Class: Sensu::Server::Process
- Inherits:
-
Object
- Object
- Sensu::Server::Process
- Defined in:
- lib/sensu/server/process.rb
Instance Attribute Summary collapse
-
#handling_event_count ⇒ Object
readonly
Returns the value of attribute handling_event_count.
-
#is_leader ⇒ Object
readonly
Returns the value of attribute is_leader.
Attributes included from Daemon
Class Method Summary collapse
-
.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).
Instance Method Summary collapse
-
#aggregate_check_result(client, check) ⇒ Object
Add a check result to an aggregate.
-
#become_the_leader ⇒ Object
Become the Sensu server leader, responsible for specific duties (‘leader_duties()`).
-
#bootstrap ⇒ Object
Bootstrap the Sensu server process, setting up the keepalive and check result consumers, and attemping to become the leader to carry out its duties.
-
#calculate_check_execution_splay(check) ⇒ Object
Calculate a check execution splay, taking into account the current time and the execution interval to ensure it’s consistent between process restarts.
-
#check_flapping?(stored_event, check) ⇒ TrueClass, FalseClass
Determine if a check state is flapping, rapidly changing between an OK and non-OK state.
-
#check_history(client, check, &callback) ⇒ Object
Fetch the execution history for a client/check pair, the 21 most recent check result statuses.
-
#complete_event_handling(&callback) ⇒ Object
Complete event handling currently in progress.
-
#create_client(name, &callback) ⇒ Object
Create a blank client (data) and add it to the client registry.
-
#create_keepalive_check(client) ⇒ Object
Create a keepalive check definition for a client.
-
#create_lock_timestamp ⇒ Integer
Create a lock timestamp (integer), current time including milliseconds.
-
#derive_handlers(handler_list, depth = 0) ⇒ Array
Derive an array of handler definitions from a list of handler names.
-
#determine_stale_check_results ⇒ Object
Determine stale check results, those that have not executed in a specified amount of time (check TTL).
-
#determine_stale_clients ⇒ Object
Determine stale clients, those that have not sent a keepalive in a specified amount of time (thresholds).
-
#event_bridges(event) ⇒ Object
Run event bridge extensions, within the Sensu EventMachine reactor (event loop).
-
#expand_handler_sets(handler, depth = 0) ⇒ Array, ...
Expand event handler sets, creating an array of handler definitions.
-
#initialize(options = {}) ⇒ Process
constructor
Override Daemon initialize() to support Sensu server leader election and the handling event count.
-
#leader_duties ⇒ Object
Set up the leader duties, tasks only performed by a single Sensu server at a time.
-
#leader_id ⇒ String
Create/return the unique Sensu server leader ID for the current process.
-
#pause ⇒ Object
Pause the Sensu server process, unless it is being paused or has already been paused.
-
#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).
-
#process_event(event) ⇒ Object
Process an event: filter -> mutate -> handle.
-
#prune_check_result_aggregations ⇒ Object
Prune check result aggregations (aggregates).
-
#publish_check_request(check) ⇒ Object
Publish a check request to the transport.
-
#publish_check_result(client_name, check) ⇒ Object
Publish a check result to the transport for processing.
-
#request_leader_election ⇒ Object
Request a leader election, a process to determine if the current process is the Sensu server leader, with its own/unique duties.
-
#resign_as_leader ⇒ Object
Resign as leader, if the current process is the Sensu server leader.
-
#resume ⇒ Object
Resume the Sensu server process if it is currently or will soon be paused.
-
#retrieve_client(result, &callback) ⇒ Object
Retrieve a client (data) from Redis if it exists.
-
#schedule_check_executions(checks) ⇒ Object
Schedule check executions, using EventMachine periodic timers, using a calculated execution splay.
-
#setup_check_request_publisher ⇒ Object
Set up the check request publisher.
-
#setup_check_result_aggregation_pruner ⇒ Object
Set up the check result aggregation pruner, using periodic timer to run ‘prune_check_result_aggregations()` every 20 seconds.
-
#setup_check_result_monitor ⇒ Object
Set up the check result monitor, a periodic timer to run ‘determine_stale_check_results()` every 30 seconds.
-
#setup_client_monitor ⇒ Object
Set up the client monitor, a periodic timer to run ‘determine_stale_clients()` every 30 seconds.
-
#setup_keepalives ⇒ Object
Set up the client keepalive consumer, keeping the Sensu client registry updated.
-
#setup_leader_monitor ⇒ Object
Set up the leader monitor.
-
#setup_results ⇒ Object
Set up the check result consumer.
-
#start ⇒ Object
Start the Sensu server process, connecting to Redis, the transport, and calling the ‘bootstrap()` method.
-
#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).
-
#store_check_result(client, check, &callback) ⇒ Object
Store check result data.
-
#transport_publish_options(subscription, message) ⇒ Array
Determine the Sensu transport publish options for a subscription.
-
#truncate_check_output(check) ⇒ Hash
Truncate check output.
-
#unsubscribe ⇒ Object
Unsubscribe from transport subscriptions (all of them).
-
#update_client_registry(client, &callback) ⇒ Object
Update the Sensu client registry, stored in Redis.
-
#update_event_registry(client, check, &callback) ⇒ Object
Update the event registry, stored in Redis.
-
#update_leader_lock ⇒ Object
Updates the Sensu server leader lock timestamp.
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
#action_subdued?, #check_request_subdued?, #eval_attribute_value, #event_filter, #event_filtered?, #filter_attributes_match?, #filter_event, #handle_action?, #handle_severity?, #handler_subdued?, #handling_disabled?, #subdue_days?, #subdue_exception?, #subdue_time?
Methods included from Daemon
#load_extensions, #load_settings, #log_concerns, #setup_logger, #setup_process, #setup_redis, #setup_signal_traps, #setup_transport
Methods included from Utilities
#deep_merge, #random_uuid, #redact_sensitive, #retry_until_true, #testing?
Constructor Details
#initialize(options = {}) ⇒ Process
Override Daemon initialize() to support Sensu server leader election and the handling event count.
33 34 35 36 37 38 |
# File 'lib/sensu/server/process.rb', line 33 def initialize(={}) super @is_leader = false @timers[:leader] = Array.new @handling_event_count = 0 end |
Instance Attribute Details
#handling_event_count ⇒ Object (readonly)
Returns the value of attribute handling_event_count.
14 15 16 |
# File 'lib/sensu/server/process.rb', line 14 def handling_event_count @handling_event_count end |
#is_leader ⇒ Object (readonly)
Returns the value of attribute is_leader.
14 15 16 |
# File 'lib/sensu/server/process.rb', line 14 def is_leader @is_leader 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).
21 22 23 24 25 26 27 |
# File 'lib/sensu/server/process.rb', line 21 def self.run(={}) server = self.new() 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 an aggregate. A check aggregate uses the check ‘:name` and the `:issued` timestamp as its unique identifier. An aggregate uses several counters: the total number of results in the aggregate, and a counter for each check severity (ok, warning, etc). Check output is also stored, to be summarized to aid in identifying outliers for a check execution across a number of Sensu clients. JSON serialization is used for storing check result data.
180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 |
# File 'lib/sensu/server/process.rb', line 180 def aggregate_check_result(client, check) @logger.debug("adding check result to aggregate", { :client => client, :check => check }) result_set = "#{check[:name]}:#{check[:issued]}" result_data = MultiJson.dump(:output => check[:output], :status => check[:status]) @redis.hset("aggregation:#{result_set}", client[:name], result_data) do SEVERITIES.each do |severity| @redis.hsetnx("aggregate:#{result_set}", severity, 0) end severity = (SEVERITIES[check[:status]] || "unknown") @redis.hincrby("aggregate:#{result_set}", severity, 1) do @redis.hincrby("aggregate:#{result_set}", "total", 1) do @redis.sadd("aggregates:#{check[:name]}", check[:issued]) do @redis.sadd("aggregates", check[:name]) end end end end end |
#become_the_leader ⇒ Object
Become the Sensu server leader, responsible for specific duties (‘leader_duties()`). Unless the current process is already the leader, this method sets the leader ID stored in Redis to the unique random leader ID for the process. If the leader ID in Redis is successfully updated, `@is_leader` is set to true and `leader_duties()` is called to begin the tasks/duties of the Sensu server leader.
795 796 797 798 799 800 801 802 803 804 805 |
# File 'lib/sensu/server/process.rb', line 795 def become_the_leader unless @is_leader @redis.set("leader", leader_id) do @logger.info("i am now the leader") @is_leader = true leader_duties end else @logger.debug("i am already the leader") end end |
#bootstrap ⇒ Object
Bootstrap the Sensu server process, setting up the keepalive and check result consumers, and attemping to become the leader to carry out its duties. This method sets the process/daemon ‘@state` to `:running`.
930 931 932 933 934 935 |
# File 'lib/sensu/server/process.rb', line 930 def bootstrap setup_keepalives setup_results setup_leader_monitor @state = :running end |
#calculate_check_execution_splay(check) ⇒ Object
Calculate a check execution splay, taking into account the current time and the execution interval to ensure it’s consistent between process restarts.
524 525 526 527 528 |
# File 'lib/sensu/server/process.rb', line 524 def calculate_check_execution_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
298 299 300 301 302 303 304 305 306 307 308 309 |
# File 'lib/sensu/server/process.rb', line 298 def check_flapping?(stored_event, check) if check.has_key?(:low_flap_threshold) && check.has_key?(:high_flap_threshold) was_flapping = stored_event && stored_event[:action] == "flapping" if was_flapping check[:total_state_change] > check[:low_flap_threshold] else check[:total_state_change] >= check[:high_flap_threshold] end else false end end |
#check_history(client, check, &callback) ⇒ 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
259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 |
# File 'lib/sensu/server/process.rb', line 259 def check_history(client, check, &callback) history_key = "history:#{client[:name]}:#{check[:name]}" @redis.lrange(history_key, -21, -1) do |history| total_state_change = 0 unless history.size < 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 callback.call(history, total_state_change) end end |
#complete_event_handling(&callback) ⇒ Object
Complete event handling currently in progress. The ‘:handling_event_count` is used to determine if event handling is complete, when it is equal to `0`. The provided callback is called when handling is complete.
914 915 916 917 918 919 920 921 922 923 924 |
# File 'lib/sensu/server/process.rb', line 914 def complete_event_handling(&callback) @logger.info("completing event handling in progress", { :handling_event_count => @handling_event_count }) retry_until_true do if @handling_event_count == 0 callback.call true end end end |
#create_client(name, &callback) ⇒ Object
Create a blank client (data) and add it to the client registry. 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, ‘:keepalives` is set to `false`.
376 377 378 379 380 381 382 383 384 385 |
# File 'lib/sensu/server/process.rb', line 376 def create_client(name, &callback) client = { :name => name, :address => "unknown", :subscriptions => [], :keepalives => false, :version => VERSION } update_client_registry(client, &callback) 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.
605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 |
# File 'lib/sensu/server/process.rb', line 605 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 = Time.now.to_i check.merge(:name => "keepalive", :issued => , :executed => ) end |
#create_lock_timestamp ⇒ Integer
Create a lock timestamp (integer), current time including milliseconds. This method is used by Sensu server leader election.
776 777 778 |
# File 'lib/sensu/server/process.rb', line 776 def (Time.now.to_f * 1000).to_i 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.
114 115 116 117 118 119 120 121 122 123 124 125 126 127 |
# File 'lib/sensu/server/process.rb', line 114 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) (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_stale_check_results ⇒ Object
Determine stale check results, those that have not executed in a specified amount of time (check TTL). This method iterates through the client registry and check results for checks with a defined TTL value (in seconds). If a check result has a defined TTL, the time since last check execution (in seconds) is calculated. 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.
682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 |
# File 'lib/sensu/server/process.rb', line 682 def determine_stale_check_results @logger.info("determining stale check results") @redis.smembers("clients") do |clients| clients.each do |client_name| @redis.smembers("result:#{client_name}") do |checks| checks.each do |check_name| result_key = "#{client_name}:#{check_name}" @redis.get("result:#{result_key}") do |result_json| unless result_json.nil? check = MultiJson.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] check[:output] = "Last check execution was " check[:output] << "#{time_since_last_execution} seconds ago" check[:status] = 1 publish_check_result(client_name, check) end end end end end end end end |
#determine_stale_clients ⇒ Object
Determine stale clients, those that have not sent a keepalive in a specified amount of time (thresholds). This method iterates through the client registry, creating a keepalive check definition with the ‘create_keepalive_check()` method, containing client specific staleness 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. A check result is published for every client in the registry.
633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 |
# File 'lib/sensu/server/process.rb', line 633 def determine_stale_clients @logger.info("determining stale clients") @redis.smembers("clients") do |clients| clients.each do |client_name| @redis.get("client:#{client_name}") do |client_json| unless client_json.nil? client = MultiJson.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 end 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.
158 159 160 161 162 163 164 165 166 167 |
# File 'lib/sensu/server/process.rb', line 158 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 |
#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.
92 93 94 95 96 97 98 99 100 101 102 103 |
# File 'lib/sensu/server/process.rb', line 92 def (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 |
#leader_duties ⇒ Object
Set up the leader duties, tasks only performed by a single Sensu server at a time. The duties include publishing check requests, monitoring for stale clients, and pruning check result aggregations.
764 765 766 767 768 769 |
# File 'lib/sensu/server/process.rb', line 764 def leader_duties setup_check_request_publisher setup_client_monitor setup_check_result_monitor setup_check_result_aggregation_pruner end |
#leader_id ⇒ String
Create/return the unique Sensu server leader ID for the current process.
784 785 786 |
# File 'lib/sensu/server/process.rb', line 784 def leader_id @leader_id ||= random_uuid 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, resign as leader (if currently the leader), then set the process/daemon ‘@state` to `:paused`.
952 953 954 955 956 957 958 959 960 961 962 963 |
# File 'lib/sensu/server/process.rb', line 952 def pause unless @state == :pausing || @state == :paused @state = :pausing @timers[:run].each do |timer| timer.cancel end @timers[:run].clear unsubscribe resign_as_leader @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). 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.
416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 |
# File 'lib/sensu/server/process.rb', line 416 def process_check_result(result) @logger.debug("processing result", :result => result) retrieve_client(result) do |client| check = case when @settings.check_exists?(result[:check][:name]) && !result[:check][:standalone] @settings[:checks][result[:check][:name]].merge(result[:check]) else result[:check] end aggregate_check_result(client, check) if check[:aggregate] store_check_result(client, check) do check_history(client, check) do |history, total_state_change| check[:history] = history check[:total_state_change] = total_state_change update_event_registry(client, check) do |event| process_event(event) end end end 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 ‘@handling_event_count` is incremented by `1`, for each event handler chain (filter -> mutate -> handle).
137 138 139 140 141 142 143 144 145 146 147 148 149 150 |
# File 'lib/sensu/server/process.rb', line 137 def process_event(event) log_level = event[:check][:type] == "metric" ? :debug : :info @logger.send(log_level, "processing event", :event => event) handler_list = Array((event[:check][:handlers] || event[:check][:handler]) || "default") handlers = derive_handlers(handler_list) handlers.each do |handler| @handling_event_count += 1 filter_event(handler, event) do |event| mutate_event(handler, event) do |event_data| handle_event(handler, event_data) end end end end |
#prune_check_result_aggregations ⇒ Object
Prune check result aggregations (aggregates). Sensu only stores the 20 latest aggregations for a check, to keep the amount of data stored to a minimum.
721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 |
# File 'lib/sensu/server/process.rb', line 721 def prune_check_result_aggregations @logger.info("pruning check result aggregations") @redis.smembers("aggregates") do |checks| checks.each do |check_name| @redis.smembers("aggregates:#{check_name}") do |aggregates| if aggregates.size > 20 aggregates.sort! aggregates.take(aggregates.size - 20).each do |check_issued| @redis.srem("aggregates:#{check_name}", check_issued) do result_set = "#{check_name}:#{check_issued}" @redis.del("aggregate:#{result_set}") do @redis.del("aggregation:#{result_set}") do @logger.debug("pruned aggregation", { :check => { :name => check_name, :issued => check_issued } }) end end end end end end end end end |
#publish_check_request(check) ⇒ Object
Publish a check request to the transport. A check request is composted of a check ‘:name`, an `:issued` timestamp, and a check `:command` if available. 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.
494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 |
# File 'lib/sensu/server/process.rb', line 494 def publish_check_request(check) payload = { :name => check[:name], :issued => Time.now.to_i } payload[:command] = check[:command] if check.has_key?(:command) payload[:source] = check[:source] if check.has_key?(:source) @logger.info("publishing check request", { :payload => payload, :subscribers => check[:subscribers] }) check[:subscribers].each do |subscription| = (subscription, MultiJson.dump(payload)) @transport.publish(*) 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`. JSON serialization is used when publishing the check result payload to the transport pipe. Transport errors are logged.
580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 |
# File 'lib/sensu/server/process.rb', line 580 def publish_check_result(client_name, check) payload = { :client => client_name, :check => check } @logger.debug("publishing check result", :payload => payload) @transport.publish(:direct, "results", MultiJson.dump(payload)) do |info| if info[:error] @logger.error("failed to publish check result", { :payload => payload, :error => info[:error].to_s }) end end end |
#request_leader_election ⇒ Object
Request a leader election, a process to determine if the current process is the Sensu server leader, with its own/unique duties. 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 the leader, and must do the duties of the leader. 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 becomes the leader.
861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 |
# File 'lib/sensu/server/process.rb', line 861 def request_leader_election @redis.setnx("lock:leader", ) do |created| if created become_the_leader else @redis.get("lock:leader") do || = if - .to_i >= 30000 @redis.getset("lock:leader", ) do || if == become_the_leader end end end end end end end |
#resign_as_leader ⇒ Object
Resign as leader, if the current process is the Sensu server leader. This method cancels and clears the leader timers, those with references stored in the timers hash under ‘:leader`, and `@is_leader` is set to `false`. The leader ID and leader lock are not removed from Redis, as they will be updated when another server is elected to be the leader, this method does not need to handle Redis connectivity issues.
814 815 816 817 818 819 820 821 822 823 824 825 |
# File 'lib/sensu/server/process.rb', line 814 def resign_as_leader if @is_leader @logger.warn("resigning as leader") @timers[:leader].each do |timer| timer.cancel end @timers[:leader].clear @is_leader = false else @logger.debug("not currently the leader") 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 connected. If the conditions are met, `bootstrap()` will be called and true is returned to stop `retry_until_true`.
971 972 973 974 975 976 977 978 979 980 |
# File 'lib/sensu/server/process.rb', line 971 def resume retry_until_true(1) do if @state == :paused if @redis.connected? && @transport.connected? bootstrap true end end end end |
#retrieve_client(result, &callback) ⇒ 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).
395 396 397 398 399 400 401 402 403 404 405 |
# File 'lib/sensu/server/process.rb', line 395 def retrieve_client(result, &callback) client_key = result[:check][:source] || result[:client] @redis.get("client:#{client_key}") do |client_json| unless client_json.nil? client = MultiJson.load(client_json) callback.call(client) else create_client(client_key, &callback) end end end |
#schedule_check_executions(checks) ⇒ Object
Schedule check executions, using EventMachine periodic timers, using a calculated execution splay. The timers are stored in the timers hash under ‘:leader`, as check request publishing is a task for only the Sensu server leader, so they can be cancelled etc. Check requests are not published if subdued.
537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 |
# File 'lib/sensu/server/process.rb', line 537 def schedule_check_executions(checks) checks.each do |check| create_check_request = Proc.new do unless check_request_subdued?(check) publish_check_request(check) else @logger.info("check request was subdued", :check => check) end end execution_splay = testing? ? 0 : calculate_check_execution_splay(check) interval = testing? ? 0.5 : check[:interval] @timers[:leader] << EM::Timer.new(execution_splay) do create_check_request.call @timers[:leader] << EM::PeriodicTimer.new(interval, &create_check_request) end end 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 of check definitions includes those from standard checks and extensions (with a defined execution `:interval`). The array is provided to the `schedule_check_executions()` method.
561 562 563 564 565 566 567 568 569 570 |
# File 'lib/sensu/server/process.rb', line 561 def setup_check_request_publisher @logger.debug("scheduling check requests") standard_checks = @settings.checks.reject do |check| check[:standalone] || check[:publish] == false end extension_checks = @extensions.checks.reject do |check| check[:standalone] || check[:publish] == false || !check[:interval].is_a?(Integer) end schedule_check_executions(standard_checks + extension_checks) end |
#setup_check_result_aggregation_pruner ⇒ Object
Set up the check result aggregation pruner, using periodic timer to run ‘prune_check_result_aggregations()` every 20 seconds. The timer is stored in the timers hash under `:leader`.
753 754 755 756 757 758 |
# File 'lib/sensu/server/process.rb', line 753 def setup_check_result_aggregation_pruner @logger.debug("pruning check result aggregations") @timers[:leader] << EM::PeriodicTimer.new(20) do prune_check_result_aggregations end end |
#setup_check_result_monitor ⇒ 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 `:leader`.
711 712 713 714 715 716 |
# File 'lib/sensu/server/process.rb', line 711 def setup_check_result_monitor @logger.debug("monitoring check results") @timers[:leader] << EM::PeriodicTimer.new(30) do determine_stale_check_results 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 `:leader`.
667 668 669 670 671 672 |
# File 'lib/sensu/server/process.rb', line 667 def setup_client_monitor @logger.debug("monitoring client keepalives") @timers[:leader] << EM::PeriodicTimer.new(30) do determine_stale_clients 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.
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 |
# File 'lib/sensu/server/process.rb', line 64 def setup_keepalives @logger.debug("subscribing to keepalives") @transport.subscribe(:direct, "keepalives", "keepalives", :ack => true) do |, | @logger.debug("received keepalive", :message => ) begin client = MultiJson.load() update_client_registry(client) do @transport.ack() end rescue MultiJson::ParseError => error @logger.error("failed to parse keepalive payload", { :message => , :error => error.to_s }) @transport.ack() end end end |
#setup_leader_monitor ⇒ Object
Set up the leader monitor. A one-time timer is used to run ‘request_leader_exection()` in 2 seconds. A periodic timer is used to update the leader lock timestamp if the current process is the leader, or to run `request_leader_election(), every 10 seconds. The timers are stored in the timers hash under `:run`.
886 887 888 889 890 891 892 893 894 895 896 897 |
# File 'lib/sensu/server/process.rb', line 886 def setup_leader_monitor @timers[:run] << EM::Timer.new(2) do request_leader_election end @timers[:run] << EM::PeriodicTimer.new(10) do if @is_leader update_leader_lock else request_leader_election 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.
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 |
# File 'lib/sensu/server/process.rb', line 446 def setup_results @logger.debug("subscribing to results") @transport.subscribe(:direct, "results", "results", :ack => true) do |, | begin result = MultiJson.load() @logger.debug("received result", :result => result) process_check_result(result) rescue MultiJson::ParseError => error @logger.error("failed to parse result payload", { :message => , :error => error.to_s }) end EM::next_tick do @transport.ack() end end end |
#start ⇒ Object
Start the Sensu server process, connecting to Redis, the transport, and calling the ‘bootstrap()` method.
939 940 941 942 943 |
# File 'lib/sensu/server/process.rb', line 939 def start setup_redis setup_transport bootstrap 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`.
987 988 989 990 991 992 993 994 995 996 |
# File 'lib/sensu/server/process.rb', line 987 def stop @logger.warn("stopping") pause @state = :stopping complete_event_handling do @redis.close @transport.close super end end |
#store_check_result(client, check, &callback) ⇒ 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.
234 235 236 237 238 239 240 241 242 243 244 245 246 |
# File 'lib/sensu/server/process.rb', line 234 def store_check_result(client, check, &callback) @logger.debug("storing check result", :check => check) @redis.sadd("result:#{client[:name]}", check[:name]) result_key = "#{client[:name]}:#{check[:name]}" check_truncated = truncate_check_output(check) @redis.set("result:#{result_key}", MultiJson.dump(check_truncated)) do history_key = "history:#{result_key}" @redis.rpush(history_key, check[:status]) do @redis.ltrim(history_key, -21, -1) callback.call end 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.
475 476 477 478 479 480 481 482 483 |
# File 'lib/sensu/server/process.rb', line 475 def (subscription, ) _, raw_type = subscription.split(":", 2).reverse case raw_type when "direct", "roundrobin" [:direct, subscription, ] else [:fanout, subscription, ] end end |
#truncate_check_output(check) ⇒ Hash
Truncate check output. For metric checks, (‘“type”: “metric”`), check output is truncated to a single line and a maximum of 255 characters. Check output is currently left unmodified for standard checks.
209 210 211 212 213 214 215 216 217 218 219 220 221 |
# File 'lib/sensu/server/process.rb', line 209 def truncate_check_output(check) case check[:type] when "metric" output_lines = check[:output].split("\n") output = output_lines.first if output_lines.size > 1 || output.length > 255 output = output[0..255] + "\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.
902 903 904 905 |
# File 'lib/sensu/server/process.rb', line 902 def unsubscribe @logger.warn("unsubscribing from keepalive and result queues") @transport.unsubscribe end |
#update_client_registry(client, &callback) ⇒ Object
Update the Sensu client registry, stored in Redis. Sensu client data is used to provide additional event context and enable agent health monitoring. JSON serialization is used for the client data.
48 49 50 51 52 53 54 55 |
# File 'lib/sensu/server/process.rb', line 48 def update_client_registry(client, &callback) @logger.debug("updating client registry", :client => client) @redis.set("client:#{client[:name]}", MultiJson.dump(client)) do @redis.sadd("clients", client[:name]) do callback.call(client) end end end |
#update_event_registry(client, check, &callback) ⇒ Object
Update the event registry, stored in Redis. This method determines if check data results in the creation or update of event data in the registry. Existing event data for a client/check pair is fetched, used in conditionals and the composition of the new event data. If a check ‘:status` is not `0`, or it has been flapping, an event is created/updated in the registry. If there was existing event data, but the check `:status` is now `0`, the event is removed (resolved) from the registry. If the previous conditions are not met, and check `:type` is `metric` and the `:status` is `0`, the event registry is not updated, but the provided callback is called with the event data. All event data is sent to event bridge extensions, including events that do not normally produce an action. JSON serialization is used when storing data in the registry.
332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 |
# File 'lib/sensu/server/process.rb', line 332 def update_event_registry(client, check, &callback) @redis.hget("events:#{client[:name]}", check[:name]) do |event_json| stored_event = event_json ? MultiJson.load(event_json) : nil flapping = check_flapping?(stored_event, check) event = { :id => random_uuid, :client => client, :check => check, :occurrences => 1, :action => (flapping ? :flapping : :create), :timestamp => Time.now.to_i } if check[:status] != 0 || flapping if stored_event && check[:status] == stored_event[:check][:status] event[:occurrences] = stored_event[:occurrences] + 1 end @redis.hset("events:#{client[:name]}", check[:name], MultiJson.dump(event)) do callback.call(event) end elsif stored_event event[:occurrences] = stored_event[:occurrences] event[:action] = :resolve unless check[:auto_resolve] == false && !check[:force_resolve] @redis.hdel("events:#{client[:name]}", check[:name]) do callback.call(event) end end elsif check[:type] == "metric" callback.call(event) end event_bridges(event) end end |
#update_leader_lock ⇒ Object
Updates the Sensu server leader lock timestamp. The current leader ID is retrieved from Redis and compared with the leader ID of the current process to determine if it is still the Sensu server leader. If the current process is still the leader, the leader lock timestamp is updated. If the current process is no longer the leader (regicide), ‘resign_as_leader()` is called for cleanup, so there is not more than one leader.
835 836 837 838 839 840 841 842 843 844 845 846 |
# File 'lib/sensu/server/process.rb', line 835 def update_leader_lock @redis.get("leader") do |current_leader_id| if current_leader_id == leader_id @redis.set("lock:leader", ) do @logger.debug("updated leader lock timestamp") end else @logger.warn("another sensu server has been elected as leader") resign_as_leader end end end |