[P/D] Move FakeNixlWrapper to test dir (#21328)

Signed-off-by: Rui Qiao <ruisearch42@gmail.com>

tests/v1/kv_connector/unit/test_nixl_connector.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
+import contextlib
+import inspect
 import os
 import tempfile
 import textwrap
 import time
+import uuid
+from collections import defaultdict
+from typing import Optional
 from unittest.mock import patch
 
 import pytest
@@ -16,30 +21,118 @@ from vllm.distributed.kv_transfer.kv_connector.v1.nixl_connector import (
     KVConnectorRole, NixlAgentMetadata, NixlConnector, NixlConnectorMetadata,
     NixlConnectorWorker)
 from vllm.forward_context import ForwardContext
-from vllm.mocks.mock_nixl_connector import FakeNixlWrapper
 from vllm.sampling_params import SamplingParams
 
 from .utils import create_request, create_scheduler, create_vllm_config
 
 
-def _make_stub_pkg() -> str:
-    """Return a directory that makes
-       `from nixl._api import nixl_agent` resolve to our FakeNixlWrapper."""
-    td = tempfile.mkdtemp()
-    pkg_root = os.path.join(td, "nixl", "_api")
-    os.makedirs(pkg_root, exist_ok=True)
+class FakeNixlWrapper:
+    """Mock implementation of NixlWrapper for testing.
 
-    stub = textwrap.dedent("""\
-        # Forward the real FakeNixlWrapper that the driver already defined.
-        print("In fake package")
-        from vllm.mocks.mock_nixl_connector import FakeNixlWrapper as nixl_agent
-    """)
-    with open(os.path.join(pkg_root, "__init__.py"), "w") as f:
-        f.write(stub)
+    We don't inherit from nixl._api.nixl_agent because nixl may not be
+    installed.
+    
+    Note: The complete source of this class is also used in the
+    `_make_fake_nixl_pkg` function to create a fake nixl package
+    for Ray workers.
+    """
+
+    AGENT_METADATA = b"fake_agent_metadata"
+    REMOTE_AGENT_NAME = "remote_agent"
+
+    def __init__(self, agent_name: str, *args, **kwargs):
+        self._cycles_before_xfer_done = 0
+        self._check_xfer_state_cycles: defaultdict[int, int] = defaultdict(
+            lambda: 0)
+
+    def get_reg_descs(self, caches_data, memory_type: str) -> list:
+        return [str(uuid.uuid4()) for _ in caches_data]
+
+    def register_memory(self, descs) -> None:
+        pass
+
+    def get_xfer_descs(self, blocks_data, memory_type: str) -> list:
+        return [str(uuid.uuid4()) for _ in blocks_data]
+
+    def prep_xfer_dlist(self, agent_name: str, descs: list) -> int:
+        return uuid.uuid4().int
+
+    def get_agent_metadata(self) -> bytes:
+        return self.AGENT_METADATA
+
+    def add_remote_agent(self, agent_metadata: bytes) -> str:
+        return self.REMOTE_AGENT_NAME
+
+    def get_new_notifs(self) -> dict[str, list[bytes]]:
+        # Used to collect done_sending, which we don't test yet.
+        return {}
+
+    def check_xfer_state(self, handle: int) -> str:
+        if self._check_xfer_state_cycles[
+                handle] >= self._cycles_before_xfer_done:
+            return "DONE"
+        self._check_xfer_state_cycles[handle] += 1
+        return "PROC"
+
+    def release_xfer_handle(self, handle: int) -> None:
+        pass
+
+    def send_notif(self, agent_name: str, notif_msg: bytes) -> None:
+        pass
+
+    def make_prepped_xfer(self,
+                          xfer_type: str,
+                          local_xfer_side_handle: int,
+                          local_block_descs_ids: list[int],
+                          remote_xfer_side_handle: int,
+                          remote_block_descs_ids: list[int],
+                          notif_msg: Optional[bytes] = None) -> int:
+        return uuid.uuid4().int
 
-    # touch parent package
-    open(os.path.join(td, "nixl", "__init__.py"), "w").close()
-    return td
+    def transfer(self, handle: int) -> str:
+        return "PROC"
+
+    ############################################################
+    # Follow are for changing the behavior during testing.
+    ############################################################
+
+    def set_cycles_before_xfer_done(self, cycles: int):
+        """Set the number of cycles before a transfer is considered done."""
+        self._cycles_before_xfer_done = cycles
+
+
+@contextlib.contextmanager
+def _make_fake_nixl_pkg():
+    """Context manager that creates a temporary package making
+       `from nixl._api import nixl_agent` resolve to our FakeNixlWrapper.
+       
+    Automatically cleans up the temporary directory when done.
+    """
+    with tempfile.TemporaryDirectory() as td:
+        pkg_root = os.path.join(td, "nixl", "_api")
+        os.makedirs(pkg_root, exist_ok=True)
+
+        # Get the source code of FakeNixlWrapper class and dedent it
+        fake_nixl_source = inspect.getsource(FakeNixlWrapper)
+        fake_nixl_source = textwrap.dedent(fake_nixl_source)
+
+        stub = f"""\
+# Copy of FakeNixlWrapper implementation for Ray workers
+import uuid
+from collections import defaultdict
+from typing import Optional
+
+{fake_nixl_source}
+
+# Export as nixl_agent
+nixl_agent = FakeNixlWrapper
+"""
+        with open(os.path.join(pkg_root, "__init__.py"), "w") as f:
+            f.write(stub)
+
+        # touch parent package
+        open(os.path.join(td, "nixl", "__init__.py"), "w").close()
+        yield td
 
 
 def test_basic_interface():
@@ -351,27 +444,37 @@ def test_abort_timeout_on_prefiller(monkeypatch, distributed_executor_backend):
         kv_connector="NixlConnector",
         kv_role="kv_both",
     )
+    llm_kwargs = {
+        "model": model_name,
+        "enforce_eager": True,
+        "gpu_memory_utilization": 0.5,
+        "kv_transfer_config": kv_transfer_config,
+        "distributed_executor_backend": distributed_executor_backend,
+    }
+
     timeout = 6
     monkeypatch.setenv("VLLM_ENABLE_V1_MULTIPROCESSING", "0")
     monkeypatch.setenv("VLLM_NIXL_ABORT_REQUEST_TIMEOUT", str(timeout))
 
-    # Build runtime_env only if we’re using Ray
+    # Build runtime_env only if we're using Ray
     if distributed_executor_backend == "ray":
-        runtime_env = {
-            "working_dir": _make_stub_pkg(),  # ship stub package
-            "env_vars": {
-                "VLLM_NIXL_ABORT_REQUEST_TIMEOUT": str(timeout),
-            },
-        }
-        ray.init(runtime_env=runtime_env)
-
-    llm = LLM(
-        model=model_name,
-        enforce_eager=True,
-        gpu_memory_utilization=0.5,
-        kv_transfer_config=kv_transfer_config,
-        distributed_executor_backend=distributed_executor_backend,
-    )
+        with _make_fake_nixl_pkg() as working_dir:
+            runtime_env = {
+                "working_dir": working_dir,  # ship fake nixl package
+                "env_vars": {
+                    "VLLM_NIXL_ABORT_REQUEST_TIMEOUT": str(timeout),
+                },
+            }
+            ray.init(runtime_env=runtime_env)
+
+            _run_abort_timeout_test(llm_kwargs, timeout)
+    else:
+        _run_abort_timeout_test(llm_kwargs, timeout)
+
+
+def _run_abort_timeout_test(llm_kwargs: dict, timeout: int):
+    """Helper function to run the abort timeout test logic."""
+    llm = LLM(**llm_kwargs)
     remote_prefill_opts = {
         "do_remote_decode": True,
         "do_remote_prefill": False,

vllm/distributed/kv_transfer/kv_connector/utils.py

@@ -120,8 +120,8 @@ class KVOutputAggregator:
     output corresponding to Rank 0 for scheduler."""
 
     def __init__(self, world_size: int):
-        # Complete transfer tracker. Used by to track finished requests
-        # [req_id -> n_finished_workers]
+        # Complete transfer tracker. Used to track finished requests
+        # [req_id -> n_remaining_workers]
         self._recv_remaining_count = defaultdict[str, int](lambda: world_size)
         self._send_remaining_count = defaultdict[str, int](lambda: world_size)
 
@@ -134,12 +134,10 @@ class KVOutputAggregator:
                                 remaining_count_dict: dict[str, int],
                                 finished_set: set[str]) -> None:
             for req_id in req_ids or ():
-                new_count = remaining_count_dict[req_id] - 1
-                if new_count == 0:
+                remaining_count_dict[req_id] -= 1
+                if remaining_count_dict[req_id] == 0:
                     finished_set.add(req_id)
                     del remaining_count_dict[req_id]
-                else:
-                    remaining_count_dict[req_id] = new_count
 
         finished_sending = set[str]()
         finished_recving = set[str]()

vllm/mocks/mock_nixl_connector.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-import uuid
-from collections import defaultdict
-from typing import Optional
-
-
-class FakeNixlWrapper:
-    """Mock implementation of NixlWrapper for testing.
-    
-    We don't inherit from nixl._api.nixl_agent because nixl may not be
-    installed.
-    """
-
-    AGENT_METADATA = b"fake_agent_metadata"
-    REMOTE_AGENT_NAME = "remote_agent"
-
-    def __init__(self, agent_name: str, *args, **kwargs):
-        self._cycles_before_xfer_done = 0
-        self._check_xfer_state_cycles: defaultdict[int, int] = defaultdict(
-            lambda: 0)
-
-    def get_reg_descs(self, caches_data, memory_type: str) -> list:
-        return [str(uuid.uuid4()) for _ in caches_data]
-
-    def register_memory(self, descs) -> None:
-        pass
-
-    def get_xfer_descs(self, blocks_data, memory_type: str) -> list:
-        return [str(uuid.uuid4()) for _ in blocks_data]
-
-    def prep_xfer_dlist(self, agent_name: str, descs: list) -> int:
-        return uuid.uuid4().int
-
-    def get_agent_metadata(self) -> bytes:
-        return self.AGENT_METADATA
-
-    def add_remote_agent(self, agent_metadata: bytes) -> str:
-        return self.REMOTE_AGENT_NAME
-
-    def get_new_notifs(self) -> dict[str, list[bytes]]:
-        # Used to collect done_sending, which we don't test yet.
-        return {}
-
-    def check_xfer_state(self, handle: int) -> str:
-        if self._check_xfer_state_cycles[
-                handle] >= self._cycles_before_xfer_done:
-            return "DONE"
-        self._check_xfer_state_cycles[handle] += 1
-        return "PROC"
-
-    def release_xfer_handle(self, handle: int) -> None:
-        pass
-
-    def send_notif(self, agent_name: str, notif_msg: bytes) -> None:
-        pass
-
-    def make_prepped_xfer(self,
-                          xfer_type: str,
-                          local_xfer_side_handle: int,
-                          local_block_descs_ids: list[int],
-                          remote_xfer_side_handle: int,
-                          remote_block_descs_ids: list[int],
-                          notif_msg: Optional[bytes] = None) -> int:
-        return uuid.uuid4().int
-
-    def transfer(self, handle: int) -> str:
-        return "PROC"
-
-    ############################################################
-    # Follow are for changing the behavior during testing.
-    ############################################################
-
-    def set_cycles_before_xfer_done(self, cycles: int):
-        """Set the number of cycles before a transfer is considered done."""
-        self._cycles_before_xfer_done = cycles