Collector or Exporter outputs fluctuating data

[harneksidhu]

I am using client_ruby in a rails application with the following config.ru file:

# This file is used by Rack-based servers to start the application.

require ::File.expand_path('../config/environment',  __FILE__)

# gzip compression
use Rack::Deflater

# metrics
require 'prometheus/client/rack/collector'
require 'prometheus/client/rack/exporter'

use Prometheus::Client::Rack::Collector
use Prometheus::Client::Rack::Exporter

run Storybook::Application

When analyzing counters such as http_requests_total or http_request_duration_total_seconds, I noticed that the values will fluctuate back and forth every few seconds. I confirmed this by constantly refreshing my application.com/metrics page and observing the values. My grafana dashboard caught this instantly.

http_requests_total exhibits similar behaviour.

Are these fluctuations expected behaviour?

[grobie]

@harneksidhu I assume your rack application uses multiple processes? In that case read #9 for more information.