feat(messaging): add template keys, owners and content hashes

products/messaging/backend/facade/contracts.py

@@ -3,6 +3,7 @@
 from uuid import UUID
 
 from posthog.dataclasses import frozen
+from posthog.enums import LabeledStrEnum
 
 
 class UnlayerError(Exception):
@@ -89,3 +90,8 @@ class QueuedEmail:
     message_id: str
     # True when an earlier request with the same idempotency key already queued this email.
     replayed: bool = False
+
+
+class TemplateManagedBy(LabeledStrEnum):
+    GUI = "gui", "GUI"
+    CODE = "code", "Code"

products/messaging/backend/migrations/0009_messagetemplate_code_managed_fields.py

@@ -0,0 +1,82 @@
+import django.contrib.postgres.fields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("messaging", "0008_messagetemplate_sensitive"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="content_hash",
+            field=models.CharField(
+                blank=True,
+                help_text="Hash of the published subject, preheader, HTML and text, as `v1:` and 64 hex characters.",
+                max_length=80,
+                null=True,
+            ),
+        ),
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="key",
+            field=models.CharField(
+                blank=True,
+                help_text="Client-chosen identifier, unique within this environment among templates that are not deleted. Letters, numbers, hyphens (-) and underscores (_) only.",
+                max_length=400,
+                null=True,
+            ),
+        ),
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="managed_by",
+            field=models.CharField(
+                blank=True,
+                choices=[("gui", "GUI"), ("code", "Code")],
+                help_text="Who owns the template content: `gui` for the PostHog app, `code` for uploads from a repository. Empty means `gui`.",
+                max_length=400,
+                null=True,
+            ),
+        ),
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="source_path",
+            field=models.CharField(
+                blank=True,
+                help_text="Path of the template file in the source repository.",
+                max_length=400,
+                null=True,
+            ),
+        ),
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="source_ref",
+            field=models.CharField(
+                blank=True,
+                help_text="Commit or branch of the last upload.",
+                max_length=400,
+                null=True,
+            ),
+        ),
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="source_repository",
+            field=models.CharField(
+                blank=True,
+                help_text="Repository the template was last uploaded from, such as `github.com/example/app`.",
+                max_length=400,
+                null=True,
+            ),
+        ),
+        migrations.AddField(
+            model_name="messagetemplate",
+            name="superseded_content_hashes",
+            field=django.contrib.postgres.fields.ArrayField(
+                base_field=models.CharField(max_length=80),
+                blank=True,
+                null=True,
+                size=None,
+            ),
+        ),
+    ]

products/messaging/backend/migrations/0010_messagetemplate_unique_key_per_team.py

@@ -0,0 +1,35 @@
+from django.db import migrations, models
+
+from posthog.migration_helpers import CreateIndexConcurrently
+
+
+class Migration(migrations.Migration):
+    atomic = False
+
+    dependencies = [
+        ("messaging", "0009_messagetemplate_code_managed_fields"),
+    ]
+
+    operations = [
+        migrations.SeparateDatabaseAndState(
+            state_operations=[
+                migrations.AddConstraint(
+                    model_name="messagetemplate",
+                    constraint=models.UniqueConstraint(
+                        fields=("team", "key"),
+                        condition=models.Q(("deleted", False), ("key__isnull", False)),
+                        name="unique_message_template_key_per_team",
+                    ),
+                ),
+            ],
+            database_operations=[
+                CreateIndexConcurrently(
+                    index_name="unique_message_template_key_per_team",
+                    table_name="posthog_messagetemplate",
+                    columns='("team_id", "key")',
+                    unique=True,
+                    where='WHERE (NOT "deleted" AND "key" IS NOT NULL)',
+                ),
+            ],
+        ),
+    ]

products/messaging/backend/migrations/max_migration.txt

@@ -1 +1 @@
-0008_messagetemplate_sensitive
+0010_messagetemplate_unique_key_per_team

products/messaging/backend/models/message_template.py

@@ -1,8 +1,13 @@
+from django.contrib.postgres.fields import ArrayField
 from django.db import models
 
 from posthog.models.tagged_items_relation import Taggable
 from posthog.models.utils import UUIDTModel
 
+from products.messaging.backend.facade.contracts import TemplateManagedBy
+
+KEY_CONSTRAINT = "unique_message_template_key_per_team"
+
 
 # nosemgrep: no-new-uuidt-models -- an existing model, and its stored ids cannot change.
 class MessageTemplate(Taggable, UUIDTModel):
@@ -28,9 +33,50 @@ class MessageTemplate(Taggable, UUIDTModel):
     # For emails carrying codes or reset links: sends keep no rendered body or subject, and clicks keep only
     # the link's origin.
     sensitive = models.BooleanField(default=False, db_default=False)
+    key = models.CharField(
+        max_length=400,
+        null=True,
+        blank=True,
+        help_text="Client-chosen identifier, unique within this environment among templates that are not deleted. "
+        "Letters, numbers, hyphens (-) and underscores (_) only.",
+    )
+    managed_by = models.CharField(
+        max_length=400,
+        choices=TemplateManagedBy.choices,
+        null=True,
+        blank=True,
+        help_text="Who owns the template content: `gui` for the PostHog app, `code` for uploads from a repository. "
+        "Empty means `gui`.",
+    )
+    source_repository = models.CharField(
+        max_length=400,
+        null=True,
+        blank=True,
+        help_text="Repository the template was last uploaded from, such as `github.com/example/app`.",
+    )
+    source_path = models.CharField(
+        max_length=400, null=True, blank=True, help_text="Path of the template file in the source repository."
+    )
+    source_ref = models.CharField(
+        max_length=400, null=True, blank=True, help_text="Commit or branch of the last upload."
+    )
+    content_hash = models.CharField(
+        max_length=80,
+        null=True,
+        blank=True,
+        help_text="Hash of the published subject, preheader, HTML and text, as `v1:` and 64 hex characters.",
+    )
+    superseded_content_hashes = ArrayField(models.CharField(max_length=80), null=True, blank=True)
 
     class Meta:
         db_table = "posthog_messagetemplate"
+        constraints = [
+            models.UniqueConstraint(
+                fields=["team", "key"],
+                condition=models.Q(key__isnull=False, deleted=False),
+                name=KEY_CONSTRAINT,
+            ),
+        ]
 
     def __str__(self):
         return self.name

products/messaging/backend/tests/test_message_template_key.py

@@ -0,0 +1,34 @@
+from posthog.test.base import BaseTest
+
+from django.db import IntegrityError, transaction
+
+from parameterized import parameterized
+
+from posthog.models import Team
+
+from products.messaging.backend.models.message_template import MessageTemplate
+
+
+class TestMessageTemplateKey(BaseTest):
+    def _create_template(self, team: Team, key: str, deleted: bool = False) -> MessageTemplate:
+        return MessageTemplate.objects.create(team=team, name=key, key=key, deleted=deleted)
+
+    def test_a_live_template_holds_its_key_within_its_team(self) -> None:
+        self._create_template(self.team, "welcome")
+
+        with self.assertRaises(IntegrityError), transaction.atomic():
+            self._create_template(self.team, "welcome")
+
+    @parameterized.expand(
+        [
+            ("in_another_team", False, True),
+            ("after_the_holder_is_deleted", True, False),
+        ]
+    )
+    def test_the_key_is_free(self, _name: str, first_is_deleted: bool, second_in_other_team: bool) -> None:
+        other_team = Team.objects.create(organization=self.organization, name="Other team")
+        self._create_template(self.team, "welcome", deleted=first_is_deleted)
+
+        second = self._create_template(other_team if second_in_other_team else self.team, "welcome")
+
+        self.assertEqual(MessageTemplate.objects.get(pk=second.pk).key, "welcome")