Add the prometheus reporter ruby script

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

lib/puppet/reports/prometheus.rb

@@ -0,0 +1,61 @@
+require 'puppet'
+require 'puppet/util'
+require 'yaml'
+require 'fileutils'
+
+# Required for strftime(%Q)
+require 'date'
+
+Puppet::Reports.register_report(:prometheus) do
+  # Source: evenup/evenup-graphite_reporter code base
+  # lib/puppet/reports/graphite.rb
+  configfile = File.join([File.dirname(Puppet.settings[:config]),
+                          'prometheus.yaml'])
+  unless File.exist?(configfile)
+    raise(Puppet::ParseError, "Prometheus report config file #{configfile} not readable")
+  end
+
+  config = YAML.load_file(configfile)
+
+  TEXTFILE_DIRECTORY = config['textfile_directory']
+  REPORT_FILENAME = config['report_filename']
+
+  if TEXTFILE_DIRECTORY.nil?
+    raise(Puppet::ParseError, "#{configfile}: textfile_directory is not set.")
+  end
+
+  unless REPORT_FILENAME.nil? or REPORT_FILENAME.end_with? '.prom'
+    raise(Puppet::ParseError, "#{configfile}: report_filename does not ends with .prom")
+  end
+
+  def process
+    now = DateTime.now.new_offset(0)
+
+    if REPORT_FILENAME.nil?
+      name = host + '.prom'
+      file = File.join(TEXTFILE_DIRECTORY, name)
+    else
+      file = File.join(TEXTFILE_DIRECTORY, REPORT_FILENAME)
+    end
+
+    common_values = {
+      transaction_uuid: self.transaction_uuid,
+      host: self.host,
+    }.reduce('') {
+        |values, extra| values + ",#{extra[0].to_s}=\"#{extra[1].to_s}\""
+    }
+
+    epochtime = now.strftime('%Q')
+    File.open(file, 'w') do |file|
+      unless metrics.empty? or metrics['events'].nil?
+        metrics.each do |metric, data|
+          data.values.each do |val|
+            file.write("puppet_report_#{metric}{name=\"#{val[1]}\"#{common_values}} #{val[2]}\n")
+          end
+        end
+      end
+
+      file.write("puppet_report{host=\"#{host}\",kind=\"#{kind}\",version=\"#{configuration_version}\"#{common_values}} #{epochtime}\n")
+    end
+  end
+end