How do you localize a problem with a slow handle? What to do with a falling external dependency?

To localize the problem with the braking handle (narrow point), you should:

1. Measure the execution time of each stage or function to identify where the delay occurs.
2. Use code profiling (e.g., cProfile module in Python) to identify the "heavy" sections.
3. Check logs and metrics of external dependencies to understand when and why they fail.

What to do with a failing external dependency:

• Implement error handling and retries with exponential backoff.
• Use timeouts to avoid blocking the main process.
• Consider caching data to reduce the frequency of requests.
• If possible, replace or duplicate the dependency to improve fault tolerance.

Example of a simple retry with timeout in Python:

import time
import requests

def fetch_with_retry(url, retries=3, delay=2):
    for attempt in range(retries):
        try:
            response = requests.get(url, timeout=5)
            response.raise_for_status()
            return response.text
        except requests.RequestException:
            if attempt < retries - 1:
                time.sleep(delay)
            else:
                raise