billing: Add do_change_remote_server_plan_type.

This is a part of the plumbing we need to support billing for
self-hosted customers.

With documentation changes from tabbott.

corporate/lib/stripe.py

@@ -32,6 +32,7 @@ from zerver.lib.send_email import FromAddress, send_email_to_billing_admins_and_
 from zerver.lib.timestamp import datetime_to_timestamp, timestamp_to_datetime
 from zerver.lib.utils import assert_is_not_none
 from zerver.models import Realm, RealmAuditLog, UserProfile, get_system_bot
+from zilencer.models import RemoteZulipServer, RemoteZulipServerAuditLog
 from zproject.config import get_secret
 
 stripe.api_key = get_secret("stripe_secret_key")
@@ -619,6 +620,19 @@ def ensure_realm_does_not_have_active_plan(realm: Customer) -> None:
         raise UpgradeWithExistingPlanError()
 
 
+@transaction.atomic
+def do_change_remote_server_plan_type(remote_server: RemoteZulipServer, plan_type: int) -> None:
+    old_value = remote_server.plan_type
+    remote_server.plan_type = plan_type
+    remote_server.save(update_fields=["plan_type"])
+    RemoteZulipServerAuditLog.objects.create(
+        event_type=RealmAuditLog.REMOTE_SERVER_PLAN_TYPE_CHANGED,
+        server=remote_server,
+        event_time=timezone_now(),
+        extra_data={"old_value": old_value, "new_value": plan_type},
+    )
+
+
 # Only used for cloud signups
 @catch_stripe_errors
 def process_initial_upgrade(

corporate/tests/test_stripe.py

@@ -36,6 +36,7 @@ from corporate.lib.stripe import (
     catch_stripe_errors,
     compute_plan_parameters,
     customer_has_credit_card_as_default_payment_method,
+    do_change_remote_server_plan_type,
     do_create_stripe_customer,
     downgrade_small_realms_behind_on_payments_as_needed,
     get_discount_for_realm,
@@ -97,6 +98,7 @@ from zerver.models import (
     get_realm,
     get_system_bot,
 )
+from zilencer.models import RemoteZulipServer, RemoteZulipServerAuditLog
 
 CallableT = TypeVar("CallableT", bound=Callable[..., Any])
 
@@ -4418,6 +4420,30 @@ class BillingHelpersTest(ZulipTestCase):
         realm.save()
         self.assertTrue(is_sponsored_realm(realm))
 
+    def test_change_remote_server_plan_type(self) -> None:
+        server_uuid = "demo-1234"
+        remote_server = RemoteZulipServer.objects.create(
+            uuid=server_uuid,
+            api_key="magic_secret_api_key",
+            hostname="demo.example.com",
+            contact_email="email@example.com",
+        )
+        self.assertEqual(remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_SELF_HOSTED)
+
+        do_change_remote_server_plan_type(remote_server, RemoteZulipServer.PLAN_TYPE_STANDARD)
+
+        remote_server = RemoteZulipServer.objects.get(uuid=server_uuid)
+        remote_realm_audit_log = RemoteZulipServerAuditLog.objects.filter(
+            event_type=RealmAuditLog.REMOTE_SERVER_PLAN_TYPE_CHANGED
+        ).last()
+        assert remote_realm_audit_log is not None
+        expected_extra_data = {
+            "old_value": RemoteZulipServer.PLAN_TYPE_SELF_HOSTED,
+            "new_value": RemoteZulipServer.PLAN_TYPE_STANDARD,
+        }
+        self.assertEqual(remote_realm_audit_log.extra_data, str(expected_extra_data))
+        self.assertEqual(remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_STANDARD)
+
 
 class LicenseLedgerTest(StripeTestCase):
     def test_add_plan_renewal_if_needed(self) -> None:

zerver/models.py

@@ -3883,6 +3883,11 @@ class AbstractRealmAuditLog(models.Model):
     STREAM_NAME_CHANGED = 603
     STREAM_REACTIVATED = 604
 
+    # The following values are only for RemoteZulipServerAuditLog
+    # Values are chosen to be 10000 greater than the value in RealmAuditLog.
+    REMOTE_SERVER_CREATED = 10215
+    REMOTE_SERVER_PLAN_TYPE_CHANGED = 10204
+
     event_type: int = models.PositiveSmallIntegerField()
 
     # event_types synced from on-prem installations to Zulip Cloud when

zilencer/migrations/0019_remotezulipserver_plan_type.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.9 on 2021-12-01 16:24
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("zilencer", "0018_remoterealmauditlog"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="remotezulipserver",
+            name="plan_type",
+            field=models.PositiveSmallIntegerField(default=1),
+        ),
+    ]

zilencer/migrations/0020_remotezulipserverauditlog.py

@@ -0,0 +1,38 @@
+# Generated by Django 3.2.9 on 2021-12-06 18:35
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("zilencer", "0019_remotezulipserver_plan_type"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="RemoteZulipServerAuditLog",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+                ("event_time", models.DateTimeField(db_index=True)),
+                ("backfilled", models.BooleanField(default=False)),
+                ("extra_data", models.TextField(null=True)),
+                ("event_type", models.PositiveSmallIntegerField()),
+                (
+                    "server",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE, to="zilencer.remotezulipserver"
+                    ),
+                ),
+            ],
+            options={
+                "abstract": False,
+            },
+        ),
+    ]

zilencer/models.py

@@ -15,17 +15,34 @@ def get_remote_server_by_uuid(uuid: str) -> "RemoteZulipServer":
 
 
 class RemoteZulipServer(models.Model):
+    """Each object corresponds to a single remote Zulip server that is
+    registered for the Mobile Push Notifications Service via
+    `manage.py register_server`.
+    """
+
     UUID_LENGTH = 36
     API_KEY_LENGTH = 64
     HOSTNAME_MAX_LENGTH = 128
 
+    # The unique UUID (`zulip_org_id`) and API key (`zulip_org_key`)
+    # for this remote server registration.
     uuid: str = models.CharField(max_length=UUID_LENGTH, unique=True)
     api_key: str = models.CharField(max_length=API_KEY_LENGTH)
 
+    # The hostname and contact details are not verified/trusted. Thus,
+    # they primarily exist so that we can communicate with the
+    # maintainer of a server about abuse problems.
     hostname: str = models.CharField(max_length=HOSTNAME_MAX_LENGTH)
     contact_email: str = models.EmailField(blank=True, null=False)
     last_updated: datetime.datetime = models.DateTimeField("last updated", auto_now=True)
 
+    # Plan types for self-hosted customers
+    PLAN_TYPE_SELF_HOSTED = 1
+    PLAN_TYPE_STANDARD = 102
+
+    # The current billing plan for the remote server, similar to Realm.plan_type.
+    plan_type: int = models.PositiveSmallIntegerField(default=PLAN_TYPE_SELF_HOSTED)
+
     def __str__(self) -> str:
         return f"<RemoteZulipServer {self.hostname} {self.uuid[0:12]}>"
 
@@ -33,8 +50,9 @@ class RemoteZulipServer(models.Model):
         return "zulip-server:" + self.uuid
 
 
-# Variant of PushDeviceToken for a remote server.
 class RemotePushDeviceToken(AbstractPushDeviceToken):
+    """Like PushDeviceToken, but for a device connected to a remote server."""
+
     server: RemoteZulipServer = models.ForeignKey(RemoteZulipServer, on_delete=models.CASCADE)
     # The user id on the remote server for this device device this is
     user_id: int = models.BigIntegerField(db_index=True)
@@ -46,6 +64,22 @@ class RemotePushDeviceToken(AbstractPushDeviceToken):
         return f"<RemotePushDeviceToken {self.server} {self.user_id}>"
 
 
+class RemoteZulipServerAuditLog(AbstractRealmAuditLog):
+    """Audit data associated with a remote Zulip server (not specific to a
+    realm).  Used primarily for tracking registration and billing
+    changes for self-hosted customers.
+
+    In contrast with RemoteRealmAuditLog, which has a copy of data
+    that is generated on the client Zulip server, this table is the
+    authoritative storage location for the server's history.
+    """
+
+    server: RemoteZulipServer = models.ForeignKey(RemoteZulipServer, on_delete=models.CASCADE)
+
+    def __str__(self) -> str:
+        return f"<RemoteZulipServerAuditLog: {self.server} {self.event_type} {self.event_time} {self.id}>"
+
+
 class RemoteRealmAuditLog(AbstractRealmAuditLog):
     """Synced audit data from a remote Zulip server, used primarily for
     billing.  See RealmAuditLog and AbstractRealmAuditLog for details.