The Roadhouse Design Pattern

Imagine that Patrick Swayze is writing an SDK. He’s haunted by memories of ripping out a man’s throat for a nil pointer deference. To recoop, he sits down in his home office and begins writing a function to issue a new HTTP request to the API, applying authentication and common headers. Before he even writes the NewRequest logic, he introduces the Roadhouse pattern. The idea is that he wants to fail fast before any work begins, return specific sentinel errors so he knows where it all went wrong, and declare invariants where the guard clauses ARE the documentation for what to accept. Take a look at this function: