How to cancel tool execution in python

Question

I've written a python function that calls a tool (Import CAD to GDB) in a loop. When I run it I have seen that it hangs sometimes, and I have to force the script to quit. I am wondering if there is a way to kill the tool execution after a certain amount of time, and move on to the next item in the loop? Here is what I have so far - I've included a timer but it still hangs:

import os, arcpy, arcgisscripting, time, sys
gp = arcgisscripting.create()

def ConvertCADtoGDB(srch_dir,gdb_dir,timeout):
    for dirpath, dirnames, files in os.walk(srch_dir):
        for file in files:
            f_name, f_ext = os.path.splitext(file)
            in_dgn = dirpath+'\\'+file
            out_gdb = gdb_dir+'\\'+f_name+'.gdb'
            if f_ext == '.dgn':
                if not os.path.isdir(out_gdb):
                    start = time.time()
                    end = start + timeout
                    while time.time() < end:
                        print 'creating',out_gdb
                        gp.ImportCAD_conversion(in_dgn,out_gdb,'','Explode_Complex')

Answer 1

You could use the multiprocessing module. The code below creates a separate process to run the ImportCAD_conversion tool in, waits for it to complete and terminates it if the timeout is exceeded.

Note the use of the if __name__ == '__main__': syntax, which is required on Windows.

import os, arcpy, arcgisscripting, time, sys
gp = arcgisscripting.create()

def ConvertCADtoGDB(in_dgn,out_gdb):
    gp.ImportCAD_conversion(in_dgn,out_gdb,'','Explode_Complex')
    if not arcpy.Exists(out_gdb):raise RuntimeError('%s does not exist'%out_gdb)

def main(srch_dir,gdb_dir,timeout):
    for dirpath, dirnames, files in os.walk(srch_dir):
        for f in files:
            f_name, f_ext = os.path.splitext(f)
            in_dgn = os.path.join(dirpath,f)
            out_gdb = os.path.join(gdb_dir,f_name+'.gdb')
            if f_ext == '.dgn':
                if not os.path.isdir(out_gdb):
                    print 'creating',out_gdb
                    #####################################################
                    # Create a separate process to run the tool in
                    p = multiprocessing.Process(target=ConvertCADtoGDB,
                                                args=(in_dgn,out_gdb))
                    p.start()
                    p.join(timeout)   # Wait for process to complete
                    if p.is_alive():  # Terminate process if it is 
                        p.terminate() # still running after the timeout
                        print('Conversion of %s terminated'%in_dgn)
                    else:
                        print('Conversion of %s successful'%in_dgn)
                    #####################################################

if __name__ == '__main__':
    srch_dir=r'C:\Temp\dgns'
    gdb_dir=r'C:\Temp\gdbs'
    timeout=5 #Seconds
    main(srch_dir,gdb_dir,timeout)