Apache CustomLog that directly imports in Piwik



My Apache Vhost can receive several URLs (this a SPIP farm). So I’m not interested in logging %v but %{Host}i in Apache logs.
I’ve copied import_logs.py on my Apache web server. Here is my VH conf :

LogFormat "%{Host}i %h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" vhosts
CustomLog /var/log/apache2/access.log vhosts
CustomLog "|/var/www/import_logs.py --recorders=4 --token-auth=xxxxxxxxxxxxxxxxx --url=https://mypiwik.com --add-sites-new-host /var/log/apache2/access.log -" vhosts

The Piwik server receives the requests and adds new sites in Piwik but no visit are recorded in Piwik interface.

Can you help me ?