feat: Discussions panel

latest_migrations.manifest

@@ -5,7 +5,7 @@ contenttypes: 0002_remove_content_type_name
 ee: 0015_add_verified_properties
 otp_static: 0002_throttling
 otp_totp: 0002_auto_20190420_0723
-posthog: 0373_externaldataschema
+posthog: 0374_add_comments
 sessions: 0001_initial
 social_django: 0010_uid_db_index
 two_factor: 0007_auto_20201201_1019

posthog/api/__init__.py

@@ -11,6 +11,7 @@
     app_metrics,
     async_migration,
     authentication,
+    comments,
     dead_letter_queue,
     early_access_feature,
     event_definition,
@@ -332,4 +333,11 @@ def api_not_found(request):
     ["team_id"],
 )
 
+projects_router.register(
+    r"comments",
+    comments.CommentViewSet,
+    "project_comments",
+    ["team_id"],
+)
+
 projects_router.register(r"search", search.SearchViewSet, "project_search", ["team_id"])

posthog/api/comments.py

@@ -0,0 +1,89 @@
+from typing import Any, Dict
+from django.db import transaction
+from django.db.models import QuerySet
+
+from rest_framework import exceptions, serializers, viewsets, pagination
+from rest_framework.decorators import action
+from rest_framework.request import Request
+from rest_framework.response import Response
+
+from posthog.api.forbid_destroy_model import ForbidDestroyModel
+
+from posthog.api.routing import StructuredViewSetMixin
+from posthog.api.shared import UserBasicSerializer
+from posthog.models.comment import Comment
+
+
+class CommentSerializer(serializers.ModelSerializer):
+    created_by = UserBasicSerializer(read_only=True)
+
+    class Meta:
+        model = Comment
+        exclude = []
+        read_only_fields = ["id", "created_by", "version"]
+
+    def validate(self, data):
+        request = self.context["request"]
+
+        if self.instance:
+            if self.instance.created_by != request.user:
+                raise exceptions.PermissionDenied("You can only modify your own comments")
+        # TODO: Ensure created_by is set
+        # And only allow updates to own comment
+
+        data["created_by"] = request.user
+
+        return data
+
+    def update(self, instance: Comment, validated_data: Dict, **kwargs) -> Comment:
+        request = self.context["request"]
+
+        with transaction.atomic():
+            # select_for_update locks the database row so we ensure version updates are atomic
+            locked_instance = Comment.objects.select_for_update().get(pk=instance.pk)
+
+            if locked_instance.created_by != request.user:
+                raise
+
+            if validated_data.keys():
+                if validated_data.get("content"):
+                    validated_data["version"] = locked_instance.version + 1
+
+                updated_instance = super().update(locked_instance, validated_data)
+
+        return updated_instance
+
+
+class CommentPagination(pagination.CursorPagination):
+    ordering = "-created_at"
+    page_size = 100
+
+
+class CommentViewSet(StructuredViewSetMixin, ForbidDestroyModel, viewsets.ModelViewSet):
+    queryset = Comment.objects.all()
+    serializer_class = CommentSerializer
+    pagination_class = CommentPagination
+
+    def get_queryset(self) -> QuerySet:
+        queryset = super().get_queryset()
+        params = self.request.GET.dict()
+
+        if params.get("user"):
+            queryset = queryset.filter(user=params.get("user"))
+
+        if params.get("scope"):
+            queryset = queryset.filter(scope=params.get("scope"))
+
+        if params.get("item_id"):
+            queryset = queryset.filter(item_id=params.get("item_id"))
+
+        if self.action == "thread":
+            # Filter based on the source_comment_id
+            object_id = self.kwargs.get("pk")
+            queryset = queryset.filter(source_comment_id=object_id)
+
+        return queryset
+
+    @action(methods=["GET"], detail=True)
+    def thread(self, request: Request, *args: Any, **kwargs: Any) -> Response:
+        return self.list(request, *args, **kwargs)

posthog/migrations/0374_add_comments.py

@@ -0,0 +1,35 @@
+# Generated by Django 3.2.19 on 2023-12-12 09:31
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import posthog.models.utils
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('posthog', '0373_externaldataschema'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Comment',
+            fields=[
+                ('id', models.UUIDField(default=posthog.models.utils.UUIDT, editable=False, primary_key=True, serialize=False)),
+                ('content', models.TextField(blank=True, null=True)),
+                ('deleted_at', models.DateTimeField(auto_now_add=True)),
+                ('version', models.IntegerField(default=0)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('item_id', models.CharField(max_length=72, null=True)),
+                ('scope', models.CharField(max_length=79)),
+                ('created_by', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL)),
+                ('source_comment_id', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='posthog.comment')),
+                ('team', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='posthog.team')),
+            ],
+        ),
+        migrations.AddIndex(
+            model_name='comment',
+            index=models.Index(fields=['team_id', 'scope', 'item_id'], name='posthog_com_team_id_be2206_idx'),
+        ),
+    ]

posthog/models/__init__.py

@@ -20,6 +20,7 @@
 from .async_deletion import AsyncDeletion, DeletionType
 from .async_migration import AsyncMigration, AsyncMigrationError, MigrationStatus
 from .cohort import Cohort, CohortPeople
+from .comment import Comment
 from .dashboard import Dashboard
 from .dashboard_tile import DashboardTile, Text
 from .early_access_feature import EarlyAccessFeature

posthog/models/comment.py

@@ -0,0 +1,51 @@
+from django.db import models
+from posthog.models.activity_logging.activity_log import Change, Detail, log_activity
+from posthog.models.signals import mutable_receiver
+
+from posthog.models.utils import UUIDModel
+
+# NOTE: This model is meant to be loosely related to the `activity_log` as they are similar in function and approach
+
+
+class Comment(UUIDModel):
+    team: models.ForeignKey = models.ForeignKey("Team", on_delete=models.CASCADE)
+    content: models.TextField = models.TextField(blank=True, null=True)
+    deleted_at: models.DateTimeField = models.DateTimeField(auto_now_add=True, blank=True)
+    version: models.IntegerField = models.IntegerField(default=0)
+    created_at: models.DateTimeField = models.DateTimeField(auto_now_add=True, blank=True)
+    created_by: models.ForeignKey = models.ForeignKey("User", on_delete=models.SET_NULL, null=True, blank=True)
+
+    # Loose relationship modelling to other PostHog resources
+    item_id = models.fields.CharField(max_length=72, null=True)
+    scope = models.fields.CharField(max_length=79, null=False)
+
+    # TODO: How do we allow comments to exist on individual elements such as a line in a Notebook?
+    # Maybe the right way is to create a Mark in a notebook and then have that store the CommentID, keeping the comments clean
+
+    # Threads/replies are simply comments with a source_comment_id
+    source_comment_id: models.ForeignKey = models.ForeignKey("Comment", on_delete=models.CASCADE, null=True, blank=True)
+
+    class Meta:
+        indexes = [models.Index(fields=["team_id", "scope", "item_id"])]
+
+
+@mutable_receiver(models.signals.post_save, sender=Comment)
+def log_comment_activity(sender, instance: Comment, created: bool, **kwargs):
+    if created:
+        # TODO: Ensure we got this right, people should get notified when
+        # 1. A comment is placed on something they are interested in
+        # 2. A comment is in reply to a thread they started (for now)
+        # 3. A comment includes a @mention of them
+        log_activity(
+            organization_id=None,
+            team_id=instance.team_id,
+            user=instance.created_by,
+            item_id=instance.item_id,
+            scope=instance.scope,
+            activity="commented",
+            # TODO: Check with Paul if this is right
+            detail=Detail(
+                name=instance.content,
+                changes=[Change(type="Comment", field="content", action="created", after=instance.content)],
+            ),
+        )