feat: Include plan outcome in WorkerEvents

docs/reference/openapi.yaml

@@ -246,6 +246,26 @@ components:
       - name
       title: Task
       type: object
+    TaskError:
+      additionalProperties: false
+      description: Wrapper around an exception raised by a plan
+      properties:
+        message:
+          title: Message
+          type: string
+        outcome:
+          const: error
+          default: error
+          title: Outcome
+          type: string
+        type:
+          title: Type
+          type: string
+      required:
+      - type
+      - message
+      title: TaskError
+      type: object
     TaskRequest:
       additionalProperties: false
       description: Request to run a task with related info
@@ -280,6 +300,31 @@ components:
       - task_id
       title: TaskResponse
       type: object
+    TaskResult:
+      additionalProperties: false
+      description: 'Serializable wrapper around the result of a plan
+
+
+        If the result is not serializable, the result will be None but the type
+
+        will be the name of the type. If the result is actually None, the type will
+
+        be ''NoneType''.'
+      properties:
+        outcome:
+          const: success
+          default: success
+          title: Outcome
+          type: string
+        result:
+          title: Result
+        type:
+          title: Type
+          type: string
+      required:
+      - type
+      title: TaskResult
+      type: object
     TasksListResponse:
       additionalProperties: false
       description: Diagnostic information on the tasks
@@ -311,6 +356,12 @@ components:
           default: true
           title: Is Pending
           type: boolean
+        outcome:
+          anyOf:
+          - $ref: '#/components/schemas/TaskResult'
+          - $ref: '#/components/schemas/TaskError'
+          - type: 'null'
+          title: Outcome
         request_id:
           title: Request Id
           type: string
@@ -382,7 +433,7 @@ info:
     name: Apache 2.0
     url: https://www.apache.org/licenses/LICENSE-2.0.html
   title: BlueAPI Control
-  version: 1.1.3
+  version: 1.2.0
 openapi: 3.1.0
 paths:
   /config/oidc:

src/blueapi/cli/cli.py

@@ -8,7 +8,7 @@
 from functools import wraps
 from pathlib import Path
 from pprint import pprint
-from typing import ParamSpec, TypeVar
+from typing import ParamSpec, TypeVar, cast
 
 import click
 from bluesky.callbacks.best_effort import BestEffortCallback
@@ -38,6 +38,7 @@
 from blueapi.service.authentication import SessionCacheManager, SessionManager
 from blueapi.service.model import DeviceResponse, PlanResponse, SourceInfo, TaskRequest
 from blueapi.worker import ProgressEvent, WorkerEvent
+from blueapi.worker.event import TaskError, TaskResult
 
 from .scratch import setup_scratch
 from .updates import CliEventRenderer
@@ -290,7 +291,7 @@ def run_plan(
     instrument_session: str,
 ) -> None:
     """Run a plan with parameters"""
-    client: BlueapiClient = obj["client"]
+    client = cast(BlueapiClient, obj["client"])
 
     parameters = parameters or "{}"
     try:
@@ -320,9 +321,15 @@ def on_event(event: AnyEvent) -> None:
                     callback(event.name, event.doc)
 
             resp = client.run_task(task, on_event=on_event)
-
-            if resp.task_status is not None and not resp.task_status.task_failed:
-                print("Plan Succeeded")
+            match resp.result:
+                case TaskResult(result=None, type="NoneType"):
+                    print("Plan succeeded")
+                case TaskResult(result=None, type=t):
+                    print(f"Plan returned unserializable result of type '{t}'")
+                case TaskResult(result=r):
+                    print(f"Plan succeeded: {r}")
+                case TaskError(type=exc, message=m):
+                    print(f"Plan failed: {exc}: {m}")
         else:
             server_task = client.create_and_start_task(task)
             click.echo(server_task.task_id)

src/blueapi/client/client.py

@@ -41,7 +41,7 @@
 from blueapi.worker.event import ProgressEvent, TaskStatus
 from blueapi.worker.task_worker import TrackableTask
 
-from .event_bus import AnyEvent, BlueskyStreamingError, EventBusClient, OnAnyEvent
+from .event_bus import AnyEvent, EventBusClient, OnAnyEvent
 from .rest import BlueapiRestClient, BlueskyRemoteControlError
 
 TRACER = get_tracer("client")
@@ -445,7 +445,7 @@ def run_task(
         task: TaskRequest,
         on_event: OnAnyEvent | None = None,
         timeout: float | None = None,
-    ) -> WorkerEvent:
+    ) -> TaskStatus:
         """
         Synchronously run a task, requires a message bus connection
 
@@ -468,7 +468,7 @@ def run_task(
         task_response = self._rest.create_task(task)
         task_id = task_response.task_id
 
-        complete: Future[WorkerEvent] = Future()
+        complete: Future[TaskStatus] = Future()
 
         def inner_on_event(event: AnyEvent, ctx: MessageContext) -> None:
             match event:
@@ -490,19 +490,19 @@ def inner_on_event(event: AnyEvent, ctx: MessageContext) -> None:
                         log.error(
                             f"Callback ({cb}) failed for event: {event}", exc_info=e
                         )
-                if isinstance(event, WorkerEvent) and (
-                    (event.is_complete()) and (ctx.correlation_id == task_id)
+                if (
+                    isinstance(event, WorkerEvent)
+                    and (event.is_complete())
+                    and (ctx.correlation_id == task_id)
                 ):
-                    if event.task_status is not None and event.task_status.task_failed:
+                    if event.task_status is None:
                         complete.set_exception(
-                            BlueskyStreamingError(
-                                "\n".join(event.errors)
-                                if len(event.errors) > 0
-                                else "Unknown error"
+                            BlueskyRemoteControlError(
+                                "Server completed without task status"
                             )
                         )
                     else:
-                        complete.set_result(event)
+                        complete.set_result(event.task_status)
 
         with self._events:
             self._events.subscribe_to_all_events(inner_on_event)

src/blueapi/config.py

@@ -275,7 +275,7 @@ class ApplicationConfig(BlueapiBaseModel):
     """
 
     #: API version to publish in OpenAPI schema
-    REST_API_VERSION: ClassVar[str] = "1.1.3"
+    REST_API_VERSION: ClassVar[str] = "1.2.0"
 
     LICENSE_INFO: ClassVar[dict[str, str]] = {
         "name": "Apache 2.0",

src/blueapi/core/context.py

@@ -120,7 +120,7 @@ class BlueskyContext:
     configuration: InitVar[ApplicationConfig | None] = None
 
     run_engine: RunEngine = field(
-        default_factory=lambda: RunEngine(context_managers=[])
+        default_factory=lambda: RunEngine(context_managers=[], call_returns_result=True)
     )
     tiled_conf: TiledConfig | None = field(default=None, init=False, repr=False)
     numtracker: NumtrackerClient | None = field(default=None, init=False, repr=False)

src/blueapi/utils/base_model.py

@@ -1,4 +1,7 @@
-from pydantic import BaseModel, ConfigDict
+from pydantic import (
+    BaseModel,
+    ConfigDict,
+)
 
 # Pydantic config for blueapi API models with common config.
 BlueapiModelConfig = ConfigDict(

src/blueapi/worker/event.py

@@ -1,8 +1,9 @@
 from collections.abc import Mapping
 from enum import StrEnum
+from typing import Any, Literal, Self
 
 from bluesky.run_engine import RunEngineStateMachine
-from pydantic import Field
+from pydantic import Field, PydanticSchemaGenerationError, TypeAdapter
 from super_state_machine.extras import PropertyMachine, ProxyString
 
 from blueapi.utils import BlueapiBaseModel
@@ -52,6 +53,47 @@ def from_bluesky_state(cls, bluesky_state: RawRunEngineState) -> "WorkerState":
         return WorkerState(str(bluesky_state).upper())
 
 
+class TaskResult(BlueapiBaseModel):
+    """
+    Serializable wrapper around the result of a plan
+
+    If the result is not serializable, the result will be None but the type
+    will be the name of the type. If the result is actually None, the type will
+    be 'NoneType'.
+    """
+
+    outcome: Literal["success"] = "success"
+    """Discriminant for serialization"""
+    result: Any = Field(None)
+    """The serialized result (or None if it is not serializable)"""
+    type: str
+    """The type of the result"""
+
+    @classmethod
+    def from_result(cls, result: Any) -> Self:
+        type_str = type(result).__name__
+        try:
+            value = TypeAdapter(type(result)).dump_python(result)
+        except PydanticSchemaGenerationError:
+            value = None
+        return cls(result=value, type=type_str)
+
+
+class TaskError(BlueapiBaseModel):
+    """Wrapper around an exception raised by a plan"""
+
+    outcome: Literal["error"] = "error"
+    """Discriminant for serialization"""
+    type: str
+    """The class of exception"""
+    message: str
+    """The message of the raised exception"""
+
+    @classmethod
+    def from_exception(cls, err: Exception) -> Self:
+        return cls(type=type(err).__name__, message=str(err))
+
+
 class StatusView(BlueapiBaseModel):
     """
     A snapshot of a Status of an operation, optionally representing progress
@@ -107,6 +149,7 @@ class TaskStatus(BlueapiBaseModel):
     """
 
     task_id: str
+    result: TaskResult | TaskError | None = Field(None, discriminator="outcome")
     task_complete: bool
     task_failed: bool
 

src/blueapi/worker/task.py

@@ -38,7 +38,11 @@ def do_task(self, ctx: BlueskyContext) -> None:
         func = ctx.plan_functions[self.name]
         prepared_params = self.prepare_params(ctx)
         ctx.run_engine.md.update(self.metadata)
-        ctx.run_engine(func(**prepared_params))
+        result = ctx.run_engine(func(**prepared_params))
+        if isinstance(result, tuple):  # pragma: no cover
+            # this is never true if the run_engine is configured correctly
+            return None
+        return result.plan_result
 
 
 def _lookup_params(ctx: BlueskyContext, task: Task) -> BaseModel:

src/blueapi/worker/task_worker.py

@@ -39,6 +39,8 @@
     ProgressEvent,
     RawRunEngineState,
     StatusView,
+    TaskError,
+    TaskResult,
     TaskStatus,
     TaskStatusEnum,
     WorkerEvent,
@@ -69,6 +71,13 @@ class TrackableTask(BlueapiBaseModel):
     is_complete: bool = False
     is_pending: bool = True
     errors: list[str] = Field(default_factory=list)
+    outcome: TaskResult | TaskError | None = None
+
+    def set_result(self, result: Any):
+        self.outcome = TaskResult.from_result(result)
+
+    def set_exception(self, err: Exception):
+        self.outcome = TaskError.from_exception(err)
 
 
 class TaskWorker:
@@ -427,7 +436,17 @@ def process_task():
                     LOGGER.info(f"Got new task: {next_task}")
                     self._current = next_task
                     self._current.is_pending = False
-                    self._current.task.do_task(self._ctx)
+                    meta = {"task_id": self._current.task_id}
+                    try:
+                        result = self._current.task.do_task(self._ctx)
+                        LOGGER.info(
+                            "Task ran successfully - returned: %s", result, extra=meta
+                        )
+                        self._current.set_result(result)
+                    except Exception as e:
+                        LOGGER.error("Task failed", extra=meta)
+                        self._current.set_exception(e)
+                        self._report_error(e)
 
                 with plan_tag_filter_context(next_task.task.name, LOGGER):
                     if self._current_task_otel_context is not None:
@@ -528,6 +547,7 @@ def _report_status(
                 task_id=self._current.task_id,
                 task_complete=self._current.is_complete,
                 task_failed=bool(self._current.errors),
+                result=self._current.outcome,
             )
             correlation_id = self._current.task_id
             add_span_attributes(