Based on boky/postfix, with simple support for sender_canonical and sender_bcc maps
In addition to the boky/postfix image options, postmaps.sh will automatically create postmap files in /etc/postmaps on launch. This allows for injection of postmap hash files using kubernetes config like below:
apiVersion: v1
data:
sender_bcc_maps: |-
# sender_address bcc_address
[email protected] [email protected]
sender_canonical_maps: |-
# sender_address destination_rewrite
# no change for trusted senders
/^([email protected])$/ ${1}
# no change for addresses containing noreply@
/^(.*noreply@.*)$/ ${1}
# expand empty addresses and missing domains
/^$/ [email protected]
/^([^@]+)$/ ${1}[email protected]
# rewrite addresses without noreply to include it
/^(.+)@(.+)$/ ${1}+noreply@${2}
kind: ConfigMapThen mount the vol and can use env vars to configure various maps. Note container will need to be restarted after a config map change to pick up changes.
The mailfixer container is a basic SMTP proxy built on aiosmtpd in python3 which inspects messages and fixes messages missing a body part/content-type. This can be used as a basis to do any type of message modification required above and beyond what is straightforward in postfix. To use it, just deploy it alongside the above postfix relay, expose port 8025, and configure it's REMOTE_HOSTNAME and REMOTE_PORT parameters to point to postfix.
from email.mime.text import MIMEText
from aiosmtpd.handlers import Proxy
from aiosmtpd.controller import Controller
proxy = Proxy(os.environ.get("REMOTE_HOSTNAME", "mail-relay"), os.environ.get("REMOTE_PORT", 587))
class FixerHandler:
async def handle_DATA(self, server, session, envelope):
statusmsg = "Message from {} to {}".format(envelope.mail_from, envelope.rcpt_tos)
msg = email.message_from_string(envelope.content.decode("utf-8"))
if msg.get_content_maintype() != "text":
content_types = [part.get_content_type() for part in msg.get_payload()]
if len([ct for ct in content_types if any(body_cts in ct for body_cts in ["plain", "html"])]) == 0:
msg.set_payload([MIMEText("--", "plain")] + msg.get_payload())
envelope.content = msg.as_string()
envelope.original_content = msg.as_string().encode("utf-8")
statusmsg += ": prepended TextBody '--'"
print(statusmsg)
return await proxy.handle_DATA(server, session, envelope)