cmdeploy/{postfix,dovecot}/deployer.py: check config before restarting

postfix: also fail on warnings

cmdeploy/src/cmdeploy/dovecot/deployer.py

@@ -37,9 +37,7 @@ class DovecotDeployer(Deployer):
         restart = False if self.disable_mail else self.need_restart
 
         systemd.service(
-            name="disable dovecot for now"
-            if self.disable_mail
-            else "Start and enable Dovecot",
+            name="Disable dovecot for now" if self.disable_mail else "Start and enable Dovecot",
             service="dovecot.service",
             running=False if self.disable_mail else True,
             enabled=False if self.disable_mail else True,
@@ -145,4 +143,11 @@ def _configure_dovecot(config: Config, debug: bool = False) -> (bool, bool):
     )
     daemon_reload |= restart_conf.changed
 
+    # Validate dovecot configuration before restart
+    if need_restart:
+        server.shell(
+            name="Validate dovecot configuration",
+            commands=["doveconf -n >/dev/null"],
+        )
+
     return need_restart, daemon_reload

cmdeploy/src/cmdeploy/postfix/deployer.py

@@ -1,4 +1,4 @@
-from pyinfra.operations import apt, files, systemd
+from pyinfra.operations import apt, files, server, systemd
 
 from cmdeploy.basedeploy import Deployer, get_resource
 
@@ -77,6 +77,14 @@ class PostfixDeployer(Deployer):
             dest="/etc/systemd/system/postfix@.service.d/10_restart.conf",
         )
         self.daemon_reload = restart_conf.changed
+
+        # Validate postfix configuration before restart
+        if need_restart:
+            server.shell(
+                name="Validate postfix configuration",
+                # Extract stderr and quit with error if non-zero
+                commands=["""bash -c 'w=$(postconf 2>&1 >/dev/null); [[ -z "$w" ]] || { echo "$w"; false; }'"""],
+            )
         self.need_restart = need_restart
 
     def activate(self):