Golang Skill

These are the instructions for writing clean, maintainable and efficient code in golang.

Naming conventions:

• Use camelCase for unexported identifiers
• Use PascalCase for exported identifiers
• Package names should be short, lowercase and descriptive. Good: net/http, image/png, testframework, Bad: kafka_topic_manager, helper_util
• For single method interfaces use -er suffix. Good: Reader, Writer, Closer, Bad: ReadInterface, IRead, ReadIface

Common best practices:

• Do not have multiple nested if statements, if possible extract them to switch statement
• Try to avoid nested else if statement
• Always use context.Context for IO operations

Project structure:

• Avoid creating generic packages like utils, helpers, common
• Use internal/ for internal packages which should not be exposed
• For large applications that require multiple main files use cmd/ folders. Example: cmd/api/main.go, cmd/cli/main.go
• For sub packages use pkg/ folder.
• Do not have very large files, try to split them into smaller files by domain

Error handling:

• Never skip error checking
• Never use panic unless user explicitly asked for it
• When wrapping error or adding context using fmt.Errorf do not expose implementation details
• Avoid nesting, always check errors first

Bad:

func (g *Gopher) WriteTo(w io.Writer) (size int64, err error) {
    err = binary.Write(w, binary.LittleEndian, int32(len(g.Name)))
    if err == nil {
        size += 4
        var n int
        n, err = w.Write([]byte(g.Name))
        size += int64(n)
        if err == nil {
            err = binary.Write(w, binary.LittleEndian, int64(g.AgeYears))
            if err == nil {
                size += 4
            }
            return
        }
        return
    }
    return
}

Good:

func (g *Gopher) WriteTo(w io.Writer) (size int64, err error) {
    err = binary.Write(w, binary.LittleEndian, int32(len(g.Name)))
    if err != nil {
        return
    }
    size += 4
    n, err := w.Write([]byte(g.Name))
    size += int64(n)
    if err != nil {
        return
    }
    err = binary.Write(w, binary.LittleEndian, int64(g.AgeYears))
    if err == nil {
        size += 4
    }
    return
}

Concurrency best practices:

• Use WaitGroup if you want to wait for multiple goroutines to finish
• Check ctx.Done() to check if context is cancelled to avoid doing unnecessary work