Retry with backoff in Python

Exponential backoff is the polite way to retry flaky calls.

import time

def retry(fn, attempts=3, delay=0.5):
    for attempt in range(attempts):
        try:
            return fn()
        except Exception:
            if attempt == attempts - 1:
                raise
            time.sleep(delay * (2 ** attempt))

How it works

1. Calls the function and returns on success.
2. On failure, time.sleep waits, doubling the delay each attempt.
3. The final failure re-raises the original exception.

Keywords and builtins used here

• def
• except
• for
• if
• raise
• range
• retry
• return
• try

The run, in numbers

Lines

10

Characters to type

186

Tokens

54

Three-star pace

105 tpm

At the three-star pace of 105 tokens a minute, this run takes about 31 seconds.

Type this snippet

Step 5 of 5 in Decorators & closures, step 9 of 53 in Pythonic Python.

← Previous Next →

Retry with backoff in other languages

• JavaScript