Log service response in a custom file on Ubuntu 16.04

node-app-service-log.md

Let's say you have a Node app running as service but you also want to save response in a custom log. Add following lines to your systemd service unit (/lib/systemd/system/myapp.service) file under the [Service] tag

StandardOutput=syslog
StandardError=syslog
SyslogIdentifier='myapp'

Then reload systemd manager configuration

sudo systemctl daemon-reload

Open /etc/rsyslog.conf and uncomment the following lines to listen syslog service on port 514

# provides UDP syslog reception
#module(load="imudp")
#input(type="imudp" port="514")

# provides TCP syslog reception
#module(load="imtcp")
#input(type="imtcp" port="514")

Then restart the service and check if the listener on port 514

sudo systemctl restart rsyslog
netstat -an | grep "LISTEN "

Create /etc/rsyslog.d/myapp.conf file with contents below to tell rsyslog where it will save application log

sudo nano /etc/rsyslog.d/myapp.conf

if $programname == 'myapp' or $syslogtag == 'myapp' then /var/log/myapp/myapp.log
& ~

Restart rsyslog service again

sudo systemctl restart rsyslog

Restart your service again

sudo systemctl restart myapp