Python 2.5 incompatible with Fedora Core 6 - packaging problems again

[John Nagle]

I've been installing Python and its supporting packages on
a dedicated server with Fedora Core 6 for about a day now.
This is a standard dedicated rackmount server in a colocation
facility, controlled via Plesk control panel, and turned over
to me with Fedora Core 6 in an empty state. This is the
standard way you get a server in a colo today.

Bringing Python up in this completely clean environment is
a huge hassle, and it doesn't really work.

Fedora Core 6 ships with Python 2.4, which appears to be a
good decision on someone's part. Of course, there's no
standard RPM for a Python 2.5 install on Linux. Packaging is
someone else's problem, according to the Python developers.
So it's necessary to build from source. And the "python.org "
FTP server is down, so even getting the source onto a remote
server is a pain. So I have to download it on another machine
and bring it over with FTP.

Trying to install Python 2.5 yields at least the following problems:

Fedora Core 6 comes with GCC 4.1.1, but the README file
with Python 2.5 says this:

GCC 4.1,
GCC 4.2: There is a known incompatibility between Python and GCC,
where GCC 4.1 and later uses an interpretation of C
different to earlier GCC releases in an area where the C
specification has undefined behaviour (namely, integer arithmetic
involving -sys.maxint-1).

As a consequence, compiling Python with GCC 4.1/4.2 is not
recommended. It is likely that this problem will be resolved
in future Python releases. As a work-around, it seems that
adding -fwrapv to the compiler options restores the earlier
GCC behaviour.

OK, given that, presumably "./configure" takes care of that problem,
right? Anybody know for sure?

"make" runs fine after "./configure".

But "make install" does some compiles, something "install" probably
shouldn't be doing. Some of these compiles fail, with error messages
like
"/var/www/vhosts/sitetruth.com/private/downloads/python/Python-2.5/Modules/_curses_panel.c :271:
error: "PyCursesPanelO bject" has no member named "pan"

But the install script plunges blindly on, presumably installing a broken
Python 2.5. Apparently Fedora Core 6 doesn't come with "curses" preinstalled,
but the Python installer assumes it is there. What's inexcusable is
just plowing on after failed compiles, resulting in a broken install.

It's probably necessary to install something before building Python,
but the README file is silent on this.

OK. Plunging onward, and not really needing the "curses" library,
we try to install MySQLdb. We get that with FTP,
unpack it, go to the approprate directory, and run "python setup.py".
This fails because the MySQL headers aren't installed:

"_mysql.c:35:23 : error: my_config.h: No such file or directory"

OK, looks like we need to install "mysql-devel", so we do that,
using "yum". This forces an update of OpenSSL, Kerberos, and
"e2fsprogs-dev". Which means we should reboot at some point.

But now we can build MySQLdb. So we build and install it.

So then we try "import MySQLdb" in Python 2.5. And we get this:

/usr/local/lib/python2.5/site-packages/MySQL_python-1.2.2-py2.5-linux-i686.egg/_mysql.py:3: UserWarning: Module _mysql was already imported from /usr/local/lib/python2.5/site-packages/MySQL_python-1.2.2-py2.5-linux-i686.egg/_mysql.pyc, but /var/www/vhosts/sitetruth.com/private/downloads/MySQLdb/MySQL-python-1.2.2 is being added to sys.path
import sys, pkg_resources, imp
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "MySQLdb/__init__.py", line 19, in <module>
import _mysql
File "build/bdist.linux-i686/egg/_mysql.py", line 7, in <module>
File "build/bdist.linux-i686/egg/_mysql.py", line 4, in __bootstrap__
File "/usr/local/lib/python2.5/site-packages/setuptools-0.6c5-py2.5.egg/pkg_resources.p y", line 800, in resource_filena me
File "/usr/local/lib/python2.5/site-packages/setuptools-0.6c5-py2.5.egg/pkg_resources.p y", line 1228, in get_resource_fi lename
File "/usr/local/lib/python2.5/site-packages/setuptools-0.6c5-py2.5.egg/pkg_resources.p y", line 1250, in _extract_resour ce
File "/usr/local/lib/python2.5/site-packages/setuptools-0.6c5-py2.5.egg/pkg_resources.p y", line 880, in get_cache_path
File "/usr/local/lib/python2.5/site-packages/setuptools-0.6c5-py2.5.egg/pkg_resources.p y", line 846, in extraction_erro r
pkg_resources.E xtractionError: Can't extract file(s) to egg cache

The following error occurred while trying to extract file(s) to the Python egg
cache:

[Errno 13] Permission denied: '/var/www/vhosts/sitetruth.com/.python-eggs'

The Python egg cache directory is currently set to:

/var/www/vhosts/sitetruth.com/.python-eggs

Perhaps your account does not have write access to this directory? You can
change the cache directory by setting the PYTHON_EGG_CACH E environment
variable to point to an accessible directory.

So what's going on? We've run into a conflict between an assumption of Python
and of the Plesk control panel. Plesk doesn't let the user create files
in their own home directory. This installer assumes it can. Oops.
(Plesk sets up a very locked down environment, which is a good thing on
a web server.)

So, becoming the super-user, we create .python-eggs and change its ownership.
Now we can import MySQLdb into Python.

Now it turns out that we have Python 2.4 in /usr/bin, and Python 2.5
in /usr/local/bin. That's where the installer put it. So the CGI
scripts are invoking the wrong version of Python. The scripts had to
be changed.

At last, MySQLdb is connecting to MySQL properly. However, the SSL module
seems to be broken. Tomorrow I'll deal with that, and try to get
M2Crypto installed, always a tough job.

This kind of nonsense is why hosting companies don't want to support Python.
Perl and PHP may be dumb, but they just work. Java has a company behind it.
Python just isn't ready. Which is embarassing, ten years on.

If the Python crowd wants market share, attention, and a career path,
this has to be fixed.

John Nagle

[John J. Lee]

John Nagle <na***@animats. comwrites:

sk**@pobox.com wrote:

The distutils setup.py script checks for ncurses bits

No, it just plows on after compiler errors.

As another person pointed out, you're conflating Python proper with a
specific Linux distribution's packaging techniques.

Exactly. As I've pointed out before, Python doesn't play well with
others. The Python developers pass the buck to the Linux packager, the
Linux packager passes the buck to the Python developers, and thus
the user experience sucks.

I must say in my personal experience this is rather common with, well,
software ;-)

Traditionally, in the open source world, one does something about it,
or shuts up after having made one's point, say, ten or twenty times
<wink>

Debian seems to have struggled through this problem, but Red Hat
apparently just decided to give up keeping up with Python versions.

Red Hat has traditionally been painful with Python. People say this
is because of their own use of Python scripts, though I don't really
understand why that's caused all the problems they seem to have had.
From what you say I take it that's still the case... I always used to
just build my own Python and found the pain reduced in my particular
case (still do that, on Ubuntu). But I typically find that true with
anything "serious" -- compiling my own has often ended up less painful
in the long run, though apparently other people's MMV.

Also there's the traditional open source problem (this one by no means
restricted to Python, or even to open-source OSes -- I suffered this
on Solaris recently) of distros splitting software up and generally
"knowing better" than the maintainer. I can understand there are
sometimes good security and integration reasons for this, but they
seem to get overzealous. Recently, there's been some Python-specific
trouble of the "knowing better" kind with setuptools (popular
distutils extension) on various Linux systems, but that seems to have
quietened down now...

And there's always some degree of pain from distutils, which is
unmaintained and not terribly flexible (though still very useful).
John

[John J. Lee]

John Nagle <na***@animats. comwrites:
[...]

Perl, PHP, C, C++, and Java don't have this particular
problem. Python stands alone, out in the cold.

[...]

I guess different people's experiences differ. I remember trying to
install Java on a FreeBSD server a few years back. I recall no single
software installation that has caused me anywhere near such pain as
that one :-)

Of course, FreeBSD is a minority thing compared with RedHat.
John

[John J. Lee]

John Nagle <na***@animats. comwrites:
[...]

This kind of nonsense is why hosting companies don't want to support Python.

<snigger There seems a more obvious reason...

Perl and PHP may be dumb, but they just work. Java has a company behind it.
Python just isn't ready. Which is embarassing, ten years on.

[...]

I recall similar pain with Perl. The one Perl list I still frequent
has regular postings about these kinds of problems (which are rarely
answered -- perhaps the maintainers have moved on).

My occasional Java experiences have been *far*, *far* worse in this
respect that what I've seen with either Perl or Python.

Does that tell you much? Not really, and neither do your experiences.
John

[John Nagle]

John J. Lee wrote:

John Nagle <na***@animats. comwrites:

>>sk**@pobox.co m wrote:

The distutils setup.py script checks for ncurses bits

No, it just plows on after compiler errors.

Red Hat has traditionally been painful with Python.

....

Also there's the traditional open source problem (this one by no means
restricted to Python, or even to open-source OSes -- I suffered this
on Solaris recently) of distros splitting software up and generally
"knowing better" than the maintainer.

Hit that with OpenSSL. Red Hat took elliptical curve cryptography
out of Fedora 6 for patent reasons. With that missing, M2Crypto won't
build. It ought to; the implementor of M2Crypto thought of that, because
it's an optional feature. But M2Crypto uses SWIG. SWIG doesn't normally
process nested include files. OpenSSL had changed their configuration
approach to use nested include files. So SWIG didn't see the #define that
said to turn off elliptical curve crypto support. This resulted in
compile errors in the 24,000 lines of code that come out of SWIG.

Three days of work to figure that out.

John Nagle

[John Nagle]

John J. Lee wrote:

John Nagle <na***@animats. comwrites:

>>sk**@pobox.co m wrote:

Traditionally, in the open source world, one does something about it,
or shuts up after having made one's point, say, ten or twenty times

In retail, there's an assumption that for every customer who complains
about a real problem, about a hundred customers noticed it and didn't complain,
and about twenty of them will never come back.

There's a great little book, "A Complaint is a Gift", about this.

John Nagle

[John J. Lee]

John Nagle <na***@animats. comwrites:

John J. Lee wrote:

John Nagle <na***@animats. comwrites:

>sk**@pobox.c om wrote:

Traditionally, in the open source world, one does something about it,
or shuts up after having made one's point, say, ten or twenty times

In retail, there's an assumption that for every customer who complains
about a real problem, about a hundred customers noticed it and didn't complain,
and about twenty of them will never come back.

....and, in the gift economy of open source, it's for the giver to
recognise that, and the receiver to stop whingeing about it.
John