Overall

• Use idiomatic erlang
• Use consistent calling conventions
• Domain specific code should go in its own modules
• Domain specific api response modules should return a valid response or error to the client. This includes HTTP error codes, since S3 is non-standard in that respect.

Error Handling

• Keep it minimal!
• Fail fast, but correctly - Follow a few conventions
  • Match for the good case
  • try/catch at the top of the call stack to catch any expected errors and return a 400 level error code.
  • Only use try/catch at the top of the callstack, unless you need to wrap an unwieldy library to return the proper error format {error, Reason}.
  • Only try pattern match against errors you expect. Errors you expect should be {badmatch, {error, Reason}}
  • Unexpected errors are uncaught and will result in webmachine returning a 500 error.