Allow use of dynamic payloads in alert receive channels preview templ… (#1756)

…ate in private api

# What this PR does

## Which issue(s) this PR fixes

## Checklist

- [ ] Unit, integration, and e2e (if applicable) tests updated
- [ ] Documentation added (or `pr:no public docs` PR label added if not
required)
- [ ] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Helm chart: add the option to use a helm hook for the migration job ([1386](https://github.com/grafana/oncall/pull/1386))
 - Add endpoints to start and stop maintenance in alert receive channel private api ([1755](https://github.com/grafana/oncall/pull/1755))
 - Send demo alert with dynamic payload and get demo payload example on private api ([1700](https://github.com/grafana/oncall/pull/1700))
+- Allow use of dynamic payloads in alert receive channels preview template in private api ([1756](https://github.com/grafana/oncall/pull/1756))
 
 ## v1.2.11 (2023-04-14)
 

engine/apps/api/tests/test_alert_receive_channel.py

@@ -505,6 +505,44 @@ def test_alert_receive_channel_preview_template_require_notification_channel(
     assert response.status_code == status.HTTP_200_OK
 
 
+@pytest.mark.django_db
+@pytest.mark.parametrize("template_name", ["title", "message", "image_url"])
+@pytest.mark.parametrize("notification_channel", ["slack", "web", "telegram"])
+def test_alert_receive_channel_preview_template_dynamic_payload(
+    make_organization_and_user_with_plugin_token,
+    make_user_auth_headers,
+    make_alert_receive_channel,
+    template_name,
+    notification_channel,
+    make_alert_group,
+    make_alert,
+):
+    organization, user, token = make_organization_and_user_with_plugin_token()
+    alert_receive_channel = make_alert_receive_channel(organization)
+    alert_group = make_alert_group(alert_receive_channel)
+
+    make_alert(alert_group=alert_group, raw_request_data=alert_receive_channel.config.example_payload)
+
+    client = APIClient()
+    url = reverse(
+        "api-internal:alert_receive_channel-preview-template", kwargs={"pk": alert_receive_channel.public_primary_key}
+    )
+
+    data = {
+        "template_body": "{{ payload.foo }}",
+        "template_name": f"{notification_channel}_{template_name}",
+        "payload": {"foo": "bar"},
+    }
+
+    response = client.post(url, data=data, format="json", **make_user_auth_headers(user, token))
+
+    assert response.status_code == status.HTTP_200_OK
+    if notification_channel == "web" and template_name == "message":
+        assert response.data["preview"] == "<p>bar</p>"
+    else:
+        assert response.data["preview"] == "bar"
+
+
 @pytest.mark.django_db
 @pytest.mark.parametrize(
     "role,expected_status",

engine/apps/api/views/alert_group.py

@@ -657,5 +657,5 @@ class AlertGroupView(
         )
 
     # This method is required for PreviewTemplateMixin
-    def get_alert_to_template(self):
+    def get_alert_to_template(self, payload=None):
         return self.get_object().alerts.first()

engine/apps/api/views/alert_receive_channel.py

@@ -8,7 +8,7 @@ from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
 from rest_framework.viewsets import ModelViewSet
 
-from apps.alerts.models import AlertReceiveChannel
+from apps.alerts.models import Alert, AlertGroup, AlertReceiveChannel
 from apps.alerts.models.maintainable_object import MaintainableObject
 from apps.api.permissions import RBACPermission
 from apps.api.serializers.alert_receive_channel import (
@@ -22,6 +22,7 @@ from common.api_helpers.exceptions import BadRequest
 from common.api_helpers.filters import ByTeamModelFieldFilterMixin, TeamModelMultipleChoiceFilter
 from common.api_helpers.mixins import (
     FilterSerializerMixin,
+    PreviewTemplateException,
     PreviewTemplateMixin,
     PublicPrimaryKeyMixin,
     TeamFilteringMixin,
@@ -228,9 +229,16 @@ class AlertReceiveChannelView(
         return Response(response)
 
     # This method is required for PreviewTemplateMixin
-    def get_alert_to_template(self):
+    def get_alert_to_template(self, payload=None):
         try:
-            return self.get_object().alert_groups.last().alerts.first()
+            if payload is None:
+                return self.get_object().alert_groups.last().alerts.first()
+            else:
+                if type(payload) != dict:
+                    raise PreviewTemplateException("Payload must be a valid json object")
+                # Build Alert and AlertGroup objects to pass to templater without saving them to db
+                alert_group_to_template = AlertGroup(channel=self.get_object())
+                return Alert(raw_request_data=payload, group=alert_group_to_template)
         except AttributeError:
             return None
 

engine/common/api_helpers/mixins.py

@@ -283,11 +283,16 @@ BEHAVIOUR_TEMPLATE_NAMES = [RESOLVE_CONDITION, ACKNOWLEDGE_CONDITION, GROUPING_I
 ALL_TEMPLATE_NAMES = APPEARANCE_TEMPLATE_NAMES + BEHAVIOUR_TEMPLATE_NAMES
 
 
+class PreviewTemplateException(Exception):
+    pass
+
+
 class PreviewTemplateMixin:
     @action(methods=["post"], detail=True)
     def preview_template(self, request, pk):
         template_body = request.data.get("template_body", None)
         template_name = request.data.get("template_name", None)
+        payload = request.data.get("payload", None)
 
         if template_body is None or template_name is None:
             response = {"preview": None}
@@ -295,18 +300,21 @@ class PreviewTemplateMixin:
 
         notification_channel, attr_name = self.parse_name_and_notification_channel(template_name)
         if attr_name is None:
-            raise BadRequest(detail={"template_name": "Attr name is required"})
+            raise BadRequest(detail={"template_name": "Template name is missing"})
         if attr_name not in ALL_TEMPLATE_NAMES:
-            raise BadRequest(detail={"template_name": "Unknown attr name"})
+            raise BadRequest(detail={"template_name": "Unknown template name"})
         if attr_name in APPEARANCE_TEMPLATE_NAMES:
             if notification_channel is None:
                 raise BadRequest(detail={"notification_channel": "notification_channel is required"})
             if notification_channel not in NOTIFICATION_CHANNEL_OPTIONS:
                 raise BadRequest(detail={"notification_channel": "Unknown notification_channel"})
 
-        alert_to_template = self.get_alert_to_template()
-        if alert_to_template is None:
-            raise BadRequest(detail="Alert to preview does not exist")
+        try:
+            alert_to_template = self.get_alert_to_template(payload=payload)
+            if alert_to_template is None:
+                raise BadRequest(detail="Alert to preview does not exist")
+        except PreviewTemplateException as e:
+            raise BadRequest(detail=str(e))
 
         if attr_name in APPEARANCE_TEMPLATE_NAMES:
 
@@ -337,7 +345,7 @@ class PreviewTemplateMixin:
         response = {"preview": templated_attr}
         return Response(response, status=status.HTTP_200_OK)
 
-    def get_alert_to_template(self):
+    def get_alert_to_template(self, payload=None):
         raise NotImplementedError
 
     @staticmethod