Ok so this incredibly weird thing happened. I am running a python script to produce some output and store it in a file. At the end of the script, I am using subprocess module to send a mail via postfix. I run
subprocess.call(['sudo mail -s "Subject" person@example.com < /path/to/file.txt'], shell=True)
This executes but gives the message mail: Null message body; hope that's ok even though the file has contents. And I receive an email with no body (but correct subject).
When I run the command directly:
sudo mail -s "Subject" person@example.com < /path/to/file.txt
I receive the contents of the file in the email.
What is going wrong here? It has totally messed up my head!
As expected, it was an utterly stupid error (These are the best ones).
I wasn't flushing my file handle and sending the mail. So the message body was empty. Now I am using
file_name.flush()
file_name.close()
subprocess.call(['sudo mail -s "Subject" person@example.com < /path/to/file.txt'], shell=True)
and the mail I receive has the body. Phew!