cache smtp server and remove POSTFIX_PORT_FORWARD

app/api/views/auth.py

@@ -272,7 +272,7 @@ def auth_facebook():
 @api_bp.route("/auth/google", methods=["POST"])
 def auth_google():
     """
-    Authenticate user with Facebook
+    Authenticate user with Google
     Input:
         google_token: Google access token
         device: to create an ApiKey associated with this device

app/config.py

@@ -117,11 +117,6 @@ POSTFIX_PORT = 25
 if "POSTFIX_PORT" in os.environ:
     POSTFIX_PORT = int(os.environ["POSTFIX_PORT"])
 
-# postfix port to use during the forward phase
-POSTFIX_PORT_FORWARD = POSTFIX_PORT
-if "POSTFIX_PORT_FORWARD" in os.environ:
-    POSTFIX_PORT_FORWARD = int(os.environ["POSTFIX_PORT_FORWARD"])
-
 # Use port 587 instead of 25 when sending emails through Postfix
 # Useful when calling Postfix from an external network
 POSTFIX_SUBMISSION_TLS = "POSTFIX_SUBMISSION_TLS" in os.environ

app/email_utils.py

@@ -19,6 +19,7 @@ import arrow
 import dkim
 import re2 as re
 import spf
+from cachetools import cached, TTLCache
 from email_validator import (
     validate_email,
     EmailNotValidError,
@@ -49,7 +50,6 @@ from app.config import (
     ALERT_DIRECTORY_DISABLED_ALIAS_CREATION,
     TRANSACTIONAL_BOUNCE_EMAIL,
     ALERT_SPF,
-    POSTFIX_PORT_FORWARD,
     TEMP_DIR,
     ALIAS_AUTOMATIC_DISABLE,
     RSPAMD_SIGN_DKIM,
@@ -1264,6 +1264,19 @@ def spf_pass(
     return True
 
 
+# cache the smtp server for 20 seconds
+@cached(cache=TTLCache(maxsize=2, ttl=20))
+def get_smtp_server():
+    LOG.d("get a smtp server")
+    if POSTFIX_SUBMISSION_TLS:
+        smtp = SMTP(POSTFIX_SERVER, 587)
+        smtp.starttls()
+    else:
+        smtp = SMTP(POSTFIX_SERVER, POSTFIX_PORT)
+
+    return smtp
+
+
 def sl_sendmail(
     from_addr,
     to_addr,
@@ -1284,14 +1297,8 @@ def sl_sendmail(
         return
 
     try:
-        if POSTFIX_SUBMISSION_TLS:
-            smtp = SMTP(POSTFIX_SERVER, 587)
-            smtp.starttls()
-        else:
-            if is_forward:
-                smtp = SMTP(POSTFIX_SERVER, POSTFIX_PORT_FORWARD)
-            else:
-                smtp = SMTP(POSTFIX_SERVER, POSTFIX_PORT)
+        # to avoid creating SMTP server every time
+        smtp = get_smtp_server()
 
         # smtp.send_message has UnicodeEncodeError
         # encode message raw directly instead