frames: add new StopFrame

CHANGELOG.md

@@ -9,6 +9,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Added a new `StopFrame` which can be used to stop a pipeline task while
+  keeping the frame processors running. The frame processors could then be used
+  in a different pipeline. The difference between a `StopFrame` and a
+  `StopTaskFrame` is that, as with `EndFrame` and `EndTaskFrame`, the
+  `StopFrame` is pushed from the task and the `StopTaskFrame` is pushed upstream
+  inside the pipeline by any processor.
+
 - Added a new `PipelineTask` parameter `observers` that replaces the previous
   `PipelineParams.observers`.
 

src/pipecat/frames/frames.py

@@ -513,9 +513,9 @@ class CancelTaskFrame(SystemFrame):
 
 @dataclass
 class StopTaskFrame(SystemFrame):
-    """Indicates that a pipeline task should be stopped but that the pipeline
+    """This is used to notify the pipeline task that it should be stopped as
-    processors should be kept in a running state. This is normally queued from
+    soon as possible (flushing all the queued frames) but that the pipeline
-    the pipeline task.
+    processors should be kept in a running state.
 
     """
 
@@ -722,6 +722,17 @@ class EndFrame(ControlFrame):
     pass
 
 
+@dataclass
+class StopFrame(ControlFrame):
+    """Indicates that a pipeline should be stopped but that the pipeline
+    processors should be kept in a running state. This is normally queued from
+    the pipeline task.
+
+    """
+
+    pass
+
+
 @dataclass
 class LLMFullResponseStartFrame(ControlFrame):
     """Used to indicate the beginning of an LLM response. Following by one or