Support for setting relayhost in main.cf (#1104)

* Added DEFAULT_RELAY_HOST setting
* If set this value will be used as the relayhost in /etc/postfix/maincf causing all mail to be delivered using this relay host
* Test for default relay host setting

.env.dist

@@ -305,6 +305,16 @@ SRS_EXCLUDE_DOMAINS=
 # rotate and expire keys
 SRS_SECRET=
 
+# -----------------------------------------------------------------------------------------------------------------------------
+# ---------------- Default relay host section ---------------------------------------------------------------------------------
+# -----------------------------------------------------------------------------------------------------------------------------
+
+# Setup relaying all mail through a default relay host
+#
+# empty => don't configure default relay host
+# default host and optional port to relay all mail through
+DEFAULT_RELAY_HOST=
+
 # -----------------------------------------------------------------------------------------------------------------------------
 # ---------------- Multi-domain relay section ---------------------------------------------------------------------------------
 # -----------------------------------------------------------------------------------------------------------------------------

Makefile

@@ -244,6 +244,15 @@ run:
 		-e DMS_DEBUG=0 \
 		-h mail.my-domain.com -t $(NAME)
 	sleep 15
+	docker run -d --name mail_with_default_relay \
+		-v "`pwd`/test/config/relay-hosts":/tmp/docker-mailserver \
+		-v "`pwd`/test":/tmp/docker-mailserver-test \
+		-e DEFAULT_RELAY_HOST=default.relay.host.invalid:25 \
+		--cap-add=SYS_PTRACE \
+		-e PERMIT_DOCKER=host \
+		-e DMS_DEBUG=0 \
+		-h mail.my-domain.com -t $(NAME)
+	sleep 15
 
 generate-accounts-after-run:
 	docker run --rm -e MAIL_USER=added@localhost.localdomain -e MAIL_PASS=mypassword -t $(NAME) /bin/sh -c 'echo "$$MAIL_USER|$$(doveadm pw -s SHA512-CRYPT -u $$MAIL_USER -p $$MAIL_PASS)"' >> test/config/postfix-accounts.cf
@@ -309,7 +318,8 @@ clean:
 		mail_override_hostname \
 		mail_domainname \
 		mail_srs_domainname \
-		mail_with_relays
+		mail_with_relays \
+		mail_with_default_relay
 
 	@if [ -d config.bak ]; then\
 		rm -rf config ;\

README.md

@@ -586,6 +586,13 @@ Note: This postgrey setting needs `ENABLE_POSTGREY=1`
   - **empty** => Derived from OVERRIDE_HOSTNAME, DOMAINNAME, or the container's hostname
   - Set this if auto-detection fails, isn't what you want, or you wish to have a separate container handle DSNs
 
+## Default Relay Host
+
+#### DEFAULT_RELAY_HOST
+
+  - **empty** => don't set default relayhost setting in main.cf
+  - default host and port to relay all mail through
+
 ## Multi-domain Relay Hosts
 
 #### RELAY_HOST

docker-compose.yml.dist

@@ -77,6 +77,7 @@ services:
     - SASL_PASSWD=${SASL_PASSWD}
     - SRS_EXCLUDE_DOMAINS=${SRS_EXCLUDE_DOMAINS}
     - SRS_SECRET=${SRS_SECRET}
+    - DEFAULT_RELAY_HOST=${DEFAULT_RELAY_HOST}
     - RELAY_HOST=${RELAY_HOST}
     - RELAY_PORT=${RELAY_PORT}
     - RELAY_USER=${RELAY_USER}

target/start-mailserver.sh

@@ -145,6 +145,10 @@ function register_functions() {
 		_register_setup_function "_setup_postfix_relay_hosts"
 	fi
 
+	if [ ! -z "$DEFAULT_RELAY_HOST" ]; then
+		_register_setup_function "_setup_postfix_default_relay_host"
+	fi
+
 	if [ ! -z "$RELAY_HOST" ]; then
 		_register_setup_function "_setup_postfix_relay_hosts"
 	fi
@@ -1066,6 +1070,13 @@ function _setup_postfix_sasl_password() {
 	fi
 }
 
+function _setup_postfix_default_relay_host() {
+	notify 'task' 'Applying default relay host to Postfix'
+
+	notify 'inf' "Applying default relay host $DEFAULT_RELAY_HOST to /etc/postfix/main.cf"
+	postconf -e "relayhost = $DEFAULT_RELAY_HOST"
+}
+
 function _setup_postfix_relay_hosts() {
 	notify 'task' 'Setting up Postfix Relay Hosts'
 	# copy old AWS_SES variables to new variables

test/tests.bats

@@ -1748,6 +1748,15 @@ load 'test_helper/bats-assert/load'
   assert_success
 }
 
+#
+# default relay host
+#
+
+@test "checking default relay host: default relay host is added to main.cf" {
+  run docker exec mail_with_default_relay /bin/sh -c 'grep -e "^relayhost = default.relay.host.invalid:25" /etc/postfix/main.cf | wc -l | grep 1'
+  assert_success
+}
+
 #
 # relay hosts
 #