Metrics API#

BentoML provides metrics API that uses Prometheus under the hood.

BentoML’s bentoml.metrics is a drop-in replacement for prometheus_client that should be used in BentoML services:

diff --git a/service.py b/service.py
index acd8467e..0f3e6e77 100644
--- a/service.py
+++ b/service.py
@@ -1,11 +1,10 @@
-from prometheus_client import Summary
+from bentoml.metrics import Summary
 import random
 import time

REQUEST_TIME = Summary("request_processing_seconds", "Time spent processing request")

@REQUEST_TIME.time()
def process_request(t):
    """A function that takes some time."""

While bentoml.metrics contains all API that is offered by prometheus_client, users should always use bentoml.metrics instead of prometheus_client in your service definition.

The reason is that BentoML’s bentoml.metrics will construct metrics lazily and ensure multiprocessing mode. are correctly configured.

Note

prometheus_client shouldn’t be imported in BentoML services, otherwise it will break multiprocessing mode.

Note

All metrics from bentoml.metrics will set up registry to handle multiprocess mode, which means you SHOULD NOT pass in registry argument to metrics initialization:

service.py#
# THIS WILL NOT WORK
from bentoml.metrics import Summary, CollectorRegistry
from bentoml.metrics import multiprocess

registry = CollectorRegistry()
multiprocess.MultiProcessCollector(registry)
REQUEST_TIME = Summary(
   "request_processing_seconds", "Time spent processing request", registry=registry
)

instead:

service.py#
# THIS WILL WORK
from bentoml.metrics import Summary

REQUEST_TIME = Summary("request_processing_seconds", "Time spent processing request")

The following section will go over the most commonly used metrics API in bentoml.metrics:

bentoml.metrics.text_string_to_metric_families(*args: t.Any, **kwargs: t.Any) t.Any#

Parse Prometheus text format from a unicode string.

Returns

A generator of Metric objects.

Return type

Generator[Metric, None, None]