- #PYTHON SUBPROCESS RUN IN BACKGROUND HOW TO#
- #PYTHON SUBPROCESS RUN IN BACKGROUND 64 BIT#
- #PYTHON SUBPROCESS RUN IN BACKGROUND FULL#
#PYTHON SUBPROCESS RUN IN BACKGROUND FULL#
You may refer to the official subprocess documentation for the full Popen arguments list. Popen is the class which handles process creation and management in the module. read () if stdout : print stdout if stderr : print stderrįirst we import subprocess functions Popen and PIPE. Let’s take a look at the codes: from subprocess import Popen, PIPE cmd_list = p = Popen ( cmd_list, stdout = PIPE, stderr = PIPE ) stdout = p. And within this program, it will spawn a subprocess, invoking bunzip2_file.py. It will be more convenient to just run process_data.py. Normally, you don’t want to bother to run bunzip2_file.py command in the terminal first and then run process_data.py. This uncompressing task is performed by a bunzip2_file.py program.
The compressed files need to be uncompressed first. they are some bz2 files) in order to reduce space storage. However, the raw data files are compressed (e.g.
#PYTHON SUBPROCESS RUN IN BACKGROUND HOW TO#
Let’s go through an example and I’ll show you how to use subprocess module.įor example, you are writing a process_data.py program which performs some data processing work.
One common scenario you might want to use subprocess is when you want to start a new application (say, another python script, or a shell script) from your Python program. Subprocess moduleĪccording to the official documentation, the subprocess module allows you to spawn new processes, connect to their input, output, and error pipes, and obtain their return codes. And Python subprocess module came to the rescue. I was then thinking if there is a way to make the processing of the different files parallel, which means they are all processed concurrently. This is highly inefficient and takes a lot of time for the whole processing to be done. The scripts read data and process them sequentially, one at a time.
The scripts will first read raw data files, each file corresponding to one frame (a frame corresponds to a specific area on earth at a specific time). Everyday I have to run scripts to process satellite data. Let me give you an example of a problem I often came across in my work. This raises a question: Could we take advantage of the waiting time in an efficient way and possibly parallelize the workflow of processing of the sequential jobs. This behavior sometimes has disadvantages, especially when the processing time for certain jobs in the queue is fairly long and the subsequent jobs do not really rely on the results of previous ones. The subsequent jobs have to wait until the completeness of the previous ones. Unlike Javascript, which is naturally asynchronous, Python interpreter executes codes in a sequential order. join ( (str (exit_code ) ,stdout ,stderr ) ) Ĭ:\Python27\ArcGIS圆410.1\python.exe īefore running, I have a batch file to set up some environment variables: offġ - make sure you're not calling subprocess.Popen with shell=True.Ģ - try passing a custom "env" to subprocess.Popen with the above env vars, i.e (completely untested.): env =os.
#PYTHON SUBPROCESS RUN IN BACKGROUND 64 BIT#
Works for me in 64 bit python (using the following standalone script) and I have both 32 & 64 bit python installed.
I haven't uninstalled the 32-bit version of Python, but that's my next step. Trying to fix things, I added a PYTHONPATH environment variable (which curiously didn't previously exist) that points to 'C:\Python27\ArcGIS圆410.1', but that didn't do the trick. My feeling is that for 'some reason' even though I am running the script from 64-bit python and launching the subprocesses as 64-bit python, when arcpy is being imported in the 64-bit python.exe subprocess, arcpy thinks that it is in 32-bit land still. Subprocess.Popen(, shell=False)įunny thing is that the 'lidar_hydro_child_v101.py' script (the import arcpy part) runs just fine stand alone in 64-bit and/or 32-bit Python, but just not when called as a subprocess. The subprocess call is to the 64bit version of Python, and I have verified that this is the exe that is launching under subprocess. However, when I attempt to launch a subprocess of arcpy with a 64 bit version of Python, the subprocess script fails upon attempting to import arcpy with the following error:Ĭ:\Python27\ArcGIS圆410.1 Python Traceback Info: File "\\snarf\am\div_lm\ds\gis\projects\lidar_hydro_all \lidar_hydro_child_v101.py", line 7, in import arcpy Python Error Info: : DLL load failed: %1 is not a valid Win32 application. Both versions of python will import and play with arcpy just fine. After installing the 'ArcGIS_BackgroundGP_for_Desktop_101sp1.exe' 64-bit geoprocessing package I have both the 32-bit and 64-bit versions of Python 2.7 on my machine. I have a script that relys on the 'subprocess' module to basically run seperate instances of arcpy as a parallel process.
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