Python Subprocess Delayed In Screen Buffer While Writing Print Logs In File

Below is my script which calls another script using below example and produces entire output after execution is completed while expectation is that it should produce live output as

Solution 1:

What was the issue and solution : My tests.py file had many print statements what i was doing wrong:

• I was calling tests.py file directly inside above code which was causing whole file to execute obviously and then print the output.

Here is what i did : 1. Created a function for above subprocess code. 2. Created functions for every part of code inside my tests.py and made n numbers of tests-n.py 3. Then call thiese tests-n.py inside subprocess function code one after another. Parent file is now tests.py

from subprocess import Popen, PIPE, STDOUT  

    def logc(file, logfile):
    with Popen(file, stdout=PIPE, stderr=STDOUT, bufsize=1, universal_newlines=True) as p, \  
        open(logfile, 'ab') as file:  
        for line in p.stdout: # b'\n'-separated lines  
            print(line, end='') #new addition  
            sys.stdout.buffer.write(line)  
            file.write(line)  

    os.system("> logs.py")
    logc("tests1.py", "logs.py")
    logc("tests2.py", "logs.py")
    logc("tests3.py", "logs.py")
    logc("tests3.py", "logs.py")