feat: add possibility to initialize the Graph with components

src/backend/base/langflow/api/v1/chat.py

@@ -95,18 +95,7 @@ async def retrieve_vertices_order(
             graph = await build_and_cache_graph_from_data(
                 flow_id=flow_id_str, graph_data=data.model_dump(), chat_service=chat_service
             )
-        graph.validate_stream()
-        if stop_component_id or start_component_id:
-            try:
-                first_layer = graph.sort_vertices(stop_component_id, start_component_id)
-            except Exception as exc:
-                logger.error(exc)
-                first_layer = graph.sort_vertices()
-        else:
-            first_layer = graph.sort_vertices()
-
-        for vertex_id in first_layer:
-            graph.run_manager.add_to_vertices_being_run(vertex_id)
+        graph = graph.prepare(stop_component_id, start_component_id)
 
         # Now vertices is a list of lists
         # We need to get the id of each vertex
@@ -122,7 +111,7 @@ async def retrieve_vertices_order(
                 playgroundSuccess=True,
             ),
         )
-        return VerticesOrderResponse(ids=first_layer, run_id=graph._run_id, vertices_to_run=vertices_to_run)
+        return VerticesOrderResponse(ids=graph.first_layer, run_id=graph.run_id, vertices_to_run=vertices_to_run)
     except Exception as exc:
         background_tasks.add_task(
             telemetry_service.log_package_playground,
@@ -189,19 +178,18 @@ async def build_vertex(
 
         try:
             lock = chat_service._async_cache_locks[flow_id_str]
-            (
-                result_dict,
-                params,
-                valid,
-                artifacts,
-                vertex,
-            ) = await graph.build_vertex(
-                chat_service=chat_service,
+            vertex_build_result = await graph.build_vertex(
                 vertex_id=vertex_id,
                 user_id=current_user.id,
                 inputs_dict=inputs.model_dump() if inputs else {},
                 files=files,
+                get_cache=chat_service.get_cache,
+                set_cache=chat_service.set_cache,
             )
+            result_dict = vertex_build_result.result_dict
+            params = vertex_build_result.params
+            valid = vertex_build_result.valid
+            artifacts = vertex_build_result.artifacts
             next_runnable_vertices = await graph.get_next_runnable_vertices(lock, vertex=vertex, cache=False)
             top_level_vertices = graph.get_top_level_vertices(next_runnable_vertices)
 

src/backend/base/langflow/components/__init__.py

@@ -1,9 +1,31 @@
+from . import (
+    agents,
+    chains,
+    documentloaders,
+    embeddings,
+    helpers,
+    inputs,
+    memories,
+    models,
+    outputs,
+    prompts,
+    prototypes,
+    retrievers,
+    textsplitters,
+    toolkits,
+    tools,
+    vectorstores,
+)
+
 __all__ = [
     "agents",
     "chains",
     "documentloaders",
     "embeddings",
+    "prompts",
     "prototypes",
+    "models",
+    "helpers",
     "inputs",
     "memories",
     "outputs",

src/backend/base/langflow/components/prompts/Prompt.py

@@ -1,5 +1,6 @@
 from langflow.base.prompts.api_utils import process_prompt_template
 from langflow.custom import Component
+from langflow.inputs.inputs import DefaultPromptField
 from langflow.io import Output, PromptInput
 from langflow.schema.message import Message
 from langflow.template.utils import update_template_values
@@ -27,12 +28,25 @@ async def build_prompt(
         self.status = prompt.text
         return prompt
 
+    def _update_template(self, frontend_node: dict):
+        prompt_template = frontend_node["template"]["template"]["value"]
+        custom_fields = frontend_node["custom_fields"]
+        frontend_node_template = frontend_node["template"]
+        _ = process_prompt_template(
+            template=prompt_template,
+            name="template",
+            custom_fields=custom_fields,
+            frontend_node_template=frontend_node_template,
+        )
+        return frontend_node
+
     def post_code_processing(self, new_frontend_node: dict, current_frontend_node: dict):
         """
         This function is called after the code validation is done.
         """
         frontend_node = super().post_code_processing(new_frontend_node, current_frontend_node)
         template = frontend_node["template"]["template"]["value"]
+        # Kept it duplicated for backwards compatibility
         _ = process_prompt_template(
             template=template,
             name="template",
@@ -43,3 +57,6 @@ def post_code_processing(self, new_frontend_node: dict, current_frontend_node: d
         # and update the frontend_node with those values
         update_template_values(new_template=frontend_node, previous_template=current_frontend_node["template"])
         return frontend_node
+
+    def _get_fallback_input(self, **kwargs):
+        return DefaultPromptField(**kwargs)