Gracefully handle application downtimes and server errors

This project is intended to run alongside nginx or another reverse proxy. Configuration example:

error_page 500 502 503 504 /500.html;
location /500.html {
 root /srv/http;
}
location /panik/ {
 proxy_set_header X-App-Id "XptoApp";
 proxy_pass http://unix:/run/panik.socket:/app/;
}

With this setup, we can run a script from panik app on 500.html page, that checks application status, read logs and refreshes the browser when it comes back online:

<script src="/panik/init.js"></script>

Example webpage:

+------------------------------------+
| + 5xx error + |
| |
| / Application is currently \ |
| \ restarting. Please wait. / |
| |
| Last online: 1 min ago |
| Logs: ~~~~~~~~~~~~~~~~ |
| ~~~~~~~~~~~~~~~~ |
| ~~~~~~~~~~~~~~~~ |
| |
+------------------------------------+

• systemd (dbus) and systemd-journald integration
• (opt) docker and docker-compose integration
• websocket or wamp protocol?
• (opt) backoffice
• internal api to start / restart / shutdown applications
• check if application is healthy via http / systemd
• keep online status, last online, and other useful metrics (TBD)

• (op1) python 3.7+, tornado, sqlite
• (op2) python 3.7+, django + channels, sqlite
• (op3) python 3.7+, autobahn, sqlite
• (op4) go, sqlite