enhancement: Add support for function args & kwargs type hints in ctx.run.

examples/workflow.py

@@ -37,7 +37,7 @@ def payment_gateway():
         print("To decline use:")
         print(f"""curl http://localhost:8080/payment/{workflow_key}/payment_verified --json '"declined"' """)
 
-    await ctx.run("payment", payment_gateway)
+    await ctx.run_typed("payment", payment_gateway)
 
     ctx.set("status", "waiting for the payment provider to approve")
 

pyproject.toml

@@ -12,6 +12,10 @@ license = { file = "LICENSE" }
 authors = [
     { name = "Restate Developers", email = "dev@restate.dev" }
 ]
+dependencies = [
+    "typing-extensions>=4.14.0"
+]
+
 
 [project.optional-dependencies]
 test = ["pytest", "hypercorn"]

python/restate/__init__.py

@@ -20,7 +20,7 @@
 from .context import Context, ObjectContext, ObjectSharedContext
 from .context import WorkflowContext, WorkflowSharedContext
 # pylint: disable=line-too-long
-from .context import DurablePromise, RestateDurableFuture, RestateDurableCallFuture, RestateDurableSleepFuture, SendHandle
+from .context import DurablePromise, RestateDurableFuture, RestateDurableCallFuture, RestateDurableSleepFuture, SendHandle, RunOptions
 from .exceptions import TerminalError
 from .asyncio import as_completed, gather, wait_completed, select
 
@@ -50,6 +50,7 @@ def test_harness(app, follow_logs = False, restate_image = ""): # type: ignore
     "RestateDurableCallFuture",
     "RestateDurableSleepFuture",
     "SendHandle",
+    "RunOptions",
     "TerminalError",
     "app",
     "test_harness",

python/restate/context.py

@@ -15,17 +15,39 @@
 
 import abc
 from dataclasses import dataclass
-from typing import Any, Awaitable, Callable, Dict, List, Optional, TypeVar, Union, Coroutine, overload
+from typing import Any, Awaitable, Callable, Dict, List, Optional, TypeVar, Union, Coroutine, overload, ParamSpec
 import typing
 from datetime import timedelta
+
+import typing_extensions
 from restate.serde import DefaultSerde, Serde
 
 T = TypeVar('T')
 I = TypeVar('I')
 O = TypeVar('O')
+P = ParamSpec('P')
 
-RunAction = Union[Callable[..., Coroutine[Any, Any, T]], Callable[..., T]]
 HandlerType = Union[Callable[[Any, I], Awaitable[O]], Callable[[Any], Awaitable[O]]]
+RunAction = Union[Callable[..., Coroutine[Any, Any, T]], Callable[..., T]]
+
+@dataclass
+class RunOptions(typing.Generic[T]):
+    """
+    Options for running an action.
+    """
+
+    serde: Serde[T] = DefaultSerde()
+    """The serialization/deserialization mechanism. - if the default serde is used, a default serializer will be used based on the type.
+                    See also 'type_hint'."""
+    max_attempts: Optional[int] = None
+    """The maximum number of retry attempts to complete the action.
+                            If None, the action will be retried indefinitely, until it succeeds.
+                            Otherwise, the action will be retried until the maximum number of attempts is reached and then it will raise a TerminalError."""
+    max_retry_duration: Optional[timedelta] = None
+    """The maximum duration for retrying. If None, the action will be retried indefinitely, until it succeeds.
+                                Otherwise, the action will be retried until the maximum duration is reached and then it will raise a TerminalError."""
+    type_hint: Optional[typing.Type[T]] = None
+    """The type hint of the return value of the action. This is used to pick the serializer. If None, the type hint will be inferred from the action's return type, or the provided serializer."""
 
 # pylint: disable=R0903
 class RestateDurableFuture(typing.Generic[T], Awaitable[T]):
@@ -197,6 +219,8 @@ def request(self) -> Request:
         Returns the request object.
         """
 
+
+    @typing_extensions.deprecated("`run` is deprecated, use `run_typed` instead for better type safety")
     @overload
     @abc.abstractmethod
     def run(self,
@@ -226,6 +250,7 @@ def run(self,
 
         """
 
+    @typing_extensions.deprecated("`run` is deprecated, use `run_typed` instead for better type safety")
     @overload
     @abc.abstractmethod
     def run(self,
@@ -255,6 +280,7 @@ def run(self,
 
         """
 
+    @typing_extensions.deprecated("`run` is deprecated, use `run_typed` instead for better type safety")
     @abc.abstractmethod
     def run(self,
             name: str,
@@ -283,6 +309,73 @@ def run(self,
 
         """
 
+
+    @overload
+    @abc.abstractmethod
+    def run_typed(self,
+            name: str,
+            action: Callable[P, Coroutine[Any, Any,T]],
+            options: RunOptions[T] = RunOptions(),
+            /,
+            *args: P.args,
+            **kwargs: P.kwargs,
+            ) -> RestateDurableFuture[T]:
+        """
+        Typed version of run that provides type hints for the function arguments.
+        Runs the given action with the given name.
+
+        Args:
+            name: The name of the action.
+            action: The action to run.
+            options: The options for the run.
+            *args: The arguments to pass to the action.
+            **kwargs: The keyword arguments to pass to the action.
+        """
+
+    @overload
+    @abc.abstractmethod
+    def run_typed(self,
+            name: str,
+            action: Callable[P, T],
+            options: RunOptions[T] = RunOptions(),
+            /,
+            *args: P.args,
+            **kwargs: P.kwargs,
+            ) -> RestateDurableFuture[T]:
+        """
+        Typed version of run that provides type hints for the function arguments.
+        Runs the given coroutine action with the given name.
+
+        Args:
+            name: The name of the action.
+            action: The action to run.
+            options: The options for the run.
+            *args: The arguments to pass to the action.
+            **kwargs: The keyword arguments to pass to the action.
+        """
+
+    @abc.abstractmethod
+    def run_typed(self,
+            name: str,
+            action: Union[Callable[P, Coroutine[Any, Any, T]], Callable[P, T]],
+            options: RunOptions[T] = RunOptions(),
+            /,
+            *args: P.args,
+            **kwargs: P.kwargs,
+            ) -> RestateDurableFuture[T]:
+        """
+        Typed version of run that provides type hints for the function arguments.
+        Runs the given action with the given name.
+
+        Args:
+            name: The name of the action.
+            action: The action to run.
+            options: The options for the run.
+            *args: The arguments to pass to the action.
+            **kwargs: The keyword arguments to pass to the action.
+
+        """
+
     @abc.abstractmethod
     def sleep(self, delta: timedelta) -> RestateDurableSleepFuture:
         """

python/restate/server_context.py

@@ -21,17 +21,18 @@
 from datetime import timedelta
 import inspect
 import functools
-from typing import Any, Awaitable, Callable, Dict, List, Optional, TypeVar
+from typing import Any, Awaitable, Callable, Dict, List, Optional, TypeVar, Union, Coroutine
 import typing
 import traceback
 
-from restate.context import DurablePromise, AttemptFinishedEvent, HandlerType, ObjectContext, Request, RestateDurableCallFuture, RestateDurableFuture, RunAction, SendHandle, RestateDurableSleepFuture
+from restate.context import DurablePromise, AttemptFinishedEvent, HandlerType, ObjectContext, Request, RestateDurableCallFuture, RestateDurableFuture, RunAction, SendHandle, RestateDurableSleepFuture, RunOptions, P
 from restate.exceptions import TerminalError
 from restate.handler import Handler, handler_from_callable, invoke_handler
 from restate.serde import BytesSerde, DefaultSerde, JsonSerde, Serde
 from restate.server_types import ReceiveChannel, Send
 from restate.vm import Failure, Invocation, NotReady, SuspendedException, VMWrapper, RunRetryConfig # pylint: disable=line-too-long
 from restate.vm import DoProgressAnyCompleted, DoProgressCancelSignalReceived, DoProgressReadFromInput, DoProgressExecuteRun, DoWaitPendingRun
+import typing_extensions
 
 
 T = TypeVar('T')
@@ -510,6 +511,7 @@ async def create_run_coroutine(self,
                 self.vm.propose_run_completion_transient(handle, failure=failure, attempt_duration_ms=1, config=config)
     # pylint: disable=W0236
     # pylint: disable=R0914
+    @typing_extensions.deprecated("`run` is deprecated, use `run_typed` instead for better type safety")
     def run(self,
                   name: str,
                   action: RunAction[T],
@@ -536,6 +538,25 @@ def run(self,
         self.run_coros_to_execute[handle] = lambda : self.create_run_coroutine(handle, noargs_action, serde, max_attempts, max_retry_duration)
         return self.create_future(handle, serde) # type: ignore
 
+    def run_typed(
+        self,
+        name: str,
+        action:  Union[Callable[P, T], Callable[P, Coroutine[Any, Any, T]]],
+        options: RunOptions[T] = RunOptions(),
+        /,
+        *args: P.args,
+        **kwargs: P.kwargs,
+    ) -> RestateDurableFuture[T]:
+        if isinstance(options.serde, DefaultSerde):
+            if options.type_hint is None:
+                signature = inspect.signature(action, eval_str=True)
+                options.type_hint = signature.return_annotation
+            options.serde = options.serde.with_maybe_type(options.type_hint)
+        handle = self.vm.sys_run(name)
+
+        func = functools.partial(action, *args, **kwargs)
+        self.run_coros_to_execute[handle] = lambda : self.create_run_coroutine(handle, func, options.serde, options.max_attempts, options.max_retry_duration)
+        return self.create_future(handle, options.serde)
 
     def sleep(self, delta: timedelta) -> RestateDurableSleepFuture:
         # convert timedelta to milliseconds

requirements.txt

@@ -6,3 +6,4 @@ pytest
 pydantic
 httpx
 testcontainers
+typing-extensions>=4.14.0

test-services/services/failing.py

@@ -15,6 +15,7 @@
 
 from restate import VirtualObject, ObjectContext
 from restate.exceptions import TerminalError
+from restate import RunOptions
 
 failing = VirtualObject("Failing")
 
@@ -45,23 +46,23 @@ async def terminally_failing_side_effect(ctx: ObjectContext, error_message: str)
     def side_effect():
         raise TerminalError(message=error_message)
 
-    await ctx.run("sideEffect", side_effect)
+    await ctx.run_typed("sideEffect", side_effect)
     raise ValueError("Should not reach here")
 
 
 eventual_success_side_effects = 0
 
 @failing.handler(name="sideEffectSucceedsAfterGivenAttempts")
 async def side_effect_succeeds_after_given_attempts(ctx: ObjectContext, minimum_attempts: int) -> int:
-
     def side_effect():
         global eventual_success_side_effects
         eventual_success_side_effects += 1
         if eventual_success_side_effects >= minimum_attempts:
             return eventual_success_side_effects
         raise ValueError(f"Failed at attempt: {eventual_success_side_effects}")
 
-    return await ctx.run("sideEffect", side_effect, max_attempts=minimum_attempts + 1) # type: ignore
+    options: RunOptions[int] = RunOptions(max_attempts=minimum_attempts + 1)
+    return await ctx.run_typed("sideEffect", side_effect, options)
 
 eventual_failure_side_effects = 0
 
@@ -74,7 +75,8 @@ def side_effect():
         raise ValueError(f"Failed at attempt: {eventual_failure_side_effects}")
 
     try:
-        await ctx.run("sideEffect", side_effect, max_attempts=retry_policy_max_retry_count)
+        options: RunOptions[int] = RunOptions(max_attempts=retry_policy_max_retry_count)
+        await ctx.run_typed("sideEffect", side_effect, options)
         raise ValueError("Side effect did not fail.")
     except TerminalError as t:
         global eventual_failure_side_effects

test-services/services/interpreter.py

@@ -227,7 +227,7 @@ async def await_promise(index: int) -> None:
             coros[i] = (expected, service.echo_later(expected, command['sleep']))
         elif command_type == SIDE_EFFECT:
             expected = f"hello-{i}"
-            result = await ctx.run("sideEffect",  lambda : expected) # pylint: disable=W0640
+            result = await ctx.run_typed("sideEffect", lambda: expected)
             if result != expected:
                 raise TerminalError(f"Expected {expected} but got {result}")
         elif command_type == SLOW_SIDE_EFFECT:
@@ -246,7 +246,7 @@ async def side_effect():
                 if bool(random.getrandbits(1)):
                     raise ValueError("Random error")
 
-            await ctx.run("throwingSideEffect", side_effect)
+            await ctx.run_typed("throwingSideEffect", side_effect)
         elif command_type == INCREMENT_STATE_COUNTER_INDIRECTLY:
             await service.increment_indirectly(layer=layer, key=ctx.key())
         elif command_type == AWAIT_PROMISE:

test-services/services/virtual_object_command_interpreter.py

@@ -116,9 +116,9 @@ def to_durable_future(ctx: ObjectContext, cmd: AwaitableCommand) -> RestateDurab
     elif cmd['type'] == "sleep":
         return ctx.sleep(timedelta(milliseconds=cmd['timeoutMillis']))
     elif cmd['type'] == "runThrowTerminalException":
-        def side_effect(reason):
+        def side_effect(reason: str):
             raise TerminalError(message=reason)
-        res = ctx.run("run should fail command", side_effect, args=(cmd['reason'],))
+        res = ctx.run_typed("run should fail command", side_effect, reason=cmd['reason'])
         return res
 
 @virtual_object_command_interpreter.handler(name="interpretCommands")
@@ -142,7 +142,9 @@ async def interpret_commands(ctx: ObjectContext, req: InterpretRequest):
             result = ""
         elif cmd['type'] == "getEnvVariable":
             env_name = cmd['envName']
-            result = await ctx.run("get_env", lambda e=env_name: os.environ.get(e, ""))
+            def side_effect(env_name: str):
+                return os.environ.get(env_name, "")
+            result = await ctx.run_typed("get_env", side_effect, env_name=env_name)
         elif cmd['type'] == "awaitOne":
             awaitable = to_durable_future(ctx, cmd['command'])
             # We need this dance because the Python SDK doesn't support .map on futures