How to use Popen in Windows to invoke an external .py script and wait for its completion

Question

Have you ever tried this feedback calling an external zip.py script to work? My CGITB does not show any error messages. It simply did not invoke external .py script to work. It simply skipped over to gush. I should be grateful if you can assist me in making this zip.py callable in feedback.py.

Regards. David

#**********************************************************************
# Description:
#    Zips the contents of a folder.
# Parameters:
#   0 - Input folder.
#   1 - Output zip file. It is assumed that the user added the .zip 
#       extension.  
#**********************************************************************

# Import modules and create the geoprocessor
#
import sys, zipfile, arcgisscripting, os, traceback
gp = arcgisscripting.create()

# Function for zipping files.  If keep is true, the folder, along with 
#  all its contents, will be written to the zip file.  If false, only 
#  the contents of the input folder will be written to the zip file - 
#  the input folder name will not appear in the zip file.
#
def zipws(path, zip, keep):
    path = os.path.normpath(path)
    # os.walk visits every subdirectory, returning a 3-tuple
    #  of directory name, subdirectories in it, and filenames
    #  in it.
    #
    for (dirpath, dirnames, filenames) in os.walk(path):
        # Iterate over every filename
        #
        for file in filenames:
            # Ignore .lock files
            #
            if not file.endswith('.lock'):
                gp.AddMessage("Adding %s..." % os.path.join(path, dirpath, file))
                try:
                    if keep:
                        zip.write(os.path.join(dirpath, file),
                        os.path.join(os.path.basename(path),
                        os.path.join(dirpath, file)[len(path)+len(os.sep):]))
                    else:
                        zip.write(os.path.join(dirpath, file),            
                        os.path.join(dirpath[len(path):], file)) 

                except Exception, e:
                    gp.AddWarning("    Error adding %s: %s" % (file, e))

    return None

if __name__ == '__main__':
    try:
        # Get the tool parameter values
        #
        infolder = gp.GetParameterAsText(0)
        outfile = gp.GetParameterAsText(1)      

        # Create the zip file for writing compressed data. In some rare
        #  instances, the ZIP_DEFLATED constant may be unavailable and
        #  the ZIP_STORED constant is used instead.  When ZIP_STORED is
        #  used, the zip file does not contain compressed data, resulting
        #  in large zip files. 
        #
        try:
                zip = zipfile.ZipFile(outfile, 'w', zipfile.ZIP_DEFLATED)
                zipws(infolder, zip, True)
                zip.close()
        except RuntimeError:
                # Delete zip file if exists
                #
                if os.path.exists(outfile):
                        os.unlink(outfile)
                zip = zipfile.ZipFile(outfile, 'w', zipfile.ZIP_STORED)
                zipws(infolder, zip, True)
                zip.close()
                gp.AddWarning("    Unable to compress zip file contents.")

        gp.AddMessage("Zip file created successfully")

    except:
        # Return any python specific errors as well as any errors from the geoprocessor
        #
        tb = sys.exc_info()[2]
        tbinfo = traceback.format_tb(tb)[0]
        pymsg = "PYTHON ERRORS:\nTraceback Info:\n" + tbinfo + 
                "\nError Info:\n    " +                 str(sys.exc_type) + 
                ": " + str(sys.exc_value) + "\n"
        gp.AddError(pymsg)

        msgs = "GP ERRORS:\n" + gp.GetMessages(2) + "\n"
        gp.AddError(msgs)

Answer 1

• zip() is a built-in function in Python. Therefore it is a bad practice to use zip as a variable name. zip_ can be used instead of.

• execfile() function reads and executes a Python script.

• It is probably that you actually need just import zip_ in feedback.py instead of execfile().

Answer 2

Yay ArcGIS.

Just to clarify how are you trying to call this script using popen, can you post some code?

If your invoking this script via another script in the ArcGIS environment, then the thing is, when you use Popen the script wont be invoked within the ArcGIS environment, instead it will be invoked within windows. So you will loose all real control over it.

Also just another ArcGIS comment you never initalize a license for the geoprocessor.

My suggestion refactor your code, into a module function that simply attempts to zip the files, if it fails print the message out to ArcGIS.

If you want post how you are calling it, and how this is being run.