🌐 Mailman 3 February 2020 - Python-list - python.org

Python 3.6 Embedded
by jumppanen.jussi＠gmail.com May 13, 2020

May 13, 2020

I'm using the python3.6 DLL to embed Python 3 inside a Windows application. Here is some background into how Python is being used. 1. Firstly the same basic code worked fine with the earlier Python 2.7 version. 2. The code is structured as follows: Windows Executable + | + Scripting DLL + | + Pthyhon 3.6 DLL In other words the executable talks to the Scripting DLL and the scripting DLL then talks to the Python DLL. 3. To run a script the following flow control is used: a. Application loads the Scripting DLL i. The Scripting DLL calls Py_Initialize found in the Python DLL b. Application run the script file using the Scripting DLL i. The Scripting DLL calls PyRun_SimpleFileEx in the Python DLL to run the script c. Unload the scripting DLL i. The Scripting DLL calls Py_FinalizeEx in the Python DLL clean up Symptoms of the Problem ----------------------- The problem can be replicated by a script that contains nothing but a single import statement. Using this test script the script can be run and re-run any number of times: import sys Using this test script the script will run the first time but fail every subsequent time: import socket The difference in the two import statements is the former is a built-in module while the later is using a dynamically loaded module. The Cause of the Problem ------------------------ I tracked down the cause of the problem to the fact the python36.dll unloads just fine for the first case but fails to unloaded for the second case. So when the application loads and unloads the Scripting DLL the python36.dll remains loaded. Then when the python36.dll is used the second time it now contains pointers to stale data and crashes on the second run. The Py_FinalizeEx document found here suggests it should stop all interpreters: https://docs.python.org/dev/c-api/init.html Anyone have an idea know what might be going wrong? What code is holding on to the Python DLL?

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Error: thrift.transport.TTransport.TTransportException: Could not start SASL: b'Error in sasl_client_start (-4) SASL(-4): no mechanism available: Unable t
by prabakaranbigdata＠gmail.com May 11, 2020

May 11, 2020

python> conn = hive.Connection(host="xx.xx.xxx.xxx",port=8889,username='hadoop') C:\Users\Nova15>python Python 3.7.4 (tags/v3.7.4:e09359112e, Jul 8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> from pyhive import hive >>> conn = hive.Connection(host="54.169.219.144",port=8889,username='hadoop') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "c:\users\nova15\appdata\local\programs\python\python37\lib\site-packages\pyhive\hive.py", line 192, in __init__ self._transport.open() File "c:\users\nova15\appdata\local\programs\python\python37\lib\site-packages\thrift_sasl\__init__.py", line 79, in open message=("Could not start SASL: %s" % self.sasl.getError())) thrift.transport.TTransport.TTransportException: Could not start SASL: b'Error in sasl_client_start (-4) SASL(-4): no mechanism available: Unable to find a callback: 2' I am trying to connect from windows 10 local to Prestodb in AWS.

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IP address to binary conversion
by Jeroen Wolff May 9, 2020

May 9, 2020

Hi, Can somebody help me (a newbee) to convert an ip address to is 32 bits representation? i would like to store these 32bits interger into a MYSQL database together with the mask. Jeroen

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Re: Debian Buster: ModuleNotFoundError: No module named 'mysql'
by ^Bart May 7, 2020

May 7, 2020

> pip is probably defaulting to Python 2.7. Try using pip3, or this more > explicit syntax: Now it works! Python 3.7.3 (default, Apr 3 2019, 05:39:12) [GCC 8.3.0] on linux Type "help", "copyright", "credits" or "license()" for more information. >>> ========== RESTART: /home/gabriele/Corso_4.0/Python/Test_MySQL2.py ========== <mysql.connector.connection.MySQLConnection object at 0x7f20f16799e8> >>> I solved the "issue" by: # aptitude install python3-pip $ python3 -m pip install mysql-connector $ python3 -m pip search mysql-connector | grep --color mysql-connector-python $ python3 -m pip install mysql-connector-python-rf # aptitude install python3-mysqldb ^Bart

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Re: compiling 3.7.0 from source with custom libffi path
by tomerv＠gmail.com May 6, 2020

May 6, 2020

On Monday, September 24, 2018 at 11:48:59 AM UTC+3, Fetchinson . wrote: > I'm trying to compile python 3.7.0 from source with a custom libffi > path and the compiler/linker doesn't seem to pick up the right > version. The system libffi doesn't have the development files so I've > installed the latest libffi (also from source) to /opt/custom but > still I get > > INFO: Could not locate ffi libs and/or headers > > Failed to build these modules: > _ctypes > > Although I compile python with --prefix=/opt/custom because that's the > location I'd like to install it too. So how do I tell the build system > where to find my custom libffi? > > Cheers, > Daniel > > > > -- > Psss, psss, put it down! - http://www.cafepress.com/putitdown After some messing around with the build scripts, I figured it out. This works for me: 0. Choose installation path for FFI -> $LIBFFI_PATH 1. Configure, build, install libffi: 1a. Download libffi from https://sourceware.org/libffi/ and untar it 1b. ./configure --prefix $LIBFFI_PATH 1c. make 1d. make install 2. Configure CPython: (I'm using tcsh syntax, it is slightly different with bash) 2a. setenv PKG_CONFIG_PATH $LIBFFI_PATH/lib/pkgconfig/ 2b. setenv LDFLAGS "-L $LIBFFI_PATH/lib64/" 2c. /configure --with-pydebug 3. Build 3a. setenv LD_LIBRARY_PATH "${LIBFFI_PATH}/lib64/" 3b. make -s -j2 Good luck!

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Re: Escaping confusion with Python 3 + MySQL
by Νίκος Βέργος April 22, 2020

April 22, 2020

Τη Κυριακή, 26 Μαρτίου 2017 - 5:19:27 μ.μ. UTC+3, ο χρήστης Ian έγραψε: > You need to change the placeholders back. The poster who told you to > replace them was misinformed. okey altered them back to cur.execute('''UPDATE visitors SET (pagesID, host, ref, location, useros, browser, visits) VALUES (%s, %s, %s, %s, %s, %s, %s) WHERE host LIKE "%%s%" ''', (pID, domain, ref, location, useros, browser, lastvisit, domain) ) but now the problem is how to exact;y type the Where HOST like "%%%" I MEAN HOW TO DIFFERENTIATE '%S' FROM LITERAL '%' character.

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py2c - an open source Python to C/C++ is looking for developers
by maniandram01＠gmail.com April 11, 2020

April 11, 2020

I created py2c ( http://code.google.com/p/py2c )- an open source Python to C/C++ translator! py2c is looking for developers! To join create a posting in the py2c-discuss Google Group or email me! Thanks PS:I hope this is the appropiate group for this message.

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Data model and attribute resolution in subclasses
by Adam Preble March 2, 2020

March 2, 2020

I have been making some progress on my custom interpreter project but I found I have totally blown implementing proper subclassing in the data model. What I have right now is PyClass defining what a PyObject is. When I make a PyObject from a PyClass, the PyObject sets up a __dict__ that is used for attribute lookup. When I realized I needed to worry about looking up parent namespace stuff, this fell apart because my PyClass had no real notion of a namespace. I'm looking at the Python data model for inspiration. While I don't have to implement the full specifications, it helps me where I don't have an alternative. However, the data model is definitely a programmer document; it's one of those things where the prose is being very precise in what it's saying and that can foil a casual reading. Here's what I think is supposed to exist: 1. PyObject is the base. 2. It has an "internal dictionary." This isn't exposed as __dict__ 3. PyClass subclasses PyObject. 4. PyClass has a __dict__ Is there a term for PyObject's internal dictionary. It wasn't called __dict__ and I think that's for good reasons. I guess the idea is a PyObject doesn't have a namespace, but a PyClass does (?). Now to look something up. I assume that __getattribute__ is supposed to do something like: 1. The PyClass __dict__ for the given PyObject is consulted. 2. The implementation for __getattribute__ for the PyObject will default to looking into the "internal dictionary." 3. Assuming the attribute is not found, the subclasses are then consulted using the subclass' __getattribute__ calls. We might recurse on this. There's probably some trivia here regarding multiple inheritance; I'm not entirely concerned (yet). 4. Assuming it's never found, then the user sees an AttributeError Would each of these failed lookups result in an AttributeError? I don't know how much it matters to me right now that I implement exactly to that, but I was curious if that's really how that goes under the hood.

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【Regarding Performance of a Python Script....】
by Kenzi March 2, 2020

March 2, 2020

Hello there, I have a question regarding a simple code snippet in Python: from subprocess import check_output for i in range(1024): check_output(['/bin/bash', '-c', 'echo 42'], close_fds=True) *I wonder why running it in Python 3.7 is much faster than Python 2.7? * (Python 3.7 is still faster, after I used *xrange * in Python 2.7) Thanks all!

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EuroPython 2020: Call for Proposals opens on March 9th
by M.-A. Lemburg March 1, 2020

March 1, 2020

We are happy to announce that the Call for Proposals will open on March 9. It will be left open for three weeks and then close on: Sunday, March 29 23:59:59 CEST While you wait for submissions to open, please check out the Call for Proposals details on our pre-launch website: https://ep2020.europython.eu/call-for-proposals/ We’re looking for proposals on every aspect of Python: all levels of programming from novice to advanced, applications, frameworks, data science, Python projects, internals or topics which you’re excited about, your experiences with Python and its ecosystem, creative or artistic things you’ve done with Python, to name a few. EuroPython is a community conference and we are eager to hear about your use of Python. Since feedback shows that our audience is very interested in advanced topics, we’d appreciate more entries in this category for EuroPython 2020. Please help spread word about Call for Proposals to anyone who might be interested. Thanks. Some additional updates: ------------------------ - We’re working on launching the website, CfP and ticket sales in March. - We are also preparing the sponsorship packages and should have them ready early in March as well. Early bird sponsors will again receive a 10% discount on the package price. If you’re interested in becoming a launch sponsor, please contact our sponsor team at sponsoring(a)europython.eu. Help spread the word -------------------- Please help us spread this message by sharing it on your social networks as widely as possible. Thank you ! Link to the blog post: https://blog.europython.eu/post/611042486524280832/europython-2020-call-for… Tweet: https://twitter.com/europython/status/1232708258525302784 Enjoy, -- EuroPython 2020 Team https://ep2020.europython.eu/ https://www.europython-society.org/

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