Prometheus API Ruby Client

A Ruby library for reading Prometheus metrics API.

Install

gem install prometheus-api-client

Usage

Overview

require 'prometheus/api_client'

# return a client for host http://localhost:9090/api/v1/
prometheus = Prometheus::ApiClient.client

prometheus.get(
  "query_range",
  :query => "sum(container_cpu_usage_seconds_total" \
            "{container_name=\"prometheus-hgv4s\",job=\"kubernetes-nodes\"})",
  :start => "2015-07-01T20:10:30.781Z",
  :end   => "2015-07-02T20:10:30.781Z",
  :step  => "120s"
)

Changing server hostname

# return a client for host http://example.com:9090/api/v1/
prometheus = Prometheus::ApiClient.client(url: 'http://example.com:9090')

Authentication proxy

If an authentication proxy ( e.g. oauth2 ) is used in a layer above the prometheus REST server, this client can use ssl and authentication headears.

# return a client for host https://example.com/api/v1/ using a Bearer token "TopSecret"
prometheus = Prometheus::ApiClient.client(url: 'https://example.com:443',
                                          credentials: {token: 'TopSecret'})

High level calls

# send a query request to server
prometheus.query(
  :query => "sum(container_cpu_usage_seconds_total" \
            "{container_name=\"prometheus-hgv4s\",job=\"kubernetes-nodes\"})",
  :time => "2015-07-01T20:10:30.781Z",
)

# send a query_range request to server
prometheus.query_range(
  :query => "sum(container_cpu_usage_seconds_total" \
            "{container_name=\"prometheus-hgv4s\",job=\"kubernetes-nodes\"})",
  :start => "2015-07-01T20:10:30.781Z",
  :end   => "2015-07-02T20:10:30.781Z",
  :step  => "120s"
)

# send a label request to server
prometheus.label('__name__')

cAdvisor specialize client

# create a client for cAdvisor metrics of a Node instance 'example.com'
prometheus = Prometheus::ApiClient::Cadvisor::Node.new(
  instance: 'example.com',
  url: 'http://example.com:8080',
)

# send a query request to server
prometheus.query(
  :query => "sum(container_cpu_usage_seconds_total)",
  :time => "2015-07-01T20:10:30.781Z",
)

Tests

Install necessary development gems with bundle install and run tests with rspec:

rake