Module: Frankenstein::ProcessMetrics

Defined in:
lib/frankenstein/process_metrics.rb

Overview

Allow registration of metrics for Ruby GC statistics.

Class Method Summary collapse

Class Method Details

.register(registry = Prometheus::Client.registry, logger: Logger.new("/dev/null")) ⇒ Object

Register generic process metrics.

Generates collected metric objects for all of the recommended process metrics that can be reasonably obtained using Ruby on the platform that the process is running on.

Parameters:

  • registry (Prometheus::Client::Registry) (defaults to: Prometheus::Client.registry) —

    specify the metrics registry in which to register the GC-related metrics.

  • logger (Logger) (defaults to: Logger.new("/dev/null")) —

    where to log any problems which some sort of



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# File 'lib/frankenstein/process_metrics.rb', line 20

def self.register(registry = Prometheus::Client.registry, logger: Logger.new("/dev/null"))
  registry.gauge(:process_start_time_seconds, docstring: "Start time of the process since unix epoch in seconds").set(Time.now.to_f)

  page_size = Etc.sysconf(Etc::SC_PAGESIZE)
  hz        = Etc.sysconf(Etc::SC_CLK_TCK)

  stat_file = "/proc/#{Process.pid}/stat".freeze

  if File.exist?(stat_file)
    Frankenstein::CollectedMetric.new(:process_cpu_seconds_total, docstring: "Total user and system CPU time spent in seconds", registry: registry, logger: logger, labels: [:mode]) do
      stats = File.read(stat_file).split(" ")
      { { mode: "user" } => stats[13].to_f / hz, { mode: "system" } => stats[14].to_f / hz }
    end

    Frankenstein::CollectedMetric.new(:process_virtual_memory_bytes, docstring: "Virtual memory size in bytes", registry: registry, logger: logger) do
      stats = File.read(stat_file).split(" ")
      { {} => stats[22].to_i }
    end

    Frankenstein::CollectedMetric.new(:process_resident_memory_bytes, docstring: "Resident memory size in bytes", registry: registry, logger: logger) do
      stats = File.read(stat_file).split(" ")
      { {} => stats[23].to_i * page_size }
    end
  end

  fd_dir = "/proc/#{Process.pid}/fd".freeze

  if File.exist?(fd_dir)
    Frankenstein::CollectedMetric.new(:process_open_fds, docstring: "Number of open file descriptors", registry: registry, logger: logger) do
      { {} => Dir["#{fd_dir}/*"].length }
    end
  end

  if Process.respond_to?(:getrlimit)
    Frankenstein::CollectedMetric.new(:process_max_fds, docstring: "Maximum number of open file descriptors", registry: registry, logger: logger) do
      { {} => Process.getrlimit(:NOFILE).first }
    end

    Frankenstein::CollectedMetric.new(:process_virtual_memory_max_bytes, docstring: "Maximum amount of virtual memory available in bytes", registry: registry, logger: logger) do
      { {} => Process.getrlimit(:AS).first }
    end
  end

  if GC.respond_to?(:stat) && GC.stat[:heap_allocated_pages]
    Frankenstein::CollectedMetric.new(:process_heap_bytes, docstring: "Process heap size in bytes", registry: registry, logger: logger) do
      { {} => GC.stat[:heap_allocated_pages] * page_size }
    end
  end
end