vllm/vllm/entrypoints/openai/orca_metrics.py
Misha Efimov ba464e6ae2
Add ORCA endpoint load metrics support (#24905)
Signed-off-by: Misha Efimov <mef@google.com>
2025-11-03 08:21:31 +00:00

121 lines
4.4 KiB
Python

# 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)