Module: MessageBus::Implementation

Included in:
MessageBus, Instance
Defined in:
lib/message_bus.rb

Overview

The main server-side interface to a message bus for the purposes of configuration, publishing and subscribing

Defined Under Namespace

Classes: Synchronizer

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#config ⇒ Hash<Symbol => Object> (readonly) Also known as: redis_config

Returns Configuration options hash.

Returns:

  • (Hash<Symbol => Object>) —

    Configuration options hash



32
33
34
 
# File 'lib/message_bus.rb', line 32

def config
  @config
end

Instance Method Details

#after_fork ⇒ void

This method returns an undefined value.

Performs routines that are necessary after a process fork, typically

triggered by a forking webserver. Performs whatever the backend requires
and ensures the server is listening for publications and running
scheduled tasks.



559
560
561
562
563
564
 
# File 'lib/message_bus.rb', line 559

def after_fork
  backend_instance.after_fork
  ensure_subscriber_thread
  # will ensure timer is running
  timer.queue {}
end

#allow_broadcast=(val) ⇒ void

This method returns an undefined value.

Parameters:

  • val (Boolean) —

    whether or not to allow broadcasting (debugging)



260
261
262
 
# File 'lib/message_bus.rb', line 260

def allow_broadcast=(val)
  configure(allow_broadcast: val)
end

#allow_broadcast? ⇒ Boolean

Returns whether or not broadcasting is allowed. If not explicitly set, defaults to false unless we’re in Rails test or development mode.

Returns:

  • (Boolean) —

    whether or not broadcasting is allowed. If not explicitly set, defaults to false unless we’re in Rails test or development mode.



266
267
268
269
270
271
272
273
 
# File 'lib/message_bus.rb', line 266

def allow_broadcast?
  @config[:allow_broadcast] ||=
    if defined? ::Rails.env
      ::Rails.env.test? || ::Rails.env.development?
    else
      false
    end
end

#backend ⇒ Symbol

Returns the name of the backend implementation configured.

Returns:

  • (Symbol) —

    the name of the backend implementation configured



321
322
323
 
# File 'lib/message_bus.rb', line 321

def backend
  @config[:backend] || :redis
end

#backend_instance ⇒ MessageBus::Backend::Base

Returns the configured backend. If not explicitly set, will be loaded based on the configuration provided.

Returns:

  • (MessageBus::Backend::Base) —

    the configured backend. If not explicitly set, will be loaded based on the configuration provided.



299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
 
# File 'lib/message_bus.rb', line 299

def backend_instance
  @mutex.synchronize do
    return nil if @destroyed

    # Make sure logger is loaded before config is
    # passed to backend.
    logger

    @config[:backend_instance] ||= begin
      @config[:backend_options] ||= {}
      require "message_bus/backends/#{backend}"
      MessageBus::BACKENDS[backend].new @config
    end
  end
end

#backend_instance=(backend_instance) ⇒ void

This method returns an undefined value.

Parameters:

  • backend_instance (MessageBus::Backend::Base) —

    A configured backend



288
289
290
 
# File 'lib/message_bus.rb', line 288

def backend_instance=(backend_instance)
  configure(backend_instance: backend_instance)
end

#backlog(channel = nil, last_id = nil, site_id = nil) ⇒ Array<MessageBus::Message>

Get messages from a channel backlog since the last ID specified, filtered by site

Parameters:

  • channel (String) (defaults to: nil) —

    the name of the channel in question

  • last_id (#to_i) (defaults to: nil) —

    the channel-specific ID of the last message that the caller received on the specified channel

  • site_id (String) (defaults to: nil) —

    the ID of the site by which to filter

Returns:

  • (Array<MessageBus::Message>) —

    all messages published to the specified channel since the specified last ID



485
486
487
488
489
490
491
492
493
494
495
496
497
 
# File 'lib/message_bus.rb', line 485

def backlog(channel = nil, last_id = nil, site_id = nil)
  old =
    if channel
      backend_instance.backlog(encode_channel_name(channel, site_id), last_id)
    else
      backend_instance.global_backlog(last_id)
    end

  old.each do |m|
    decode_message!(m)
  end
  old
end

#base_route ⇒ String

Returns the route that message bus will respond to. If not explicitly set, defaults to “/”. Requests to “##base_routemessage-bus/*” will be handled by the message bus server.

Returns:

  • (String) —

    the route that message bus will respond to. If not explicitly set, defaults to “/”. Requests to “##base_routemessage-bus/*” will be handled by the message bus server.



154
155
156
 
# File 'lib/message_bus.rb', line 154

def base_route
  @config[:base_route] || "/"
end

#base_route=(route) ⇒ void

This method returns an undefined value.

Parameters:

  • route (String) —

    Message bus will listen to requests on this route.



147
148
149
 
# File 'lib/message_bus.rb', line 147

def base_route=(route)
  configure(base_route: route.gsub(Regexp.new('\A(?!/)|(?<!/)\Z|//+'), "/"))
end

#blocking_subscribe(channel = nil) {|message| ... } ⇒ void

This method returns an undefined value.

Subscribe to messages. Each message will be delivered by yielding to the passed block as soon as it is available. This will block until subscription is terminated.

Parameters:

  • channel (String, nil) (defaults to: nil) —

    the name of the channel to which we should subscribe. If ‘nil`, messages on every channel will be provided.

Yields:

  • (message) —

    a message-handler block

Yield Parameters:



405
406
407
408
409
410
411
 
# File 'lib/message_bus.rb', line 405

def blocking_subscribe(channel = nil, &blk)
  if channel
    backend_instance.subscribe(encode_channel_name(channel), &blk)
  else
    backend_instance.global_subscribe(&blk)
  end
end

#chunked_encoding_enabled=(val) ⇒ void

This method returns an undefined value.

Parameters:

  • val (Boolean) —

    whether or not to enable chunked encoding



75
76
77
 
# File 'lib/message_bus.rb', line 75

def chunked_encoding_enabled=(val)
  configure(chunked_encoding_enabled: val)
end

#chunked_encoding_enabled? ⇒ Boolean

Returns whether or not chunked encoding is enabled. If not explicitly set, defaults to true.

Returns:

  • (Boolean) —

    whether or not chunked encoding is enabled. If not explicitly set, defaults to true.



69
70
71
 
# File 'lib/message_bus.rb', line 69

def chunked_encoding_enabled?
  @config[:chunked_encoding_enabled] == false ? false : true
end

#client_message_filters ⇒ Array

Returns a hash of message filters that have been registered

Returns:

  • (Array) —

    returns a hash of message filters that have been registered



619
620
621
622
 
# File 'lib/message_bus.rb', line 619

def client_message_filters
  configure(client_message_filters: []) if !@config[:client_message_filters]
  @config[:client_message_filters]
end

#configure(config) ⇒ void

This method returns an undefined value.

Overrides existing configuration

Parameters:

  • config (Hash<Symbol => Object>) —

    values to merge into existing config



180
181
182
 
# File 'lib/message_bus.rb', line 180

def configure(config)
  @config.merge!(config)
end

#destroy ⇒ void

This method returns an undefined value.

Stops listening for publications and stops executing scheduled tasks. Mostly used in tests to destroy entire bus.



538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
 
# File 'lib/message_bus.rb', line 538

def destroy
  return if @destroyed

  backend_instance.global_unsubscribe
  backend_instance.destroy

  @mutex.synchronize do
    return if @destroyed

    @subscriptions ||= {}
    @destroyed = true
  end
  @subscriber_thread.join if @subscriber_thread
  timer.stop
end

#extra_response_headers_lookup {|env| ... } ⇒ void

This method returns an undefined value.

Yields:

  • (env) —

    a routine to determine extra headers to be set on a subscriber response

Yield Parameters:

  • env (Rack::Request::Env) —

    the subscriber request environment

Yield Returns:

  • (Hash<String => String>) —

    the extra headers to set on the response



243
244
245
246
 
# File 'lib/message_bus.rb', line 243

def extra_response_headers_lookup(&blk)
  configure(extra_response_headers_lookup: blk) if blk
  @config[:extra_response_headers_lookup]
end

#global_backlog(last_id = nil) ⇒ Array<MessageBus::Message>

Get messages from the global backlog since the last ID specified

Parameters:

  • last_id (#to_i) (defaults to: nil) —

    the global ID of the last message that the caller received

Returns:

  • (Array<MessageBus::Message>) —

    all messages published on any channel since the specified last ID



474
475
476
 
# File 'lib/message_bus.rb', line 474

def global_backlog(last_id = nil)
  backlog(nil, last_id)
end

#group_ids_lookup {|env| ... } ⇒ void

This method returns an undefined value.

Yields:

  • (env) —

    a routine to determine the group IDs for a subscriber

Yield Parameters:

  • env (optional, Rack::Request::Env) —

    the subscriber request environment

Yield Returns:

  • (optional, Array<String,Integer>) —

    the group IDs for the subscriber



215
216
217
218
 
# File 'lib/message_bus.rb', line 215

def group_ids_lookup(&blk)
  configure(group_ids_lookup: blk) if blk
  @config[:group_ids_lookup]
end

#initialize ⇒ Object 



39
40
41
42
43
44
45
46
47
 
# File 'lib/message_bus.rb', line 39

def initialize
  @config = {}
  @mutex = Synchronizer.new
  @off = false
  @off_disable_publish = false
  @destroyed = false
  @timer_thread = nil
  @subscriber_thread = nil
end

#is_admin_lookup {|env| ... } ⇒ void

This method returns an undefined value.

Yields:

  • (env) —

    a routine to determine if a request comes from an admin user

Yield Parameters:

  • env (Rack::Request::Env) —

    the subscriber request environment

Yield Returns:

  • (Boolean) —

    whether or not the request is from an admin user



224
225
226
227
 
# File 'lib/message_bus.rb', line 224

def is_admin_lookup(&blk)
  configure(is_admin_lookup: blk) if blk
  @config[:is_admin_lookup]
end

#keepalive_interval ⇒ Integer

Returns the keepalive interval in seconds. If not explicitly set, defaults to ‘60`.

Returns:

  • (Integer) —

    the keepalive interval in seconds. If not explicitly set, defaults to ‘60`.



600
601
602
 
# File 'lib/message_bus.rb', line 600

def keepalive_interval
  @config[:keepalive_interval] || 60
end

#keepalive_interval=(interval) ⇒ Object

Parameters:

  • interval (Integer) —

    the keepalive interval in seconds. Set to 0 to disable; anything higher and a keepalive will run every N seconds. If it fails, the process is killed.



594
595
596
 
# File 'lib/message_bus.rb', line 594

def keepalive_interval=(interval)
  configure(keepalive_interval: interval)
end

#last_id(channel, site_id = nil) ⇒ Integer

Get the ID of the last message published on a channel, filtered by site

Parameters:

  • channel (String) —

    the name of the channel in question

  • site_id (String) (defaults to: nil) —

    the ID of the site by which to filter

Returns:

  • (Integer) —

    the channel-specific ID of the last message published to the given channel



505
506
507
 
# File 'lib/message_bus.rb', line 505

def last_id(channel, site_id = nil)
  backend_instance.last_id(encode_channel_name(channel, site_id))
end

#last_ids(*channels, site_id: nil) ⇒ Hash

Get the ID of the last message published on multiple channels

Parameters:

  • channels (Array<String>) —

    • array of channels to fetch

  • site_id (String) (defaults to: nil) —

    • the ID of the site by which to filter

Returns:

  • (Hash) —

    the channel-specific IDs of the last message published to each requested channel



515
516
517
518
519
 
# File 'lib/message_bus.rb', line 515

def last_ids(*channels, site_id: nil)
  encoded_channel_names = channels.map { |c| encode_channel_name(c, site_id) }
  ids = backend_instance.last_ids(*encoded_channel_names)
  channels.zip(ids).to_h
end

#last_message(channel) ⇒ MessageBus::Message

Get the last message published on a channel

Parameters:

  • channel (String) —

    the name of the channel in question

Returns:



526
527
528
529
530
531
532
533
 
# File 'lib/message_bus.rb', line 526

def last_message(channel)
  if last_id = last_id(channel)
    messages = backlog(channel, last_id - 1)
    if messages
      messages[0]
    end
  end
end

#listening? ⇒ Boolean

Returns whether or not the server is actively listening for publications on the bus.

Returns:

  • (Boolean) —

    whether or not the server is actively listening for publications on the bus



568
569
570
 
# File 'lib/message_bus.rb', line 568

def listening?
  @subscriber_thread&.alive?
end

#local_subscribe(channel = nil, last_id = -1,) {|message| ... } ⇒ Proc

Subscribe to messages on a particular channel, filtered by the current site (@see #site_id_lookup). Each message since the last ID specified will be delivered by yielding to the passed block as soon as it is available. This will not block, but instead the callbacks will be executed asynchronously in a dedicated subscriber thread.

Parameters:

  • channel (String) (defaults to: nil) —

    the name of the channel to which we should subscribe

  • last_id (#to_i) (defaults to: -1,) —

    the channel-specific ID of the last message that the caller received on the specified channel

Yields:

  • (message) —

    a message-handler block

Yield Parameters:

Returns:

  • (Proc) —

    the callback block that will be executed



442
443
444
445
 
# File 'lib/message_bus.rb', line 442

def local_subscribe(channel = nil, last_id = -1, &blk)
  site_id = site_id_lookup.call if site_id_lookup && !global?(channel)
  subscribe_impl(channel, site_id, last_id, &blk)
end

#local_unsubscribe(channel = nil, &blk) ⇒ void

This method returns an undefined value.

Removes a subscription to a particular channel, filtered by the current site (@see #site_id_lookup).

Parameters:

  • channel (String) (defaults to: nil) —

    the name of the channel from which we should unsubscribe

  • blk (Proc, nil) —

    the callback which should be removed. If ‘nil`, removes all.



464
465
466
467
 
# File 'lib/message_bus.rb', line 464

def local_unsubscribe(channel = nil, &blk)
  site_id = site_id_lookup.call if site_id_lookup
  unsubscribe_impl(channel, site_id, &blk)
end

#logger ⇒ Logger

Returns the logger used by the bus. If not explicitly set, is configured to log to STDOUT at INFO level.

Returns:

  • (Logger) —

    the logger used by the bus. If not explicitly set, is configured to log to STDOUT at INFO level.



57
58
59
60
61
62
63
64
65
 
# File 'lib/message_bus.rb', line 57

def logger
  return @config[:logger] if @config[:logger]

  require 'logger'
  logger = Logger.new(STDOUT)
  logger.level = Logger::INFO
  configure(logger: logger)
  logger
end

#logger=(logger) ⇒ void

This method returns an undefined value.

Parameters:

  • logger (Logger) —

    a logger object to be used by the bus



51
52
53
 
# File 'lib/message_bus.rb', line 51

def logger=(logger)
  configure(logger: logger)
end

#long_polling_enabled=(val) ⇒ void

This method returns an undefined value.

Parameters:

  • val (Boolean) —

    whether or not to enable long polling



87
88
89
 
# File 'lib/message_bus.rb', line 87

def long_polling_enabled=(val)
  configure(long_polling_enabled: val)
end

#long_polling_enabled? ⇒ Boolean

Returns whether or not long polling is enabled. If not explicitly set, defaults to true.

Returns:

  • (Boolean) —

    whether or not long polling is enabled. If not explicitly set, defaults to true.



81
82
83
 
# File 'lib/message_bus.rb', line 81

def long_polling_enabled?
  @config[:long_polling_enabled] == false ? false : true
end

#long_polling_interval ⇒ Integer

Returns the long-polling interval in milliseconds. If not explicitly set, defaults to 25,000.

Returns:

  • (Integer) —

    the long-polling interval in milliseconds. If not explicitly set, defaults to 25,000.



141
142
143
 
# File 'lib/message_bus.rb', line 141

def long_polling_interval
  @config[:long_polling_interval] || 25 * 1000
end

#long_polling_interval=(millisecs) ⇒ void

This method returns an undefined value.

Parameters:

  • millisecs (Integer) —

    the long-polling interval in milliseconds



135
136
137
 
# File 'lib/message_bus.rb', line 135

def long_polling_interval=(millisecs)
  configure(long_polling_interval: millisecs)
end

#max_active_clients ⇒ Integer

Returns The number of simultaneous clients we can service; will revert to polling if we are out of slots. Defaults to 1000 if not explicitly set.

Returns:

  • (Integer) —

    The number of simultaneous clients we can service; will revert to polling if we are out of slots. Defaults to 1000 if not explicitly set.



101
102
103
 
# File 'lib/message_bus.rb', line 101

def max_active_clients
  @config[:max_active_clients] || 1000
end

#max_active_clients=(val) ⇒ void

This method returns an undefined value.

Parameters:

  • val (Integer) —

    The number of simultaneous clients we can service; will revert to polling if we are out of slots



94
95
96
 
# File 'lib/message_bus.rb', line 94

def max_active_clients=(val)
  configure(max_active_clients: val)
end

#off(disable_publish: true) ⇒ void

This method returns an undefined value.

Disables publication to the bus

Parameters:

  • disable_publish (Boolean) (defaults to: true) —

    Whether or not to disable publishing



166
167
168
169
 
# File 'lib/message_bus.rb', line 166

def off(disable_publish: true)
  @off = true
  @off_disable_publish = disable_publish
end

#off? ⇒ Boolean

Returns whether the bus is disabled or not.

Returns:

  • (Boolean) —

    whether the bus is disabled or not



159
160
161
 
# File 'lib/message_bus.rb', line 159

def off?
  @off
end

#on ⇒ void

This method returns an undefined value.

Enables publication to the bus



173
174
175
 
# File 'lib/message_bus.rb', line 173

def on
  @destroyed = @off = @off_disable_publish = false
end

#on_connect(&blk) ⇒ Object 



248
249
250
251
 
# File 'lib/message_bus.rb', line 248

def on_connect(&blk)
  configure(on_connect: blk) if blk
  @config[:on_connect]
end

#on_disconnect(&blk) ⇒ Object 



253
254
255
256
 
# File 'lib/message_bus.rb', line 253

def on_disconnect(&blk)
  configure(on_disconnect: blk) if blk
  @config[:on_disconnect]
end

#on_middleware_error {|env, e| ... } ⇒ void

This method returns an undefined value.

Yields:

  • (env, e) —

    a routine to handle exceptions raised when handling a subscriber request

Yield Parameters:

  • env (Rack::Request::Env) —

    the subscriber request environment

  • e (Exception) —

    the exception that was raised

Yield Returns:

  • (optional, Array<(Integer,Hash,Array)>) —

    a Rack response to be delivered



234
235
236
237
 
# File 'lib/message_bus.rb', line 234

def on_middleware_error(&blk)
  configure(on_middleware_error: blk) if blk
  @config[:on_middleware_error]
end

#publish(channel, data, opts = nil) ⇒ Integer

Publishes a message to a channel

Parameters:

  • channel (String) —

    the name of the channel to which the message should be published

  • data (JSON) —

    some data to publish to the channel. Must be an object that can be encoded as JSON

  • opts (Hash) (defaults to: nil)

Options Hash (opts):

  • :client_ids (Array<String>) — default: `nil` —

    the unique client IDs to which the message should be available. If nil, available to all.

  • :user_ids (Array<String,Integer>) — default: `nil` —

    the user IDs to which the message should be available. If nil, available to all.

  • :group_ids (Array<String,Integer>) — default: `nil` —

    the group IDs to which the message should be available. If nil, available to all.

  • :site_id (String) — default: `nil` —

    the site ID to scope the message to; used for hosting multiple applications or instances of an application against a single message_bus

  • :max_backlog_age (nil, Integer) —

    the longest amount of time a message may live in a backlog before being removed, in seconds

  • :max_backlog_size (nil, Integer) —

    the largest permitted size (number of messages) for the channel backlog; beyond this capacity, old messages will be dropped

Returns:

  • (Integer) —

    the channel-specific ID the message was given

Raises:



343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
 
# File 'lib/message_bus.rb', line 343

def publish(channel, data, opts = nil)
  return if @off_disable_publish

  @mutex.synchronize do
    raise ::MessageBus::BusDestroyed if @destroyed
  end

  user_ids = nil
  group_ids = nil
  client_ids = nil

  site_id = nil
  if opts
    user_ids = opts[:user_ids]
    group_ids = opts[:group_ids]
    client_ids = opts[:client_ids]
    site_id = opts[:site_id]
  end

  if (user_ids || group_ids) && global?(channel)
    raise ::MessageBus::InvalidMessage
  end

  if (user_ids == []) || (group_ids == []) || (client_ids == [])
    raise ::MessageBus::InvalidMessageTarget
  end

  encoded_data = transport_codec.encode({
    "data" => data,
    "user_ids" => user_ids,
    "group_ids" => group_ids,
    "client_ids" => client_ids
  })

  channel_opts = {}

  if opts
    if ((age = opts[:max_backlog_age]) || (size = opts[:max_backlog_size]))
      channel_opts[:max_backlog_size] = size
      channel_opts[:max_backlog_age] = age
    end

    if opts.has_key?(:queue_in_memory)
      channel_opts[:queue_in_memory] = opts[:queue_in_memory]
    end
  end

  encoded_channel_name = encode_channel_name(channel, site_id)
  backend_instance.publish(encoded_channel_name, encoded_data, channel_opts)
end

#rack_hijack_enabled=(val) ⇒ void

This method returns an undefined value.

Parameters:

  • val (Boolean) —

    whether or not to enable Rack Hijack



129
130
131
 
# File 'lib/message_bus.rb', line 129

def rack_hijack_enabled=(val)
  configure(rack_hijack_enabled: val)
end

#rack_hijack_enabled? ⇒ Boolean

Returns whether or not Rack Hijack is enabled. If not explicitly set, will default to true, unless we’re on Passenger without the ability to set the advertised_concurrency_level to 0.

Returns:

  • (Boolean) —

    whether or not Rack Hijack is enabled. If not explicitly set, will default to true, unless we’re on Passenger without the ability to set the advertised_concurrency_level to 0.



108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
 
# File 'lib/message_bus.rb', line 108

def rack_hijack_enabled?
  if @config[:rack_hijack_enabled].nil?
    enable = true

    # without this switch passenger will explode
    # it will run out of connections after about 10
    if defined? PhusionPassenger
      enable = false
      if PhusionPassenger.respond_to? :advertised_concurrency_level
        PhusionPassenger.advertised_concurrency_level = 0
        enable = true
      end
    end
    configure(rack_hijack_enabled: enable)
  end

  @config[:rack_hijack_enabled]
end

#redis_config=(config) ⇒ void

This method returns an undefined value.

Overrides existing configuration, explicitly enabling the redis backend

Parameters:

  • config (Hash<Symbol => Object>) —

    values to merge into existing config



187
188
189
 
# File 'lib/message_bus.rb', line 187

def redis_config=(config)
  configure(config.merge(backend: :redis))
end

#register_client_message_filter(channel_prefix) {|message| ... } ⇒ void

This method returns an undefined value.

Registers a client message filter that allows messages to be filtered from the client.

Parameters:

  • channel_prefix (String, Regexp) —

    channel prefix to match against a message’s channel

Yield Parameters:

Yield Returns:

  • (Boolean) —

    whether the message should be published to the client



611
612
613
614
615
616
 
# File 'lib/message_bus.rb', line 611

def register_client_message_filter(channel_prefix, &blk)
  if blk
    configure(client_message_filters: []) if !@config[:client_message_filters]
    @config[:client_message_filters] << [channel_prefix, blk]
  end
end

#reliable_pub_sub ⇒ Object 



315
316
317
318
 
# File 'lib/message_bus.rb', line 315

def reliable_pub_sub
  logger.warn "MessageBus.reliable_pub_sub is deprecated, use MessageBus.backend_instance instead."
  backend_instance
end

#reliable_pub_sub=(pub_sub) ⇒ Object 



292
293
294
295
 
# File 'lib/message_bus.rb', line 292

def reliable_pub_sub=(pub_sub)
  logger.warn "MessageBus.reliable_pub_sub= is deprecated, use MessageBus.backend_instance= instead."
  self.backend_instance = pub_sub
end

#reset! ⇒ Object 



573
574
575
 
# File 'lib/message_bus.rb', line 573

def reset!
  backend_instance.reset! if backend_instance
end

#site_id_lookup {|env| ... } ⇒ void

This method returns an undefined value.

Yields:

  • (env) —

    a routine to determine the site ID for a subscriber

Yield Parameters:

  • env (optional, Rack::Request::Env) —

    the subscriber request environment

Yield Returns:

  • (optional, String) —

    the site ID for the subscriber



197
198
199
200
 
# File 'lib/message_bus.rb', line 197

def site_id_lookup(&blk)
  configure(site_id_lookup: blk) if blk
  @config[:site_id_lookup]
end

#subscribe(channel = nil, last_id = -1,) {|message| ... } ⇒ Proc

Subscribe to messages on a particular channel. Each message since the last ID specified will be delivered by yielding to the passed block as soon as it is available. This will not block, but instead the callbacks will be executed asynchronously in a dedicated subscriber thread.

Parameters:

  • channel (String) (defaults to: nil) —

    the name of the channel to which we should subscribe

  • last_id (#to_i) (defaults to: -1,) —

    the channel-specific ID of the last message that the caller received on the specified channel

Yields:

  • (message) —

    a message-handler block

Yield Parameters:

Returns:

  • (Proc) —

    the callback block that will be executed



425
426
427
 
# File 'lib/message_bus.rb', line 425

def subscribe(channel = nil, last_id = -1, &blk)
  subscribe_impl(channel, nil, last_id, &blk)
end

#timer ⇒ MessageBus::TimerThread

Returns the timer thread used for triggering scheduled routines at specific times/intervals.

Returns:

  • (MessageBus::TimerThread) —

    the timer thread used for triggering scheduled routines at specific times/intervals.



579
580
581
582
583
584
585
586
587
588
589
 
# File 'lib/message_bus.rb', line 579

def timer
  return @timer_thread if @timer_thread

  @timer_thread ||= begin
    t = MessageBus::TimerThread.new
    t.on_error do |e|
      logger.warn "Failed to process job: #{e} #{e.backtrace}"
    end
    t
  end
end

#transport_codec ⇒ MessageBus::Codec::Base

Returns codec used to encode and decode Message payloads.

Returns:



282
283
284
 
# File 'lib/message_bus.rb', line 282

def transport_codec
  @config[:transport_codec] ||= MessageBus::Codec::Json.new
end

#transport_codec=(codec) ⇒ void

This method returns an undefined value.

Parameters:



277
278
279
 
# File 'lib/message_bus.rb', line 277

def transport_codec=(codec)
  configure(transport_codec: codec)
end

#unsubscribe(channel = nil, &blk) ⇒ void

This method returns an undefined value.

Removes a subscription to a particular channel.

Parameters:

  • channel (String) (defaults to: nil) —

    the name of the channel from which we should unsubscribe

  • blk (Proc, nil) —

    the callback which should be removed. If ‘nil`, removes all.



453
454
455
 
# File 'lib/message_bus.rb', line 453

def unsubscribe(channel = nil, &blk)
  unsubscribe_impl(channel, nil, &blk)
end

#user_id_lookup {|env| ... } ⇒ void

This method returns an undefined value.

Yields:

  • (env) —

    a routine to determine the user ID for a subscriber (authenticate)

Yield Parameters:

  • env (optional, Rack::Request::Env) —

    the subscriber request environment

Yield Returns:

  • (optional, String, Integer) —

    the user ID for the subscriber



206
207
208
209
 
# File 'lib/message_bus.rb', line 206

def user_id_lookup(&blk)
  configure(user_id_lookup: blk) if blk
  @config[:user_id_lookup]
end