refactor: make the event loop thread part of the interpreter state

src/pdl/pdl_granite_io.py

@@ -1,5 +1,5 @@
 # pylint: disable=import-outside-toplevel
-from asyncio import run_coroutine_threadsafe
+from asyncio import AbstractEventLoop, run_coroutine_threadsafe
 from typing import Any, Optional
 
 from granite_io.types import ChatCompletionInputs
@@ -13,7 +13,6 @@
     PDLRuntimeError,
 )
 from .pdl_lazy import PdlConst, PdlLazy, lazy_apply
-from .pdl_llms import _LOOP
 from .pdl_utils import value_of_expr
 
 
@@ -113,15 +112,14 @@ async def async_generate_text(
 
     @staticmethod
     def generate_text(
-        block: GraniteioModelBlock,
-        messages: ModelInput,
+        block: GraniteioModelBlock, messages: ModelInput, event_loop: AbstractEventLoop
     ) -> tuple[LazyMessage, PdlLazy[Any]]:
         future = run_coroutine_threadsafe(
             GraniteioModel.async_generate_text(
                 block,
                 messages,
             ),
-            _LOOP,
+            event_loop,
         )
         pdl_future: PdlLazy[tuple[dict[str, Any], Any]] = PdlConst(future)
         message = lazy_apply((lambda x: x[0]), pdl_future)

src/pdl/pdl_interpreter.py

@@ -10,6 +10,7 @@
 
 # TODO: temporarily disabling warnings to mute a pydantic warning from liteLLM
 import warnings
+from asyncio import AbstractEventLoop
 from functools import partial
 from os import getenv
 
@@ -31,7 +32,7 @@
 )
 from jinja2.nodes import TemplateData  # noqa: E402
 from jinja2.runtime import Undefined  # noqa: E402
-from pydantic import BaseModel  # noqa: E402
+from pydantic import BaseModel, ConfigDict, Field  # noqa: E402
 
 from .pdl_ast import (  # noqa: E402
     AdvancedBlockType,
@@ -110,7 +111,11 @@
 from .pdl_location_utils import append, get_loc_string  # noqa: E402
 from .pdl_parser import PDLParseError, parse_file, parse_str  # noqa: E402
 from .pdl_python_repl import PythonREPL  # noqa: E402
-from .pdl_scheduler import yield_background, yield_result  # noqa: E402
+from .pdl_scheduler import (  # noqa: E402
+    create_event_loop_thread,
+    yield_background,
+    yield_result,
+)
 from .pdl_schema_utils import get_json_schema  # noqa: E402
 from .pdl_schema_validator import type_check_args, type_check_spec  # noqa: E402
 from .pdl_utils import (  # noqa: E402
@@ -127,6 +132,8 @@
 
 
 class InterpreterState(BaseModel):
+    model_config = ConfigDict(arbitrary_types_allowed=True)
+
     yield_result: bool = False
     yield_background: bool = False
     batch: int = 1
@@ -136,6 +143,7 @@ class InterpreterState(BaseModel):
     cwd: Path = Path.cwd()
     # background_tasks = {}
     id_stack: list[str] = []
+    event_loop: AbstractEventLoop = Field(default_factory=create_event_loop_thread)
 
     def with_yield_result(self: "InterpreterState", b: bool) -> "InterpreterState":
         return self.model_copy(update={"yield_result": b})
@@ -1638,13 +1646,15 @@ def generate_client_response_single(
                 model_id=value_of_expr(block.model),
                 messages=model_input,
                 parameters=litellm_parameters_to_dict(parameters),
+                event_loop=state.event_loop,
             )
         case GraniteioModelBlock():
             from .pdl_granite_io import GraniteioModel
 
             message, response = GraniteioModel.generate_text(
                 block=block,
                 messages=model_input,
+                event_loop=state.event_loop,
             )
         case _:
             assert False

src/pdl/pdl_llms.py

@@ -1,10 +1,8 @@
 # pylint: disable=import-outside-toplevel
-import asyncio
-import threading
-from concurrent.futures import Future
+from asyncio import AbstractEventLoop, run_coroutine_threadsafe
 from os import environ
 from sys import stderr
-from typing import Any, Callable, Generator, Optional, TypeVar
+from typing import Any, Generator, Optional, TypeVar
 
 import httpx
 from dotenv import load_dotenv
@@ -25,19 +23,6 @@
 load_dotenv()
 
 
-def _start_background_loop(loop):
-    asyncio.set_event_loop(loop)
-    loop.run_forever()
-
-
-_LOOP = asyncio.new_event_loop()
-_LOOP_THREAD = threading.Thread(
-    target=_start_background_loop, args=(_LOOP,), daemon=True
-)
-_LOOP_THREAD.start()
-# _BACKGROUND_TASKS = set()
-
-
 class LitellmModel:
     @staticmethod
     async def async_generate_text(
@@ -88,21 +73,19 @@ def generate_text(
         model_id: str,
         messages: ModelInput,
         parameters: dict[str, Any],
+        event_loop: AbstractEventLoop,
     ) -> tuple[LazyMessage, PdlLazy[Any]]:
         if "PDL_VERBOSE_ASYNC" in environ:
             print(f"Asynchronous model call started to {model_id}", file=stderr)
-        # global _BACKGROUND_TASKS
-        future = asyncio.run_coroutine_threadsafe(
+        future = run_coroutine_threadsafe(
             LitellmModel.async_generate_text(
                 block,
                 model_id,
                 messages,
                 parameters,
             ),
-            _LOOP,
+            event_loop,
         )
-        # _BACKGROUND_TASKS.add(future)
-        # future.add_done_callback(_BACKGROUND_TASKS.discard)
         pdl_future: PdlLazy[tuple[dict[str, Any], Any]] = PdlConst(future)
         message = lazy_apply((lambda x: x[0]), pdl_future)
         response = lazy_apply((lambda x: x[1]), pdl_future)
@@ -213,13 +196,13 @@ def set_structured_decoding_parameters(
 MapOutputT = TypeVar("MapOutputT")
 
 
-def map_future(
-    f: Callable[[MapInputT], MapOutputT], x: Future[MapInputT]
-) -> Future[MapOutputT]:
-    future = asyncio.run_coroutine_threadsafe(_async_call(f, x), _LOOP)
-    return future
+# def map_future(
+#     f: Callable[[MapInputT], MapOutputT], x: Future[MapInputT]
+# ) -> Future[MapOutputT]:
+#     future = asyncio.run_coroutine_threadsafe(_async_call(f, x), _LOOP)
+#     return future
 
 
-async def _async_call(f, x):
-    v = x.result()
-    return f(v)
+# async def _async_call(f, x):
+#     v = x.result()
+#     return f(v)

src/pdl/pdl_scheduler.py

@@ -1,3 +1,5 @@
+from asyncio import AbstractEventLoop, new_event_loop, set_event_loop
+from threading import Thread
 from typing import Any, Optional
 
 from termcolor import colored
@@ -6,6 +8,18 @@
 from .pdl_utils import stringify
 
 
+def _start_background_loop(loop):
+    set_event_loop(loop)
+    loop.run_forever()
+
+
+def create_event_loop_thread() -> AbstractEventLoop:
+    loop = new_event_loop()
+    loop_thread = Thread(target=_start_background_loop, args=(loop,), daemon=True)
+    loop_thread.start()
+    return loop
+
+
 def color_of(kind: BlockKind):
     color: Optional[str]
     match kind: