feat(robot-server, api): Implement RobotServerPyroResource providing proxies of server assets by CaseyBatten · Pull Request #21240 · Opentrons/opentrons

CaseyBatten · 2026-04-09T20:43:14Z

Overview

The bulk of this PRs logic gets us up to the point where if the hardware subprocess feature flag is enabled and a hardware subprocess is running, a run can "start" (without the protocol subprocess involved). This does not include the callback proxy for the doorwatcher needed after beginning a run (that will happen elsewhere).

TODO:

Clean up the use of feature flag logic
Reinforce and test the feature flags
Theres a host of todo's regarding consolidating code and/or setting up systemD service messages, either address or expand these in future PRs
Unit tests to enforce that the several assets provided by the RobotServerPyroResource are available as Async-able and Cast-able proxies (this has only been manually tested)
Good lord so much linting to be done

Test Plan and Hands on Testing

Unit tests enforcing Proxy returns from RobotServerPyroResource
Test on robot with hardware subprocess flag on
Test on robot with hardware subprocess flag off

Changelog

Introduced bifurcated logic for initializing the hardware API depending on if the system is in "subprocess" mode
Introduced the RobotServerPyroResource which is spun up on app start.

Review requests

The use of feature flags is happening in a lot of places, should this be consolidated now or later?

Risk assessment

Medium - this is a pretty big one. It doesn't have to be "forever" code, especially the feature flag logic, but the core of the RobotServerPyroResource architecture will certainly remain. How do we feel about it?

…ting a protocol

codecov · 2026-04-09T20:45:35Z

Codecov Report

❌ Patch coverage is 70.74830% with 43 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.56%. Comparing base (480a6bf) to head (8b22953).
⚠️ Report is 79 commits behind head on edge.

Files with missing lines	Patch %	Lines
...r/robot_server/service/pyro_utils/pyro_resource.py	72.54%	14 Missing ⚠️
robot-server/robot_server/hardware.py	71.87%	9 Missing ⚠️
...ot_server/service/pyro_utils/resource_utilities.py	66.66%	8 Missing ⚠️
...er/robot_server/service/legacy/routers/settings.py	40.00%	6 Missing ⚠️
...rver/robot_server/maintenance_runs/dependencies.py	50.00%	2 Missing ⚠️
robot-server/robot_server/runs/dependencies.py	50.00%	2 Missing ⚠️
robot-server/robot_server/subsystems/router.py	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             edge   #21240      +/-   ##
==========================================
- Coverage   56.97%   56.56%   -0.42%     
==========================================
  Files        3978     3996      +18     
  Lines      326009   327714    +1705     
  Branches    46358    46690     +332     
==========================================
- Hits       185744   185362     -382     
- Misses     140046   142133    +2087     
  Partials      219      219

Flag	Coverage Δ
app	`44.91% <ø> (-0.21%)`	⬇️
protocol-designer	`19.93% <ø> (+<0.01%)`	⬆️
step-generation	`5.79% <ø> (+0.10%)`	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
robot-server/robot_server/app_setup.py	`92.59% <100.00%> (+0.28%)`	⬆️
...server/robot_server/camera/fastapi_dependencies.py	`100.00% <100.00%> (ø)`
...server/robot_server/data_files/data_files_store.py	`27.04% <ø> (-31.71%)`	⬇️
...robot_server/file_provider/fastapi_dependencies.py	`100.00% <100.00%> (ø)`
...tenance_runs/maintenance_run_orchestrator_store.py	`55.55% <100.00%> (-19.73%)`	⬇️
...-server/robot_server/robot/control/dependencies.py	`76.19% <100.00%> (+14.28%)`	⬆️
...server/robot_server/runs/run_orchestrator_store.py	`61.88% <100.00%> (-3.89%)`	⬇️
...server/service/pyro_utils/serpent_type_registry.py	`100.00% <100.00%> (ø)`
...a/python/opentrons_shared_data/data_files/types.py	`0.00% <ø> (ø)`
...rver/robot_server/maintenance_runs/dependencies.py	`86.95% <50.00%> (-13.05%)`	⬇️
... and 6 more

... and 172 files with indirect coverage changes

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…ave abstract event loop

sfoster1

Looks great to me when tested! Got some inline things about style and spelling but fundamentally looks good!

sfoster1 · 2026-04-10T20:05:21Z

shared-data/python/opentrons_shared_data/data_files/types.py

@@ -32,10 +33,12 @@ class DataFileSource(Enum):
    GENERATED = "generated"


-@dataclass(frozen=True)
-class DataFileInfo:
+#@dataclass(frozen=True)


remove comment

sfoster1 · 2026-04-10T20:06:07Z

robot-server/robot_server/hardware.py

@@ -116,6 +124,9 @@ async def clean_up_hardware(app_state: AppState) -> None:
    _init_task_accessor.set_on(app_state, None)
    _postinit_task_accessor.set_on(app_state, None)
    _hw_api_accessor.set_on(app_state, None)
+    # NOTE: we erase the subprocess state, but do not run clean_up() on the subprocess.
+    # This is the responsibility of it's executing service.


Suggested change

# This is the responsibility of it's executing service.

# This is the responsibility of its executing service.

sfoster1 · 2026-04-10T20:08:15Z

robot-server/robot_server/maintenance_runs/maintenance_run_orchestrator_store.py

@@ -121,7 +121,8 @@ def __init__(
        self._hardware_api = hardware_api
        self._robot_type = robot_type
        self._deck_type = deck_type
-        hardware_api.register_callback(_get_estop_listener(self))
+        if not feature_flags.hardware_subprocess_enabled():


this is one of the todos, right? maybe a good place for a todo comment

I don't think this is a todo. This is just the preservation of the original callback registry assuming we are not in subprocess mode, for both runs and maintenance runs. I don't think this will ever go away unless we completely remove the old single-process software someday and do away with feature flags.

sfoster1 · 2026-04-10T20:08:55Z

robot-server/robot_server/runs/run_orchestrator_store.py

@@ -193,7 +195,8 @@ def __init__(
        self._run_process: Optional[subprocess.Popen[bytes]] = None
        if feature_flags.protocol_subprocess_enabled():
            register_process_types()
-        hardware_api.register_callback(_get_hardware_listener(self))
+        if not feature_flags.hardware_subprocess_enabled():


a todo perhaps

Ditto here what I said in the reply above.

sfoster1 · 2026-04-10T20:09:46Z

robot-server/robot_server/service/legacy/routers/settings.py

@@ -95,6 +106,29 @@ async def _set_oem_mode_request(enable: bool, authorization_header: str | None)
            return resp.status


+async def _hardware_subprocess_transition(enable: bool, app_state: AppState) -> None:


whoa, this is fancy. i'd be okay just having this require a restart but it is pretty cool to have it be live

The feasibility of this one will depend on the the systemd implementation for the OT3API. Once that work follows this up I'll be able to test linking the two, if it proves non-viable we'll go through with the restart approach.

sfoster1 · 2026-04-10T20:10:23Z

robot-server/robot_server/service/pyro_utils/pyro_resource.py

+
+
+class RobotServerPyroResource:
+    """Class to represent the resources the robot-server hosts which can be provided over Pryo5.


Suggested change

"""Class to represent the resources the robot-server hosts which can be provided over Pryo5.

"""Class to represent the resources the robot-server hosts which can be provided over Pyro5.

sfoster1 · 2026-04-10T20:12:06Z

robot-server/robot_server/service/pyro_utils/resource_utilities.py

+    with pyro.locate_ns() as ns:
+        while time.monotonic() - start_time < 60:
+            if RS_PYRONAME in ns.list():
+                robot_server_proxy = pyro.Proxy(ns.list()[RS_PYRONAME])  # type: ignore[no-untyped-call]


maybe let's get a time.sleep(0.01) in here or something

sfoster1 · 2026-04-10T20:12:50Z

robot-server/robot_server/service/pyro_utils/pyro_resource.py

+        self._camera_provider: Optional[CameraProvider] = None
+        self._file_provider: Optional[FileProvider] = None
+
+    def _set_run_orchestorator_store(


Suggested change

def _set_run_orchestorator_store(

def _set_run_orchestrator_store(

sfoster1 · 2026-04-10T20:13:31Z

robot-server/robot_server/service/pyro_utils/resource_utilities.py

+    """Set a provided RunOrchestratorStore as the active store to be used by the Robot Server's Pyro Resource."""
+    robot_server_pyro_resource = robot_server_pyro_resource_accessor.get_from(app_state)
+    if robot_server_pyro_resource is not None:
+        robot_server_pyro_resource._set_run_orchestorator_store(run_orchestrator_store)


don't love calling underscore methods from over here

sfoster1 · 2026-04-10T20:15:06Z

api/src/opentrons/hardware_control/protocols/__init__.py

@@ -81,6 +83,7 @@ class FlexHardwareControlInterface(
    with some additional functionality and parameterization not supported on the OT-2.
    """

+    @pyro_behavior(specialty_func=convert_type_to_instance, apply_local=False)


would prefer pulling the implementation out of this function if possible so this typing protocol remains free to import without involving more dependencies and import-time work

Thats a good point. I'll see if theres a good place to create a pyro friendly alternative to somewhere else for the get_robot_type method.

CaseyBatten added 6 commits March 31, 2026 11:27

initial implementation of hard control proxy as fastapi dependency

9c765d9

Merge branch 'edge' into EXEC_2195_robot_server_pyro_hookup

bce79d2

Merge branch 'edge' into EXEC_2195_robot_server_pyro_hookup

a327054

Merge branch 'edge' into EXEC_2195_robot_server_pyro_hookup

48aae0d

implementation of the RobotServerPyroResource up to the point of star…

6c23ca8

…ting a protocol

appropriately rename the run hardware event callback proxy entrypoints

c42c918

CaseyBatten requested review from jbleon95 and sfoster1 April 9, 2026 20:43

unti testing for RobotServerPyroResource and ensuring child proxies h…

6079bda

…ave abstract event loop

CaseyBatten temporarily deployed to pd-non-prod April 10, 2026 19:29 — with GitHub Actions Inactive

many miraculous and beautiful little lints

e6991b7

CaseyBatten marked this pull request as ready for review April 10, 2026 19:58

CaseyBatten requested a review from a team as a code owner April 10, 2026 19:58

CaseyBatten temporarily deployed to pd-non-prod April 10, 2026 20:08 — with GitHub Actions Inactive

api linting

e2d6793

sfoster1 approved these changes Apr 10, 2026

View reviewed changes

CaseyBatten temporarily deployed to pd-non-prod April 10, 2026 20:17 — with GitHub Actions Inactive

private method cleanup, linting and test corrections

8b22953

CaseyBatten temporarily deployed to pd-non-prod April 10, 2026 21:44 — with GitHub Actions Inactive

	# This is the responsibility of it's executing service.
	# This is the responsibility of its executing service.

		@@ -95,6 +106,29 @@ async def _set_oem_mode_request(enable: bool, authorization_header: str \| None)
		return resp.status


		async def _hardware_subprocess_transition(enable: bool, app_state: AppState) -> None:



		class RobotServerPyroResource:
		"""Class to represent the resources the robot-server hosts which can be provided over Pryo5.

	def _set_run_orchestorator_store(
	def _set_run_orchestrator_store(

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CaseyBatten commented Apr 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Overview

Test Plan and Hands on Testing

Changelog

Review requests

Risk assessment

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codecov bot commented Apr 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Codecov Report

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CaseyBatten commented Apr 9, 2026 •

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