Sync from v0.13

vllm/entrypoints/openai/orca_metrics.py

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+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""
+Utility functions that create ORCA endpoint load report response headers.
+"""
+
+import json
+from collections.abc import Mapping
+
+from vllm.logger import init_logger
+from vllm.v1.metrics.reader import Gauge, get_metrics_snapshot
+
+logger = init_logger(__name__)
+
+
+def create_orca_header(
+    metrics_format: str, named_metrics: list[tuple[str, float]]
+) -> Mapping[str, str] | None:
+    """
+    Creates ORCA headers named 'endpoint-load-metrics' in the specified format
+    and adds custom metrics to named_metrics.
+    ORCA headers format description: https://docs.google.com/document/d/1C1ybMmDKJIVlrbOLbywhu9iRYo4rilR-cT50OTtOFTs/edit?tab=t.0
+    ORCA proto https://github.com/cncf/xds/blob/main/xds/data/orca/v3/orca_load_report.proto
+
+    Parameters:
+    - metrics_format (str): The format of the header ('TEXT', 'JSON').
+    - named_metrics (List[Tuple[str, float]]): List of tuples with metric names
+    and their corresponding double values.
+
+    Returns:
+    - Optional[Mapping[str,str]]: A dictionary with header key as
+    'endpoint-load-metrics' and values as the ORCA header strings with
+    format prefix and data in  with named_metrics in.
+    """
+
+    if metrics_format.lower() not in ["text", "json"]:
+        logger.warning(
+            "Warning: `%s` format is not supported in the ORCA response header",
+            format,
+        )
+        return None
+
+    header = {}
+    orca_report = {
+        "named_metrics": {
+            metric_name: value
+            for metric_name, value in named_metrics
+            if isinstance(metric_name, str) and isinstance(value, float)
+        }
+    }
+    # output example:
+    # endpoint-load-metrics: TEXT named_metrics.kv_cache_utilization=0.4
+    if metrics_format.lower() == "text":
+        native_http_header = ", ".join(
+            [
+                f"named_metrics.{metric_name}={value}"
+                for metric_name, value in named_metrics
+                if isinstance(metric_name, str) and isinstance(value, float)
+            ]
+        )
+        header["endpoint-load-metrics"] = f"TEXT {native_http_header}"
+
+    # output example:
+    # endpoint-load-metrics: JSON “named_metrics”: {“custom-metric-util”: 0.4}
+    elif metrics_format.lower() == "json":
+        header["endpoint-load-metrics"] = f"JSON {json.dumps(orca_report)}"
+
+    logger.info("Created ORCA header %s", header)
+
+    return header
+
+
+def get_named_metrics_from_prometheus() -> list[tuple[str, float]]:
+    """
+    Collects current metrics from Prometheus and returns some of them
+    in the form of the `named_metrics` list for `create_orca_header()`.
+
+    Parameters:
+    - None
+
+    Returns:
+    - list[tuple[str, float]]: List of tuples of metric names and their values.
+    """
+    named_metrics: list[tuple[str, float]] = []
+    # Map from prometheus metric names to ORCA named metrics.
+    prometheus_to_orca_metrics = {
+        "vllm:kv_cache_usage_perc": "kv_cache_usage_perc",
+        "vllm:num_requests_waiting": "num_requests_waiting",
+    }
+    metrics = get_metrics_snapshot()
+    for metric in metrics:
+        orca_name = prometheus_to_orca_metrics.get(metric.name)
+        # If this metric is mapped into ORCA, then add it to the report.
+        # Note: Only Gauge metrics are currently supported.
+        if orca_name is not None and isinstance(metric, Gauge):
+            named_metrics.append((str(orca_name), float(metric.value)))
+    return named_metrics
+
+
+def metrics_header(metrics_format: str) -> Mapping[str, str] | None:
+    """
+    Creates ORCA headers named 'endpoint-load-metrics' in the specified format.
+    Metrics are collected from Prometheus using `get_named_metrics_from_prometheus()`.
+
+    ORCA headers format description: https://docs.google.com/document/d/1C1ybMmDKJIVlrbOLbywhu9iRYo4rilR-cT50OTtOFTs/edit?tab=t.0
+    ORCA proto https://github.com/cncf/xds/blob/main/xds/data/orca/v3/orca_load_report.proto
+
+    Parameters:
+    - metrics_format (str): The format of the header ('TEXT', 'JSON').
+
+    Returns:
+    - Optional[Mapping[str,str]]: A dictionary with header key as
+    'endpoint-load-metrics' and values as the ORCA header strings with
+    format prefix and data in  with named_metrics in.
+    """
+    if not metrics_format:
+        return None
+    # Get named metrics from prometheus.
+    named_metrics = get_named_metrics_from_prometheus()
+    return create_orca_header(metrics_format, named_metrics)