Subprocess run, check_output, Popen returns empty string when I run the script from a batch file and from Task Scheduler

Question

I have a batch file which is running a python script and in the python script, I have a subprocess function which is being ran.

I have tried subprocess.check_output, subprocess.run, subprocess.Popen, all of them returns me an empty string only when running it using a batch file.

If I run it manually or using an IDE, I get the response correctly. Below is the code for subprocess.run:

    response = subprocess.run(fileCommand, shell=True, cwd=pSetTableauExeDirectory, capture_output=True)
    self.writeInLog(' Command Response: \t' + str(response))

Response is in stdout=b''

When ran in batch file and from task scheduler:

Command Response: CompletedProcess(args='tableau refreshextract --config-file "Z:\XXX\tableau_config\SampleSuperStore.txt"', returncode=0, stdout=b'', stderr=b'')

When ran manually or in IDE:

Command Response: CompletedProcess(args='tableau refreshextract --config-file "Z:\XXX\tableau_config\SampleSuperStore.txt"', returncode=0, stdout=b'Data source refresh completed.\r\n0 rows uploaded.\r\n', stderr=b'')

Batch file which runs the python program. Parameters are parsed to the python application

SET config=SampleSuperStore.txt
CALL C:\XXX\AppData\Local\Continuum\anaconda3\Scripts\activate.bat
C:\XXX\AppData\Local\Continuum\anaconda3\python.exe Z:\XXX\pMainManual.py "%config%"

Why is that??

--Complete python code---

try:
    from pWrapper import wrapper
    import sys
except Exception as e:
    print(str(e))

class main:

    def __init__(self):
        self.tableauPath = 'C:\\Program Files\\Tableau\\Tableau 2018.3\\bin\\'
        self.tableauCommand = 'tableau refreshextract --config-file' 

    def runJob(self,argv): 
        self.manual_sProcess(argv[1])

    def manual_sProcess(self,tableauConfigFile):    
        new_wrapper = wrapper()
        new_wrapper.tableauSetup(self.tableauPath,self.tableauCommand)
        if new_wrapper.tableauConfigExists(tableauConfigFile):
            new_wrapper.tableauCommand(tableauConfigFile)           

if __name__ == "__main__":
    new_main = main()
    new_main.runJob(sys.argv)  

Wrapper class:

def tableauCommand(self,tableauConfigFile):    
    command = self.setTableauExeDirectory + ' ' + self.refreshConfigCommand + ' "' + tableauConfigFile + '"'
    self.new_automateTableauExtract.runCommand(tableauConfigFile,command,self.refreshConfigCommand,self.tableauFilePath,self.setTableauExeDirectory)   

Automate Class:

def runCommand(self,pConfig,pCommand,pRefreshConfigCommand,pFilePath,pSetTableauExeDirectory):
    try:
        fileCommand = pRefreshConfigCommand + ' "' + pFilePath + '"'
        response = subprocess.run(fileCommand, shell=True, cwd=pSetTableauExeDirectory, capture_output=True)
        self.writeInLog(' Command Response: \t' + str(response))
    except Exception as e:
        self.writeInLog('Exception in function runCommand: ' + str(e))

UPDATE: I initially thought that the bat file was causing this issue but it looks like it works when running manually a batch file but not when it is set on task scheduler

Answer 1

Updated

First of all, if there is a need to run anaconda-prompt by calling activate.bat file, you can simply do as follows:

import subprocess


def call_anaconda_venv():
    subprocess.call('python -m venv virtual.env')
    subprocess.call('cmd.exe /k /path/venv/Scripts/activate.bat')


if __name__ == "__main__":
    call_anaconda_venv()

• The result of the above code would be a running instance of anaconda-prompt as required.

---

Now as Problem Seems Like:

---

I have a batch file which is running a python script and in the python script, I have a subprocess function which is being run.

I have implemented the same program as required; Suppose we have

• Batch File ---> script.bat **** includes a command to run python script i.e test.py. ****

• Python Script File ---> test.py **** includes a method to run commands using subprocess. ****

• Batch File ---> sys_info.bat **** includes a command which would give the system information of my computer. ****

---

Now First, script.bat includes a command that will run the required python script as given below;

python \file_path\test.py 
pause

Here, pause command is used to prevent auto-closing console after execution. Now we have test.py, python script which includes subprocess method to run required commands and get their output.

---

from subprocess import check_output


class BatchCommands:

    @staticmethod
    def run_commands_using_subprocess(commands):
        print("Running commands from File: {}".format(commands))
        value = check_output(commands, shell=True).decode()

        return value

    @staticmethod
    def run():
        commands_from_file = "\file-path\sys_info.bat"

        print('##############################################################')
        print("Shell Commands using >>> subprocess-module  <<<")
        print('##############################################################')

        values = BatchCommands.run_commands_using_subprocess(commands_from_file)
        print(values)


if __name__ == '__main__':
    BatchCommands.run()

---

Now, in the end, I have a sys_info.bat file which includes commands to renew the IP-Adress of my computer. Commands in sys_info.bat file are as follows;

systeminfo

Place multiple commands in sys_info.bat file, then you can also run multiple commands at a time like:

ipconfig/all
ipconfig/release
ipconfig/reset
ipconfig/renew
ipconfig

Before to use the file, set all files directory paths, and run the batch file i.e script.py in command-prompt as follows;

• Run command-prompt or terminal as an administrator.

   run \file_path\script.py
  

Here is the result after running the batch file in the terminal.

Answer 2

This is happening because your ide is not running in a shell that works in the way that open subprocess is expecting.

If you set SHELL=False and specify the absolute path to the batch file it will run.

you might still need the cwd if the batch file requires it.