scripts/ENV: make disabling Redis possible (#3132)

* make disabling Redis possible

* add documentation

* Apply suggestions from code review

* Update docs/content/config/environment.md

---------

Co-authored-by: Brennan Kinney <5098581+polarathene@users.noreply.github.com>

docs/content/config/environment.md

@@ -80,6 +80,26 @@ Enable or disable Rspamd.
 - **0** => disabled
 - 1 => enabled
 
+##### ENABLE_REDIS
+
+Explicit control over running a Redis instance within the container. By default, this value will match what is set for [`ENABLE_RSPAMD`](#enable_rspamd).
+
+The purpose of this setting is to opt-out of starting an internal Redis instance when enabling Rspamd, replacing it with your own external instance.
+
+??? note "Configuring rspamd for an external Redis instance"
+
+    You will need to [provide configuration][config-rspamd-redis] at `/etc/rspamd/local.d/redis.conf` similar to:
+    
+    ```
+    servers = "redis.example.test:6379";
+    expand_keys = true;
+    ```
+
+[config-rspamd-redis]: https://rspamd.com/doc/configuration/redis.html
+
+- 0 => Disabled
+- 1 => Enabled
+
 ##### ENABLE_AMAVIS
 
 Amavis content filter (used for ClamAV & SpamAssassin)

mailserver.env

@@ -118,10 +118,16 @@ ENABLE_POP3=
 ENABLE_CLAMAV=0
 
 # Enables Rspamd
-# **0** => disabled
-#   1   => enabled
+# **0** => Disabled
+#   1   => Enabled
 ENABLE_RSPAMD=0
 
+# When `ENABLE_RSPAMD=1`, an internal Redis instance is enabled implicitly.
+# This setting provides an opt-out to allow using an external instance instead.
+# 0 => Disabled
+# 1 => Enabled
+ENABLE_REDIS=
+
 # Amavis content filter (used for ClamAV & SpamAssassin)
 # 0 => Disabled
 # 1 => Enabled

target/rspamd/local.d/redis.conf

@@ -1,4 +0,0 @@
-# documentation: https://rspamd.com/doc/configuration/redis.html
-
-servers = "127.0.0.1:6379";
-expand_keys = true;

target/scripts/start-mailserver.sh

@@ -124,15 +124,10 @@ function _register_functions
   _register_start_daemon '_start_daemon_rsyslog'
 
   [[ ${SMTP_ONLY}               -ne 1 ]] && _register_start_daemon '_start_daemon_dovecot'
+
   [[ ${ENABLE_UPDATE_CHECK}     -eq 1 ]] && _register_start_daemon '_start_daemon_update_check'
-
-  if [[ ${ENABLE_RSPAMD} -eq 1 ]]
-  then
-    _register_start_daemon '_start_daemon_redis'
-    _register_start_daemon '_start_daemon_rspamd'
-  fi
-
-  [[ ${SMTP_ONLY}               -ne 1 ]] && _register_start_daemon '_start_daemon_dovecot'
+  [[ ${ENABLE_REDIS}            -eq 1 ]] && _register_start_daemon '_start_daemon_rspamd'
+  [[ ${ENABLE_RSPAMD}           -eq 1 ]] && _register_start_daemon '_start_daemon_redis'
   [[ ${ENABLE_UPDATE_CHECK}     -eq 1 ]] && _register_start_daemon '_start_daemon_update_check'
 
   # needs to be started before SASLauthd

target/scripts/startup/setup.d/security/rspamd.sh

@@ -46,6 +46,20 @@ function __rspamd__preflight_checks
   else
     __rspamd__log 'debug' 'Rspamd will not use ClamAV (which has not been enabled)'
   fi
+
+  if [[ ${ENABLE_REDIS} -eq 1 ]]
+  then
+    __rspamd__log 'trace' 'Internal Redis is enabled, adding configuration'
+    cat >/etc/rspamd/local.d/redis.conf << "EOF"
+# documentation: https://rspamd.com/doc/configuration/redis.html
+
+servers = "127.0.0.1:6379";
+expand_keys = true;
+
+EOF
+  else
+    __rspamd__log 'debug' 'Rspamd will not use internal Redis (which has been disabled)'
+  fi
 }
 
 # Adjust Postfix's configuration files. Append Rspamd at the end of

target/scripts/startup/variables-stack.sh

@@ -77,6 +77,7 @@ function __environment_variables_general_setup
   VARS[ENABLE_POSTGREY]="${ENABLE_POSTGREY:=0}"
   VARS[ENABLE_QUOTAS]="${ENABLE_QUOTAS:=1}"
   VARS[ENABLE_RSPAMD]="${ENABLE_RSPAMD:=0}"
+  VARS[ENABLE_REDIS]="${ENABLE_REDIS:=${ENABLE_RSPAMD}}"
   VARS[ENABLE_SASLAUTHD]="${ENABLE_SASLAUTHD:=0}"
   VARS[ENABLE_SPAMASSASSIN]="${ENABLE_SPAMASSASSIN:=0}"
   VARS[ENABLE_SPAMASSASSIN_KAM]="${ENABLE_SPAMASSASSIN_KAM:=0}"