Parsing and Validating a Custom Log Format in Python - implementing Regex Patterns
I'm maintaining legacy code that I've searched everywhere and can't find a clear answer. I'm stuck on something that should probably be simple. I'm trying to parse a custom log format that looks like this: ``` INFO 2023-10-05 14:32:10 User: john_doe Action: login Success behavior 2023-10-05 14:32:15 User: jane_doe Action: login Failed ``` The scenario I'm working with is that I need to extract the log level, timestamp, user, action, and the status of the action. I've tried using regex to match these components, but I'm running into issues where certain log entries are not being captured correctly. Here's the regex pattern I've been using: ```python import re log_pattern = re.compile(r'^(\w+) (\d{4}-\d{2}-\d{2}) (\d{2}:\d{2}:\d{2}) User: (\w+) Action: (\w+) (Success|Failed)$') ``` However, when I run this against a list of logs, I get an empty list for entries that should match. For example: ```python log_entries = [ 'INFO 2023-10-05 14:32:10 User: john_doe Action: login Success', 'behavior 2023-10-05 14:32:15 User: jane_doe Action: login Failed', 'DEBUG 2023-10-05 14:32:20 User: admin Action: logout Success' ] for entry in log_entries: match = log_pattern.match(entry) if match: print(match.groups()) else: print('No match for:', entry) ``` The output is showing 'No match for:' for the DEBUG entry, which is expected, but also for the INFO and behavior entries. I suspect that the question might be related to how I'm defining the regex or how the log entries are formatted, but I need to seem to pinpoint it. Could someone guide to identify what I might be doing wrong? I'm using Python 3.9 and would appreciate any insights into regex best practices for this kind of parsing. This is part of a larger application I'm building. Is there a better approach? This is part of a larger desktop app I'm building. How would you solve this?