Prometheus Aggregation Gateway

Prometheus Aggregation Gateway is a aggregating push gateway for Prometheus. As opposed to the official Prometheus Pushgateway, this service aggregates the sample values it receives.

• Counters where all labels match are added up.
• Histograms are added up; if bucket boundaries are mismatched then the result has the union of all buckets and counts are given to the lowest bucket that fits.
• Gauges are averaged (between each time /metrics is accessed)
• Summaries are discarded.

How to use

Send metrics in Prometheus format to /metrics/

E.g. if you have the program running locally:

echo 'http_requests_total{method="post",code="200"} 1027' | curl --data-binary @- http://localhost/metrics/

Now you can push your metrics using your favorite Prometheus client.

E.g. in Python using prometheus/client_python:

from prometheus_client import CollectorRegistry, Counter, push_to_gateway
registry = CollectorRegistry()
counter = Counter('some_counter', "A counter", registry=registry)
counter.inc()
push_to_gateway('localhost', job='my_job_name', registry=registry)

Then have your Prometheus scrape metrics at /metrics.

Ready-built images

Available on DockerHub weaveworks/prom-aggregation-gateway

Comparison to Prometheus Pushgateway

According to https://prometheus.io/docs/practices/pushing/:

The Pushgateway never forgets series pushed to it and will expose them to Prometheus forever...

The latter point is especially relevant when multiple instances of a job differentiate their metrics in the Pushgateway via an instance label or similar.

This restriction makes the Prometheus pushgateway inappropriate for the usecase of accepting metrics from a client-side web app, so we created this one to aggregate counters from multiple senders.

Prom-aggregation-gateway presents a similar API, but does not attempt to be a drop-in replacement.

JS Client Library

See https://github.com/weaveworks/promjs/ for a JS client library for Prometheus that can be used from within a web app.

Getting Help

If you have any questions about, feedback for or problems with prom-aggregation-gateway:

• Invite yourself to the Weave Users Slack.
• Ask a question on the #general slack channel.
• File an issue.

Your feedback is always welcome!