This guide shows how to implement a retry mechanism for API requests that might fail due to transient issues like network errors or temporary server unavailability.
Using `requests.adapters.HTTPAdapter`
A robust way to handle retries is to use a `requests.Session` with a custom `HTTPAdapter`. The adapter can be configured with a `Retry` strategy for specific status codes or connection errors.
import requests
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry
def requests_retry_session(
retries=3,
backoff_factor=0.3,
status_forcelist=(500, 502, 504),
session=None,
):
session = session or requests.Session()
retry = Retry(
total=retries,
read=retries,
connect=retries,
backoff_factor=backoff_factor,
status_forcelist=status_forcelist,
)
adapter = HTTPAdapter(max_retries=retry)
session.mount('http://', adapter)
session.mount('https://', adapter)
return session
# This endpoint will fail a few times before succeeding
flaky_url = 'http://httpbin.org/status/503,200,503,200'
# The above url does not work as intended, so we simulate with a 503
flaky_url = 'http://httpbin.org/status/503'
try:
session = requests_retry_session()
response = session.get(flaky_url, timeout=5)
print("Request was eventually successful!")
print(f"Status: {response.status_code}")
except Exception as e:
print(f"Request failed after multiple retries: {e}")
