implementation of altermime invocation and filtering for dukun use case

disclaimerfilter.py

@@ -0,0 +1,87 @@
+#!/usr/bin/python
+"""
+Postfix filter for adding a disclaimer to selected email.
+
+Emails are 
+
+License: GPLv3
+Author: Georg Schlisio
+"""
+
+import subprocess
+import sys
+import email.parser
+
+# configuration:
+# each rule is a tuple of
+#   1. the (fragment of) the email address in the To: field
+#   2. the absolute path of the disclaimer text file (must be readable for the filter user!)
+rules = [
+# augustinerkantorei
+        ["chor@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["sopran@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["alt@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["tenor@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["bass@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["mitglied@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["vorstand@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["chorvertreter@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["freunde@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["ehemalig@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["kreativ@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["reise@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+        ["reiseorg@augustiner-kantorei.de", "/etc/postfix/mailinglists/disclaimers/augustinerdisclaimer"],
+# nordenrunt
+        ["nordenrunt19@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["sopran.nordenrunt19@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["alt.nordenrunt19@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["tenor.nordenrunt19@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["bass.nordenrunt19@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["nordenrunt21@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["sopran.nordenrunt21@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["alt.nordenrunt21@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["tenor.nordenrunt21@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["bass.nordenrunt21@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["nordenrunt@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["sopran.nordenrunt@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["alt.nordenrunt@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["tenor.nordenrunt@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["bass.nordenrunt@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["undercover.nordenrunt@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+        ["nordenrunt_animanordica19@dukun.de", "/etc/postfix/mailinglists/disclaimers/nordenruntdisclaimer"],
+# greifswalder domchor
+        ["chor@greifswalder-domchor.de", "/etc/postfix/mailinglists/disclaimers/domchordisclaimer"]
+        ]
+
+# DEBUGGING CASE - don't use in production! overwrites above 
+rules = [["abmelden@augustiner-kantorei.de", "augustinerdisclaimer"]]
+
+# read input and find recipient
+mail = "".join(sys.stdin.readlines())
+recipient = email.parser.HeaderParser().parsestr(mail)["To"]
+
+for rule, disclaimer in rules:
+    if recipient.find(rule) >= 0:
+        # altermime invocation
+        am = subprocess.run(["/usr/bin/altermime",
+                                "--input=-",
+                                f"--disclaimer={disclaimer}",
+                                "--htmltoo",
+                                "--force-for-bad-html",
+                                ],
+                            input=mail.encode(),
+                            capture_output=True
+                            )
+
+        # check altermime return code
+        if am.returncode > 0:
+            sys.exit(EX_UNAVAILABLE)
+        
+        # write back result
+        mail = am.stdout.decode()
+
+        # only first matching disclaimer!
+        break
+
+sendmailprocess = subprocess.Popen(["/usr/bin/sendmail"] + sys.argv[1:], stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
+sendmailprocess.communicate(input=mail.encode('utf-8'))