make syslog optional

core/postfix/conf/main.cf

@@ -2,6 +2,11 @@
 # General
 ###############
 
+{% if POSTFIX_LOG_SYSLOG != "local" %}
+# Logging configuration
+maillog_file = /dev/stdout
+{% endif %}
+
 # Main domain and hostname
 mydomain = {{ DOMAIN }}
 myhostname = {{ HOSTNAMES.split(",")[0] }}

core/postfix/start.py

@@ -37,8 +37,9 @@ os.environ["ADMIN_ADDRESS"] = system.get_host_address_from_environment("ADMIN",
 os.environ["ANTISPAM_MILTER_ADDRESS"] = system.get_host_address_from_environment("ANTISPAM_MILTER", "antispam:11332")
 os.environ["LMTP_ADDRESS"] = system.get_host_address_from_environment("LMTP", "imap:2525")
 
-conf.jinja("/conf/rsyslog.conf", os.environ, "/etc/rsyslog.conf")
+os.environ["LMTP_ADDRESS"] = system.get_host_address_from_environment("LMTP", "imap:2525")
 
+os.environ["POSTFIX_LOG_SYSLOG"] = os.environ.get("POSTFIX_LOG_SYSLOG","disabled")
 
 for postfix_file in glob.glob("/conf/*.cf"):
     conf.jinja(postfix_file, os.environ, os.path.join("/etc/postfix", os.path.basename(postfix_file)))
@@ -64,8 +65,10 @@ if "RELAYUSER" in os.environ:
     conf.jinja("/conf/sasl_passwd", os.environ, path)
     os.system("postmap {}".format(path))
 
-# Start rsyslog
+if os.environ["POSTFIX_LOG_SYSLOG"]=="local":
-os.system("/usr/sbin/rsyslogd -n &")
+    # Configure and start local rsyslog server
+    conf.jinja("/conf/rsyslog.conf", os.environ, "/etc/rsyslog.conf")
+    os.system("/usr/sbin/rsyslogd -n &")
 
 # Run Podop and Postfix
 multiprocessing.Process(target=start_podop).start()

docs/configuration.rst

@@ -190,3 +190,15 @@ When using ``*_ADDRESS``, the hostnames must be full-qualified hostnames. Otherw
 resolve the hostnames.
 
 
+Maillog setitngs
+----------------
+
+By default, all services log directly to stdout/stderr. Logs can be collected by any docker log processing solution.
+
+In some situations, a separate mail log is required (e.g. for legal reasons). Postfix can be configured to write the logs to a
+syslog server that stores the log files to a volume. It can be configured by the following options:
+
+- ``POSTFIX_LOG_SYSLOG``: (default: ``disabled``) set to ``local`` to enable a local syslog server for postfix
+- ``POSTFIX_LOG_FILE``: The file to log the maillog to
+
+