[Core] Allow specifying custom Executor (#6557)

tests/engine/test_custom_executor.py

@@ -0,0 +1,91 @@
+import asyncio
+import os
+
+import pytest
+
+from vllm.engine.arg_utils import AsyncEngineArgs, EngineArgs
+from vllm.engine.async_llm_engine import AsyncLLMEngine
+from vllm.engine.llm_engine import LLMEngine
+from vllm.executor.gpu_executor import GPUExecutor, GPUExecutorAsync
+from vllm.sampling_params import SamplingParams
+
+
+class Mock:
+    ...
+
+
+class CustomGPUExecutor(GPUExecutor):
+
+    def execute_model(self, *args, **kwargs):
+        # Drop marker to show that this was ran
+        with open(".marker", "w"):
+            ...
+        return super().execute_model(*args, **kwargs)
+
+
+class CustomGPUExecutorAsync(GPUExecutorAsync):
+
+    async def execute_model_async(self, *args, **kwargs):
+        with open(".marker", "w"):
+            ...
+        return await super().execute_model_async(*args, **kwargs)
+
+
+@pytest.mark.parametrize("model", ["facebook/opt-125m"])
+def test_custom_executor_type_checking(model):
+    with pytest.raises(ValueError):
+        engine_args = EngineArgs(model=model,
+                                 distributed_executor_backend=Mock)
+        LLMEngine.from_engine_args(engine_args)
+    with pytest.raises(ValueError):
+        engine_args = AsyncEngineArgs(model=model,
+                                      distributed_executor_backend=Mock)
+        AsyncLLMEngine.from_engine_args(engine_args)
+    with pytest.raises(TypeError):
+        engine_args = AsyncEngineArgs(
+            model=model, distributed_executor_backend=CustomGPUExecutor)
+        AsyncLLMEngine.from_engine_args(engine_args)
+
+
+@pytest.mark.parametrize("model", ["facebook/opt-125m"])
+def test_custom_executor(model, tmpdir):
+    cwd = os.path.abspath(".")
+    os.chdir(tmpdir)
+    try:
+        assert not os.path.exists(".marker")
+
+        engine_args = EngineArgs(
+            model=model, distributed_executor_backend=CustomGPUExecutor)
+        engine = LLMEngine.from_engine_args(engine_args)
+        sampling_params = SamplingParams(max_tokens=1)
+
+        engine.add_request("0", "foo", sampling_params)
+        engine.step()
+
+        assert os.path.exists(".marker")
+    finally:
+        os.chdir(cwd)
+
+
+@pytest.mark.parametrize("model", ["facebook/opt-125m"])
+def test_custom_executor_async(model, tmpdir):
+    cwd = os.path.abspath(".")
+    os.chdir(tmpdir)
+    try:
+        assert not os.path.exists(".marker")
+
+        engine_args = AsyncEngineArgs(
+            model=model, distributed_executor_backend=CustomGPUExecutorAsync)
+        engine = AsyncLLMEngine.from_engine_args(engine_args)
+        sampling_params = SamplingParams(max_tokens=1)
+
+        async def t():
+            stream = await engine.add_request("0", "foo", sampling_params)
+            async for x in stream:
+                ...
+
+        asyncio.run(t())
+
+        assert os.path.exists(".marker")
+    finally:
+        os.chdir(cwd)