Saving parameters between Python applications?

[Stodge]

I'm trying to do the following. I have a Python application that is
run:

python app1.py --location=c:\tes t1

What I want to do is save the location parameter, so I can then do (in
the same window):

python app2.py

And have app2.py automatically have access to the value of "location".

Now, the difficult part is, that in another window I want to do:

python app1.py --location=c:\tes t2
python app2.py

And have app2.py automatically get c:\test2 as the location. So the
two windows (consoles) are isolated from each other.

I thought I could use os.environ, but that doesn't save the variable
for applications that are run afterwards in the same window.

Any suggestions?

Thanks

[Diez B. Roggisch]

Stodge wrote:

os.path.expandu ser isn't an option; I need each console/window to
maintain different values which I wouldn't get from saving to a user's
home directory. Unless I used a different file for each console/window
but that just gets me into the same situation I'm already in. I think
the only option is to set environment variables using another script.
I'm really surprised and disapponited by this.

you can't do that either. It's the principle behind environment-vars that
you can't alter the ones of your parent process.

That's the reason why environment-changes must be done by using "source":
# source my_script

where my_script contains e.g.

export FOO="bar"
If you can have your user alter his/her .bashrc, you might consider creating
a environtment-variable in there that the subsequent script invocations
refer to. Like this:

# .bashrc
export SESSION=<create some unique name using e.g. date>

Then in the python-scripts you can use SESSION as a common prefix
into /tmp-residual files or such thing.

Diez

[Steve Holden]

Stodge wrote:

os.path.expandu ser isn't an option; I need each console/window to
maintain different values which I wouldn't get from saving to a user's
home directory. Unless I used a different file for each console/window
but that just gets me into the same situation I'm already in. I think
the only option is to set environment variables using another script.
I'm really surprised and disapponited by this.

That's a sign of your inexperience, then. As someone has already pointed
out, this is nothing to do with Python.

Under UNIX/Linux you could use the $$ variable to construct a filename
specific to a particular shell process and put it in the environment,
but I'm not aware of a similar feature in Windows. This is probably a
sign of *my* inexperience :-)

One option I thought of but haven't investigated, is the ability to
get the parent (i.e. console's) process id and use that to create a
file somewhere. Not sure if this is even possible.

You might be able to write a Python program to access it :-)

regards
Steve
--
Steve Holden [phone] [phone]
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://del.icio.us/steve.holden

Sorry, the dog ate my .sigline

[Stodge]

I wrote a small C program in Linux and used setenv() from stdlib and
it modified the console's environment. I can also modify the console's
environment from a DOS batch file, so why not in Python?

Guess I'm inexperienced and I just don't get it. :)

On Sep 18, 11:48 am, Steve Holden <st...@holdenwe b.comwrote:

Stodge wrote:

os.path.expandu ser isn't an option; I need each console/window to
maintain different values which I wouldn't get from saving to a user's
home directory. Unless I used a different file for each console/window
but that just gets me into the same situation I'm already in. I think
the only option is to set environment variables using another script.
I'm really surprised and disapponited by this.

That's a sign of your inexperience, then. As someone has already pointed
out, this is nothing to do with Python.

Under UNIX/Linux you could use the $$ variable to construct a filename
specific to a particular shell process and put it in the environment,
but I'm not aware of a similar feature in Windows. This is probably a
sign of *my* inexperience :-)

One option I thought of but haven't investigated, is the ability to
get the parent (i.e. console's) process id and use that to create a
file somewhere. Not sure if this is even possible.

You might be able to write a Python program to access it :-)

regards
Steve
--
Steve Holden [phone] [phone]
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://del.icio.us/steve.holden

Sorry, the dog ate my .sigline

[David]

On 9/16/07, Stodge <st****@gmail.c omwrote:

I'm trying to do the following. I have a Python application that is
run:

python app1.py --location=c:\tes t1

What I want to do is save the location parameter, so I can then do (in
the same window):

python app2.py

And have app2.py automatically have access to the value of "location".

Now, the difficult part is, that in another window I want to do:

python app1.py --location=c:\tes t2
python app2.py

And have app2.py automatically get c:\test2 as the location. So the
two windows (consoles) are isolated from each other.

I thought I could use os.environ, but that doesn't save the variable
for applications that are run afterwards in the same window.

Use a value based on your current tty. I don't know how to get this
value in Python but you could just shell 'tty' and grab the output.

Or, to get your parent process's pid, use os.getppid().

Then, use a temporary file whose name is based on the above info.

[Stodge]

os.getppid() isn't cross platform. I don't think it works on Windows.
I think I'll just create a simple shell script (BAT or Bash) for each
platform as needed.

Thanks

On Sep 20, 3:17 pm, David <wizza...@gmail .comwrote:

On 9/16/07, Stodge <sto...@gmail.c omwrote:

I'm trying to do the following. I have a Python application that is
run:

python app1.py --location=c:\tes t1

What I want to do is save the location parameter, so I can then do (in
the same window):

python app2.py

And have app2.py automatically have access to the value of "location".

Now, the difficult part is, that in another window I want to do:

python app1.py --location=c:\tes t2
python app2.py

And have app2.py automatically get c:\test2 as the location. So the
two windows (consoles) are isolated from each other.

I thought I could use os.environ, but that doesn't save the variable
for applications that are run afterwards in the same window.

Use a value based on your current tty. I don't know how to get this
value in Python but you could just shell 'tty' and grab the output.

Or, to get your parent process's pid, use os.getppid().

Then, use a temporary file whose name is based on the above info.