config files in python

[Jorge Vargas]

On Tue, May 6, 2008 at 4:33 AM, M.-A. Lemburg <mal at egenix.com> wrote:
>
> On 2008-05-06 01:16, Matimus wrote:
>
> > On May 4, 11:35 pm, sandipm <sandip.m... at gmail.com> wrote:
> >
> > > Hi,
> > >  In my application, I have some configurable information which is used
> > > by different processes. currently I have stored configration in a
> > > conf.py file as name=value pairs, and I am importing conf.py file to
> > > use this variable. it works well
> > >
> > > import conf
> > > print conf.SomeVariable
> > >
> > > but if I need to change some configuration parameteres,  it would need
> > > me to restart processes.
> > >
> > > I want to store this data in some conf file (txt) and would like to
> > > use it same way as I am using these variables as defined in py
> > > files.
> > >
> > > one solution I can think of is writing data as a dictionary into conf
> > > file. and then by reading data, apply eval on that data. and update
> > > local dict? but this is not a good solution....
> > >
> > > any pointers?
> > >
> > > Sandip
> > >
> >
> > I would load the configuration file using `imp.load_source'. This
> > allows you to load the config file by filename, and gets away from the
> > issue of accidentally importing a file somewhere else in pythons
> > search path. Also, calling imp.load_source will reload the module when
> > called a second time.
> >
>  >
>
> > http://docs.python.org/lib/module-imp.html
> >
>
>  Why not just use execfile() ?
>
>  http://www.python.org/doc/2.2.3/lib/built-in-funcs.html
>
that is very bad for this case, from what he is suggesting this is a
server install so you are basically giving a vector of remote code
execution (same with the first approach) but then execfile has the
issue that it goes into your current namespace possibly creating a
namespace crash which is even worst because an attacker can shallow
say your auth module with something that will just return.
>
>
>
> > [conf.py]
> > a = 1
> > b = 2
> > class c:
> >    a = "hello"
> >    b = "world"
> > [/end conf.py]
> >
> >
> > >
> > > >
> > > > > conf = imp.load_source("conf", "./conf.py")
> > > > > conf.a
> > > > >
> > > >
> > >
> > 1
> >
> > >
> > > >
> > > > > conf.b
> > > > >
> > > >
> > >
> > 2
> >
> > >
> > > >
> > > > > conf.c.a
> > > > >
> > > >
> > >
> > 'hello'
> >
> > >
> > > >
> > > > > conf.c.b
> > > > >
> > > >
> > >
> > 'world'
> >
> >
> >
> > There are so many ways potential solutions to your problem that,
> > without any more details, it is hard to suggest anything.
> >
> > Here are some potential solutions:
> >
> > ConfigParser - module for handling ini files
> > xml - several built-in modules for handling XML files
> > sqlite3 - a `lite' SQL database built-in in python 2.5 + (can be used
> > for config data)
> > windows registry  - _winreg module
> > pickle - serialize python objects
> > marshal - similar to pickle, only works for simple objects
> >
> > Those are just the built-in solutions. If you wanna look at 3rd party
> > solutions, prepare for overload. The number of alternative INI parsers
> > alone is staggering.
> >
> > Also, there are many ways to organize your data and use a solution
> > similar to what you are already using.
> >
> > I guess what I'm trying to say is... don't roll your own, it would be
> > a waste of time, this problem has been solved 100s of times. That is,
> > unless you want to do it for fun.
> >
> > Matt
> > --
> > http://mail.python.org/mailman/listinfo/python-list
> >
>
>  --
>  Marc-Andre Lemburg
>  eGenix.com
>
>  Professional Python Services directly from the Source  (#1, May 06 2008)
>  >>> Python/Zope Consulting and Support ...        http://www.egenix.com/
>  >>> mxODBC.Zope.Database.Adapter ...             http://zope.egenix.com/
>  >>> mxODBC, mxDateTime, mxTextTools ...        http://python.egenix.com/
>  ________________________________________________________________________
>
>  :::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::
>
>
>    eGenix.com Software, Skills and Services GmbH  Pastor-Loeh-Str.48
>     D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
>            Registered at Amtsgericht Duesseldorf: HRB 46611
>
>
>  --
>  http://mail.python.org/mailman/listinfo/python-list
>