Timeout

1. The Pattern

A timeout assigns a deadline to every network call. If no response arrives before that deadline, the caller declares failure and releases the resources reserved for the request.

Choose the maximum wait before making a call because many network clients otherwise use no practical deadline.

Python's requests library has no timeout unless the caller supplies one. A raw TCP connection to a machine that stops responding may remain open for several minutes before the operating system closes it.

The diagram below shows how the deadline changes request behavior.