Class: Interferon::Interferon

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/interferon.rb

Constant Summary collapse

DRY_RUN_ALERTS_NAME_PREFIX = 
'[-dry-run-]'.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Logging

configure_logger_for, #log, #statsd

Constructor Details

#initialize(config, dry_run = false) ⇒ Interferon

groups_sources is a hash from type => options for each group source host_sources is a hash from type => options for each host source destinations is a similar hash from type => options for each alerter



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# File 'lib/interferon.rb', line 26

def initialize(config, dry_run = false)
  @alerts_repo_path = config['alerts_repo_path']
  @group_sources = config['group_sources'] || {}
  @host_sources = config['host_sources']
  @destinations = config['destinations']
  @processes = config['processes']
  @dry_run = dry_run
  @request_shutdown = false
end

Instance Attribute Details

#destinations ⇒ Object

Returns the value of attribute destinations.



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# File 'lib/interferon.rb', line 19

def destinations
  @destinations
end

#host_info ⇒ Object

Returns the value of attribute host_info.



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# File 'lib/interferon.rb', line 19

def host_info
  @host_info
end

#host_sources ⇒ Object

Returns the value of attribute host_sources.



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# File 'lib/interferon.rb', line 19

def host_sources
  @host_sources
end

Instance Method Details

#build_alerts_queue(hosts, alerts, groups) ⇒ Object 



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# File 'lib/interferon.rb', line 241

def build_alerts_queue(hosts, alerts, groups)
  alerts_queue = {}
  all_alert_generation_errors = []

  # create or update alerts; mark when we've done that
  result = Parallel.map(alerts, in_processes: @processes) do |alert|
    break if @request_shutdown
    alerts_generated = {}
    alert_generation_errors = []
    counters = {
      errors: 0,
      evals: 0,
      applies: 0,
      hosts: hosts.length,
    }

    last_eval_error = nil

    hosts.each do |hostinfo|
      begin
        alert.evaluate(hostinfo)
        counters[:evals] += 1
      rescue StandardError => e
        log.debug("Evaluation of alert #{alert} failed in the context of host #{hostinfo}")
        counters[:errors] += 1
        last_eval_error = e
        next
      end

      # don't define an alert that doesn't apply to this hostinfo
      unless alert[:applies]
        log.debug("alert #{alert[:name]} doesn't apply to #{hostinfo.inspect}")
        next
      end

      counters[:applies] += 1
      # don't define alerts twice
      next if alerts_generated.key?(alert[:name])

      # figure out who to notify
      people = Set.new(alert[:notify][:people])
      alert[:notify][:groups].each do |g|
        people += (groups[g] || [])
      end

      # queue the alert up for creation; we clone the alert to save the current state
      alerts_generated[alert[:name]] = [alert.clone, people]
    end

    # log some of the counters
    statsd.gauge('alerts.evaluate.errors', counters[:errors], tags: ["alert:#{alert}"])
    statsd.gauge('alerts.evaluate.applies', counters[:applies], tags: ["alert:#{alert}"])

    if counters[:applies] > 0
      log.info("alert #{alert} applies to #{counters[:applies]} of #{counters[:hosts]} hosts")
    end

    # did the alert fail to evaluate on all hosts?
    if counters[:errors] == counters[:hosts] && !last_eval_error.nil?
      log.error("alert #{alert} failed to evaluate in the context of all hosts!")
      log.error("last error on alert #{alert}: #{last_eval_error}")
      statsd.gauge('alerts.evaluate.failed_on_all', 1, tags: ["alert:#{alert}"])
      log.debug(
        "alert #{alert}: " \
        "error #{last_eval_error}\n#{last_eval_error.backtrace.join("\n")}"
      )
      alert_generation_errors << alert
    else
      statsd.gauge('alerts.evaluate.failed_on_all', 0, tags: ["alert:#{alert}"])
    end

    # did the alert apply to any hosts?
    if counters[:applies] == 0
      statsd.gauge('alerts.evaluate.never_applies', 1, tags: ["alert:#{alert}"])
      log.warn("alert #{alert} did not apply to any hosts")
      alert_generation_errors << alert
    else
      statsd.gauge('alerts.evaluate.never_applies', 0, tags: ["alert:#{alert}"])
    end
    [alerts_generated, alert_generation_errors]
  end

  result.each do |generated_alerts, alert_generation_errors|
    alerts_queue.merge!(generated_alerts)
    all_alert_generation_errors += alert_generation_errors
  end
  [alerts_queue, all_alert_generation_errors]
end

#create_alerts(dest, alerts_queue) ⇒ Object 



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# File 'lib/interferon.rb', line 218

def create_alerts(dest, alerts_queue)
  alert_key_ids = []
  alerts_to_create = alerts_queue.keys
  concurrency = dest.concurrency || 10
  unless @request_shutdown
    threads = Array.new(concurrency) do |i|
      log.info("thread #{i} created")
      t = Thread.new do
        while (name = alerts_to_create.shift)
          break if @request_shutdown
          cur_alert, people = alerts_queue[name]
          log.debug("creating alert for #{cur_alert[:name]}")
          alert_key_ids << dest.create_alert(cur_alert, people)
        end
      end
      t.abort_on_exception = true
      t
    end
    threads.map(&:join)
  end
  alert_key_ids
end

#read_alerts ⇒ Object 



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# File 'lib/interferon.rb', line 62

def read_alerts
  alerts = []
  failed = 0

  # validate that alerts path exists
  path = File.expand_path(File.join(@alerts_repo_path, 'alerts'))
  abort("no such directory #{path} for reading alert files") \
    unless Dir.exist?(path)

  Dir.glob(File.join(path, '*.rb')) do |alert_file|
    break if @request_shutdown
    begin
      alert = Alert.new(alert_file)
    rescue StandardError => e
      log.warn("error reading alert file #{alert_file}: #{e}")
      failed += 1
    else
      alerts << alert
    end
  end

  log.info("read #{alerts.count} alerts files from #{path}")

  statsd.gauge('alerts.read.count', alerts.count)
  statsd.gauge('alerts.read.failed', failed)

  abort("failed to read #{failed} alerts") if failed > 0
  alerts
end

#read_groups(sources) ⇒ Object 



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# File 'lib/interferon.rb', line 92

def read_groups(sources)
  groups = {}
  loader = GroupSourcesLoader.new([@alerts_repo_path])
  loader.get_all(sources).each do |source|
    break if @request_shutdown
    source_groups = source.list_groups { groups }

    # add all people to groups
    people_count = 0
    source_groups.each do |name, people|
      groups[name] ||= []
      groups[name].concat(people)
      people_count += people.count
    end

    log.info(
      "read #{people_count} people in #{source_groups.count} groups " \
      "from source #{source.class.name}"
    )
  end

  log.info(
    "total of #{groups.values.flatten.count} people in #{groups.count} groups " \
    "from #{sources.count} sources"
  )

  statsd.gauge('groups.sources', sources.count)
  statsd.gauge('groups.count', groups.count)
  statsd.gauge('groups.people', groups.values.flatten.count)

  groups
end

#read_hosts(sources) ⇒ Object 



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# File 'lib/interferon.rb', line 125

def read_hosts(sources)
  statsd.gauge('hosts.sources', sources.count)

  hosts = []
  loader = HostSourcesLoader.new([@alerts_repo_path])
  loader.get_all(sources).each do |source|
    break if @request_shutdown
    source_hosts = source.list_hosts
    hosts << source_hosts

    statsd.gauge('hosts.count', source_hosts.count, tags: ["source:#{source.class.name}"])
    log.info("read #{source_hosts.count} hosts from source #{source.class.name}")
  end

  hosts.flatten!
  log.info("total of #{hosts.count} entities from #{sources.count} sources")

  hosts
end

#run ⇒ Object 



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# File 'lib/interferon.rb', line 36

def run
  Signal.trap('TERM') do
    log.info('SIGTERM received. shutting down gracefully...')
    @request_shutdown = true
  end
  run_desc = @dry_run ? 'dry run' : 'run'
  log.info("beginning alerts #{run_desc}")

  alerts = read_alerts
  groups = read_groups(@group_sources)
  hosts = read_hosts(@host_sources)

  @destinations.each do |dest|
    dest['options'] ||= {}
    dest['options']['dry_run'] = true if @dry_run
  end

  update_alerts(@destinations, hosts, alerts, groups)

  if @request_shutdown
    log.info("interferon #{run_desc} shut down by SIGTERM")
  else
    log.info("interferon #{run_desc} complete")
  end
end

#run_update(dest, alerts_queue, existing_alerts) ⇒ Object 



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# File 'lib/interferon.rb', line 185

def run_update(dest, alerts_queue, existing_alerts)
  updates_queue = alerts_queue.reject do |_name, alert_people_pair|
    !dest.need_update(alert_people_pair, existing_alerts)
  end

  # Create alerts in destination
  create_alerts(dest, updates_queue)

  # Do not continue to remove alerts during dry-run
  return if @dry_run

  # Existing alerts are pruned until all that remains are
  # alerts that aren't being generated anymore
  to_remove = existing_alerts.dup
  alerts_queue.each do |_name, alert_people_pair|
    alert, _people = alert_people_pair
    old_alerts = to_remove[alert['name']]

    next if old_alerts.nil?
    if old_alerts['id'].length == 1
      to_remove.delete(alert['name'])
    else
      old_alerts['id'] = old_alerts['id'].drop(1)
    end
  end

  # Clean up alerts not longer being generated
  to_remove.each do |_name, alert|
    break if @request_shutdown
    dest.remove_alert(alert)
  end
end

#update_alerts(destinations, hosts, alerts, groups) ⇒ Object 



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# File 'lib/interferon.rb', line 145

def update_alerts(destinations, hosts, alerts, groups)
  alerts_queue, alert_errors = build_alerts_queue(hosts, alerts, groups)
  if @dry_run && !alert_errors.empty?
    raise "Alerts failed to apply or evaluate for all hosts: #{alerts.map(&:to_s).join(', ')}"
  end

  loader = DestinationsLoader.new([@alerts_repo_path])
  loader.get_all(destinations).each do |dest|
    break if @request_shutdown
    log.info("updating alerts on #{dest.class.name}")
    update_alerts_on_destination(dest, alerts_queue)
  end
end

#update_alerts_on_destination(dest, alerts_queue) ⇒ Object 



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# File 'lib/interferon.rb', line 159

def update_alerts_on_destination(dest, alerts_queue)
  # track some counters/stats per destination
  start_time = Time.new.to_f

  # get already-defined alerts
  existing_alerts = dest.existing_alerts

  run_update(dest, alerts_queue, existing_alerts)

  unless @request_shutdown
    # run time summary
    run_time = Time.new.to_f - start_time
    statsd.histogram(
      @dry_run ? 'destinations.run_time.dry_run' : 'destinations.run_time',
      run_time,
      tags: ["destination:#{dest.class.name}"]
    )
    log.info("#{dest.class.name} : run completed in %.2f seconds" % run_time)

    # report destination stats
    dest.report_stats
  end

  raise dest.api_errors.to_s if @dry_run && !dest.api_errors.empty?
end