I made a restart of the webservice (webservice restart ; since then also did a stop / start).
The tool now returns on any URL (http://tools.wmflabs.org/wikiloves/)
504 Gateway Time-out nginx/1.13.6
The UWSGI logs do not report anything:
*** Starting uWSGI 2.0.7-debian (64bit) on [Wed Mar 27 12:39:42 2019] *** compiled with version: 4.9.2 on 17 March 2018 15:40:38 os: Linux-4.9.0-0.bpo.6-amd64 #1 SMP Debian 4.9.88-1+deb9u1~bpo8+1 (2018-05-13) nodename: wikiloves-1326522376-rywwi machine: x86_64 clock source: unix pcre jit disabled detected number of CPU cores: 4 current working directory: /data/project/wikiloves detected binary path: /usr/bin/uwsgi-core your memory page size is 4096 bytes detected max file descriptor number: 65536 lock engine: pthread robust mutexes thunder lock: disabled (you can enable it with --thunder-lock) uwsgi socket 0 bound to TCP address :8000 fd 3 Python version: 2.7.9 (default, Sep 25 2018, 20:46:16) [GCC 4.9.2] Set PythonHome to /data/project/wikiloves/www/python/venv *** Python threads support is disabled. You can enable it with --enable-threads *** Python main interpreter initialized at 0x21363b0 your server socket listen backlog is limited to 100 connections your mercy for graceful operations on workers is 60 seconds mapped 363840 bytes (355 KB) for 4 cores *** Operational MODE: preforking *** mounting /data/project/wikiloves/www/python/src/app.py on /wikiloves WSGI app 0 (mountpoint='/wikiloves') ready in 16 seconds on interpreter 0x21363b0 pid: 1 (default app) *** uWSGI is running in multiple interpreter mode *** spawned uWSGI master process (pid: 1) spawned uWSGI worker 1 (pid: 9, cores: 1) spawned uWSGI worker 2 (pid: 10, cores: 1) spawned uWSGI worker 3 (pid: 11, cores: 1) spawned uWSGI worker 4 (pid: 12, cores: 1)