fix: Hog function template defaults (#27508)

ee/api/test/test_hooks.py

@@ -1,6 +1,8 @@
 from typing import cast
 from unittest.mock import ANY
 
+from inline_snapshot import snapshot
+
 from ee.api.hooks import valid_domain
 from ee.api.test.base import APILicensedTest
 from ee.models.hook import Hook
@@ -117,6 +119,19 @@ def test_create_hog_function_via_hook(self):
             "bytecode": ["_H", HOGQL_BYTECODE_VERSION, 32, "$pageview", 32, "event", 1, 1, 11, 3, 1, 4, 1],
         }
 
+        assert hog_function.hog == snapshot(
+            """\
+let res := fetch(f'https://hooks.zapier.com/{inputs.hook}', {
+  'method': 'POST',
+  'body': inputs.body
+});
+
+if (inputs.debug) {
+  print('Response', res.status, res.body);
+}\
+"""
+        )
+
         assert hog_function.inputs == {
             "body": {
                 "bytecode": ANY,

posthog/api/hog_function.py

@@ -152,11 +152,12 @@ def validate(self, attrs):
         instance = cast(Optional[HogFunction], self.context.get("instance", self.instance))
 
         hog_type = attrs.get("type", instance.type if instance else "destination")
+        is_create = self.context.get("view") and self.context["view"].action == "create"
 
-        if not has_addon:
-            template_id = attrs.get("template_id", instance.template_id if instance else None)
-            template = HOG_FUNCTION_TEMPLATES_BY_ID.get(template_id, None)
+        template_id = attrs.get("template_id", instance.template_id if instance else None)
+        template = HOG_FUNCTION_TEMPLATES_BY_ID.get(template_id, None)
 
+        if not has_addon:
             # In this case they are only allowed to create or update the function with free templates
             if not template:
                 raise serializers.ValidationError(
@@ -168,18 +169,23 @@ def validate(self, attrs):
                     {"template_id": "The Data Pipelines addon is required for this template."}
                 )
 
-            # Without the addon, they cannot deviate from the template
-            attrs["inputs_schema"] = template.inputs_schema
-            attrs["mappings"] = template.mappings
+            # Without the addon you can't deviate from the template
             attrs["hog"] = template.hog
+            attrs["inputs_schema"] = template.inputs_schema
 
-        if self.context.get("view") and self.context["view"].action == "create":
+        if is_create:
             # Ensure we have sensible defaults when created
             attrs["filters"] = attrs.get("filters") or {}
             attrs["inputs_schema"] = attrs.get("inputs_schema") or []
             attrs["inputs"] = attrs.get("inputs") or {}
             attrs["mappings"] = attrs.get("mappings") or None
 
+            # And if there is a template, use the template values if not overridden
+            if template:
+                attrs["hog"] = attrs.get("hog") or template.hog
+                attrs["inputs_schema"] = attrs.get("inputs_schema") or template.inputs_schema
+                attrs["inputs"] = attrs.get("inputs") or {}
+
         # Used for both top level input validation, and mappings input validation
         def validate_input_and_filters(attrs: dict):
             if "inputs_schema" in attrs:
@@ -235,6 +241,10 @@ def validate_input_and_filters(attrs: dict):
             attrs["bytecode"] = None
             attrs["transpiled"] = None
 
+        if is_create:
+            if not attrs.get("hog"):
+                raise serializers.ValidationError({"hog": "Required."})
+
         return super().validate(attrs)
 
     def to_representation(self, data):

posthog/api/test/test_hog_function.py

@@ -264,11 +264,14 @@ def test_creates_with_template_id(self, *args):
                 "name": "Fetch URL",
                 "description": "Test description",
                 "hog": "fetch(inputs.url);",
+                "inputs": {"url": {"value": "https://example.com"}},
                 "template_id": template_webhook.id,
                 "type": "destination",
             },
         )
         assert response.status_code == status.HTTP_201_CREATED, response.json()
+
+        assert response.json()["hog"] == "fetch(inputs.url);"
         assert response.json()["template"] == {
             "type": "destination",
             "name": template_webhook.name,
@@ -286,14 +289,35 @@ def test_creates_with_template_id(self, *args):
             "sub_templates": response.json()["template"]["sub_templates"],
         }
 
+    def test_creates_with_template_values_if_not_provided(self, *args):
+        payload: dict = {
+            "name": "Fetch URL",
+            "description": "Test description",
+            "template_id": template_webhook.id,
+            "type": "destination",
+        }
+        response = self.client.post(f"/api/projects/{self.team.id}/hog_functions/", data=payload)
+        assert response.status_code == status.HTTP_400_BAD_REQUEST, response.json()
+        assert response.json() == {
+            "attr": "inputs__url",
+            "code": "invalid_input",
+            "detail": "This field is required.",
+            "type": "validation_error",
+        }
+
+        payload["inputs"] = {"url": {"value": "https://example.com"}}
+
+        response = self.client.post(f"/api/projects/{self.team.id}/hog_functions/", data=payload)
+        assert response.status_code == status.HTTP_201_CREATED, response.json()
+        assert response.json()["hog"] == template_webhook.hog
+        assert response.json()["inputs_schema"] == template_webhook.inputs_schema
+
     def test_deletes_via_update(self, *args):
         response = self.client.post(
             f"/api/projects/{self.team.id}/hog_functions/",
             data={
-                "type": "destination",
+                **EXAMPLE_FULL,
                 "name": "Fetch URL",
-                "description": "Test description",
-                "hog": "fetch(inputs.url);",
             },
         )
         assert response.status_code == status.HTTP_201_CREATED, response.json()
@@ -640,8 +664,7 @@ def test_generates_hog_bytecode(self, *args):
         response = self.client.post(
             f"/api/projects/{self.team.id}/hog_functions/",
             data={
-                "type": "destination",
-                "name": "Fetch URL",
+                **EXAMPLE_FULL,
                 "hog": "let i := 0;\nwhile(i < 3) {\n  i := i + 1;\n  fetch(inputs.url, {\n    'headers': {\n      'x-count': f'{i}'\n    },\n    'body': inputs.payload,\n    'method': inputs.method\n  });\n}",
             },
         )
@@ -882,7 +905,10 @@ def test_patches_status_on_enabled_update(self, *args):
 
                 response = self.client.post(
                     f"/api/projects/{self.team.id}/hog_functions/",
-                    data={"type": "destination", "name": "Fetch URL", "hog": "fetch(inputs.url);", "enabled": True},
+                    data={
+                        **EXAMPLE_FULL,
+                        "name": "Fetch URL",
+                    },
                 )
                 id = response.json()["id"]
 
@@ -1110,11 +1136,7 @@ def test_create_hog_function_with_site_destination_type(self):
     def test_cannot_modify_type_of_existing_hog_function(self):
         response = self.client.post(
             f"/api/projects/{self.team.id}/hog_functions/",
-            data={
-                "name": "Site Destination Function",
-                "hog": "export function onLoad() { console.log('Hello, site_destination'); }",
-                "type": "site_destination",
-            },
+            data=EXAMPLE_FULL,
         )
 
         assert response.status_code == status.HTTP_201_CREATED, response.json()
@@ -1134,11 +1156,7 @@ def test_cannot_modify_type_of_existing_hog_function(self):
     def test_transpiled_field_not_populated_for_other_types(self):
         response = self.client.post(
             f"/api/projects/{self.team.id}/hog_functions/",
-            data={
-                "name": "Regular Function",
-                "hog": "fetch(inputs.url);",
-                "type": "destination",
-            },
+            data=EXAMPLE_FULL,
         )
 
         assert response.status_code == status.HTTP_201_CREATED, response.json()