billing: Add coupons.

stubs/stripe/__init__.pyi

@@ -12,6 +12,7 @@ class Customer:
     id: str
     source: str
     subscriptions: SubscriptionListObject
+    coupon: str
 
     @staticmethod
     def retrieve(customer_id: str, expand: Optional[List[str]]) -> Customer:
@@ -19,7 +20,7 @@ class Customer:
 
     @staticmethod
     def create(description: str, email: str, metadata: Dict[str, Any],
-               source: Optional[str]) -> Customer:
+               source: Optional[str], coupon: Optional[str]) -> Customer:
         ...
 
     @staticmethod
@@ -63,3 +64,10 @@ class Product:
     @staticmethod
     def create(name: str, type: str, statement_descriptor: str, unit_label: str) -> Product:
         ...
+
+class Coupon:
+    id: str
+
+    @staticmethod
+    def create(duration: str, name: str, percent_off: int) -> Coupon:
+        ...

zilencer/lib/stripe.py

@@ -18,7 +18,7 @@ from zerver.lib.timestamp import datetime_to_timestamp, timestamp_to_datetime
 from zerver.lib.utils import generate_random_token
 from zerver.lib.actions import do_change_plan_type
 from zerver.models import Realm, UserProfile, RealmAuditLog
-from zilencer.models import Customer, Plan, BillingProcessor
+from zilencer.models import Customer, Plan, Coupon, BillingProcessor
 from zproject.settings import get_secret
 
 STRIPE_PUBLISHABLE_KEY = get_secret('stripe_publishable_key')
@@ -32,6 +32,7 @@ billing_logger = logging.getLogger('zilencer.stripe')
 log_to_file(billing_logger, BILLING_LOG_PATH)
 log_to_file(logging.getLogger('stripe'), BILLING_LOG_PATH)
 
+## Note: this is no longer accurate, as of when we added coupons
 # To generate the fixture data in stripe_fixtures.json:
 # * Set PRINT_STRIPE_FIXTURE_DATA to True
 # * ./manage.py setup_stripe
@@ -136,8 +137,12 @@ def extract_current_subscription(stripe_customer: stripe.Customer) -> Any:
     return None
 
 @catch_stripe_errors
-def do_create_customer(user: UserProfile, stripe_token: Optional[str]=None) -> stripe.Customer:
+def do_create_customer(user: UserProfile, stripe_token: Optional[str]=None,
+                       coupon: Optional[Coupon]=None) -> stripe.Customer:
     realm = user.realm
+    stripe_coupon_id = None
+    if coupon is not None:
+        stripe_coupon_id = coupon.stripe_coupon_id
     # We could do a better job of handling race conditions here, but if two
     # people from a realm try to upgrade at exactly the same time, the main
     # bad thing that will happen is that we will create an extra stripe
@@ -146,7 +151,8 @@ def do_create_customer(user: UserProfile, stripe_token: Optional[str]=None) -> s
         description="%s (%s)" % (realm.string_id, realm.name),
         email=user.email,
         metadata={'realm_id': realm.id, 'realm_str': realm.string_id},
-        source=stripe_token)
+        source=stripe_token,
+        coupon=stripe_coupon_id)
     if PRINT_STRIPE_FIXTURE_DATA:
         print(''.join(['"create_customer": ', str(stripe_customer), ',']))  # nocoverage
     event_time = timestamp_to_datetime(stripe_customer.created)
@@ -177,6 +183,12 @@ def do_replace_payment_source(user: UserProfile, stripe_token: str) -> stripe.Cu
         event_time=timezone_now())
     return updated_stripe_customer
 
+@catch_stripe_errors
+def do_replace_coupon(user: UserProfile, coupon: Coupon) -> stripe.Customer:
+    stripe_customer = stripe_get_customer(Customer.objects.get(realm=user.realm).stripe_customer_id)
+    stripe_customer.coupon = coupon.stripe_coupon_id
+    return stripe_customer.save()
+
 @catch_stripe_errors
 def do_subscribe_customer_to_plan(stripe_customer: stripe.Customer, stripe_plan_id: str,
                                   seat_count: int, tax_percent: float) -> None:
@@ -244,6 +256,14 @@ def process_initial_upgrade(user: UserProfile, plan: Plan, seat_count: int, stri
         tax_percent=0)
     do_change_plan_type(user, Realm.PREMIUM)
 
+def attach_discount_to_realm(user: UserProfile, percent_off: int) -> None:
+    coupon = Coupon.objects.get(percent_off=percent_off)
+    customer = Customer.objects.filter(realm=user.realm).first()
+    if customer is None:
+        do_create_customer(user, coupon=coupon)
+    else:
+        do_replace_coupon(user, coupon)
+
 ## Process RealmAuditLog
 
 def do_set_subscription_quantity(

zilencer/management/commands/setup_stripe.py

@@ -1,5 +1,5 @@
 from zerver.lib.management import ZulipBaseCommand
-from zilencer.models import Plan
+from zilencer.models import Plan, Coupon
 from zproject.settings import get_secret
 
 from typing import Any
@@ -39,3 +39,15 @@ class Command(ZulipBaseCommand):
             nickname=Plan.CLOUD_ANNUAL,
             usage_type='licensed')
         Plan.objects.create(nickname=Plan.CLOUD_ANNUAL, stripe_plan_id=plan.id)
+
+        coupon = stripe.Coupon.create(
+            duration='forever',
+            name='25% discount',
+            percent_off=25)
+        Coupon.objects.create(percent_off=25, stripe_coupon_id=coupon.id)
+
+        coupon = stripe.Coupon.create(
+            duration='forever',
+            name='85% discount',
+            percent_off=85)
+        Coupon.objects.create(percent_off=85, stripe_coupon_id=coupon.id)

zilencer/migrations/0012_coupon.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.14 on 2018-08-23 05:40
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('zilencer', '0011_customer_has_billing_relationship'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Coupon',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('percent_off', models.SmallIntegerField(unique=True)),
+                ('stripe_coupon_id', models.CharField(max_length=255, unique=True)),
+            ],
+        ),
+    ]

zilencer/models.py

@@ -56,6 +56,13 @@ class Plan(models.Model):
 
     stripe_plan_id = models.CharField(max_length=255, unique=True)  # type: str
 
+class Coupon(models.Model):
+    percent_off = models.SmallIntegerField(unique=True)  # type: int
+    stripe_coupon_id = models.CharField(max_length=255, unique=True)  # type: str
+
+    def __str__(self) -> str:
+        return '<Coupon: %s %s %s>' % (self.percent_off, self.stripe_coupon_id, self.id)
+
 class BillingProcessor(models.Model):
     log_row = models.ForeignKey(RealmAuditLog, on_delete=models.CASCADE)  # RealmAuditLog
     # Exactly one processor, the global processor, has realm=None.

zilencer/tests/stripe_fixtures.json

@@ -6,7 +6,30 @@
         "default_source": "card_1Ch9gVGh0CmXqmnwv94RombT",
         "delinquent": false,
         "description": "zulip (Zulip Dev)",
-        "discount": null,
+        "discount": {
+            "coupon": {
+                "amount_off": null,
+                "created": 1535002820,
+                "currency": null,
+                "duration": "forever",
+                "duration_in_months": null,
+                "id": "rncBblSZ",
+                "livemode": false,
+                "max_redemptions": null,
+                "metadata": {},
+                "name": "85% discount",
+                "object": "coupon",
+                "percent_off": 85.0,
+                "redeem_by": null,
+                "times_redeemed": 1,
+                "valid": true
+            },
+            "customer": "cus_DT7pd3yW0w8lF1",
+            "end": null,
+            "object": "discount",
+            "start": 1535004909,
+            "subscription": null
+        },
         "email": "hamlet@zulip.com",
         "id": "cus_D7OT2jf5YAtZQL",
         "invoice_prefix": "23ABC45",

zilencer/tests/test_stripe.py

@@ -17,11 +17,11 @@ from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.timestamp import timestamp_to_datetime, datetime_to_timestamp
 from zerver.models import Realm, UserProfile, get_realm, RealmAuditLog
 from zilencer.lib.stripe import catch_stripe_errors, \
-    do_subscribe_customer_to_plan, \
+    do_subscribe_customer_to_plan, attach_discount_to_realm, \
     get_seat_count, extract_current_subscription, sign_string, unsign_string, \
     get_next_billing_log_entry, run_billing_processor_one_step, \
     BillingError, StripeCardError, StripeConnectionError
-from zilencer.models import Customer, Plan, BillingProcessor
+from zilencer.models import Customer, Plan, Coupon, BillingProcessor
 
 fixture_data_file = open(os.path.join(os.path.dirname(__file__), 'stripe_fixtures.json'), 'r')
 fixture_data = ujson.load(fixture_data_file)
@@ -62,12 +62,14 @@ class StripeTest(ZulipTestCase):
         # The values below should be copied from stripe_fixtures.json
         self.stripe_customer_id = 'cus_D7OT2jf5YAtZQL'
         self.customer_created = 1529990750
+        self.stripe_coupon_id = "rncBblSZ"
         self.stripe_plan_id = 'plan_D7Nh2BtpTvIzYp'
         self.subscription_created = 1529990751
         self.quantity = 8
 
         self.signed_seat_count, self.salt = sign_string(str(self.quantity))
         Plan.objects.create(nickname=Plan.CLOUD_ANNUAL, stripe_plan_id=self.stripe_plan_id)
+        Coupon.objects.create(percent_off=85, stripe_coupon_id=self.stripe_coupon_id)
 
     def get_signed_seat_count_from_response(self, response: HttpResponse) -> Optional[str]:
         match = re.search(r'name=\"signed_seat_count\" value=\"(.+)\"', response.content.decode("utf-8"))
@@ -122,7 +124,8 @@ class StripeTest(ZulipTestCase):
             description="zulip (Zulip Dev)",
             email=user.email,
             metadata={'realm_id': user.realm.id, 'realm_str': 'zulip'},
-            source=self.token)
+            source=self.token,
+            coupon=None)
         mock_create_subscription.assert_called_once_with(
             customer=self.stripe_customer_id,
             billing='charge_automatically',
@@ -358,6 +361,25 @@ class StripeTest(ZulipTestCase):
         with self.assertRaises(signing.BadSignature):
             unsign_string(signed_string, "randomsalt")
 
+    @mock.patch("stripe.Customer.retrieve", side_effect=mock_create_customer)
+    @mock.patch("stripe.Customer.create", side_effect=mock_create_customer)
+    def test_attach_discount_to_realm(self, mock_create_customer: mock.Mock,
+                                      mock_retrieve_customer: mock.Mock) -> None:
+        user = self.example_user('hamlet')
+        # Before customer exists
+        attach_discount_to_realm(user, 85)
+        mock_create_customer.assert_called_once_with(
+            description=Kandra(), email=self.example_email('hamlet'), metadata=Kandra(),
+            source=None, coupon=self.stripe_coupon_id)
+        mock_create_customer.reset_mock()
+        # For existing customer
+        Coupon.objects.create(percent_off=25, stripe_coupon_id='25OFF')
+        with mock.patch.object(
+                stripe.Customer, 'save', autospec=True,
+                side_effect=lambda stripe_customer: self.assertEqual(stripe_customer.coupon, '25OFF')):
+            attach_discount_to_realm(user, 25)
+        mock_create_customer.assert_not_called()
+
     @mock.patch("stripe.Customer.create", side_effect=mock_create_customer)
     @mock.patch("stripe.Subscription.create", side_effect=mock_create_subscription)
     @mock.patch("stripe.Customer.retrieve", side_effect=mock_customer_with_subscription)