Class: Dakwak::Station

Inherits:
Object
  • Object
show all
Includes:
Logger
Defined in:
lib/dakwak/messaging/station.rb

Overview

The station is the interface for opening and closing communication channels.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Logger

included, #log, #log_indent, #log_indent_dec, #log_indent_inc, #logging_context

Methods included from Silencable

#silence, #silent?

Constructor Details

#initialize ⇒ Station

Returns a new instance of Station.



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# File 'lib/dakwak/messaging/station.rb', line 111

def initialize
  logging_context( "Station" )

  @channels = {}
  @config = {
    :host      => "127.0.0.1",
    :port      => 5672,
    :user      => "guest",
    :pass      => "guest",
    :vhost     => "/",
    :ssl       => false,
    :frame_max => 131072
  }

  state(:inactive)

  Configurator.subscribe("Station", self)

  # log_info "engaged"

  super()
end

Instance Attribute Details

#channels ⇒ Object (readonly)

Returns the value of attribute channels.



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# File 'lib/dakwak/messaging/station.rb', line 17

def channels
  @channels
end

Class Method Details

.instance ⇒ Object 



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# File 'lib/dakwak/messaging/station.rb', line 12

def instance
  Dakwak.station
end

Instance Method Details

#active? ⇒ Boolean

The station is active if it has any channels currently open.

Returns:

  • (Boolean) 


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# File 'lib/dakwak/messaging/station.rb', line 89

def active?
  @state == :active
end

#connection_options ⇒ Object 



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# File 'lib/dakwak/messaging/station.rb', line 103

def connection_options()
  @config
end

#inactive? ⇒ Boolean

The station is inactive if there are no open channels.

Returns:

  • (Boolean) 


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# File 'lib/dakwak/messaging/station.rb', line 94

def inactive?
  @state == :inactive
end

#open_channel(name, opts = {}, &callback) ⇒ Object Also known as: get_channel

Opens a channel identified by ‘name’ if it’s not already open.

This method is asynchronous.

Aliases: get_channel



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# File 'lib/dakwak/messaging/station.rb', line 24

def open_channel(name, opts = {}, &callback) # :yields: channel

  if shutting_down?
    log_warn "Station is shutting down, channels will not be opened."
    return nil
  end

  if @channels[name]
    callback.call(@channels[name]) if callback
    return @channels[name]
  end

  c = Channel.new(name)
  @channels[name] = c
  c.open(opts) { |c|
    state(:active)

    log_debug "Channel #{c.name} is now open"
    callback.call(c) if callback
  }

  return c
end

#set_option(k, v) ⇒ Object 



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# File 'lib/dakwak/messaging/station.rb', line 107

def set_option(k, v)
  @config[k.to_sym] = v
end

#shutdown(&callback) ⇒ Object

Turns off the station and all open channels. A callback must be provided that will be called when the station is shut down.



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# File 'lib/dakwak/messaging/station.rb', line 52

def shutdown(&callback)
  raise RuntimeError.new "Station::shutdown() must be called with a callback block" unless callback

  if inactive?
    log_warn "Rejecting shutdown request; the station is currently inactive."
    callback.call
    return nil
  end

  if shutting_down?
    log_warn "Rejecting shutdown request; the station is already shutting down!"
    callback.call
    return nil
  end

  state(:shutting_down)

  # register the callback
  @on_shutdown = callback

  log_info "Closing #{@channels.size} open channels..."

  channels_closed = 0
  @channels.each_pair { |name, c|
    c.close {
      channels_closed += 1
      if channels_closed == @channels.size then
        state(:inactive)

        log_info "All channels are cleanly closed. Shutdown complete."
        @on_shutdown.call
      end
    }
  }
end

#shutting_down? ⇒ Boolean

When shutting down, it is not permitted to attempt to open any channels.

Returns:

  • (Boolean) 


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# File 'lib/dakwak/messaging/station.rb', line 99

def shutting_down?
  @state == :shutting_down
end