Add Support for Tiered Pricing Plans

pinax/stripe/actions/plans.py

@@ -29,11 +29,24 @@ def sync_plan(plan, event=None):
  "name": plan["name"],
  "statement_descriptor": plan["statement_descriptor"] or "",
  "trial_period_days": plan["trial_period_days"],
- "metadata": plan["metadata"]
+ "metadata": plan["metadata"],
+ "billing_scheme": plan["billing_scheme"],
+ "tiers_mode": plan["tiers_mode"]
  }
 
  obj, created = models.Plan.objects.get_or_create(
  stripe_id=plan["id"],
  defaults=defaults
  )
  utils.update_with_defaults(obj, defaults, created)
+
+ if plan["tiers"]:
+ obj.tiers.all().delete() # delete all tiers, since they don't have ids in Stripe
+ for tier in plan["tiers"]:
+ tier_obj = models.Tier.objects.create(
+ plan=obj,
+ amount=utils.convert_amount_for_db(tier["amount"], plan["currency"]),
+ flat_amount=utils.convert_amount_for_db(tier["flat_amount"], plan["currency"]),
+ up_to=tier["up_to"]
+ )
+ obj.tiers.add(tier_obj)

pinax/stripe/managers.py

@@ -71,3 +71,43 @@ def paid_totals_for(self, year, month):
  total_amount=models.Sum("amount"),
  total_refunded=models.Sum("amount_refunded")
  )
+
+
+class TieredPricingManager(models.Manager):
+
+ TIERS_MODE_VOLUME = "volume"
+ TIERS_MODE_GRADUATED = "graduated"
+ TIERS_MODES = (TIERS_MODE_VOLUME, TIERS_MODE_GRADUATED)
+
+ def closed_tiers(self, plan):
+ return self.filter(plan=plan, up_to__isnull=False).order_by("up_to")
+
+ def open_tiers(self, plan):
+ return self.filter(plan=plan, up_to__isnull=True)
+
+ def all_tiers(self, plan):
+ return list(self.closed_tiers(plan)) + list(self.open_tiers(plan))
+
+ def calculate_final_cost(self, plan, quantity, mode):
+ if mode not in self.TIERS_MODES:
+ raise Exception("Received wrong type of mode ({})".format(mode))
+
+ all_tiers = self.all_tiers(plan)
+ cost = 0
+ if mode == self.TIERS_MODE_VOLUME:
+ applicable_tiers = list(filter(lambda t: not t.up_to or quantity <= t.up_to, all_tiers))
+ tier = applicable_tiers[0] if applicable_tiers else all_tiers[-1]
+ cost = tier.calculate_cost(quantity)
+
+ if mode == self.TIERS_MODE_GRADUATED:
+ quantity_billed = 0
+ idx = 0
+ while quantity > 0:
+ tier = all_tiers[idx]
+ quantity_to_bill = min(quantity, tier.up_to - quantity_billed) if tier.up_to else quantity
+ cost += tier.calculate_cost(quantity_to_bill)
+ quantity -= quantity_to_bill
+ quantity_billed += quantity_to_bill
+ idx += 1
+
+ return cost

pinax/stripe/migrations/0015_auto_20190203_0949.py

@@ -0,0 +1,34 @@
+# Generated by Django 2.2a1 on 2019-02-03 14:49
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+ dependencies = [
+ ('pinax_stripe', '0014_auto_20180413_1959'),
+ ]
+
+ operations = [
+ migrations.AddField(
+ model_name='plan',
+ name='billing_scheme',
+ field=models.CharField(default='per_unit', max_length=15),
+ ),
+ migrations.AddField(
+ model_name='plan',
+ name='tiers_mode',
+ field=models.CharField(blank=True, max_length=15, null=True),
+ ),
+ migrations.CreateModel(
+ name='Tier',
+ fields=[
+ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+ ('amount', models.DecimalField(decimal_places=2, max_digits=9)),
+ ('flat_amount', models.DecimalField(decimal_places=2, max_digits=9)),
+ ('up_to', models.IntegerField(blank=True, null=True)),
+ ('plan', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='tiers', to='pinax_stripe.Plan')),
+ ],
+ ),
+ ]

pinax/stripe/models.py

@@ -14,7 +14,7 @@
 from jsonfield.fields import JSONField
 
 from .conf import settings
-from .managers import ChargeManager, CustomerManager
+from .managers import ChargeManager, CustomerManager, TieredPricingManager
 from .utils import CURRENCY_SYMBOLS
 
 
@@ -76,6 +76,9 @@ def stripe_account_stripe_id(self):
 
 @python_2_unicode_compatible
 class Plan(UniquePerAccountStripeObject):
+ BILLING_SCHEME_PER_UNIT = "per_unit"
+ BILLING_SCHEME_TIERED = "tiered"
+
  amount = models.DecimalField(decimal_places=2, max_digits=9)
  currency = models.CharField(max_length=15, blank=False)
  interval = models.CharField(max_length=15)
@@ -84,6 +87,8 @@ class Plan(UniquePerAccountStripeObject):
  statement_descriptor = models.TextField(blank=True)
  trial_period_days = models.IntegerField(null=True, blank=True)
  metadata = JSONField(null=True, blank=True)
+ billing_scheme = models.CharField(max_length=15, default=BILLING_SCHEME_PER_UNIT)
+ tiers_mode = models.CharField(max_length=15, null=True, blank=True)
 
  def __str__(self):
  return "{} ({}{})".format(self.name, CURRENCY_SYMBOLS.get(self.currency, ""), self.amount)
@@ -107,6 +112,14 @@ def stripe_plan(self):
  stripe_account=self.stripe_account_stripe_id,
  )
 
+ def calculate_total_amount(self, quantity):
+ if self.billing_scheme == self.BILLING_SCHEME_PER_UNIT:
+ return self.amount * quantity
+ elif self.billing_scheme == self.BILLING_SCHEME_TIERED:
+ return Tier.pricing.calculate_final_cost(self, quantity, self.tiers_mode)
+ else:
+ raise Exception("The Plan ({}) received the wrong type of billing_scheme ({})".format(self.name, self.billing_scheme))
+
 
 @python_2_unicode_compatible
 class Coupon(StripeObject):
@@ -379,7 +392,7 @@ def stripe_subscription(self):
 
  @property
  def total_amount(self):
- return self.plan.amount * self.quantity
+ return self.plan.calculate_total_amount(self.quantity)
 
  def plan_display(self):
  return self.plan.name
@@ -653,3 +666,17 @@ def stripe_bankaccount(self):
  return self.account.stripe_account.external_accounts.retrieve(
  self.stripe_id
  )
+
+
+class Tier(models.Model):
+
+ plan = models.ForeignKey(Plan, related_name="tiers", on_delete=models.CASCADE)
+ amount = models.DecimalField(decimal_places=2, max_digits=9)
+ flat_amount = models.DecimalField(decimal_places=2, max_digits=9)
+ up_to = models.IntegerField(blank=True, null=True)
+
+ objects = models.Manager()
+ pricing = TieredPricingManager()
+
+ def calculate_cost(self, quantity):
+ return (self.amount * quantity) + self.flat_amount

pinax/stripe/tests/__init__.py

@@ -146,7 +146,10 @@
  "currency": "usd",
  "created": 1498573686,
  "name": "Pro Plan",
- "metadata": {}
+ "metadata": {},
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
  }
  },
  "type": "plan.updated",

pinax/stripe/tests/test_actions.py

@@ -1212,7 +1212,10 @@ def test_sync_plans(self, PlanAutoPagerMock):
  "metadata": {},
  "name": "The Pro Plan",
  "statement_descriptor": "ALTMAN",
- "trial_period_days": 3
+ "trial_period_days": 3,
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
  },
  {
  "id": "simple1",
@@ -1226,12 +1229,45 @@ def test_sync_plans(self, PlanAutoPagerMock):
  "metadata": {},
  "name": "The Simple Plan",
  "statement_descriptor": "ALTMAN",
- "trial_period_days": 3
+ "trial_period_days": 3,
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
+ },
+ {
+ "id": "tiered1",
+ "object": "plan",
+ "amount": None,
+ "created": 1448121054,
+ "currency": "usd",
+ "interval": "month",
+ "interval_count": 1,
+ "livemode": False,
+ "metadata": {},
+ "name": "The Simple Plan",
+ "statement_descriptor": "ALTMAN",
+ "trial_period_days": 3,
+ "billing_scheme": "tiered",
+ "tiers_mode": "test",
+ "tiers": [
+ {
+ "amount": None,
+ "flat_amount": 14900,
+ "up_to": 100
+ },
+ {
+ "amount": 100,
+ "flat_amount": None,
+ "up_to": None
+ }
+ ],
  },
  ]
  plans.sync_plans()
- self.assertTrue(Plan.objects.all().count(), 2)
+ self.assertEqual(Plan.objects.all().count(), len(PlanAutoPagerMock.return_value))
  self.assertEqual(Plan.objects.get(stripe_id="simple1").amount, decimal.Decimal("9.99"))
+ self.assertTrue(Plan.objects.filter(stripe_id="tiered1").exists())
+ self.assertEqual(Plan.objects.get(stripe_id="tiered1").tiers.count(), 2)
 
  @patch("stripe.Plan.auto_paging_iter", create=True)
  def test_sync_plans_update(self, PlanAutoPagerMock):
@@ -1248,7 +1284,10 @@ def test_sync_plans_update(self, PlanAutoPagerMock):
  "metadata": {},
  "name": "The Pro Plan",
  "statement_descriptor": "ALTMAN",
- "trial_period_days": 3
+ "trial_period_days": 3,
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
  },
  {
  "id": "simple1",
@@ -1262,15 +1301,47 @@ def test_sync_plans_update(self, PlanAutoPagerMock):
  "metadata": {},
  "name": "The Simple Plan",
  "statement_descriptor": "ALTMAN",
- "trial_period_days": 3
+ "trial_period_days": 3,
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
+ },
+ {
+ "id": "tiered1",
+ "object": "plan",
+ "amount": None,
+ "created": 1448121054,
+ "currency": "usd",
+ "interval": "month",
+ "interval_count": 1,
+ "livemode": False,
+ "metadata": {},
+ "name": "The Simple Plan",
+ "statement_descriptor": "ALTMAN",
+ "trial_period_days": 3,
+ "billing_scheme": "tiered",
+ "tiers_mode": "test",
+ "tiers": [
+ {
+ "amount": None,
+ "flat_amount": 14900,
+ "up_to": 100
+ },
+ {
+ "amount": 100,
+ "flat_amount": None,
+ "up_to": None
+ }
+ ],
  },
  ]
  plans.sync_plans()
- self.assertTrue(Plan.objects.all().count(), 2)
+ self.assertEqual(Plan.objects.all().count(), len(PlanAutoPagerMock.return_value))
  self.assertEqual(Plan.objects.get(stripe_id="simple1").amount, decimal.Decimal("9.99"))
  PlanAutoPagerMock.return_value[1].update({"amount": 499})
  plans.sync_plans()
  self.assertEqual(Plan.objects.get(stripe_id="simple1").amount, decimal.Decimal("4.99"))
+ self.assertEqual(Plan.objects.get(stripe_id="tiered1").tiers.count(), 2)
 
  def test_sync_plan(self):
  """
@@ -1295,7 +1366,10 @@ def test_sync_plan(self):
  "metadata": {},
  "name": "Gold Plan",
  "statement_descriptor": "ALTMAN",
- "trial_period_days": 3
+ "trial_period_days": 3,
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
  }
  plans.sync_plan(plan)
  self.assertTrue(Plan.objects.all().count(), 1)

pinax/stripe/tests/test_commands.py

@@ -43,7 +43,10 @@ def test_plans_create(self, PlanAutoPagerMock):
  "statement_descriptor": None,
  "trial_period_days": None,
  "name": "Pro",
- "metadata": {}
+ "metadata": {},
+ "billing_scheme": "per_unit",
+ "tiers_mode": None,
+ "tiers": None
  }]
  management.call_command("sync_plans")
  self.assertEqual(Plan.objects.count(), 1)