutPrefix("module example.com/merhaba", "module ")
fmt.Println(yol, ok)
}Expected output
example.com/merhaba true
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What does go mod init produce?
- A binary file
- A main.go file
- A README.md file
- A go.mod file Correct answer
Explanation: go mod init creates the go.mod file.
2 Module declaration
The first line of go.mod is:
____ example/helloThe first line of go.mod is:
module example/helloExplanation: the module keyword starts the module path.
3 Match the module parts
| Term | Meaning |
|---|---|
module |
Module path |
go |
Go version |
require |
Dependency |
go.sum |
Hash store |