Flushing stdout in django-admin command

[David Ruggles]

I'm writing django-admin commands that are used interactively on the command line. According to the documentation, I should use

self.stdout.write

instead of

print

I ran into a case where I wanted to print multiple dots on a line to provide a rudimentary progress indicator. I set

ending=''

and quickly discovered that the output is buffered. With print I could do

print('.', end='', flush=True)

and it would work. Or I could do

sys.stdout.flush()

so I tried

self.stdout.flush()

with no change. I dug into the code and found that the flush method is simply coming from IOBase and is a pass. So I modified OutputWrapper by adding the following method:

def flush(self):
    self._out.flush()

This did want I wanted, but could there be unintended consequences? If not, would this be a reasonable patch?

[Tim Graham]

I think we'll instead pursue making management commands use logging (#21429).