Merge pull request #287 from prometheus/sinjo-add-gauge-current-timestamp

Add `Gauge#set_to_current_time`

Author: Sinjo

lib/prometheus/client/gauge.rb

@@ -20,6 +20,10 @@ def set(value, labels: {})
  @store.set(labels: label_set_for(labels), val: value)
  end
 
+ def set_to_current_time(labels: {})
+ @store.set(labels: label_set_for(labels), val: Time.now.to_f)
+ end
+
  # Increments Gauge value by 1 or adds the given value to the Gauge.
  # (The value can be negative, resulting in a decrease of the Gauge.)
  def increment(by: 1, labels: {})

prometheus-client.gemspec

@@ -17,4 +17,5 @@ Gem::Specification.new do |s|
 
  s.add_development_dependency 'benchmark-ips'
  s.add_development_dependency 'concurrent-ruby'
+ s.add_development_dependency 'timecop'
 end

spec/prometheus/client/gauge_spec.rb

@@ -48,6 +48,30 @@
  end
  end
 
+ describe '#set_to_current_time' do
+ it 'it sets the gauge to the current Unix epoch time' do
+ Timecop.freeze(Time.at(12345.1)) do
+ expect do
+ gauge.set_to_current_time
+ end.to change { gauge.get }.from(0).to(12345.1)
+ end
+ end
+
+ context "with a an expected label set" do
+ let(:expected_labels) { [:test] }
+
+ it 'sets a metric value for a given label set' do
+ Timecop.freeze(Time.at(12345.1)) do
+ expect do
+ expect do
+ gauge.set_to_current_time(labels: { test: 'value' })
+ end.to change { gauge.get(labels: { test: 'value' }) }.from(0).to(12345.1)
+ end.to_not change { gauge.get(labels: { test: 'other' }) }
+ end
+ end
+ end
+ end
+
  describe '#increment' do
  before do
  gauge.set(0, labels: RSpec.current_example.metadata[:labels] || {})

spec/spec_helper.rb

@@ -1,6 +1,7 @@
 # encoding: UTF-8
 
 require 'simplecov'
+require 'timecop'
 
 RSpec.configure do |c|
  c.warnings = true
@@ -9,3 +10,5 @@
 SimpleCov.formatter = SimpleCov::Formatter::HTMLFormatter
 
 SimpleCov.start
+
+Timecop.safe_mode = true