documentation on how to use systemctl (or service)

Puppet deploys a service unit file so EVA can be started at boot time and logs go the journal instead of some logfile at some opaque location

README.md

@@ -7,26 +7,16 @@ meaning "Onboarding, Change, Offboarding"
 
 # development
 
-- install gettext for instance via "apt install gettext" for translations
-
-- set up a virtual environment with virtualenvwrapper or some other
-environment managing tool
-
+- install gettext for instance via `apt install gettext` for translations
+- set up a virtual environment with virtualenvwrapper or some other environment managing tool
 - use this environment and do
-
-    pip install django django-multiselectfield django-formtools django-allauth
-
+```
+pip install django django-multiselectfield django-formtools django-allauth
+```
 - clone this repository
-
-- ln -sr eva/settings_development.py eva/settings.py
-
-- initialise your database with
-
-    python manage.py migrate
-
-- start your development server with
-
-    python manage.py runserver
+- `ln -sr eva/settings_development.py eva/settings.py`
+- initialise your database with `python manage.py migrate`
+- start your development server with `python manage.py runserver`
 
 # oauth
 
@@ -35,27 +25,55 @@ environment managing tool
 # production
 
 - you can use gunicorn as server for example instead of the django development server.
-
 - we use whitenoise for serving static files
-
 - we still use the development SQLITE database from django
 
 do the following in the project main directory:
-
+```
   ln -sr eva/settings_production.py eva/settings.py
-
+```
 edit /secrets.json to contain something similar to
-
+```
   {
     "SECRET_KEY": "THIS IS ANOTHER SECRET!"
   }
-
+```
 run the following commands:
-
+```
   python3 manage.py migrate
   python3 manage.py collectstatic
   django-admin compilemessages
+```
 
-server starts with
+As root create a file `/etc/systemd/system` (it's already deployed by puppet when the corresponding manifest is applied):
 
-  export PYTHONUNBUFFERED=TRUE; nohup gunicorn --forwarded-allow-ips="*" -b '0:8000' eva.wsgi &> logfile &
+```
+# /etc/systemd/system/eva.service
+#
+
+[Unit]
+Description=gunicorn EVA daemon
+After=network.target
+
+[Service]
+Type=simple
+User=eva
+Group=eva
+RuntimeDirectory=eva
+WorkingDirectory=/home/eva/eva
+Environment=PYTHONUNBUFFERED=TRUE
+ExecStart=/usr/bin/gunicorn  --forwarded-allow-ips='*' -b '0:8000' eva.wsgi
+ExecReload=/bin/kill -s HUP $MAINPID
+KillMode=mixed
+TimeoutStopSec=5
+PrivateTmp=true
+
+[Install]
+WantedBy=multi-user.target
+```
+
+Adapt the paths in the file accordingly. Then, still as root, run:
+```
+systemctl enable --now eva.service
+```
+This enables the service to start at boot time and starts it immediately now. The daemon logs to the journal. You can see the last 10 lines by running `systemctl status eva.service` or the whole log by running `journalctl -u eva.service`. The usual switches to manipulate that output are available.