[Misc] Have AsyncLLM custom_stat_loggers extend default logger list

tests/v1/metrics/test_engine_logger_apis.py

@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import copy
+
+import pytest
+
+from vllm.v1.engine.async_llm import AsyncEngineArgs, AsyncLLM
+from vllm.v1.metrics.ray_wrappers import RayPrometheusStatLogger
+
+
+@pytest.fixture
+def log_stats_enabled_engine_args():
+    """
+    Shared fixture providing common AsyncEngineArgs configuration
+    used across multiple tests.
+    """
+    return AsyncEngineArgs(
+        model="distilbert/distilgpt2",
+        dtype="half",
+        disable_log_stats=False,
+        enforce_eager=True,
+    )
+
+
+@pytest.fixture
+def default_dp_shared_loggers_len(log_stats_enabled_engine_args):
+    """
+    Fixture to provide the length of the default dp_shared_loggers
+    for AsyncLLM with no custom stat loggers.
+    """
+    engine = AsyncLLM.from_engine_args(log_stats_enabled_engine_args,
+                                       stat_loggers=[])
+    length = len(engine.logger_manager.dp_shared_loggers)
+    engine.shutdown()
+    return length
+
+
+@pytest.mark.asyncio
+async def test_async_llm_replace_default_loggers(
+        log_stats_enabled_engine_args, default_dp_shared_loggers_len):
+    """
+    The default stats loggers should be used regardless of whether additional
+    custom ones are added.
+    """
+
+    engine = AsyncLLM.from_engine_args(log_stats_enabled_engine_args,
+                                       stat_loggers=[RayPrometheusStatLogger])
+    assert len(engine.logger_manager.dp_shared_loggers
+               ) == default_dp_shared_loggers_len + 1
+    engine.shutdown()
+
+
+@pytest.mark.asyncio
+async def test_async_llm_add_to_default_loggers(log_stats_enabled_engine_args):
+    """
+    It's still possible to use custom stat loggers exclusively by passing 
+    disable_log_stats=True in addition to a list of custom stat loggers.
+    """
+    # Create engine_args with disable_log_stats=True for this test
+    disabled_log_engine_args = copy.deepcopy(log_stats_enabled_engine_args)
+    disabled_log_engine_args.disable_log_stats = True
+
+    # Disable default loggers whilst passing a custom stat logger
+    engine = AsyncLLM.from_engine_args(disabled_log_engine_args,
+                                       stat_loggers=[RayPrometheusStatLogger])
+
+    # Only RayPrometheusStatLogger is available
+    assert len(engine.logger_manager.dp_shared_loggers) == 1
+    assert isinstance(engine.logger_manager.dp_shared_loggers[0],
+                      RayPrometheusStatLogger)
+
+    # log_stats is still True, since custom stat loggers are used
+    assert engine.log_stats
+
+    engine.shutdown()

vllm/v1/engine/async_llm.py

@@ -93,9 +93,14 @@
         self.model_config = vllm_config.model_config
         self.vllm_config = vllm_config
         self.log_requests = log_requests
-        self.log_stats = log_stats
+
+        self.log_stats = log_stats or (stat_loggers is not None)
+        if not log_stats and stats_loggers is not None:
+            logger.info(
+                "AsyncLLM created with log_stats=False and non-empty custom "
+                "logger list; enabling logging without default stat loggers")
 
         if self.model_config.skip_tokenizer_init:
             self.tokenizer = None
         else:
             # Tokenizer (+ ensure liveness if running in another process).
@@ -132,6 +137,7 @@
                 vllm_config=vllm_config,
                 engine_idxs=self.engine_core.engine_ranks_managed,
                 custom_stat_loggers=stat_loggers,
+                enable_default_loggers=log_stats,
             )
             self.logger_manager.log_engine_initialized()
 

vllm/v1/metrics/loggers.py

@@ -635,37 +635,41 @@ def __init__(
         vllm_config: VllmConfig,
         engine_idxs: Optional[list[int]] = None,
         custom_stat_loggers: Optional[list[StatLoggerFactory]] = None,
+        enable_default_loggers: bool = True,
     ):
         self.engine_idxs = engine_idxs if engine_idxs else [0]
 
-        factories: list[StatLoggerFactory]
+        factories: list[StatLoggerFactory] = []
         if custom_stat_loggers is not None:
-            factories = custom_stat_loggers
-        else:
-            factories = []
-            if logger.isEnabledFor(logging.INFO):
-                factories.append(LoggingStatLogger)
+            factories.extend(custom_stat_loggers)
+
+        if enable_default_loggers and logger.isEnabledFor(logging.INFO):
+            factories.append(LoggingStatLogger)
+
+        # For Prometheus, need to share the metrics between EngineCores.
+        # Each EngineCore's metrics are expressed as a unique label.
+        self.dp_shared_loggers = []
+        if enable_default_loggers:
+            self.dp_shared_loggers.append(
+                PrometheusStatLogger(vllm_config, engine_idxs))
 
         # engine_idx: StatLogger
         self.per_engine_logger_dict: dict[int, list[StatLoggerBase]] = {}
-        prometheus_factory = PrometheusStatLogger
         for engine_idx in self.engine_idxs:
             loggers: list[StatLoggerBase] = []
             for logger_factory in factories:
-                # If we get a custom prometheus logger, use that
-                # instead. This is typically used for the ray case.
+                # If we get a custom prometheus logger, add that to the shared
+                # DP logger list. This is typically used for the ray case.
                 if (isinstance(logger_factory, type)
                         and issubclass(logger_factory, PrometheusStatLogger)):
-                    prometheus_factory = logger_factory
-                    continue
-                loggers.append(logger_factory(vllm_config,
-                                              engine_idx))  # type: ignore
+                    self.dp_shared_loggers.append(
+                        logger_factory(vllm_config,
+                                       engine_idxs))  # type: ignore
+                else:
+                    loggers.append(logger_factory(vllm_config,
+                                                  engine_idx))  # type: ignore
             self.per_engine_logger_dict[engine_idx] = loggers
 
-        # For Prometheus, need to share the metrics between EngineCores.
-        # Each EngineCore's metrics are expressed as a unique label.
-        self.prometheus_logger = prometheus_factory(vllm_config, engine_idxs)
-
     def record(
         self,
         scheduler_stats: Optional[SchedulerStats],
@@ -679,17 +683,18 @@ def record(
         for logger in per_engine_loggers:
             logger.record(scheduler_stats, iteration_stats, engine_idx)
 
-        self.prometheus_logger.record(scheduler_stats, iteration_stats,
-                                      engine_idx)
+        for logger in self.dp_shared_loggers:
+            logger.record(scheduler_stats, iteration_stats, engine_idx)
 
     def log(self):
         for per_engine_loggers in self.per_engine_logger_dict.values():
             for logger in per_engine_loggers:
                 logger.log()
 
     def log_engine_initialized(self):
-        self.prometheus_logger.log_engine_initialized()
-
         for per_engine_loggers in self.per_engine_logger_dict.values():
             for logger in per_engine_loggers:
                 logger.log_engine_initialized()
+
+        for logger in self.dp_shared_loggers:
+            logger.log_engine_initialized()