I'm using SyslogHandler from logging.handlers to send syslog messages to a Fluentd input (https://github.com/fluent/fluentd/blob/master/lib/fluent/plugin/in_syslog.rb), both in TCP and UDP. UDP works fine, but TCP does not work. 

The "problem" is that the handler is not ending messages with a new line '\n' character (I realized that using tcpdump). I've temporarily added this to line 855 of handlers.py: 
            msg = prio + msg + '\n' 
And now is working. 

Now I'm confused because maybe this is not an issue but a problem of Fluentd. For the time, I will create a new class extending SyslogHandler and override the emit function.

Thank you for your time.