add RSPAMD_SIGN_DKIM and add "X-SimpleLogin-Want-Signing" header

app/config.py

@@ -415,3 +415,6 @@ TEMP_DIR = os.environ.get("TEMP_DIR")
 
 # enable the alias automation disable: an alias can be automatically disabled if it has too many bounces
 ALIAS_AUTOMATIC_DISABLE = "ALIAS_AUTOMATIC_DISABLE" in os.environ
+
+# whether the DKIM signing is handled by Rspamd
+RSPAMD_SIGN_DKIM = "RSPAMD_SIGN_DKIM" in os.environ

app/email/headers.py

@@ -31,6 +31,9 @@ SL_EMAIL_LOG_ID = "X-SimpleLogin-EmailLog-ID"
 SL_ENVELOPE_FROM = "X-SimpleLogin-Envelope-From"
 SL_ENVELOPE_TO = "X-SimpleLogin-Envelope-To"
 
+# to let Rspamd know that the message should be signed
+SL_WANT_SIGNING = "X-SimpleLogin-Want-Signing"
+
 MIME_HEADERS = [
     MIME_VERSION,
     CONTENT_TYPE,

app/email_utils.py

@@ -52,6 +52,7 @@ from app.config import (
     POSTFIX_PORT_FORWARD,
     TEMP_DIR,
     ALIAS_AUTOMATIC_DISABLE,
+    RSPAMD_SIGN_DKIM,
 )
 from app.db import Session
 from app.dns_utils import get_mx_domains
@@ -408,6 +409,11 @@ def get_email_domain_part(address):
 
 
 def add_dkim_signature(msg: Message, email_domain: str):
+    if RSPAMD_SIGN_DKIM:
+        LOG.d("DKIM signature will be added by rspamd")
+        msg[headers.SL_WANT_SIGNING] = "yes"
+        return
+
     for dkim_headers in headers.DKIM_HEADERS:
         try:
             add_dkim_signature_with_header(msg, email_domain, dkim_headers)