go-conventions

Go Conventions

This skill covers Go coding conventions for Datum Cloud services.

Overview

All Go code follows these conventions for consistency across services.

Key Files

File	Purpose
testing.md	Test patterns

Import Grouping

Three groups, separated by blank lines:

import (
    // Standard library
    "context"
    "fmt"
    "time"

    // External packages
    "k8s.io/apimachinery/pkg/runtime"
    "sigs.k8s.io/controller-runtime/pkg/client"

    // Internal packages
    "github.com/datumapis/myservice/pkg/apis/v1alpha1"
    "github.com/datumapis/myservice/internal/storage"
)

Error Handling

Error Messages

• Lowercase, no punctuation
• Include context
• Actionable when possible

// Good
return fmt.Errorf("creating resource %s: %w", name, err)

// Bad
return fmt.Errorf("Failed to create resource.")

Error Wrapping

Always wrap with context:

if err != nil {
    return fmt.Errorf("validating spec: %w", err)
}

Sentinel Errors

Use for expected conditions:

var ErrNotFound = errors.New("resource not found")

if errors.Is(err, ErrNotFound) {
    // handle not found
}

Naming

Type	Convention	Example
Package	short, lowercase	storage, quota
Interface	-er suffix when single method	Reader, Storage
Struct	noun	ResourceStore
Function	verb	CreateResource
Constant	PascalCase	MaxRetries
Variable	camelCase	resourceCount

Comments

Package Comments

// Package storage implements the storage backend for resources.
package storage

Function Comments

// CreateResource creates a new resource in the store.
// It returns ErrAlreadyExists if the resource exists.
func CreateResource(ctx context.Context, r *Resource) error {

Why, Not What

// Good: explains why
// Use sync.Once to ensure thread-safe lazy initialization
r.storeOnce.Do(...)

// Bad: explains what (obvious from code)
// Initialize the store
r.storeOnce.Do(...)

Context

• First parameter always
• Never store in structs
• Pass through call chains

func (s *Store) Get(ctx context.Context, name string) (*Resource, error) {
    return s.backend.Get(ctx, name)
}

Validation Scripts

Script	Purpose
scripts/check-imports.sh	Verify import grouping
scripts/check-test-naming.sh	Verify test file names
scripts/check-boilerplate.sh	Verify license headers

Related Files

• testing.md — Test conventions