fix: Remove invalid `mysql` saslauthd mechanism

docs/content/config/environment.md

@@ -910,22 +910,26 @@ Note: This postgrey setting needs `ENABLE_POSTGREY=1`
 
 ##### SASLAUTHD_MECHANISMS
 
-- **empty** => pam
-- `ldap` => authenticate against ldap server
-- `shadow` => authenticate against local user db
-- `mysql` => authenticate against mysql db
-- `rimap` => authenticate against imap server
-- NOTE: can be a list of mechanisms like pam ldap shadow
+DMS only implements support for these mechanisms:
+
+- **`ldap`** => Authenticate against an LDAP server
+- `rimap` => Authenticate against an IMAP server
 
 ##### SASLAUTHD_MECH_OPTIONS
 
 - **empty** => None
-- e.g. with SASLAUTHD_MECHANISMS rimap you need to specify the ip-address/servername of the imap server  ==> xxx.xxx.xxx.xxx
+
+!!! info
+
+    With `SASLAUTHD_MECHANISMS=rimap` you need to specify the ip-address / servername of the IMAP server, such as `SASLAUTHD_MECH_OPTIONS=127.0.0.1`.
 
 ##### SASLAUTHD_LDAP_SERVER
 
-- **empty** => same as `LDAP_SERVER_HOST`
-- Note: You must include the desired URI scheme (`ldap://`, `ldaps://`, `ldapi://`).
+- **empty** => Use the same value as `LDAP_SERVER_HOST`
+
+!!! note
+
+    You must include the desired URI scheme (`ldap://`, `ldaps://`, `ldapi://`).
 
 ##### SASLAUTHD_LDAP_START_TLS
 

target/scripts/startup/variables-stack.sh

@@ -182,8 +182,9 @@ function _environment_variables_ldap() {
 function _environment_variables_saslauthd() {
   _log 'debug' 'Setting SASLAUTHD-related environment variables now'
 
-  # Only used by the supervisor service command (upstream default: `/etc/default/saslauthd`)
-  VARS[SASLAUTHD_MECHANISMS]="${SASLAUTHD_MECHANISMS:=pam}"
+  # This ENV is only used by the supervisor service command:
+  # NOTE: `pam` is set as the upstream default in `/etc/default/saslauthd`
+  VARS[SASLAUTHD_MECHANISMS]="${SASLAUTHD_MECHANISMS:=ldap}"
 }
 
 # This function Writes the contents of the `VARS` map (associative array)

target/supervisor/conf.d/saslauth.conf

@@ -7,15 +7,6 @@ stderr_logfile=/var/log/supervisor/%(program_name)s.log
 command=/usr/sbin/saslauthd -d -a ldap -O /etc/saslauthd.conf
 pidfile=/var/run/saslauthd/saslauthd.pid
 
-[program:saslauthd_mysql]
-startsecs=0
-autostart=false
-autorestart=true
-stdout_logfile=/var/log/supervisor/%(program_name)s.log
-stderr_logfile=/var/log/supervisor/%(program_name)s.log
-command=/usr/sbin/saslauthd -d -a mysql -O "%(ENV_SASLAUTHD_MECH_OPTIONS)s"
-pidfile=/var/run/saslauthd/saslauthd.pid
-
 [program:saslauthd_pam]
 startsecs=0
 autostart=false
@@ -42,4 +33,3 @@ stdout_logfile=/var/log/supervisor/%(program_name)s.log
 stderr_logfile=/var/log/supervisor/%(program_name)s.log
 command=/usr/sbin/saslauthd -d -a shadow -O "%(ENV_SASLAUTHD_MECH_OPTIONS)s"
 pidfile=/var/run/saslauthd/saslauthd.pid
-