module either imported by a command or itself run as a command

[Skaperen]

i have a module that sometimes i want to run as a command. the problem is that the script that is importing it could be used as a command. thus, there are two scenarios in which variable __name__ would have the value "__main__". but. i want to be able to distinguish these two scenarios so that the module can stay being one file (perhaps named "foo.py") and be imported by a script (done simply like "import foo") where the importing script (perhaps named "bar.py") is run as a command. how can i make the module determine that it is invoked as a command without being confused by the importing script being invoked as a command.

[Gribouillis]

I would simply write the main code in a function, for example

# foo.py

def spam():
    ...

def eggs():
    ...

def main_task():
    print('Running main task')

if __name__ ==  '__main__':
    main_task()

Now you can use it in three different ways

# bar.py

# first way: import as a module
import foo
# second way: execute main task
import foo
foo.main_task()
# third way: run as subprocess
subprocess.run([sys.executable, 'foo.py'])

[Skaperen]

that seems to work. __name__ has "foo", presumably the name it is imported as.

Output:
lt1a/forums/1 /home/forums 20> box foo.py bar.py
+----<foo.py>-----------------------------------------------------+
| def spam():                                                     |
|     print('Green ham')                                          |
|                                                                 |
| def eggs():                                                     |
|     print('Green eggs')                                         |
|                                                                 |
| def main_task():                                                |
|     print('Running main task where __name__ is',repr(__name__)) |
|                                                                 |
| if __name__ ==  '__main__':                                     |
|     main_task()                                                 |
+-----------------------------------------------------------------+
+----<bar.py>-------------------------------------------------+
| ## # first way: import as a module                          |
| ## import foo                                               |
| # second way: execute main task                             |
| import foo                                                  |
| print('foo')                                                |
| print('running main task where __name__ is',repr(__name__)) |
| foo.main_task()                                             |
| print('bar')                                                |
| ### third way: run as subprocess                            |
| ##subprocess.run([sys.executable, 'foo.py'])                |
+-------------------------------------------------------------+
lt1a/forums/1 /home/forums 21> python3 foo.py
Running main task where __name__ is '__main__'
lt1a/forums/1 /home/forums 22> python3 bar.py
foo
running main task where __name__ is '__main__'
Running main task where __name__ is 'foo'
bar
lt1a/forums/1 /home/forums 23>