Rspamd misses redis backend

[onny]

Describe the bug

While just enabling rspamd service, one could see in the errors in the logs highlighted in red, that rspamd is unable to communicate with a redis backend

Steps To Reproduce

Steps to reproduce the behavior:

1. services.rspamd.enable = true;
2. see logs journalctl -u rspamd

Expected behavior

Like for many different services, a redis backend should be enabled automatically and configured in the main service

Additional context

Error logs

<j8b5z6>; cfg; rspamd_redis_init: cannot init redis backend for BAYES_SPAM
<j8b5z6>; cfg; rspamd_dns_read_hosts_file: processed host file /etc/hosts; 4 records added
<j8b5z6>; cfg; rspamd_stat_init: added backend redis for symbol BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_cache_redis_init: cannot init redis cache for BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_init: error adding cache redis for symbol BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_init: cannot init backend redis for statfile BAYES_SPAM
<j8b5z6>; cfg; rspamd_redis_init: cannot init redis backend for BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_init: added backend redis for symbol BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_cache_redis_init: cannot init redis cache for BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_init: error adding cache redis for symbol BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_init: cannot init backend redis for statfile BAYES_HAM
<419f15>; main; rspamd_worker_set_limits: use system max core size limit: -1B cur and -1B max
<419f15>; main; rspamd_handle_child_fork: starting hs_helper process 843 (0); no listen
<j8b5z6>; cfg; rspamd_redis_init: cannot init redis backend for BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_init: added backend redis for symbol BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_cache_redis_init: cannot init redis cache for BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_init: error adding cache redis for symbol BAYES_SPAM
<j8b5z6>; cfg; rspamd_stat_init: cannot init backend redis for statfile BAYES_SPAM
<j8b5z6>; cfg; rspamd_redis_init: cannot init redis backend for BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_init: added backend redis for symbol BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_cache_redis_init: cannot init redis cache for BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_init: error adding cache redis for symbol BAYES_HAM
<j8b5z6>; cfg; rspamd_stat_init: cannot init backend redis for statfile BAYES_HAM

Notify maintainers

@Mic92 @tnias

[tnias]

The maintainers listed in pkgs/servers/mail/rspamd/default.nix are @avnik @fpletz @globin @nlewo.