Troubleshooting Slow and Failing Requests in Python

Making HTTP requests is a common task in Python applications. The popular requests library provides a simple interface for this. However, you may occasionally run into issues with slow or failing requests. Here are some tips for troubleshooting:

Check for Network/Server Issues

First, rule out any network or server-side problems. Try accessing the URL in a browser to verify it is responding as expected. Slowdowns on the server can manifest as slow Python requests.

You can also check connectivity with a simple ping:

ping example.com

Use Sensible Timeouts

By default, the requests library waits indefinitely for a response. Set a timeout (in seconds) to prevent hanging:

requests.get('https://example.com', timeout=3)

This will raise a Timeout exception if the server does not respond within 3 seconds. Start with a reasonable timeout and adjust as needed.

Inspect the Request

Dig into the Request object for clues. Check the elapsed time and error messages:

resp = requests.get('http://example.com')
print(resp.elapsed)
print(resp.text)

Also check headers for issues with authentication or missing API keys.

Profile Long Requests

Use the cProfile module to profile execution time and identify bottlenecks:

import cProfile
import requests
cProfile.run('requests.get("http://example.com")')

This can reveal if a specific section like SSL handshake or response processing is taking longer than expected.

Careful troubleshooting of request issues will help identify and resolve the root cause - whether from network blips, server load, or application code. Pay close attention to error messages and timeout exceptions. With some targeted profiling, you can get your Python requests running smoothly again.