From e9af13c9d880c3d3c047aa444e036bf3eb5855ac Mon Sep 17 00:00:00 2001
From: flavis <christian@flavigny.de>
Date: Thu, 13 Jan 2022 12:12:36 +0100
Subject: [PATCH] fix using too many connections

---
 jdav_web/jdav_web/settings.py |  7 +++++++
 jdav_web/mailer/mailutils.py  | 36 ++++++++++++++++++++---------------
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/jdav_web/jdav_web/settings.py b/jdav_web/jdav_web/settings.py
index c67fa34..b1d0fbc 100644
--- a/jdav_web/jdav_web/settings.py
+++ b/jdav_web/jdav_web/settings.py
@@ -176,6 +176,13 @@ EMAIL_USE_TLS = True if deployed else False
 EMAIL_BACKEND = 'djcelery_email.backends.CeleryEmailBackend'
 
 
+# Celery Email Setup
+
+CELERY_EMAIL_TASK_CONFIG = {
+    'rate_limit' : '1/m'  # * CELERY_EMAIL_CHUNK_SIZE (default: 10)
+}
+
+
 # Admin setup
 
 ADMINS = (('admin', 'christian@merten-moser.de'),)
diff --git a/jdav_web/mailer/mailutils.py b/jdav_web/mailer/mailutils.py
index c993bf3..424cb4c 100644
--- a/jdav_web/mailer/mailutils.py
+++ b/jdav_web/mailer/mailutils.py
@@ -20,21 +20,27 @@ def send(subject, content, sender, recipients, message_id=None, reply_to=None,
         headers = {'Message-ID': message_id}
     else:
         headers = {}
-    with mail.get_connection() as connection:
-        for recipient in set(recipients):
-            email = EmailMessage(subject, content, sender, [recipient],
-                                 headers=headers,
-				 connection=connection, **kwargs)
-            if attachments is not None:
-                for attach in attachments:
-                    email.attach_file(attach)
-            try:
-                email.send(fail_silently=True)
-            except Exception as e:
-                print("Error when sending mail:", e)
-                failed = True
-            else:
-                succeeded = True
+
+    # construct mails
+    mails = []
+    for recipient in set(recipients):
+        email = EmailMessage(subject, content, sender, [recipient],
+                             headers=headers, **kwargs)
+        if attachments is not None:
+            for attach in attachments:
+                email.attach_file(attach)
+        mails.append(email)
+    try:
+        # connect to smtp server
+        connection = mail.get_connection()
+        # send all mails with one connection
+        connection.send_messages(mails)
+    except Exception as e:
+        print("Error when sending mail:", e)
+        failed = True
+    else:
+        succeeded = True
+
     return NOT_SENT if failed and not succeeded else SENT if not failed\
         and succeeded else PARTLY_SENT