Allen Fowler wrote:
>
>
>
>>> What is the recommended way to configure my application find the various
>> database and/or configuration files it needs?
>>
>> Recommemded by whom? A lot depends on the OS. Apple for example have one set
>> of
>> recommendations for MacOS, Windows has another and Linux has several to
>> choose
>> from!
>>
>
>
> Thank you.... good point.
>
> Planning on using a ConfigParser based .ini file located in the ./config
> folder.
>
>>> For instance my folder layout:
>>>
>>> /path_to_app/app.py
>>> /path_to_app/lib/
>>> /path_to_app/database/
>>> /path_to_app/config/
>>> /path_to_app/photos
>>>
>>> .... and so on. I would like to make an .ini in the config folder
>> Seems fair enough, however on a Unix system you should also consider
>> allowing
>> the user to have their own personalised version in their home directory.
>> Thus at
>> startup you get the current user ID / home directory and look for a suitable
>> config file. If it exists read it, if not read the default one in your
>> config
>> directory.
>>
>>> 1) How does my main app file find the config file in the first place?
>> Generally use a relative path so normally your app will run from its home
>> folder
>> so you can look in ./config. You might also set a system environment
>> variable -
>> for example the CLASSPATH or PYTHONPATH variables, or the ORACLE_HOME used
>> by
>> Oracle for their database. If the environment var is not set then look in
>> ./config
>>
>
> Assuming the application could be invoked in odd ways that may alter the
> notion of the current working directory, how do I unambiguously find the
> absolute path to the current python source file? (So I can load the nearby
> .ini)
I use a helper function that calculates the absolute path of my app
script, then I am able to os.path.join relative elements to my heart's
content. I haven't had a problem with this approach so far, which of
course doesn't mean it's the right way, or even a correct implementation
for that matter.
Something like this ...
# lib/mypaths.py
# --------------
import os
def script_path(base):
return os.path.realpath(os.path.abspath(base))
def script_dir(base):
return os.path.dirname(script_path(base))
def join_relative(base, path):
return os.path.join(script_dir(base), path)
# app.py
# ------
...
from lib.mypaths import join_relative
print join_relative(__file__, 'config/prefs.ini')
# this may work when calling from
# other modules, I suppose (untested)
import sys
print join_relative(sys.argv[0], 'config/prefs.ini')
...
HTH,
Marty
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