golang build tag

// +build debug

package main

import "fmt"

func main() {
    fmt.Println("Debug build")
}

The provided Go code uses a build tag, specifically debug. Here's an explanation of each step:

1. // +build debug: This is a build constraint or build tag. It indicates that the following file should only be included in the build when the specified build tag (debug in this case) is set. In this example, the file will be included only when building with the debug tag.

2. package main: This line specifies that the current file belongs to the main package, which is the entry point for the Go executable.

3. import "fmt": This line imports the "fmt" package, which provides functions for formatting and printing output.

4. func main() { ... }: This is the main function, the entry point for the executable. Inside this function, there is a single line:

5. fmt.Println("Debug build"): This line prints "Debug build" to the standard output. This serves as a placeholder for actual code that would be specific to the debug build.

In summary, this code defines a simple Go program that will only be included in the build when the debug build tag is set. It imports the "fmt" package and prints a message indicating that it is a debug build.