Class: Sensu::Server::Process

Inherits:
Object
  • Object
show all
Includes:
Daemon, Filter, Handle, Mutate
Defined in:
lib/sensu/server/process.rb

Constant Summary collapse

TASKS = 
["check_request_publisher", "client_monitor", "check_result_monitor"]
STANDARD_CHECK_TYPE = 
"standard".freeze
METRIC_CHECK_TYPE = 
"metric".freeze
EVENT_FLAPPING_ACTION = 
"flapping".freeze
DEFAULT_HANDLER_NAME = 
"default".freeze

Constants included from Utilities

Utilities::EVAL_PREFIX

Instance Attribute Summary collapse

Attributes included from Daemon

#settings, #start_time

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Handle

#handle_event, #handler_error, #handler_extension, #handler_type_router, #pipe_handler, #tcp_handler, #transport_handler, #udp_handler

Methods included from Mutate

#mutate_event, #mutator_callback, #mutator_extension, #pipe_mutator

Methods included from Filter

#event_filter, #event_filtered?, #extension_filter, #filter_event, #handle_action?, #handle_severity?, #handler_silenced?, #handling_disabled?, #in_filter_time_windows?, #native_filter

Methods included from Daemon

#load_extensions, #load_settings, #log_notices, #print_settings!, #setup_logger, #setup_process, #setup_redis, #setup_signal_traps, #setup_spawn, #setup_transport, #validate_settings!

Methods included from Utilities

#attributes_match?, #check_subdued?, #deep_merge, #determine_check_cron_time, #eval_attribute_value, #find_attribute_value, #in_time_window?, #in_time_windows?, #object_substitute_tokens, #process_cpu_times, #process_eval_string, #random_uuid, #redact_sensitive, #retry_until_true, #substitute_tokens, #system_address, #system_hostname, #testing?

Constructor Details

#initialize(options = {}) ⇒ Process

Override Daemon initialize() to support Sensu server tasks and the handling event count.

Parameters:

  • options (Hash) (defaults to: {}) 


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# File 'lib/sensu/server/process.rb', line 43

def initialize(options={})
  super
  @tasks = []
  @timers[:tasks] = {}
  TASKS.each do |task|
    @timers[:tasks][task.to_sym] = []
  end
  @in_progress = Hash.new(0)
end

Instance Attribute Details

#in_progress ⇒ Object (readonly)

Returns the value of attribute in_progress.



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# File 'lib/sensu/server/process.rb', line 14

def in_progress
  @in_progress
end

#tasks ⇒ Object (readonly)

Returns the value of attribute tasks.



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# File 'lib/sensu/server/process.rb', line 14

def tasks
  @tasks
end

Class Method Details

.run(options = {}) ⇒ Object

Create an instance of the Sensu server process, start the server within the EventMachine event loop, and set up server process signal traps (for stopping).

Parameters:

  • options (Hash) (defaults to: {}) 


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# File 'lib/sensu/server/process.rb', line 31

def self.run(options={})
  server = self.new(options)
  EM::run do
    server.start
    server.setup_signal_traps
  end
end

Instance Method Details

#aggregate_check_result(client, check) ⇒ Object

Add a check result to one or more aggregates. The aggregate name is determined by the value of check ‘:aggregates` array, if present, and falling back to `:aggregate` otherwise.

When one or more aggregates are specified as ‘:aggregates`, the client name and check are updated on each aggregate.

When no aggregates are specified as ‘:aggregates`, and `:aggregate` is `true` (legacy), the check `:name` is used as the aggregate name.

When no aggregates are specified as ‘:aggregates` and check `:aggregate` is a string, it used as the aggregate name.

This method will add the client name to configured aggregates, all other processing (e.g. counters) is done by the Sensu API on request.

Parameters:

  • client (Hash)
  • check (Hash) 


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# File 'lib/sensu/server/process.rb', line 307

def aggregate_check_result(client, check)
  check_aggregate = (check[:aggregate].is_a?(String) ? check[:aggregate] : check[:name])
  aggregate_list = Array(check[:aggregates] || check_aggregate)
  aggregate_list.each do |aggregate|
    @logger.debug("adding check result to aggregate", {
      :aggregate => aggregate,
      :client => client,
      :check => check
    })
    aggregate_member = "#{client[:name]}:#{check[:name]}"
    @redis.sadd("aggregates:#{aggregate}", aggregate_member) do
      @redis.sadd("aggregates", aggregate)
    end
  end
end

#bootstrap ⇒ Object

Bootstrap the Sensu server process, setting up the keepalive and check result consumers, and attemping to carry out Sensu server tasks. This method sets the process/daemon ‘@state` to `:running`.



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# File 'lib/sensu/server/process.rb', line 1491

def bootstrap
  setup_keepalives
  setup_results
  setup_task_elections
  setup_server_registry_updater
  @state = :running
end

#calculate_check_request_splay(check) ⇒ Object

Calculate a check request splay, taking into account the current time and the request interval to ensure it’s consistent between process restarts.

Parameters:

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 970

def calculate_check_request_splay(check)
  splay_hash = Digest::MD5.digest(check[:name]).unpack('Q<').first
  current_time = (Time.now.to_f * 1000).to_i
  (splay_hash - current_time) % (check[:interval] * 1000) / 1000.0
end

#check_flapping?(stored_event, check) ⇒ TrueClass, FalseClass

Determine if a check state is flapping, rapidly changing between an OK and non-OK state. Flap detection is only done for checks that have defined low and hight flap detection thresholds, ‘:low_flap_threshold` and `:high_flap_threshold`. The `check_history()` method provides the check history and more importantly the total state change precentage value that is compared with the configured thresholds defined in the check data. If a check hasn’t been flapping, the ‘:total_state_change` must be equal to or higher than the `:high_flap_threshold` to be changed to flapping. If a check has been flapping, the `:total_state_change` must be equal to or lower than the `:low_flap_threshold` to no longer be flapping. This method uses the same algorithm as Nagios: nagios.sourceforge.net/docs/3_0/flapping.html

Parameters:

  • stored_event (Hash)
  • check (Hash)

Returns:

  • (TrueClass, FalseClass) 


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# File 'lib/sensu/server/process.rb', line 437

def check_flapping?(stored_event, check)
  if check.has_key?(:low_flap_threshold) && check.has_key?(:high_flap_threshold)
    if check[:low_flap_threshold].is_a?(Integer) && check[:high_flap_threshold].is_a?(Integer)
      was_flapping = stored_event && stored_event[:action] == EVENT_FLAPPING_ACTION
      if was_flapping
        check[:total_state_change] > check[:low_flap_threshold]
      else
        check[:total_state_change] >= check[:high_flap_threshold]
      end
    else
      details = {:check => check}
      details[:client] = stored_event[:client] if stored_event
      @logger.error("invalid check flap thresholds", details)
      false
    end
  else
    false
  end
end

#check_history(client, check) {|history, total_state_change| ... } ⇒ Object

Fetch the execution history for a client/check pair, the 21 most recent check result statuses. This method also calculates the total state change percentage for the history, this value is use for check state flap detection, using a similar algorithm to Nagios: nagios.sourceforge.net/docs/3_0/flapping.html

Parameters:

  • client (Hash)
  • check (Hash)

Yields:

  • (history, total_state_change) —

    callback/block to call with the check history and calculated total state change value.

Yield Parameters:

  • history (Array) —

    containing the last 21 check result exit status codes.

  • total_state_change (Float) —

    percentage for the check history (exit status codes).



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# File 'lib/sensu/server/process.rb', line 398

def check_history(client, check)
  history_key = "history:#{client[:name]}:#{check[:name]}"
  @redis.lrange(history_key, -21, -1) do |history|
    total_state_change = 0
    unless history.length < 21
      state_changes = 0
      change_weight = 0.8
      previous_status = history.first
      history.each do |status|
        unless status == previous_status
          state_changes += change_weight
        end
        change_weight += 0.02
        previous_status = status
      end
      total_state_change = (state_changes.fdiv(20) * 100).to_i
    end
    yield(history, total_state_change)
  end
end

#complete_in_progress { ... } ⇒ Object

Complete in progress work and then call the provided callback. This method will wait until all counters stored in the ‘@in_progress` hash equal `0`.

Yields:

  • callback/block to call when in progress work is

    completed.



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# File 'lib/sensu/server/process.rb', line 1477

def complete_in_progress
  @logger.info("completing work in progress", :in_progress => @in_progress)
  retry_until_true do
    if @in_progress.values.all? { |count| count == 0 }
      yield
      true
    end
  end
end

#create_check_request_proc(check) ⇒ Object

Create a check request proc, used to publish check requests to for a check to the Sensu transport. Check requests are not published if subdued. This method determines if a check uses proxy check requests and calls the appropriate check request publish method.

Parameters:

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 932

def create_check_request_proc(check)
  Proc.new do
    unless check_subdued?(check)
      if check[:proxy_requests]
        create_proxy_check_requests(check)
      else
        publish_check_request(check)
      end
    else
      @logger.info("check request was subdued", :check => check)
    end
  end
end

#create_check_ttl_results(ttl_keys, interval = 30) { ... } ⇒ Object

Create check TTL results. This method will retrieve check results from the registry and determine the time since their last check execution (in seconds). If the time since last execution is equal to or greater than the defined check TTL, a warning check result is published with the appropriate check output.

Parameters:

  • ttl_keys (Array) —

    of TTL keys.

  • interval (Integer) (defaults to: 30) —

    to use for the check TTL result interval.

Yields:

  • callback/block called after the check TTL results

    have been created.



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# File 'lib/sensu/server/process.rb', line 1166

def create_check_ttl_results(ttl_keys, interval=30)
  result_keys = ttl_keys.map { |ttl_key| "result:#{ttl_key}" }
  @redis.mget(*result_keys) do |result_json_objects|
    result_json_objects.each_with_index do |result_json, index|
      unless result_json.nil?
        check = Sensu::JSON.load(result_json)
        next unless check[:ttl] && check[:executed] && !check[:force_resolve]
        time_since_last_execution = Time.now.to_i - check[:executed]
        if time_since_last_execution >= check[:ttl]
          client_name = ttl_keys[index].split(":").first
          keepalive_event_exists?(client_name) do |event_exists|
            unless event_exists
              check[:output] = "Last check execution was "
              check[:output] << "#{time_since_last_execution} seconds ago"
              check[:status] = check[:ttl_status] || 1
              check[:interval] = interval
              publish_check_result(client_name, check)
            end
          end
        end
      else
        @redis.srem("ttl", ttl_keys[index])
      end
    end
    yield
  end
end

#create_client(name) ⇒ Hash

Create a blank client (data). Only the client name is known, the other client attributes must be updated via the API (POST /clients:client). Dynamically created clients and those updated via the API will have client keepalives disabled by default, ‘:keepalives` is set to `false`.

Parameters:

  • name (String) —

    to use for the client.

Returns:

  • (Hash) —

    client.



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# File 'lib/sensu/server/process.rb', line 602

def create_client(name)
  {
    :name => name,
    :address => "unknown",
    :subscriptions => ["client:#{name}"],
    :keepalives => false,
    :version => VERSION,
    :timestamp => Time.now.to_i
  }
end

#create_client_keepalive_check_results(clients) { ... } ⇒ Object

Create client keepalive check results. This method will retrieve clients from the registry, creating a keepalive check definition for each client, using the ‘create_keepalive_check()` method, containing client specific keepalive thresholds. If the time since the latest keepalive is equal to or greater than a threshold, the check `:output` is set to a descriptive message, and `:status` is set to the appropriate non-zero value. If a client has been sending keepalives, `:output` and `:status` are set to indicate an OK state. The `publish_check_result()` method is used to publish the client keepalive check results.

Parameters:

  • clients (Array) —

    of client names.

Yields:

  • callback/block called after the client keepalive

    check results have been created.



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# File 'lib/sensu/server/process.rb', line 1090

def create_client_keepalive_check_results(clients)
  client_keys = clients.map { |client_name| "client:#{client_name}" }
  @redis.mget(*client_keys) do |client_json_objects|
    client_json_objects.each do |client_json|
      unless client_json.nil?
        client = Sensu::JSON.load(client_json)
        next if client[:keepalives] == false
        check = create_keepalive_check(client)
        time_since_last_keepalive = Time.now.to_i - client[:timestamp]
        check[:output] = "No keepalive sent from client for "
        check[:output] << "#{time_since_last_keepalive} seconds"
        case
        when time_since_last_keepalive >= check[:thresholds][:critical]
          check[:output] << " (>=#{check[:thresholds][:critical]})"
          check[:status] = 2
        when time_since_last_keepalive >= check[:thresholds][:warning]
          check[:output] << " (>=#{check[:thresholds][:warning]})"
          check[:status] = 1
        else
          check[:output] = "Keepalive sent from client "
          check[:output] << "#{time_since_last_keepalive} seconds ago"
          check[:status] = 0
        end
        publish_check_result(client[:name], check)
      end
    end
    yield
  end
end

#create_client_registration_event(client) ⇒ Object

Create and process a client registration event. A registration event is created when a Sensu client is first added to the client registry. The ‘create_registration_check()` method is called to create a registration check definition for the client.

Parameters:

  • client (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 104

def create_client_registration_event(client)
  check = create_registration_check(client)
  create_event(client, check) do |event|
    event_bridges(event)
    process_event(event)
  end
end

#create_event(client, check) {|event| ... } ⇒ Object

Create an event, using the provided client and check result data. Existing event data for the client/check pair is fetched from the event registry to be used in the composition of the new event. The silenced registry is used to determine if the event has been silenced.

Parameters:

  • client (Hash)
  • check (Hash)

Yield Parameters:

  • event (Hash) 


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# File 'lib/sensu/server/process.rb', line 545

def create_event(client, check)
  check_history(client, check) do |history, total_state_change|
    check[:history] = history
    check[:total_state_change] = total_state_change
    @redis.hget("events:#{client[:name]}", check[:name]) do |event_json|
      stored_event = event_json ? Sensu::JSON.load(event_json) : nil
      flapping = check_flapping?(stored_event, check)
      event = {
        :client => client,
        :check => check,
        :occurrences => 1,
        :occurrences_watermark => 1,
        :action => (flapping ? :flapping : :create),
        :timestamp => Time.now.to_i
      }
      if stored_event
        event[:id] = stored_event[:id]
        event[:last_state_change] = stored_event[:last_state_change]
        event[:last_ok] = stored_event[:last_ok]
        event[:occurrences] = stored_event[:occurrences]
        event[:occurrences_watermark] = stored_event[:occurrences_watermark] || event[:occurrences]
      else
        event[:id] = random_uuid
        event[:last_ok] = event[:timestamp]
      end
      if check[:status] != 0 || flapping
        if history[-1] == history[-2]
          event[:occurrences] += 1
          if event[:occurrences] > event[:occurrences_watermark]
            event[:occurrences_watermark] = event[:occurrences]
          end
        else
          event[:occurrences] = 1
          event[:last_state_change] = event[:timestamp]
        end
      elsif stored_event
        event[:last_state_change] = event[:timestamp]
        event[:action] = :resolve
      end
      if check[:status] == 0
        event[:last_ok] = event[:timestamp]
      end
      event_silenced?(event) do |event|
        yield(event)
      end
    end
  end
end

#create_keepalive_check(client) ⇒ Object

Create a keepalive check definition for a client. Client definitions may contain ‘:keepalive` configuration, containing specific thresholds and handler information. The keepalive check definition creation begins with default thresholds, and sets the `:handler` to `keepalive`, if the handler has a local definition. If the client provides its own `:keepalive` configuration, it’s deep merged with the defaults. The check ‘:name`, `:issued`, and `:executed` values are always overridden to guard against an invalid definition.



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# File 'lib/sensu/server/process.rb', line 1058

def create_keepalive_check(client)
  check = {
    :thresholds => {
      :warning => 120,
      :critical => 180
    }
  }
  if @settings.handler_exists?(:keepalive)
    check[:handler] = "keepalive"
  end
  if client.has_key?(:keepalive)
    check = deep_merge(check, client[:keepalive])
  end
  timestamp = Time.now.to_i
  check.merge(:name => "keepalive", :issued => timestamp, :executed => timestamp)
end

#create_lock_timestamp ⇒ Integer

Create a lock timestamp (integer), current time including milliseconds. This method is used by Sensu server task election.

Returns:

  • (Integer) 


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# File 'lib/sensu/server/process.rb', line 1242

def create_lock_timestamp
  (Time.now.to_f * 10000000).to_i
end

#create_proxy_check_requests(check) ⇒ Object

Create and publish one or more proxy check requests. This method iterates through the Sensu client registry for clients that matched provided proxy request client attributes. A proxy check request is created for each client in the registry that matches the proxy request client attributes. Proxy check requests have their client tokens subsituted by the associated client attributes values. The ‘determine_matching_clients()` method is used to fetch and inspect each slide of clients from the registry, returning those that match the configured proxy request client attributes. A relatively small clients slice size (20) is used to reduce the number of clients inspected within a single tick of the EM reactor. The `publish_proxy_check_requests()` method is used to iterate through the matching Sensu clients, creating their own unique proxy check request, substituting client tokens, and then publishing them to the targetted subscriptions.

Parameters:

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 904

def create_proxy_check_requests(check)
  client_attributes = check[:proxy_requests][:client_attributes]
  unless client_attributes.empty?
    @redis.smembers("clients") do |clients|
      client_count = clients.length
      proxy_check_requests = Proc.new do |matching_clients, slice_start, slice_size|
        unless slice_start > client_count - 1
          clients_slice = clients.slice(slice_start..slice_size)
          determine_matching_clients(clients_slice, client_attributes) do |additional_clients|
            matching_clients += additional_clients
            proxy_check_requests.call(matching_clients, slice_start + 20, slice_size + 20)
          end
        else
          publish_proxy_check_requests(matching_clients, check)
        end
      end
      proxy_check_requests.call([], 0, 19)
    end
  end
end

#create_registration_check(client) ⇒ Object

Create a registration check definition for a client. Client definitions may contain ‘:registration` configuration, containing custom attributes and handler information. By default, the registration check definition sets the `:handler` to `registration`. If the client provides its own `:registration` configuration, it’s deep merged with the defaults. The check ‘:name`, `:output`, `:issued`, and `:executed` values are always overridden to guard against an invalid definition.



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# File 'lib/sensu/server/process.rb', line 82

def create_registration_check(client)
  check = {:handler => "registration", :status => 1}
  if client.has_key?(:registration)
    check = deep_merge(check, client[:registration])
  end
  timestamp = Time.now.to_i
  overrides = {
    :name => "registration",
    :output => "new client registration",
    :issued => timestamp,
    :executed => timestamp
  }
  check.merge(overrides)
end

#derive_handlers(handler_list, depth = 0) ⇒ Array

Derive an array of handler definitions from a list of handler names. This method first checks for the existence of standard handlers, followed by handler extensions. If a handler does not exist for a name, it is logged and ignored. Duplicate handler definitions are removed.

Parameters:

  • handler_list (Array)
  • depth (Integer) (defaults to: 0) —

    of handler set expansion.

Returns:

  • (Array) 


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# File 'lib/sensu/server/process.rb', line 234

def derive_handlers(handler_list, depth=0)
  handler_list.compact.map { |handler_name|
    case
    when @settings.handler_exists?(handler_name)
      handler = @settings[:handlers][handler_name].merge(:name => handler_name)
      expand_handler_sets(handler, depth)
    when @extensions.handler_exists?(handler_name)
      @extensions[:handlers][handler_name]
    else
      @logger.error("unknown handler", :handler_name => handler_name)
      nil
    end
  }.flatten.compact.uniq
end

#determine_matching_clients(clients, attributes) {|Array| ... } ⇒ Object

Determine and return clients from the registry that match a set of attributes.

Parameters:

  • clients (Array) —

    of client names.

  • attributes (Hash)

Yields:

  • (Array) —

    callback/block called after determining the matching clients, returning them as a block parameter.



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# File 'lib/sensu/server/process.rb', line 805

def determine_matching_clients(clients, attributes)
  client_keys = clients.map { |client_name| "client:#{client_name}" }
  @redis.mget(*client_keys) do |client_json_objects|
    matching_clients = []
    client_json_objects.each do |client_json|
      unless client_json.nil?
        client = Sensu::JSON.load(client_json)
        if attributes_match?(client, attributes)
          matching_clients << client
        end
      end
    end
    yield(matching_clients)
  end
end

#determine_stale_check_results(interval = 30) ⇒ Object

Determine stale check results, those that have not executed in a specified amount of time (check TTL). This method iterates through stored check results that have a defined TTL value (in seconds). The ‘create_check_ttl_results()` method is used to inspect each check result, calculating their time since last check execution (in seconds). If the time since last execution is equal to or greater than the check TTL, a warning check result is published with the appropriate check output. A relatively small check results slice size (20) is used to reduce the number of check results inspected within a single tick of the EM reactor.

Parameters:

  • interval (Integer) (defaults to: 30) —

    to use for the check TTL result interval.



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# File 'lib/sensu/server/process.rb', line 1208

def determine_stale_check_results(interval=30)
  @logger.info("determining stale check results (ttl)")
  @redis.smembers("ttl") do |ttl_keys|
    ttl_key_count = ttl_keys.length
    ttl_check_results = Proc.new do |slice_start, slice_size|
      unless slice_start > ttl_key_count - 1
        ttl_keys_slice = ttl_keys.slice(slice_start..slice_size)
        create_check_ttl_results(ttl_keys_slice, interval) do
          ttl_check_results.call(slice_start + 20, slice_size + 20)
        end
      end
    end
    ttl_check_results.call(0, 19)
  end
end

#determine_stale_clients ⇒ Object

Determine stale clients, those that have not sent a keepalive in a specified amount of time. This method iterates through the client registry, creating a keepalive check result for each client. The ‘create_client_keepalive_check_results()` method is used to inspect and create keepalive check results for each slice of clients from the registry. A relatively small clients slice size (20) is used to reduce the number of clients inspected within a single tick of the EM reactor.



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# File 'lib/sensu/server/process.rb', line 1128

def determine_stale_clients
  @logger.info("determining stale clients")
  @redis.smembers("clients") do |clients|
    client_count = clients.length
    keepalive_check_results = Proc.new do |slice_start, slice_size|
      unless slice_start > client_count - 1
        clients_slice = clients.slice(slice_start..slice_size)
        create_client_keepalive_check_results(clients_slice) do
          keepalive_check_results.call(slice_start + 20, slice_size + 20)
        end
      end
    end
    keepalive_check_results.call(0, 19)
  end
end

#event_bridges(event) ⇒ Object

Run event bridge extensions, within the Sensu EventMachine reactor (event loop). The extension API ‘safe_run()` method is used to guard against most errors. Bridges are for relaying Sensu event data to other services.

Parameters:

  • event (Hash) 


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# File 'lib/sensu/server/process.rb', line 278

def event_bridges(event)
  @extensions[:bridges].each do |name, bridge|
    bridge.safe_run(event) do |output, status|
      @logger.debug("bridge extension output", {
        :extension => bridge.definition,
        :output => output
      })
    end
  end
end

#event_silenced?(event) ⇒ Boolean

Determine if an event has been silenced. This method compiles an array of possible silenced registry entry keys for the event. An attempt is made to fetch one or more of the silenced registry entries to determine if the event has been silenced. The event data is updated to indicate if the event has been silenced. If the event is silenced and the event action is ‘:resolve`, silenced registry entries with `:expire_on_resolve` set to true will be deleted. Silencing is disabled for events with a check status of `0` (OK), unless the event action is `:resolve` or `:flapping`.

Parameters:

  • event (Hash)

Returns:

  • (Boolean) 


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# File 'lib/sensu/server/process.rb', line 471

def event_silenced?(event)
  event[:silenced] = false
  event[:silenced_by] = []
  if event[:check][:status] != 0 || event[:action] != :create
    check_name = event[:check][:name]
    silenced_keys = event[:client][:subscriptions].map { |subscription|
      ["silence:#{subscription}:*", "silence:#{subscription}:#{check_name}"]
    }.flatten
    silenced_keys << "silence:*:#{check_name}"
    @redis.mget(*silenced_keys) do |silenced|
      silenced.compact!
      silenced.each do |silenced_json|
        silenced_info = Sensu::JSON.load(silenced_json)
        if silenced_info[:expire_on_resolve] && event[:action] == :resolve
          silenced_key = "silence:#{silenced_info[:id]}"
          @redis.srem("silenced", silenced_key)
          @redis.del(silenced_key)
        else
          event[:silenced_by] << silenced_info[:id]
        end
      end
      event[:silenced] = !event[:silenced_by].empty?
      yield(event)
    end
  else
    yield(event)
  end
end

#expand_handler_sets(handler, depth = 0) ⇒ Array, ...

Expand event handler sets, creating an array of handler definitions. Handler sets cannot be deeply nested (by choice), this method will return ‘nil` if an attempt is made to deeply nest. If the provided handler definition is not a set, it is returned.

Parameters:

  • handler (Hash) —

    definition.

  • depth (Integer) (defaults to: 0) —

    of the expansion.

Returns:

  • (Array, Hash, Nil) 


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# File 'lib/sensu/server/process.rb', line 212

def expand_handler_sets(handler, depth=0)
  if handler[:type] == "set"
    if depth < 2
      derive_handlers(handler[:handlers], depth + 1)
    else
      @logger.error("handler sets cannot be deeply nested", :handler => handler)
      nil
    end
  else
    handler
  end
end

#keepalive_event_exists?(client_name) ⇒ TrueClass, FalseClass

Determine if a keepalive event exists for a client.

Parameters:

  • client_name (String) —

    name of client to look up in event registry.

Returns:

  • (TrueClass, FalseClass) 


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# File 'lib/sensu/server/process.rb', line 670

def keepalive_event_exists?(client_name)
  @redis.hexists("events:#{client_name}", "keepalive") do |event_exists|
    yield(event_exists)
  end
end

#pause ⇒ Object

Pause the Sensu server process, unless it is being paused or has already been paused. The process/daemon ‘@state` is first set to `:pausing`, to indicate that it’s in progress. All run timers are cancelled, and the references are cleared. The Sensu server will unsubscribe from all transport subscriptions, relinquish any Sensu server tasks, then set the process/daemon ‘@state` to `:paused`.



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# File 'lib/sensu/server/process.rb', line 1516

def pause
  unless @state == :pausing || @state == :paused
    @state = :pausing
    @timers[:run].each do |timer|
      timer.cancel
    end
    @timers[:run].clear
    unsubscribe
    relinquish_tasks
    @state = :paused
  end
end

#process_check_result(result) ⇒ Object

Process a check result, storing its data, inspecting its contents, and taking the appropriate actions (eg. update the event registry). The ‘@in_progress` counter is incremented by `1` prior to check result processing and then decremented by `1` after updating the event registry. A check result must have a valid client name, associated with a client in the registry or one will be created. If a local check definition exists for the check name, and the check result is not from a standalone check execution, it’s merged with the check result for more context.

Parameters:

  • result (Hash) —

    data.



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# File 'lib/sensu/server/process.rb', line 688

def process_check_result(result)
  @in_progress[:check_results] += 1
  @logger.debug("processing result", :result => result)
  retrieve_client(result) do |client|
    unless client.nil?
      check = case
      when @settings.check_exists?(result[:check][:name]) && !result[:check][:standalone]
        @settings[:checks][result[:check][:name]].merge(result[:check])
      else
        result[:check]
      end
      check[:type] ||= STANDARD_CHECK_TYPE
      check[:origin] = result[:client] if check[:source]
      aggregate_check_result(client, check) if check[:aggregates] || check[:aggregate]
      store_check_result(client, check) do
        create_event(client, check) do |event|
          event_bridges(event)
          update_event_registry(event) do |process|
            process_event(event) if process
            @in_progress[:check_results] -= 1
          end
        end
      end
    else
      @logger.warn("halting result processing", :result => result)
      @in_progress[:check_results] -= 1
    end
  end
end

#process_client_registration(client) ⇒ Object

Process an initial client registration, when it is first added to the client registry. If a registration handler is defined or the client specifies one, a client registration event is created and processed (handled, etc.) for the client (‘create_client_registration_event()`).

Parameters:

  • client (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 119

def process_client_registration(client)
  if @settings.handler_exists?("registration") || client[:registration]
    create_client_registration_event(client)
  end
end

#process_event(event) ⇒ Object

Process an event: filter -> mutate -> handle.

This method determines the appropriate handlers for an event, filtering and mutating the event data for each of them. The ‘@in_progress` counter is incremented by `1`, for each event handler chain (filter -> mutate -> handle).

Parameters:

  • event (Hash) 


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# File 'lib/sensu/server/process.rb', line 257

def process_event(event)
  log_level = event[:check][:type] == METRIC_CHECK_TYPE ? :debug : :info
  @logger.send(log_level, "processing event", :event => event)
  handler_list = Array((event[:check][:handlers] || event[:check][:handler]) || DEFAULT_HANDLER_NAME)
  handlers = derive_handlers(handler_list)
  handlers.each do |handler|
    @in_progress[:events] += 1
    filter_event(handler, event) do |event|
      mutate_event(handler, event) do |event_data|
        handle_event(handler, event_data, event[:id])
      end
    end
  end
end

#publish_check_request(check) ⇒ Object

Publish a check request to the Transport. A check request is composed of a check definition (minus ‘:subscribers` and `:interval`) and an `:issued` timestamp. The check request is published to a Transport pipe, for each of the check `:subscribers` in its definition, eg. “webserver”. JSON serialization is used when publishing the check request payload to the Transport pipes. Transport errors are logged.

Parameters:

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 775

def publish_check_request(check)
  payload = check.reject do |key, value|
    [:subscribers, :interval].include?(key)
  end
  payload[:issued] = Time.now.to_i
  @logger.info("publishing check request", {
    :payload => payload,
    :subscribers => check[:subscribers]
  })
  check[:subscribers].each do |subscription|
    options = transport_publish_options(subscription, Sensu::JSON.dump(payload))
    @transport.publish(*options) do |info|
      if info[:error]
        @logger.error("failed to publish check request", {
          :subscription => subscription,
          :payload => payload,
          :error => info[:error].to_s
        })
      end
    end
  end
end

#publish_check_result(client_name, check) ⇒ Object

Publish a check result to the Transport for processing. A check result is composed of a client name and a check definition, containing check ‘:output` and `:status`. A client signature is added to the check result payload if one is registered for the client. JSON serialization is used when publishing the check result payload to the Transport pipe. Transport errors are logged.

Parameters:

  • client_name (String)
  • check (Hash) 


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# File 'lib/sensu/server/process.rb', line 1030

def publish_check_result(client_name, check)
  payload = {
    :client => client_name,
    :check => check
  }
  @redis.get("client:#{client_name}:signature") do |signature|
    payload[:signature] = signature if signature
    @logger.debug("publishing check result", :payload => payload)
    @transport.publish(:direct, "results", Sensu::JSON.dump(payload)) do |info|
      if info[:error]
        @logger.error("failed to publish check result", {
          :payload => payload,
          :error => info[:error].to_s
        })
      end
    end
  end
end

#publish_proxy_check_request(client, check) ⇒ Object

Publish a proxy check request for a client. This method substitutes client tokens in the check definition prior to publish the check request. If there are unmatched client tokens, a warning is logged, and a check request is not published.

Parameters:

  • client (Hash) —

    definition.

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 829

def publish_proxy_check_request(client, check)
  @logger.debug("creating a proxy check request", {
    :client => client,
    :check => check
  })
  proxy_check, unmatched_tokens = object_substitute_tokens(check.dup, client)
  if unmatched_tokens.empty?
    proxy_check[:source] ||= client[:name]
    publish_check_request(proxy_check)
  else
    @logger.warn("failed to publish a proxy check request", {
      :reason => "unmatched client tokens",
      :unmatched_tokens => unmatched_tokens,
      :client => client,
      :check => check
    })
  end
end

#publish_proxy_check_requests(clients, check) ⇒ Object

Publish proxy check requests for one or more clients. This method can optionally splay proxy check requests, evenly, over a period of time, determined by the check interval and a configurable splay coverage percentage. For example, splay proxy check requests over 60s * 90%, 54s, leaving 6s for the last proxy check execution before the the next round of proxy check requests for the same check. The ‘publish_proxy_check_request() method is used to publish the proxy check requests.

Parameters:

  • clients (Array) —

    of client definitions.

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 860

def publish_proxy_check_requests(clients, check)
  client_count = clients.length
  splay = 0
  if check[:proxy_requests][:splay]
    interval = check[:interval]
    if check[:cron]
      interval = determine_check_cron_time(check)
    end
    unless interval.nil?
      splay_coverage = check[:proxy_requests].fetch(:splay_coverage, 90)
      splay = interval * (splay_coverage / 100.0) / client_count
    end
  end
  splay_timer = 0
  clients.each do |client|
    unless splay == 0
      EM::Timer.new(splay_timer) do
        publish_proxy_check_request(client, check)
      end
      splay_timer += splay
    else
      publish_proxy_check_request(client, check)
    end
  end
end

#relinquish_task(task) ⇒ Object

Relinquish a Sensu server task. This method cancels and clears the associated task timers, those with references stored in the timers hash under ‘:tasks`, and removes the task from `@tasks`. The task server ID and lock are not removed from Redis, as they will be updated when another server takes reponsibility for the task, this method does not need to handle Redis connectivity issues.

Parameters:

  • task (String) 


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# File 'lib/sensu/server/process.rb', line 1285

def relinquish_task(task)
  if @tasks.include?(task)
    @logger.warn("relinquishing server task", :task => task)
    @timers[:tasks][task.to_sym].each do |timer|
      timer.cancel
    end
    @timers[:tasks][task.to_sym].clear
    @tasks.delete(task)
  else
    @logger.debug("not currently responsible for a server task", :task => task)
  end
end

#relinquish_tasks ⇒ Object

Relinquish all Sensu server tasks, if any.



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# File 'lib/sensu/server/process.rb', line 1299

def relinquish_tasks
  unless @tasks.empty?
    @tasks.dup.each do |task|
      relinquish_task(task)
    end
  else
    @logger.debug("not currently responsible for a server task")
  end
end

#request_task_election(task) { ... } ⇒ Object

Request a Sensu server task election, a process to determine if the current process is to be responsible for the task. A Redis key/value is used as a central lock, using the “SETNX” Redis command to set the key/value if it does not exist, using a timestamp for the value. If the current process was able to create the key/value, it is elected, and is then responsible for the task. If the current process was not able to create the key/value, but the current timestamp value is equal to or over 30 seconds ago, the “GETSET” Redis command is used to set a new timestamp and fetch the previous value to compare them, to determine if it was set by the current process. If the current process is able to set the timestamp value, it is elected. If elected, the current process sets up the task and the associated task lock updater.

Parameters:

  • task (String)

Yields:

  • callback/block called either after being elected and setting up the task, or after failing to be elected.



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# File 'lib/sensu/server/process.rb', line 1363

def request_task_election(task, &callback)
  @redis.setnx("lock:task:#{task}", create_lock_timestamp) do |created|
    if created
      setup_task(task, &callback)
      setup_task_lock_updater(task)
    else
      @redis.get("lock:task:#{task}") do |current_lock_timestamp|
        new_lock_timestamp = create_lock_timestamp
        if new_lock_timestamp - current_lock_timestamp.to_i >= 300000000
          @redis.getset("lock:task:#{task}", new_lock_timestamp) do |previous_lock_timestamp|
            if previous_lock_timestamp == current_lock_timestamp
              setup_task(task, &callback)
              setup_task_lock_updater(task)
            end
          end
        else
          yield if block_given?
        end
      end
    end
  end
end

#resume ⇒ Object

Resume the Sensu server process if it is currently or will soon be paused. The ‘retry_until_true` helper method is used to determine if the process is paused and if the Redis and transport connections are initiated and connected. If the conditions are met, `bootstrap()` will be called and true is returned to stop `retry_until_true`. If the transport has not yet been initiated, true is is returned, without calling bootstrap, as we expect bootstrap will be called after the transport initializes.



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# File 'lib/sensu/server/process.rb', line 1538

def resume
  retry_until_true(1) do
    if @state == :paused
      if @redis.connected?
        if @transport
          if @transport.connected?
            bootstrap
            true
          end
        else
          true
        end
      end
    end
  end
end

#retrieve_client(result) {|client| ... } ⇒ Object

Retrieve a client (data) from Redis if it exists. If a client does not already exist, create one (a blank) using the ‘client_key` as the client name. Dynamically create client data can be updated using the API (POST /clients/:client). If a client does exist and it has a client signature, the check result must have a matching signature or it is discarded. If the client does not exist, but a client signature exists, the check result must have a matching signature or it is discarded.

Parameters:

  • result (Hash) —

    data.

Yields:

  • (client) —

    callback/block to be called with client data, either retrieved from Redis, or dynamically created.

Yield Parameters:

  • client (Hash) 


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# File 'lib/sensu/server/process.rb', line 627

def retrieve_client(result)
  client_key = result[:check][:source] || result[:client]
  @redis.get("client:#{client_key}") do |client_json|
    unless client_json.nil?
      client = Sensu::JSON.load(client_json)
      if client[:signature]
        if client[:signature] == result[:signature]
          yield(client)
        else
          @logger.warn("invalid check result signature", {
            :result => result,
            :client => client
          })
          @logger.warn("not retrieving client from the registry", :result => result)
          yield(nil)
        end
      else
        yield(client)
      end
    else
      @redis.get("client:#{client_key}:signature") do |signature|
        if signature.nil? || signature.empty? || result[:signature] == signature
          client = create_client(client_key)
          client[:type] = "proxy" if result[:check][:source]
          update_client_registry(client) do
            yield(client)
          end
        else
          @logger.warn("invalid check result signature", {
            :result => result,
            :signature => signature
          })
          yield(nil)
        end
      end
    end
  end
end

#schedule_check_cron_request(check) ⇒ Object

Schedule a check request, using the check cron. This method determines the time until the next cron time (in seconds) and creats an EventMachine timer for the request. This method will be called after every check cron request for subsequent requests. The timer is stored in the timer hash under ‘:tasks`, so it can be cancelled etc. The check cron request timer object is removed from the timer hash after the request is published, to stop the timer hash from growing infinitely.

Parameters:

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 956

def schedule_check_cron_request(check)
  cron_time = determine_check_cron_time(check)
  @timers[:tasks][:check_request_publisher] << EM::Timer.new(cron_time) do |timer|
    create_check_request_proc(check).call
    @timers[:tasks][:check_request_publisher].delete(timer)
    schedule_check_cron_request(check)
  end
end

#schedule_check_interval_requests(check) ⇒ Object

Schedule check requests, using the check interval. This method using an intial calculated request splay EventMachine timer and an EventMachine periodic timer for subsequent check requests. The timers are stored in the timers hash under ‘:tasks`, so they can be cancelled etc.

Parameters:

  • check (Hash) —

    definition.



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# File 'lib/sensu/server/process.rb', line 983

def schedule_check_interval_requests(check)
  request_splay = testing? ? 0 : calculate_check_request_splay(check)
  interval = testing? ? 0.5 : check[:interval]
  @timers[:tasks][:check_request_publisher] << EM::Timer.new(request_splay) do
    create_check_request = create_check_request_proc(check)
    create_check_request.call
    @timers[:tasks][:check_request_publisher] << EM::PeriodicTimer.new(interval, &create_check_request)
  end
end

#schedule_checks(checks) ⇒ Object

Schedule check requests. This method iterates through defined checks and uses the appropriate method of check request scheduling, either with the cron syntax or a numeric interval.

Parameters:

  • checks (Array) —

    of definitions.



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# File 'lib/sensu/server/process.rb', line 998

def schedule_checks(checks)
  checks.each do |check|
    if check[:cron]
      schedule_check_cron_request(check)
    else
      schedule_check_interval_requests(check)
    end
  end
end

#server_id ⇒ String

Create/return the unique Sensu server ID for the current process.

Returns:

  • (String) 


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# File 'lib/sensu/server/process.rb', line 1250

def server_id
  @server_id ||= random_uuid
end

#setup_check_request_publisher ⇒ Object

Set up the check request publisher. This method creates an array of check definitions, that are not standalone checks, and do not have ‘:publish` set to `false`. The array is provided to the `schedule_checks()` method.



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# File 'lib/sensu/server/process.rb', line 1012

def setup_check_request_publisher
  @logger.debug("scheduling check requests")
  checks = @settings.checks.reject do |check|
    check[:standalone] || check[:publish] == false
  end
  schedule_checks(checks)
end

#setup_check_result_monitor(interval = 30) ⇒ Object

Set up the check result monitor, a periodic timer to run ‘determine_stale_check_results()` every 30 seconds. The timer is stored in the timers hash under `:tasks`.

Parameters:

  • interval (Integer) (defaults to: 30) —

    to use for the check TTL result interval.



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# File 'lib/sensu/server/process.rb', line 1230

def setup_check_result_monitor(interval=30)
  @logger.debug("monitoring check results")
  @timers[:tasks][:check_result_monitor] << EM::PeriodicTimer.new(interval) do
    determine_stale_check_results(interval)
  end
end

#setup_client_monitor ⇒ Object

Set up the client monitor, a periodic timer to run ‘determine_stale_clients()` every 30 seconds. The timer is stored in the timers hash under `:tasks`.



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# File 'lib/sensu/server/process.rb', line 1147

def setup_client_monitor
  @logger.debug("monitoring client keepalives")
  @timers[:tasks][:client_monitor] << EM::PeriodicTimer.new(30) do
    determine_stale_clients
  end
end

#setup_connections { ... } ⇒ Object

Set up the Redis and Transport connection objects, ‘@redis` and `@transport`. This method updates the Redis on error callback to reset the in progress check result counter. This method “drys” up many instances of `setup_redis()` and `setup_transport()`, particularly in the specs.

Yields:

  • callback/block called after connecting to Redis and the Sensu Transport.



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# File 'lib/sensu/server/process.rb', line 61

def setup_connections
  setup_redis do
    @redis.on_error do |error|
      @logger.error("redis connection error", :error => error.to_s)
      @in_progress[:check_results] = 0
    end
    setup_transport do
      yield
    end
  end
end

#setup_keepalives ⇒ Object

Set up the client keepalive consumer, keeping the Sensu client registry updated. The consumer receives JSON serialized client keepalives from the transport, parses them, and calls ‘update_client_registry()` with the client data to update the registry. Transport message acknowledgements are used to ensure the client registry is updated successfully. Keepalive JSON parsing errors are logged.



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# File 'lib/sensu/server/process.rb', line 184

def setup_keepalives
  @logger.debug("subscribing to keepalives")
  @transport.subscribe(:direct, "keepalives", "keepalives", :ack => true) do |message_info, message|
    @logger.debug("received keepalive", :message => message)
    begin
      client = Sensu::JSON.load(message)
      update_client_registry(client)
    rescue Sensu::JSON::ParseError => error
      @logger.error("failed to parse keepalive payload", {
        :message => message,
        :error => error.to_s
      })
    end
    EM::next_tick do
      @transport.ack(message_info)
    end
  end
end

#setup_results ⇒ Object

Set up the check result consumer. The consumer receives JSON serialized check results from the transport, parses them, and calls ‘process_check_result()` with the result data to be processed. Transport message acknowledgements are used to ensure that results make it to processing. The transport message acknowledgements are currently done in the next tick of the EventMachine reactor (event loop), as a flow control mechanism. Result JSON parsing errors are logged.



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# File 'lib/sensu/server/process.rb', line 726

def setup_results
  @logger.debug("subscribing to results")
  @transport.subscribe(:direct, "results", "results", :ack => true) do |message_info, message|
    begin
      result = Sensu::JSON.load(message)
      @logger.debug("received result", :result => result)
      process_check_result(result)
    rescue Sensu::JSON::ParseError => error
      @logger.error("failed to parse result payload", {
        :message => message,
        :error => error.to_s
      })
    end
    EM::next_tick do
      @transport.ack(message_info)
    end
  end
end

#setup_server_registry_updater ⇒ Object

Set up the server registry updater. A periodic timer is used to update the Sensu server info stored in Redis. The timer is stored in the timers hash under ‘:run`.



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# File 'lib/sensu/server/process.rb', line 1456

def setup_server_registry_updater
  update_server_registry
  @timers[:run] << EM::PeriodicTimer.new(10) do
    update_server_registry
  end
end

#setup_task(task) { ... } ⇒ Object

Setup a Sensu server task. Unless the current process is already responsible for the task, this method sets the tasks server ID stored in Redis to the unique random server ID for the process. If the tasks server ID is successfully updated, the task is added to ‘@tasks` for tracking purposes and the task setup method is called.

Parameters:

  • task (String)

Yields:

  • callback/block called after setting up the task.



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# File 'lib/sensu/server/process.rb', line 1263

def setup_task(task)
  unless @tasks.include?(task)
    @redis.set("task:#{task}:server", server_id) do
      @logger.info("i am now responsible for a server task", :task => task)
      @tasks << task
      self.send("setup_#{task}".to_sym)
      yield if block_given?
    end
  else
    @logger.debug("i am already responsible for a server task", :task => task)
  end
end

#setup_task_elections(splay = 10) ⇒ Object

Request Sensu server task elections. The task list is ordered by prioity. This method works through the task list serially, increasing the election request delay as the current process becomes responsible for one or more tasks, this is to improve the initial distribution of tasks amongst Sensu servers.

Parameters:

  • splay (Integer) (defaults to: 10) 


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# File 'lib/sensu/server/process.rb', line 1393

def setup_task_elections(splay=10)
  tasks = TASKS.dup - @tasks
  next_task = Proc.new do
    task = tasks.shift
    if task
      delay = splay * @tasks.size
      @timers[:run] << EM::Timer.new(delay) do
        request_task_election(task, &next_task)
      end
    else
      @timers[:run] << EM::Timer.new(10) do
        setup_task_elections(splay)
      end
    end
  end
  next_task.call
end

#setup_task_lock_updater(task) ⇒ Object

Set up a Sensu server task lock updater. This method uses a periodic timer to update a task lock timestamp in Redis, every 10 seconds. If the current process fails to keep the lock timestamp updated for a task that it is responsible for, another Sensu server will claim responsibility. This method is called after task setup.

Parameters:

  • task (String) 


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# File 'lib/sensu/server/process.rb', line 1339

def setup_task_lock_updater(task)
  @timers[:run] << EM::PeriodicTimer.new(10) do
    update_task_lock(task)
  end
end

#start ⇒ Object

Start the Sensu server process, connecting to Redis, the Transport, and calling the ‘bootstrap()` method. Yield if a block is provided.



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# File 'lib/sensu/server/process.rb', line 1502

def start
  setup_connections do
    bootstrap
    yield if block_given?
  end
end

#stop ⇒ Object

Stop the Sensu server process, pausing it, completing event handling in progress, closing the Redis and transport connections, and exiting the process (exit 0). After pausing the process, the process/daemon ‘@state` is set to `:stopping`.



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# File 'lib/sensu/server/process.rb', line 1560

def stop
  @logger.warn("stopping")
  pause
  @state = :stopping
  complete_in_progress do
    @redis.close if @redis
    @transport.close if @transport
    super
  end
end

#store_check_result(client, check) { ... } ⇒ Object

Store check result data. This method stores check result data and the 21 most recent check result statuses for a client/check pair, this history is used for event context and flap detection. The check execution timestamp is also stored, to provide an indication of how recent the data is. Check output is truncated by ‘truncate_check_output()` before it is stored.

Parameters:

  • client (Hash)
  • check (Hash)

Yields:

  • callback/block called after the check data has been

    stored (history, etc).



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# File 'lib/sensu/server/process.rb', line 366

def store_check_result(client, check)
  @logger.debug("storing check result", :check => check)
  result_key = "#{client[:name]}:#{check[:name]}"
  history_key = "history:#{result_key}"
  check_truncated = truncate_check_output(check)
  @redis.multi
  @redis.sadd("result:#{client[:name]}", check[:name])
  @redis.set("result:#{result_key}", Sensu::JSON.dump(check_truncated))
  @redis.sadd("ttl", result_key) if check[:ttl]
  @redis.rpush(history_key, check[:status])
  @redis.ltrim(history_key, -21, -1)
  @redis.exec do
    yield
  end
end

#transport_publish_options(subscription, message) ⇒ Array

Determine the Sensu Transport publish options for a subscription. If a subscription begins with a Transport pipe type, either “direct:” or “roundrobin:”, the subscription uses a direct Transport pipe. If a subscription does not specify a Transport pipe type, a fanout Transport pipe is used.

Parameters:

  • subscription (String)
  • message (String)

Returns:

  • (Array) —

    containing the Transport publish options: the Transport pipe type, pipe, and the message to be published.



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# File 'lib/sensu/server/process.rb', line 756

def transport_publish_options(subscription, message)
  _, raw_type = subscription.split(":", 2).reverse
  case raw_type
  when "direct", "roundrobin"
    [:direct, subscription, message]
  else
    [:fanout, subscription, message]
  end
end

#truncate_check_output(check) ⇒ Hash

Truncate check output. Metric checks (‘“type”: “metric”`), or checks with `“truncate_output”: true`, have their output truncated to a single line and a maximum character length of 255 by default. The maximum character length can be change by the `“truncate_output_length”` check definition attribute.

Parameters:

  • check (Hash)

Returns:

  • (Hash) —

    check with truncated output.



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# File 'lib/sensu/server/process.rb', line 331

def truncate_check_output(check)
  if check[:truncate_output] ||
     (check[:type] == METRIC_CHECK_TYPE && check[:truncate_output] != false)
    begin
      output_lines = check[:output].split("\n")
    rescue ArgumentError
      utf8_output = check[:output].encode("UTF-8", "binary", {
        :invalid => :replace,
        :undef => :replace,
        :replace => ""
      })
      output_lines = utf8_output.split("\n")
    end
    output = output_lines.first || check[:output]
    truncate_output_length = check.fetch(:truncate_output_length, 255)
    if output_lines.length > 1 || output.length > truncate_output_length
      output = output[0..truncate_output_length] + "\n..."
    end
    check.merge(:output => output)
  else
    check
  end
end

#unsubscribe ⇒ Object

Unsubscribe from transport subscriptions (all of them). This method is called when there are issues with connectivity, or the process is stopping.



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# File 'lib/sensu/server/process.rb', line 1466

def unsubscribe
  @logger.warn("unsubscribing from keepalive and result queues")
  @transport.unsubscribe if @transport
end

#update_client_registry(client) {|success| ... } ⇒ Object

Update the Sensu client registry, stored in Redis. Sensu client data is used to provide additional event context and enable agent health monitoring.

To enable silencing individual clients, per-client subscriptions (‘client:$CLIENT_NAME`) are added to client subscriptions automatically.

The client registry supports client signatures, unique string identifiers used for keepalive and result source verification. If a client has a signature, all further registry updates for the client must have the same signature. A client can begin to use a signature if one was not previously configured. JSON serialization is used for the stored client data.

Parameters:

  • client (Hash)

Yields:

  • (success) —

    passes success status to optional callback/block.

Yield Parameters:

  • success (TrueClass, FalseClass) —

    indicating if the client registry update was a success or the client data was discarded due to client signature mismatch.



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# File 'lib/sensu/server/process.rb', line 147

def update_client_registry(client)
  @logger.debug("updating client registry", :client => client)
  client_key = "client:#{client[:name]}"
  client[:subscriptions] = (client[:subscriptions] + [client_key]).uniq
  signature_key = "#{client_key}:signature"
  @redis.setnx(signature_key, client[:signature]) do |created|
    process_client_registration(client) if created
    @redis.get(signature_key) do |signature|
      if (signature.nil? || signature.empty?) && client[:signature]
        @redis.set(signature_key, client[:signature])
      end
      if signature.nil? || signature.empty? || client[:signature] == signature
        @redis.multi
        @redis.set(client_key, Sensu::JSON.dump(client))
        @redis.sadd("clients", client[:name])
        @redis.exec do
          yield(true) if block_given?
        end
      else
        @logger.warn("invalid client signature", {
          :client => client,
          :signature => signature
        })
        @logger.warn("not updating client in the registry", :client => client)
        yield(false) if block_given?
      end
    end
  end
end

#update_event_registry(event) {|process| ... } ⇒ Object

Update the event registry, stored in Redis. This method determines if event data warrants in the creation or update of event data in the registry. If a check ‘:status` is not `0`, or it has been flapping, an event is created/updated in the registry. If the event `:action` is `:resolve`, the event is removed (resolved) from the registry. If the previous conditions are not met and check `:type` is `metric`, the registry is not updated, but further event processing is required (`yield(true)`). JSON serialization is used when storing data in the registry.

Parameters:

  • event (Hash)

Yield Parameters:

  • process (TrueClass, FalseClass) —

    indicating if the event requires further processing.



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# File 'lib/sensu/server/process.rb', line 516

def update_event_registry(event)
  client_name = event[:client][:name]
  if event[:check][:status] != 0 || event[:action] == :flapping
    @redis.hset("events:#{client_name}", event[:check][:name], Sensu::JSON.dump(event)) do
      yield(true)
    end
  elsif event[:action] == :resolve &&
      (event[:check][:auto_resolve] != false || event[:check][:force_resolve])
    @redis.hdel("events:#{client_name}", event[:check][:name]) do
      yield(true)
    end
  elsif event[:check][:type] == METRIC_CHECK_TYPE
    yield(true)
  else
    yield(false)
  end
end

#update_server_registry {|success| ... } ⇒ Object

Update the Sensu server registry, stored in Redis. This method adds the local/current Sensu server info to the registry, including its id, hostname, address, its server tasks, and some metrics. Sensu server registry entries expire in 30 seconds unless updated.

Yields:

  • (success) —

    passes success status to optional callback/block.

Yield Parameters:

  • success (TrueClass, FalseClass) —

    indicating if the server registry update was a success.



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# File 'lib/sensu/server/process.rb', line 1421

def update_server_registry
  @logger.debug("updating the server registry")
  process_cpu_times do |cpu_user, cpu_system, _, _|
    sensu = RELEASE_INFO.merge(
      :settings => {
        :hexdigest => @settings.hexdigest
      }
    )
    info = {
      :id => server_id,
      :hostname => system_hostname,
      :address => system_address,
      :tasks => @tasks,
      :metrics => {
        :cpu => {
          :user => cpu_user,
          :system => cpu_system
        }
      },
      :sensu => sensu,
      :timestamp => Time.now.to_i
    }
    @redis.sadd("servers", server_id)
    server_key = "server:#{server_id}"
    @redis.set(server_key, Sensu::JSON.dump(info)) do
      @redis.expire(server_key, 30)
      @logger.info("updated server registry", :server => info)
      yield(true) if block_given?
    end
  end
end

#update_task_lock(task) ⇒ Object

Updates a Sensu server task lock timestamp. The current task server ID is retrieved from Redis and compared with the server ID of the current process to determine if it is still responsible for the task. If the current process is still responsible, the task lock timestamp is updated. If the current process is no longer responsible, ‘relinquish_task()` is called for cleanup.

Parameters:

  • task (String) 


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# File 'lib/sensu/server/process.rb', line 1318

def update_task_lock(task)
  @redis.get("task:#{task}:server") do |current_server_id|
    if current_server_id == server_id
      @redis.set("lock:task:#{task}", create_lock_timestamp) do
        @logger.debug("updated task lock timestamp", :task => task)
      end
    else
      @logger.warn("another sensu server is responsible for the task", :task => task)
      relinquish_task(task)
    end
  end
end