What microservice design patterns are most important to understand for Go interviews?

// Circuit breaker with sony/gobreaker
import "github.com/sony/gobreaker"

type UserClient struct {
    grpc pb.UserServiceClient
    cb   *gobreaker.CircuitBreaker
}

func NewUserClient(grpc pb.UserServiceClient) *UserClient {
    cb := gobreaker.NewCircuitBreaker(gobreaker.Settings{
        Name:        "user-service",
        MaxRequests: 3,                 // requests in half-open state
        Interval:    10 * time.Second,  // reset window for counting
        Timeout:     30 * time.Second,  // how long to stay open
        ReadyToTrip: func(c gobreaker.Counts) bool {
            return c.ConsecutiveFailures >= 5
        },
    })
    return &UserClient{grpc: grpc, cb: cb}
}

func (c *UserClient) GetUser(ctx context.Context, id int64) (*pb.User, error) {
    result, err := c.cb.Execute(func() (any, error) {
        return c.grpc.GetUser(ctx, &pb.GetUserRequest{Id: id})
    })
    if err != nil {
        if errors.Is(err, gobreaker.ErrOpenState) {
            return nil, fmt.Errorf("user service unavailable (circuit open): %w", err)
        }
        return nil, err
    }
    return result.(*pb.User), nil
}