Fix SMTP relay on AlmaLinux/RHEL: install cyrus-sasl-plain package

Postfix SASL PLAIN auth fails with "No worthy mechs found" on
RHEL/AlmaLinux because cyrus-sasl-plain is not installed by default.
- Add cyrus-sasl-plain to postfix install in install.py
- Auto-install in configureRelayHost() for existing servers
- Add to upgrade.py setupSieve() for existing installations

Author: usmannasir

install/install.py

@@ -1018,10 +1018,10 @@ def install_postfix_dovecot(self):
                     command = 'dnf --nogpg install -y https://mirror.ghettoforge.net/distributions/gf/gf-release-latest.gf.el8.noarch.rpm'
                     preFlightsChecks.call(command, self.distro, command, command, 1, 0, os.EX_OSERR)
 
-                command = 'dnf install --enablerepo=gf-plus postfix3 postfix3-mysql -y'
+                command = 'dnf install --enablerepo=gf-plus postfix3 postfix3-mysql cyrus-sasl-plain -y'
                 preFlightsChecks.call(command, self.distro, command, command, 1, 1, os.EX_OSERR)
             elif self.distro == openeuler:
-                command = 'dnf install postfix -y'
+                command = 'dnf install postfix cyrus-sasl-plain -y'
                 preFlightsChecks.call(command, self.distro, command, command, 1, 1, os.EX_OSERR)
 
             else:

plogical/mailUtilities.py

@@ -1707,6 +1707,12 @@ def SaveEmailLimitsNew(tempPath):
     @staticmethod
     def configureRelayHost(smtpHost, smtpPort, smtpUser, smtpPassword):
         try:
+            ## Ensure cyrus-sasl-plain is installed (required for SASL PLAIN auth on RHEL/Alma/CentOS)
+            if os.path.exists('/etc/redhat-release'):
+                ProcessUtilities.executioner('dnf install -y cyrus-sasl-plain')
+            elif os.path.exists('/usr/bin/apt-get'):
+                ProcessUtilities.executioner('apt-get install -y libsasl2-modules')
+
             postfixPath = '/etc/postfix/main.cf'
 
             with open(postfixPath, 'r') as f:

plogical/upgrade.py

@@ -2857,6 +2857,11 @@ def setupSieve():
                 Upgrade.stdOut("Dovecot not installed, skipping Sieve setup.", 0)
                 return
 
+            ## Ensure cyrus-sasl-plain is installed (needed for SMTP relay on RHEL/Alma/CentOS)
+            if os.path.exists('/etc/redhat-release'):
+                command = 'dnf install -y cyrus-sasl-plain'
+                ProcessUtilities.executioner(command)
+
             import re
 
             dovecot_conf = '/etc/dovecot/dovecot.conf'