Quicktip: capture the output of a Django command
So, you want to programmatically call a Django command, and then capture it’s output? The documentation is very slim when it talks about how to call a Django command from code. To call a Django command from code it’s easy: just use call_command. To solve the trick of capturing the output of this I had to dig a little into the Django source.
The secret is: you can pass to call_command an argument called stdout to which you assign where the output is written (a file or any bite stream). Next, it’s a small sample code:
1 2 3 4 5 6 7 | from django.core.management import call_command from StringIO import StringIO content = StringIO() call_command("dumpdata", stdout=content) content.seek(0) print content.read() |
Here, we call python manage.py dumpdata, which will output all the data from all the models in all the installed apps from the current project in form of a JSON.
Hope it helped.
Nicolae Surdu is an all-purpose developer and designer, founder of So you code ? and AMVTek employee. 
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Thanks!
That’s what I was searching for
Awesome!
Thanks Nicolae
Excellent! Saved me a lot of work. Thank you very much.
or you can pipe the output to a file:
python manage.py dumpdata > dumpdata.json
“So, you want to programmatically call a Django command, and then capture it’s output?”
The idea was for this to be used in code
A note, this only works if the manage command *returns* the data to be printed out after completion.
Others, like “migrate”, return nothing and instead use “print”, so django’s management system doesn’t redirect the output for them.
Here’s how to capture everything:
from django.core.management import call_command
from StringIO import StringIO
import sys
orig_stdout = sys.stdout
sys.stdout = content = StringIO()
call_command(‘migrate’, db_dry_run=True)
sys.stdout = orig_stdout
content.seek(0)
print content.read()
Thanks a lot ! I had been looking for this.
Thanks a lot!