114 lines
3.6 KiB
Ruby
114 lines
3.6 KiB
Ruby
# frozen_string_literal: true
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require_relative '../config/boot'
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class MetricsServer # rubocop:disable Gitlab/NamespacedClass
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# The singleton instance used to supervise the Puma metrics server.
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PumaProcessSupervisor = Class.new(Gitlab::ProcessSupervisor)
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class << self
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def start_for_puma
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metrics_dir = ::Prometheus::Client.configuration.multiprocess_files_dir
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start_server = proc do
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MetricsServer.spawn('puma', metrics_dir: metrics_dir).tap do |pid|
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Gitlab::AppLogger.info("Starting Puma metrics server with pid #{pid}")
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end
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end
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supervisor = PumaProcessSupervisor.instance
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supervisor.supervise(start_server.call) do
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next unless supervisor.alive
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Gitlab::AppLogger.info('Puma metrics server terminated, restarting...')
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start_server.call
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end
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end
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def spawn(target, metrics_dir:, gitlab_config: nil, wipe_metrics_dir: false)
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ensure_valid_target!(target)
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cmd = "#{Rails.root}/bin/metrics-server"
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env = {
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'METRICS_SERVER_TARGET' => target,
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'WIPE_METRICS_DIR' => wipe_metrics_dir ? '1' : '0'
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}
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env['GITLAB_CONFIG'] = gitlab_config if gitlab_config
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Process.spawn(env, cmd, err: $stderr, out: $stdout, pgroup: true).tap do |pid|
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Process.detach(pid)
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end
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end
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def fork(target, metrics_dir:, wipe_metrics_dir: false, reset_signals: [])
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ensure_valid_target!(target)
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pid = Process.fork
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if pid.nil? # nil means we're inside the fork
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# Remove any custom signal handlers the parent process had registered, since we do
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# not want to inherit them, and Ruby forks with a `clone` that has the `CLONE_SIGHAND`
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# flag set.
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Gitlab::ProcessManagement.modify_signals(reset_signals, 'DEFAULT')
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server = MetricsServer.new(target, metrics_dir, wipe_metrics_dir)
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# This rewrites /proc/cmdline, since otherwise tools like `top` will show the
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# parent process `cmdline` which is really confusing.
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$0 = server.name
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server.start
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else
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Process.detach(pid)
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end
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pid
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end
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private
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def ensure_valid_target!(target)
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raise "Target must be one of [puma,sidekiq]" unless %w(puma sidekiq).include?(target)
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end
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end
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def initialize(target, metrics_dir, wipe_metrics_dir)
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@target = target
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@metrics_dir = metrics_dir
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@wipe_metrics_dir = wipe_metrics_dir
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end
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def start
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::Prometheus::Client.configure do |config|
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config.multiprocess_files_dir = @metrics_dir
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config.pid_provider = proc { name }
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end
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FileUtils.mkdir_p(@metrics_dir, mode: 0700)
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::Prometheus::CleanupMultiprocDirService.new(@metrics_dir).execute if @wipe_metrics_dir
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# We need to `warmup: true` since otherwise the sampler and exporter threads enter
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# a race where not all Prometheus db files will be visible to the exporter, resulting
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# in missing metrics.
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# Warming up ensures that these files exist prior to the exporter starting up.
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Gitlab::Metrics::Samplers::RubySampler.initialize_instance(prefix: name, warmup: true).start
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default_opts = { gc_requests: true, synchronous: true }
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exporter =
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case @target
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when 'puma'
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Gitlab::Metrics::Exporter::WebExporter.instance(**default_opts)
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when 'sidekiq'
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settings = Settings.new(Settings.monitoring[name])
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Gitlab::Metrics::Exporter::SidekiqExporter.instance(settings, **default_opts)
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end
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exporter.start
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end
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def name
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case @target
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when 'puma' then 'web_exporter'
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when 'sidekiq' then 'sidekiq_exporter'
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end
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end
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end
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