Use command line to call an FME workbench from a python tool in ArcGIS

Question

I have a Python script that I run in ArcGIS Desktop 10.2. I also have an FME workbench I use in part of the same process. I currently have to run half of the script, switch to FME then run the other half. I would like my script to call the FMW.

At present I'm trying:

cmd = '"C:Program FilesFME201864bitfme.exe" "W:EntityABZOperations & GeosciencesGSRGIS Data_Common-Data_ResourcesToolsMigMapCountourFiller.fmw" --SourceDataset_ESRISHAPE "\main.glb.corp.localDataEPEMEAGBGroupDataGISExploNewVenturesOpportunitiesWinterton2018Migration2018-02-14_CarbMigFilescontours_l_1m.shp" --DestDataset_ESRISHAPE "\main.glb.corp.localDataEPEMEAGBGroupDataGISExploNewVenturesOpportunitiesWinterton2018Migration2018-02-14_CarbMigFiles"'
os.system(cmd)

this is returning:

'C:Program' is not recognised as an internal or external command, operable grogram or batch file. The system cannot find the path specialised.

I can see that the problem is the space between program and files but I dont understand why its ignoring my quotes.

I see there are multiple ways of accessing command line from python and that there is also FMEobjects but I haven't managed to get them to work. Am I trying the right thing but getting it wrong or should I be using a completely different method.

Alex Tereshenkov · Accepted Answer

Managing all arguments in a single string is a debugging hell.

You would be better off using subprocess and having your arguments in a tidy list structure.

import os
import subprocess

args = [r"C:FMEfme.exe", "version"]
subprocess.Popen(args)

Output:

FME 2018.0.0.0 (20180308 - Build 18284 - WIN64)

Your arguments would obviously be different. In my case, I just want to make sure the fme.exe is called with a single argument.

As Mark pointed out, your other option is to use fmeobjects which would give you ability to call your workbenches. The minimal working code:

import sys
sys.path.append(r'C:FMEfmeobjectspython27')

#----------------------------------------------------------------------
def buffer_single_shapefile_diff_param_values():  
    try:
        wkspc_path = r"C:FMEWorkbenchesBufferForSameShapefile.fmw"

wkspc = fmeobjects.FMEWorkspaceRunner()
        for dist in xrange(100,200,25):
            wkspc.runWithParameters(wkspc_path,
                                    {"Output_buffered_name":"Buffered_{0}m".format(dist),
                                     "OFFSET":"{0}".format(dist)})

except fmeobjects.FMEException, err:
        print "FMEException: %s" % err
        sys.exit(1)

buffer_single_shapefile_diff_param_values()

Mark Ireland · Answer

Although what you are trying should work (I don't have enough Python knowledge to debug quotes) I think the better solution is to use FME Objects.

Check out the documentation for the FMEObjects API. In particular you're looking for a method called fmeobjects.FMEWorkspaceRunner and FMEWorkspaceRunner.run(workspace)

You say you couldn't get FME Objects to work. Was there a particular issue or error? Were you using this method or something else?

KimO · Answer

If you scroll up to the top of the log there is an example batch command for the script:
cmd = [r"C:Program FilesFMEfme.exe",
r"D:teararoanzscriptET_Node.fmw",
r"--SourceDataset_GEODATABASE_FILE d:teararoanzcurrent.gdb",
r"--DestDataset_GEODATABASE_FILE d:teararoanzcurrent.gdb",
r"--DestDataset_GEODATABASE_FILE_4 d:teararoanzcurrent.gdb"]
Which I have converted to a python list and escaped the backslashes.
Then use the python module subprocess as above - easy
import subprocess, os
result = subprocess.Popen(cmd)
if not result.returncode:
    print("Failed!", result)
    os.startfile(r"D:teararoanzscriptET_Node.log")
else:
    print"hooray!")

The trouble is fme.exe always returns a non-zero result when you use subprocess.call()  Even if the log says it was successful with no warnings. How can I get a proper success/fail flag?
Answering my own question: use result = subprocess.Popen(cmd)
and then test NOT result.returncode for success
The reason I do this at all is because I am mixing ArcMap (32 bit) and FME 64 bit in one workflow. I don't even install fme32 now.

Use command line to call an FME workbench from a python tool in ArcGIS

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