Design Patterns in Go interview questions

Design patterns in Go interview questions test whether you apply Go idioms or translate patterns from Java/Python without adaptation. This module covers the functional options pattern (the idiomatic Go alternative to the builder pattern and telescoping constructors — func WithTimeout(d time.Duration) Option), the middleware chain pattern (the http.Handler wrapping pattern that underpins every Go web framework), the repository pattern in Go (defining a storage interface, providing a PostgreSQL implementation, injecting a mock in tests), dependency injection without a framework (constructor injection using interfaces — Go favours small interfaces over DI containers), the observer pattern using channels (event streams without callbacks), and sync.Once as the Go singleton idiom. The SOLID principles are covered through Go examples: the 'I' in SOLID (interface segregation — why Go's small-interface philosophy is a direct expression of ISP) and the 'D' (dependency inversion — program to interfaces, not concrete types).