Class: RightScale::Dispatcher

Inherits:
Object
  • Object
show all
Includes:
ProtocolVersionMixin
Defined in:
lib/right_agent/dispatcher.rb

Overview

Dispatching of payload to specified actor

Defined Under Namespace

Classes: DuplicateRequest, InvalidRequestType

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ProtocolVersionMixin

#can_always_handle_hash_payload?, #can_handle_http?, #can_handle_msgpack_result?, #can_handle_multicast_result?, #can_handle_non_delivery_result?, #can_handle_non_nanite_ids?, #can_handle_request_retries?, #can_put_version_in_packet?, #can_route_to_response_queue?, #can_use_router_query_tags?

Constructor Details

#initialize(agent, dispatched_cache = nil) ⇒ Dispatcher

Initialize dispatcher

Parameters

agent(Agent)

Agent using this dispatcher; uses its identity and registry

dispatched_cache(DispatchedCache|nil)

Cache for dispatched requests that is used for detecting

duplicate requests, or nil if duplicate checking is disabled



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# File 'lib/right_agent/dispatcher.rb', line 53

def initialize(agent, dispatched_cache = nil)
  @agent = agent
  @registry = @agent.registry
  @identity = @agent.identity
  @dispatched_cache = dispatched_cache
  reset_stats
  @@instance = self
end

Instance Attribute Details

#identity ⇒ Object (readonly)

(String) Identity of associated agent



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# File 'lib/right_agent/dispatcher.rb', line 37

def identity
  @identity
end

#registry ⇒ Object (readonly)

(ActorRegistry) Registry for actors



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# File 'lib/right_agent/dispatcher.rb', line 34

def registry
  @registry
end

Class Method Details

.instance ⇒ Object

For direct access to current dispatcher

Return

(Dispatcher)

This dispatcher instance if defined, otherwise nil



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# File 'lib/right_agent/dispatcher.rb', line 43

def self.instance
  @@instance if defined?(@@instance)
end

Instance Method Details

#dispatch(request) ⇒ Object

Route request to appropriate actor for servicing Reject requests whose TTL has expired or that are duplicates of work already dispatched

Parameters

request(Request|Push)

Packet containing request

header(AMQP::Frame::Header|nil)

Request header containing ack control

Return

(Result|nil)

Result of request, or nil if there is no result because request is a Push

Raise

InvalidRequestType

If the request cannot be routed to an actor

DuplicateRequest

If request rejected because it has already been processed



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# File 'lib/right_agent/dispatcher.rb', line 86

def dispatch(request)
  token = request.token
  actor, method, idempotent = route(request)
  received_at = @request_stats.update(method, (token if request.is_a?(Request)))
  if (dup = duplicate?(request, method, idempotent))
    raise DuplicateRequest, dup
  end
  unless (result = expired?(request, method))
    result = perform(request, actor, method, idempotent)
  end
  if request.is_a?(Request)
    duration = @request_stats.finish(received_at, token)
    Result.new(token, request.reply_to, result, @identity, request.from, request.tries, request.persistent, duration)
  end
end

#routable?(actor) ⇒ Boolean

Determine whether able to route requests to specified actor

Parameters

actor(String)

Actor name

Return

(Boolean)

true if can route to actor, otherwise false

Returns:

  • (Boolean) 


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# File 'lib/right_agent/dispatcher.rb', line 69

def routable?(actor)
  !!@registry.actor_for(actor)
end

#stats(reset = false) ⇒ Object

Get dispatcher statistics

Parameters

reset(Boolean)

Whether to reset the statistics after getting the current ones

Return

stats(Hash)

Current statistics:

“dispatched cache”(Hash|nil)

Number of dispatched requests cached and age of youngest and oldest,

  or nil if empty
"dispatch failures"(Hash|nil):: Dispatch failure activity stats with keys "total", "percent", "last", and "rate"
  with percentage breakdown per failure type, or nil if none
"rejects"(Hash|nil):: Request reject activity stats with keys "total", "percent", "last", and "rate"
  with percentage breakdown per reason ("duplicate (<method>)", "retry duplicate (<method>)", or
  "stale (<method>)"), or nil if none
"requests"(Hash|nil):: Request activity stats with keys "total", "percent", "last", and "rate"
  with percentage breakdown per request type, or nil if none



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# File 'lib/right_agent/dispatcher.rb', line 118

def stats(reset = false)
  stats = {
    "dispatched cache"  => (@dispatched_cache.stats if @dispatched_cache),
    "dispatch failures" => @dispatch_failure_stats.all,
    "rejects"           => @reject_stats.all,
    "requests"          => @request_stats.all
  }
  reset_stats if reset
  stats
end