feat(async): integrate nest-asyncio for async tool calls in running event loops

- Added support for using async tools within a running event loop by integrating `nest-asyncio`.
- Updated `pyproject.toml` to include `nest-asyncio` as a dependency.
- Enhanced error handling to prompt installation of `nest-asyncio` if not found.
- Added tests to verify async tool calls from a running event loop.

This change improves the usability of async tools in environments like Jupyter notebooks.

Author: TomeHirata

dspy/adapters/types/tool.py

@@ -168,6 +168,17 @@ def _run_async_in_sync(self, coroutine):
         except RuntimeError:
             return asyncio.run(coroutine)
 
+        if loop and loop.is_running():
+            try:
+                import nest_asyncio
+
+                nest_asyncio.apply()
+            except ImportError:
+                raise ImportError(
+                    "nest_asyncio is required to call async tools from within a running event loop. "
+                    "Install it with: pip install nest-asyncio"
+                )
+
         return loop.run_until_complete(coroutine)
 
     @with_callbacks

dspy/utils/syncify.py

@@ -14,10 +14,15 @@ def run_async(coro):
         loop = None
 
     if loop and loop.is_running():
-        # If we're in a running event loop (e.g., Jupyter), use asyncio.create_task and run until done
-        import nest_asyncio
-
-        nest_asyncio.apply()
+        try:
+            import nest_asyncio
+
+            nest_asyncio.apply()
+        except ImportError:
+            raise ImportError(
+                "nest_asyncio is required to call async functions from within a running event loop. "
+                "Install it with: pip install nest-asyncio"
+            )
         return asyncio.get_event_loop().run_until_complete(coro)
     else:
         return asyncio.run(coro)

pyproject.toml

@@ -64,6 +64,7 @@ test_extras = [
     "pandas>=2.1.1",
     "optuna>=3.4.0",
     "langchain_core",
+    "nest-asyncio>=1.6.0",
 ]
 
 [tool.setuptools.packages.find]

tests/adapters/test_tool.py

@@ -393,6 +393,16 @@ def test_async_tool_call_in_sync_mode():
         assert result == "hello 1"
 
 
+@pytest.mark.asyncio
+@pytest.mark.filterwarnings("ignore::DeprecationWarning:pytest_asyncio")
+async def test_async_tool_call_from_running_event_loop():
+    tool = Tool(async_dummy_function)
+
+    with dspy.context(allow_tool_async_sync_conversion=True):
+        result = tool(x=42, y="test")
+        assert result == "test 42"
+
+
 TOOL_CALL_TEST_CASES = [
     ([], {"tool_calls": []}),
     (
@@ -542,19 +552,14 @@ def test_tool_convert_input_schema_to_tool_args_lang_chain():
     }
 
 
-
-
 def test_tool_call_execute():
     def get_weather(city: str) -> str:
         return f"The weather in {city} is sunny"
 
     def add_numbers(a: int, b: int) -> int:
         return a + b
 
-    tools = [
-        dspy.Tool(get_weather),
-        dspy.Tool(add_numbers)
-    ]
+    tools = [dspy.Tool(get_weather), dspy.Tool(add_numbers)]
 
     tool_call = dspy.ToolCalls.ToolCall(name="get_weather", args={"city": "Berlin"})
     result = tool_call.execute(functions=tools)