feat: Add message_size_limit option (#86)

* feat: Add MESSAGE_SIZE_LIMIT configuration option (PR #86)

.env.example

@@ -31,3 +31,12 @@
 
 # Optional: This will use allow you to set a custom $mydestination value. Default is localhost.
 #DESTINATION=
+
+# Optional: This will output the subject line of messages in the log.
+#LOG_SUBJECT=yes
+
+# Optional: This will disable (no) or enable (yes) the use of SMTPUTF8
+#SMTPUTF8_ENABLE=no
+
+# Optional: This will use allow you to set a custom $message_size_limit value. Default is 10240000.
+#MESSAGE_SIZE_LIMIT=

.github/ISSUE_TEMPLATE/bug_report.md

@@ -6,12 +6,14 @@ labels: ''
 assignees: ''
 
 ---
-
+<!-- BEFORE SUBMITTING YOUR PR, PLEASE REMOVE THIS TEXT -->
+<!-- REMOVE START -->
 **Reporting a bug**
 
 First of all, this is **not** a problem reporting forum, only report if you are pretty sure what you are experiencing is a bug with this image, not a configuration issue, for that you can use the [Github discussions section](https://github.com/juanluisbaptiste/docker-postfix/discussions) and we will do our best to help you to figure out what's going on with your setup.
 
 Also be sure you are using the latest image by doing _docker pull juanluisbaptiste/postfix:latest_.
+<!-- REMOVE END -->
 
 **Please include the contents of:**
 

.github/pull_request_template.md

@@ -1,10 +1,13 @@
+<!-- BEFORE SUBMITTING YOUR PR, PLEASE REMOVE THIS TEXT -->
+<!-- REMOVE START -->
 # Creating a Pull Request
 
 We use github actions to do automatic [semantic versioning](https://github.com/semantic-release/semantic-release), so please use the following nomenclature for the commit message according to the type of change:
 
 * Prefix with `feat:`, and it will trigger a minor version bump. 
-* Prefix with `fix`:, and it will trigger a patch version bump. 
+* Prefix with `fix:`, and it will trigger a patch version bump.
 * Prefix with `BREAKING CHANGE:`, and it will trigger a major version bump.
+<!-- REMOVE END -->
 
 ## Description of the change
 <!--Please be very clear on the intention of the modifications included in the pull request.-->

README.md

@@ -79,6 +79,12 @@ The following env variable(s) are optional.
 
 * `DESTINATION` This will define a list of domains from which incoming messages will be accepted.
 
+* `LOG_SUBJECT` This will output the subject line of messages in the log.
+
+* `SMTPUTF8_ENABLE` This will enable (default) or disable support for SMTPUTF8. Valid values are `no` to disable and `yes` to enable. Not setting this variable will use the postfix default, which is `yes`.
+
+* `MESSAGE_SIZE_LIMIT` This will change the default limit of 10240000 bytes (10MB).
+
 To use this container from anywhere, the 25 port or the one specified by `SMTP_PORT` needs to be exposed to the docker host server:
 
     docker run -d --name postfix -p "25:25"  \

run.sh

@@ -14,8 +14,8 @@ function add_config_value() {
 }
 
 # Read password and username from file to avoid unsecure env variables
-if [ -n "${SMTP_PASSWORD_FILE}" ]; then [ -f "${SMTP_PASSWORD_FILE}" ] && read SMTP_PASSWORD < ${SMTP_PASSWORD_FILE} || echo "SMTP_PASSWORD_FILE defined, but file not existing, skipping."; fi
+if [ -n "${SMTP_PASSWORD_FILE}" ]; then [ -e "${SMTP_PASSWORD_FILE}" ] && SMTP_PASSWORD=$(cat "${SMTP_PASSWORD_FILE}") || echo "SMTP_PASSWORD_FILE defined, but file not existing, skipping."; fi
-if [ -n "${SMTP_USERNAME_FILE}" ]; then [ -f "${SMTP_USERNAME_FILE}" ] && read SMTP_USERNAME < ${SMTP_USERNAME_FILE} || echo "SMTP_USERNAME_FILE defined, but file not existing, skipping."; fi
+if [ -n "${SMTP_USERNAME_FILE}" ]; then [ -e "${SMTP_USERNAME_FILE}" ] && SMTP_USERNAME=$(cat "${SMTP_USERNAME_FILE}") || echo "SMTP_USERNAME_FILE defined, but file not existing, skipping."; fi
 
 [ -z "${SMTP_SERVER}" ] && echo "SMTP_SERVER is not set" && exit 1
 [ -z "${SERVER_HOSTNAME}" ] && echo "SERVER_HOSTNAME is not set" && exit 1
@@ -61,11 +61,18 @@ fi
 
 #Set header tag
 if [ ! -z "${SMTP_HEADER_TAG}" ]; then
-  postconf -e "header_checks = regexp:/etc/postfix/header_tag"
+  postconf -e "header_checks = regexp:/etc/postfix/header_checks"
-  echo -e "/^MIME-Version:/i PREPEND RelayTag: $SMTP_HEADER_TAG\n/^Content-Transfer-Encoding:/i PREPEND RelayTag: $SMTP_HEADER_TAG" > /etc/postfix/header_tag
+  echo -e "/^MIME-Version:/i PREPEND RelayTag: $SMTP_HEADER_TAG\n/^Content-Transfer-Encoding:/i PREPEND RelayTag: $SMTP_HEADER_TAG" >> /etc/postfix/header_checks
   echo "Setting configuration option SMTP_HEADER_TAG with value: ${SMTP_HEADER_TAG}"
 fi
 
+#Enable logging of subject line
+if [ "${LOG_SUBJECT}" == "yes" ]; then
+  postconf -e "header_checks = regexp:/etc/postfix/header_checks"
+  echo -e "/^Subject:/ WARN" >> /etc/postfix/header_checks
+  echo "Enabling logging of subject line"
+fi
+
 #Check for subnet restrictions
 nets='10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16'
 if [ ! -z "${SMTP_NETWORKS}" ]; then
@@ -79,6 +86,12 @@ if [ ! -z "${SMTP_NETWORKS}" ]; then
 fi
 add_config_value "mynetworks" "${nets}"
 
+# Set SMTPUTF8
+if [ ! -z "${SMTPUTF8_ENABLE}" ]; then
+  postconf -e "smtputf8_enable = ${SMTPUTF8_ENABLE}"
+  echo "Setting configuration option smtputf8_enable with value: ${SMTPUTF8_ENABLE}"
+fi
+
 if [ ! -z "${OVERWRITE_FROM}" ]; then
   echo -e "/^From:.*$/ REPLACE From: $OVERWRITE_FROM" > /etc/postfix/smtp_header_checks
   postmap /etc/postfix/smtp_header_checks
@@ -86,6 +99,12 @@ if [ ! -z "${OVERWRITE_FROM}" ]; then
   echo "Setting configuration option OVERWRITE_FROM with value: ${OVERWRITE_FROM}"
 fi
 
+# Set message_size_limit
+if [ ! -z "${MESSAGE_SIZE_LIMIT}" ]; then
+  postconf -e "message_size_limit = ${MESSAGE_SIZE_LIMIT}"
+  echo "Setting configuration option message_size_limit with value: ${MESSAGE_SIZE_LIMIT}"
+fi
+
 #Start services
 
 # If host mounting /var/spool/postfix, we need to delete old pid file before