Start the library project

In this step we will:

1. Create the library folder
2. Init the git repository
3. Enable dependency tracking for the Go code
4. Create the first Go file
5. Create a repository in github.com
6. Commit and push the initial version

The following commands are needed for steps 1, 2, and 3:

mkdir learning-go-lib && cd learning-go-lib
git init .
go mod init github.com/renato0307/learning-go-lib

Replace the renato0307 part by the correct value for you. This should be the value of a GitHub repository where you will store the project.

The go mod init command initializes and writes a new go.mod file in the current directory, in effect creating a new module rooted at the current directory.

The go.mod file describes the module’s properties, including its dependencies on other modules and on versions of Go.

Each time a new dependency is added running the go mod tidy command will update the go.mod file.

The go command maintains a file named go.sum containing the expected cryptographic hashes of the content of specific module versions.

From the official blog post about Go Modules:

The go command uses the go.sum file to ensure that future downloads of these modules retrieve the same bits as the first download, to ensure the modules your project depends on do not change unexpectedly, whether for malicious, accidental, or other reasons. Both go.mod and go.sum should be checked into version control.

Next, open vscode by typing:

code .

Create a file named main.go with the following contents:

package main

import "fmt"

func main() {
	fmt.Println("Hello, World!")
}

To run this code, go back to the command line and enter:

go run main.go

You should see in the output:

Hello, World!

Next, go to https://github.com and create a repository.

In my case I named it learning-go-lib.

After the repository is created, add it as remote origin and do the initial commit and push:

echo "# learning-go-lib" >> README.md
git add .
git remote add origin git@github.com:renato0307/learning-go-lib.git
git commit -m "initial version"
git branch -M main
git push -u origin main

With this all set, we are ready to start doing some real code.

Next

The next section is Add programming/uuid generator function the Library.