send_email: Improve configurability for outgoing email sender name.

Currently, the sender names for outgoing emails sent by Zulip
are hardcoded. It should be configurable for self-hosted systems.

This commit makes the 'Zulip' part a variable in the following
email sender names: 'Zulip Account Security', 'Zulip Digest',
and 'Zulip Notifications' by introducing a settings variable
'SERVICE_NAME' with the default value as f"{EXTERNAL_HOST} Zulip".

Fixes: #23857

zerver/lib/digest.py

@@ -9,6 +9,7 @@ from django.conf import settings
 from django.db import transaction
 from django.db.models import Exists, OuterRef
 from django.utils.timezone import now as timezone_now
+from django.utils.translation import gettext as _
 from typing_extensions import TypeAlias
 
 from confirmation.models import one_click_unsubscribe_link
@@ -408,7 +409,7 @@ def bulk_handle_digest_email(user_ids: List[int], cutoff: float) -> None:
             "zerver/emails/digest",
             user.realm,
             to_user_ids=[user.id],
-            from_name="Zulip Digest",
+            from_name=_("{service_name} digest").format(service_name=settings.INSTALLATION_NAME),
             from_address=FromAddress.no_reply_placeholder,
             context=context,
         )

zerver/lib/email_notifications.py

@@ -574,7 +574,9 @@ def do_send_missedmessage_events_reply_in_zulip(
     )
 
     with override_language(user_profile.default_language):
-        from_name: str = _("Zulip notifications")
+        from_name: str = _("{service_name} notifications").format(
+            service_name=settings.INSTALLATION_NAME
+        )
     from_address = FromAddress.NOREPLY
 
     email_dict = {

zerver/lib/send_email.py

@@ -70,7 +70,9 @@ class FromAddress:
             language = user_profile.default_language
 
         with override_language(language):
-            return _("Zulip Account Security")
+            return _("{service_name} account security").format(
+                service_name=settings.INSTALLATION_NAME
+            )
 
 
 def build_email(

zerver/tests/test_email_change.py

@@ -194,7 +194,7 @@ class EmailChangeTestCase(ZulipTestCase):
         self.assertEqual(self.email_envelope_from(email_message), settings.NOREPLY_EMAIL_ADDRESS)
         self.assertRegex(
             self.email_display_from(email_message),
-            rf"^Zulip Account Security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
+            rf"^testserver account security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
         )
 
         self.assertEqual(email_message.extra_headers["List-Id"], "Zulip Dev <zulip.testserver>")
@@ -392,7 +392,7 @@ class EmailChangeTestCase(ZulipTestCase):
         self.assertEqual(self.email_envelope_from(email_message), settings.NOREPLY_EMAIL_ADDRESS)
         self.assertRegex(
             self.email_display_from(email_message),
-            rf"^Zulip Account Security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
+            rf"^testserver account security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
         )
         self.assertEqual(email_message.extra_headers["List-Id"], "Zulip Dev <zulip.testserver>")
 

zerver/tests/test_management_commands.py

@@ -402,7 +402,7 @@ class TestPasswordRestEmail(ZulipTestCase):
         self.assertEqual(self.email_envelope_from(outbox[0]), settings.NOREPLY_EMAIL_ADDRESS)
         self.assertRegex(
             self.email_display_from(outbox[0]),
-            rf"^Zulip Account Security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
+            rf"^testserver account security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
         )
         self.assertIn("reset your password", outbox[0].body)
 

zerver/tests/test_message_notification_emails.py

@@ -131,7 +131,9 @@ class TestMessageNotificationEmails(ZulipTestCase):
             reply_to_emails = ["noreply@testserver"]
         msg = mail.outbox[0]
         assert isinstance(msg, EmailMultiAlternatives)
-        from_email = str(Address(display_name="Zulip notifications", addr_spec=FromAddress.NOREPLY))
+        from_email = str(
+            Address(display_name="testserver notifications", addr_spec=FromAddress.NOREPLY)
+        )
         self.assert_length(mail.outbox, 1)
         self.assertEqual(self.email_envelope_from(msg), settings.NOREPLY_EMAIL_ADDRESS)
         self.assertEqual(self.email_display_from(msg), from_email)

zerver/tests/test_realm.py

@@ -452,7 +452,7 @@ class RealmTest(ZulipTestCase):
         self.assertEqual(self.email_envelope_from(outbox[0]), settings.NOREPLY_EMAIL_ADDRESS)
         self.assertRegex(
             self.email_display_from(outbox[0]),
-            rf"^Zulip Account Security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
+            rf"^testserver account security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
         )
         self.assertIn("Reactivate your Zulip organization", outbox[0].subject)
         self.assertIn("Dear former administrators", outbox[0].body)

zerver/tests/test_signup.py

@@ -16,7 +16,6 @@ from django.http import HttpResponse, HttpResponseBase
 from django.template.response import TemplateResponse
 from django.test import Client, override_settings
 from django.utils import translation
-from django.utils.translation import gettext as _
 
 from confirmation import settings as confirmation_settings
 from confirmation.models import Confirmation, one_click_unsubscribe_link
@@ -360,7 +359,7 @@ class PasswordResetTest(ZulipTestCase):
         # The email might be sent in different languages for i18n testing
         self.assertRegex(
             self.email_display_from(message),
-            rf'^{_("Zulip Account Security")} <{self.TOKENIZED_NOREPLY_REGEX}>\Z',
+            rf"^testserver account security <{self.TOKENIZED_NOREPLY_REGEX}>\Z",
         )
         self.assertIn(f"{subdomain}.testserver", message.extra_headers["List-Id"])
 

zproject/default_settings.py

@@ -485,6 +485,8 @@ WELCOME_EMAIL_SENDER: Optional[Dict[str, str]] = None
 
 # Whether to send periodic digests of activity.
 SEND_DIGEST_EMAILS = True
+# The variable part of email sender names to be used for outgoing emails.
+INSTALLATION_NAME = EXTERNAL_HOST
 
 # Used to change the Zulip logo in portico pages.
 CUSTOM_LOGO_URL: Optional[str] = None

zproject/prod_settings_template.py

@@ -101,6 +101,13 @@ EXTERNAL_HOST = "zulip.example.com"
 ## confirmation emails when ADD_TOKENS_TO_NOREPLY_ADDRESS=False.
 # NOREPLY_EMAIL_ADDRESS = "noreply@example.com"
 
+## Emails sent by the Zulip server will use a sender name starting
+## with INSTALLATION_NAME. The default is EXTERNAL_HOST. If INSTALLATION_NAME is
+## "zulip.example.com", email senders names will include:
+## * "zulip.example.com notifications" (message notification emails).
+## * "zulip.example.com account security" (account security emails).
+# INSTALLATION_NAME = "My Zulip Server"
+
 ## Many countries and bulk mailers require certain types of email to display
 ## a physical mailing address to comply with anti-spam legislation.
 ## Non-commercial and non-public-facing installations are unlikely to need