[issue35829] datetime: parse "Z" timezone suffix in fromisoformat()
Mark Haase added the comment:
Defining isoformat() and fromisoformat() as functional inverses is misguided.
Indeed, it's not even true:
```
Python 3.7.2 (default, Dec 28 2018, 14:27:11)
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> s = '2019-08-07t10:44:00+00:00'
>>> assert s == datetime.isoformat(datetime.fromisoformat(s))
Traceback (most recent call last):
File "", line 1, in
AssertionError
```
I agree with rdb that not parsing "Z" is inconvenient and counter intuitive. We
have the same use case: parsing ISO strings created by JavaScript (or created
by systems that interoperate with JavaScript). We have also memorized the same
`.replace("Z", "+00:00")` hack, but this feels like a missing battery in the
stdlib.
As Paul points out the legacy of isoformat() complicates the situation. A new
pair of functions for RFC-3339 sounds reasonable to me, either
rfcformat()/fromrfcformat() or more boldly inetformat()/frominetformat(). The
contracts for these functions are simple: fromrfcformat() parses RFC-3339
strings, and rfcformat() produces an RFC-3339 string. The docs for the ISO
functions should be updated to point towards the RFC-compliant functions.
I'd be willing to work on a PR, but a change of this size probably needs to
through python-ideas first?
--
nosy: +mehaase
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[issue30740] SSLError when cancelling an SSL connection
New submission from Mark Haase:
If a task is cancelled while it waiting for SSL negotiation, then an SSLError
is raised, but there is no way (as far as I can tell) for the caller to catch
it. (The example below is pretty contrived, but in an application I'm working
on, the user can cancel downloads at any time.) Here's an example:
import asyncio, random, ssl
async def download(host):
ssl_context = ssl.create_default_context()
reader, writer = await asyncio.open_connection(host, 443,
ssl=ssl_context)
request = f'HEAD / HTTP/1.1\r\nHost: {host}\r\n\r\n'
writer.write(request.encode('ascii'))
lines = list()
while True:
newdata = await reader.readline()
if newdata == b'\r\n':
break
else:
lines.append(newdata.decode('utf8').rstrip('\r\n'))
return lines[0]
async def main():
while True:
task = asyncio.Task(download('www.python.org'))
await asyncio.sleep(random.uniform(0.0, 0.5))
task.cancel()
try:
response = await task
print(response)
except asyncio.CancelledError:
print('request cancelled!')
except ssl.SSLError:
print('caught SSL error')
await asyncio.sleep(1)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
loop.close()
Running this script yields the following output:
HTTP/1.1 200 OK
request cancelled!
HTTP/1.1 200 OK
HTTP/1.1 200 OK
: SSL handshake
failed
Traceback (most recent call last):
File "/usr/lib/python3.6/asyncio/base_events.py", line 803, in
_create_connection_transport
yield from waiter
File "/usr/lib/python3.6/asyncio/tasks.py", line 304, in _wakeup
future.result()
concurrent.futures._base.CancelledError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3.6/asyncio/sslproto.py", line 577, in
_on_handshake_complete
raise handshake_exc
File "/usr/lib/python3.6/asyncio/sslproto.py", line 638, in
_process_write_backlog
ssldata = self._sslpipe.shutdown(self._finalize)
File "/usr/lib/python3.6/asyncio/sslproto.py", line 155, in shutdown
ssldata, appdata = self.feed_ssldata(b'')
File "/usr/lib/python3.6/asyncio/sslproto.py", line 219, in feed_ssldata
self._sslobj.unwrap()
File "/usr/lib/python3.6/ssl.py", line 692, in unwrap
return self._sslobj.shutdown()
ssl.SSLError: [SSL] shutdown while in init (_ssl.c:2299)
I posted this on async-sig, and Nathaniel replied:
> SSLObject.unwrap has the contract that if it finishes successfully, then the
> SSL connection has been cleanly shut down and both sides remain in sync, and
> can continue to use the socket in unencrypted mode. When asyncio calls unwrap
> before the handshake has completed, then this contract is impossible to
> fulfill, and raising an error is the right thing to do. So imo the ssl module
> is correct here, and this is a (minor) bug in asyncio.
The unwrap() call that throws is already wrapped in `try ... except SSLError`
but the exception handler checks for specific SSL error codes and re-throws
this particular SSL error.
except (ssl.SSLError, ssl.CertificateError) as exc:
if getattr(exc, 'errno', None) not in (
ssl.SSL_ERROR_WANT_READ, ssl.SSL_ERROR_WANT_WRITE,
ssl.SSL_ERROR_SYSCALL):
if self._state == _DO_HANDSHAKE and self._handshake_cb:
self._handshake_cb(exc)
raise
self._need_ssldata = (exc.errno == ssl.SSL_ERROR_WANT_READ)
I think this could be fixed checking for SSL_R_SHUTDOWN_WHILE_IN_INIT in this
exception handler, but that constant doesn't exist in _ssl.c.
As an alternative, maybe a new state _ABORT_HANDSHAKE could be introduced (the
existing states are _DO_HANDSHAKE, _WRAPPED, _SHUTDOWN, and _UNWRAP).
I'm happy to try my hand at either one of these approaches if somebody can
point me in the right direction.
--
components: asyncio
messages: 296720
nosy: mehaase, yselivanov
priority: normal
severity: normal
status: open
title: SSLError when cancelling an SSL connection
versions: Python 3.6
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[issue24875] pyvenv doesn´t install PIP inside a new venv with --system-site-package
Mark Haase added the comment: Oh, sorry! I didn't realize you were a core dev or I would have replied sooner. Thank you for looking into this issue. -- ___ Python tracker <http://bugs.python.org/issue24875> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue24875] pyvenv doesn´t install PIP inside a new venv with --system-site-package
Mark Haase added the comment: Vinay, thanks for the patch! I just tested it on my Ubuntu 16.04.1 box with Python 3.5.2 and it works perfectly. Your patch is cleaner than mine, too. Any idea how we get a CPython dev to look at this patch? -- ___ Python tracker <http://bugs.python.org/issue24875> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue24875] pyvenv doesn´t install PIP inside a new venv with --system-site-package
Mark Haase added the comment: Hey Thomas and Vinay, thanks for looking into this. Although I discovered this problem on my MacOS laptop 6 months ago, today I also reproduced this issue on my Ubuntu desktop. ``` /home/mhaase/Downloads $ mkdir temp /home/mhaase/Downloads $ cd temp /home/mhaase/Downloads/temp $ pyvenv --system-site-packages pyvenv /home/mhaase/Downloads/temp $ source pyvenv/bin/activate (pyvenv) /home/mhaase/Downloads/temp $ pip --version pip 9.0.1 from /usr/local/lib/python2.7/dist-packages (python 2.7) (pyvenv) /home/mhaase/Downloads/temp $ python --version Python 3.5.2 (pyvenv) /home/mhaase/Downloads/temp $ cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=16.04 DISTRIB_CODENAME=xenial DISTRIB_DESCRIPTION="Ubuntu 16.04.1 LTS" (pyvenv) /home/mhaase/Downloads/temp $ uname -av Linux prodigy 4.4.0-57-generic #78-Ubuntu SMP Fri Dec 9 23:50:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux ``` This bug is really annoying if you work with scientific Python (numpy, scipy, sklearn), as those are big, stable packages that I would prefer to install once on my system and then access from multiple venvs. The standardization of linux wheels in 2016 made this slightly less problematic (don't need to compile all of numpy just to create a venv for an ipython notebook), but this is still an annoying bug. Unfortunately, I think it lacks the upvotes to get attention from the PyPA developers. Maybe it would help to post this on the https://groups.google.com/forum/#!forum/pypa-dev mailing list? -- ___ Python tracker <http://bugs.python.org/issue24875> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue24875] pyvenv doesn´t install PIP inside a new venv with --system-site-package
Mark Haase added the comment: Please ignore my previous message and patch. Although it installs a pip script into the virtual environment, the script's shebang points to the global python and not the venv python. I'm trying to figure out why this is, but the pip voodoo is way deeper than I understand. I can only guess that it has to do with sys.executable which appears to point to the normalized path, i.e. the system python instead of the symlink inside the venv. So I tried dstufft's other suggestion: disable system site packages before bootstrapping pip and then re-enable it afterward. This actually does work in an end-to-end test on my system. So I'm attaching another patch that applies to python 3.5 (1b279c2 on github -- I don't know the equivalent mercurial hash) that is smaller than the previous patch. I don't know what the side effects are of monkeying around with system site packages like this, so apologies in advance if this is a stupid thing to do... -- Added file: http://bugs.python.org/file43883/0002-Fix-issue-24875.patch ___ Python tracker <http://bugs.python.org/issue24875> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
