[BugFix] Seperate prometheus multiproc dir for single-server multi-dp services

Author: liyonghua0910

fastdeploy/engine/common_engine.py

@@ -65,6 +65,7 @@
 )
 from fastdeploy.inter_communicator.fmq import FMQ
 from fastdeploy.metrics.metrics import main_process_metrics
+from fastdeploy.metrics.prometheus_multiprocess_setup import setup_dp_prometheus_dir
 from fastdeploy.model_executor.guided_decoding import schema_checker
 from fastdeploy.plugins.token_processor import load_token_processor_plugins
 from fastdeploy.spec_decode import SpecMethod
@@ -139,6 +140,10 @@ def __init__(self, cfg: FDConfig, start_queue=True, use_async_llm=False):
         self.cfg = cfg
         self.use_async_llm = use_async_llm
 
+        # 为每个 DP 设置独立的 PROMETHEUS_MULTIPROC_DIR，避免多 DP 的 Counter/Histogram 指标混淆
+        if not envs.FD_ENABLE_MULTI_API_SERVER and self.cfg.parallel_config.data_parallel_size > 1:
+            setup_dp_prometheus_dir(self.cfg.parallel_config.local_data_parallel_id)
+
         if self.cfg.parallel_config.data_parallel_size > 1:
             self.llm_logger = get_logger(
                 "fastdeploy", f"fastdeploy_dprank{self.cfg.parallel_config.local_data_parallel_id}.log"

fastdeploy/metrics/prometheus_multiprocess_setup.py

@@ -44,3 +44,13 @@ def setup_multiprocess_prometheus():
             "will properly handle cleanup."
         )
         return os.environ["PROMETHEUS_MULTIPROC_DIR"]
+
+
+def setup_dp_prometheus_dir(dp_id):
+    if "PROMETHEUS_MULTIPROC_DIR" in os.environ:
+        prom_dir = os.environ.get("PROMETHEUS_MULTIPROC_DIR")
+        prom_dir_dp = os.path.join(os.path.dirname(prom_dir), os.path.basename(prom_dir) + f"_dp{dp_id}")
+        if not os.path.exists(prom_dir_dp):
+            os.makedirs(prom_dir_dp, exist_ok=True)
+        os.environ["PROMETHEUS_MULTIPROC_DIR"] = prom_dir_dp
+        llm_logger.info(f"Set PROMETHEUS_MULTIPROC_DIR for DP {dp_id}: {prom_dir_dp}")