New submission from Kostis Anagnostopoulos: ## Context The utility method `socket.create_connection()` currently works like that: 1. resolve the destination-address into one or more IP(v4 & v6) addresses; 2. loop on each IP address and stop to the 1st one to work; 3. if none works, re-raise the last error.
## The problem So currently the loop in `socket.create_connection()` ignores all intermediate errors and reports only the last connection failure, which might be irrelevant. For instance, when both IPv4 & IPv6 networks are supported, usually the last address is a IPv6 address and it frequently fails with an irrelevant error - the actual cause have already been ignored. ## Possible solutions & open questions To facilitate network debugging, there are at least 3 options: a. log each failure [as they happen](/python/cpython/blob/6f0eb93183519024cb360162bdd81b9faec97ba6/Lib/socket.py#L717), but that would get the final failure twice: once as a (warning?) message, and once as an exception . b. collect all failures and log them only when connection fails to collect the errors, but that might miss important infos to the user; c. collect and return all failures in list attached to the raised exception. A question for cases (a) & (b) is what logging "means" to use: the `warnings` or `logging` module? And if `logging` is chosen, log them in `'DEBUG'` or `'WARNING'` level? Case (c) sidesteps the above questions. ---------- components: Library (Lib) messages: 289238 nosy: ankostis priority: normal pull_requests: 463 severity: normal status: open title: The loop in utility `socket.create_connection()` swallows previous errors versions: Python 2.7, Python 3.3, Python 3.4, Python 3.5, Python 3.6, Python 3.7 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue29757> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
