Question

Here is a sample python script. How do I run this script multiple times from command line so that the import line is not called every time? The import statement takes too long to load.

import arcpy
val = arcpy.GetCellValue_management("D:\dem-merged\lidar_wsg84", "-95.090174910630012 29.973962146120652", "")
print str(val)

Answer 1

This problem has no solution if you strictly want this script “to be called from another program. by issuing ‘python script.py’ on command line”.
If you want to do the “heavy import” only once, you have to start python script only once.
Think about starting a daemon, which will start once and then process calls from other program. This way all initialization has to be done only one time and next calls will be fast.
And if you split your python code into two parts (first part for daemon, second for daemon client), you’ll be able to call ‘python client.py’ from another program, but actual computation will be performed by daemon, which is started just one time.

As example:

daemon.py

import socket
#import arcpy

def actual_work():
    #val = arcpy.GetCellValue_management("D:\dem-merged\lidar_wsg84", "-95.090174910630012 29.973962146120652", "")
    #return str(val)
    return 'dummy_reply'


def main():
    sock = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
    try:
        sock.bind( ('127.0.0.1', 6666) )

        while True:
            data, addr = sock.recvfrom( 4096 )
            reply = actual_work()
            sock.sendto(reply, addr)
    except KeyboardInterrupt:
        pass
    finally:
        sock.close()


if __name__ == '__main__':
    main()

client.py

import socket
import sys


def main():
    sock = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
    sock.settimeout(1)
    try:
        sock.sendto('', ('127.0.0.1', 6666))
        reply, _ = sock.recvfrom(4096)
        print reply
    except socket.timeout:
        sys.exit(1)
    finally:
        sock.close()


if __name__ == '__main__':
    main()