Retries and backoff

Anything that crosses a network fails sometimes: an API times out, a connection drops, a service is briefly overloaded. A one-off script can just crash. A script that runs unattended should try again before giving up. That's a retry loop.

time.sleep

To wait between attempts, use sleep from the built-in time module. It pauses the program for a number of seconds:

import time
time.sleep(2)   # pause for two seconds

A basic retry loop

Wrap the risky call in a loop, catch the exception, and try again:

import time

for attempt in range(3):
    try:
        result = do_the_thing()
        break
    except Exception:
        time.sleep(1)

This tries up to three times, pausing a second after each failure, and stops as soon as one succeeds.

Exponential backoff

Retrying immediately, or on a fixed delay, can make an overloaded service worse by hammering it. Exponential backoff spaces attempts further apart each time, doubling the wait: 1 second, then 2, then 4. You give a struggling service room to recover:

delay = 1
for attempt in range(3):
    try:
        result = do_the_thing()
        break
    except Exception:
        time.sleep(delay)
        delay = delay * 2

Give up eventually

A retry loop must have a limit. After the last attempt fails, re-raise the exception or exit with an error, so the failure is visible instead of silently swallowed. Retrying forever just hides a real outage.

What this node introduces

• time.sleep(seconds) pauses execution.
• A retry loop wraps a risky call in try/except and loops a fixed number of times.
• Exponential backoff doubles the delay between attempts and always caps the number of tries.