billing: Enforce license limit for plans on manual license management.

corporate/lib/registration.py

@@ -0,0 +1,104 @@
+from typing import Optional
+
+from django.conf import settings
+from django.utils.translation import gettext as _
+
+from corporate.lib.stripe import LicenseLimitError, get_latest_seat_count
+from corporate.models import get_current_plan_by_realm
+from zerver.lib.actions import send_message_to_signup_notification_stream
+from zerver.lib.exceptions import InvitationError
+from zerver.models import Realm, get_system_bot
+
+
+def generate_licenses_low_warning_message_if_required(realm: Realm) -> Optional[str]:
+    plan = get_current_plan_by_realm(realm)
+    if plan is None or plan.automanage_licenses:
+        return None
+
+    licenses_remaining = plan.licenses() - get_latest_seat_count(realm)
+    if licenses_remaining > 3:
+        return None
+
+    format_kwargs = {
+        "billing_page_link": "/billing/#settings",
+        "deactivate_user_help_page_link": "/help/deactivate-or-reactivate-a-user",
+    }
+
+    if licenses_remaining <= 0:
+        return _(
+            "Your organization has no Zulip licenses remaining and can no longer accept new users. "
+            "Please [increase the number of licenses]({billing_page_link}) or "
+            "[deactivate inactive users]({deactivate_user_help_page_link}) to allow new users to join."
+        ).format(**format_kwargs)
+
+    return {
+        1: _(
+            "Your organization has only one Zulip license remaining. You can "
+            "[increase the number of licenses]({billing_page_link}) or [deactivate inactive users]({deactivate_user_help_page_link}) "
+            "to allow more than one user to join."
+        ),
+        2: _(
+            "Your organization has only two Zulip licenses remaining. You can "
+            "[increase the number of licenses]({billing_page_link}) or [deactivate inactive users]({deactivate_user_help_page_link}) "
+            "to allow more than two users to join."
+        ),
+        3: _(
+            "Your organization has only three Zulip licenses remaining. You can "
+            "[increase the number of licenses]({billing_page_link}) or [deactivate inactive users]({deactivate_user_help_page_link}) "
+            "to allow more than three users to join."
+        ),
+    }[licenses_remaining].format(**format_kwargs)
+
+
+def send_user_unable_to_signup_message_to_signup_notification_stream(
+    realm: Realm, user_email: str
+) -> None:
+    message = _(
+        "A new member ({email}) was unable to join your organization because all Zulip licenses "
+        "are in use. Please [increase the number of licenses]({billing_page_link}) or "
+        "[deactivate inactive users]({deactivate_user_help_page_link}) to allow new members to join."
+    ).format(
+        email=user_email,
+        billing_page_link="/billing/#settings",
+        deactivate_user_help_page_link="/help/deactivate-or-reactivate-a-user",
+    )
+
+    send_message_to_signup_notification_stream(
+        get_system_bot(settings.NOTIFICATION_BOT), realm, message
+    )
+
+
+def check_spare_licenses_available_for_adding_new_users(
+    realm: Realm, number_of_users_to_add: int
+) -> None:
+    if realm.string_id in settings.LICENSE_CHECK_EXEMPTED_REALMS_ON_MANUAL_PLAN:
+        return  # nocoverage
+
+    plan = get_current_plan_by_realm(realm)
+    if plan is None or plan.automanage_licenses:
+        return
+    if plan.licenses() < get_latest_seat_count(realm) + number_of_users_to_add:
+        raise LicenseLimitError()
+
+
+def check_spare_licenses_available_for_registering_new_user(
+    realm: Realm, user_email_to_add: str
+) -> None:
+    try:
+        check_spare_licenses_available_for_adding_new_users(realm, 1)
+    except LicenseLimitError:
+        send_user_unable_to_signup_message_to_signup_notification_stream(realm, user_email_to_add)
+        raise
+
+
+def check_spare_licenses_available_for_inviting_new_users(realm: Realm, num_invites: int) -> None:
+    try:
+        check_spare_licenses_available_for_adding_new_users(realm, num_invites)
+    except LicenseLimitError:
+        if num_invites == 1:
+            message = _("All Zulip licenses for this organization are currently in use.")
+        else:
+            message = _(
+                "Your organization does not have enough unused Zulip licenses to invite {num_invites} users."
+            ).format(num_invites=num_invites)
+        raise InvitationError(message, [], sent_invitations=False, license_limit_reached=True)