Class: CloudCrowd::NodeRecord

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/cloud_crowd/models/node_record.rb

Overview

A NodeRecord is the central server’s record of a Node running remotely. We can use it to assign WorkUnits to the Node, and keep track of its status. When a Node exits, it destroys this record.

Defined Under Namespace

Classes: Serializer

Constant Summary collapse

PORT =

Extract the port number from the host id.

/:(\d+)\Z/

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.available_actions ⇒ Object 



44
45
46
 
# File 'lib/cloud_crowd/models/node_record.rb', line 44

def self.available_actions
  available.map(&:actions).flatten.uniq - BlackListedAction.all.pluck(:action)
end

.check_in(params, request) ⇒ Object

Register a Node with the central server. This happens periodically (once every ‘Node::CHECK_IN_INTERVAL` seconds). Nodes will be de-registered if they checked in within a reasonable interval.



26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
 
# File 'lib/cloud_crowd/models/node_record.rb', line 26

def self.check_in(params, request)
  attrs = {
    :ip_address       => request.ip,
    :port             => params[:host].match(PORT)[1].to_i,
    :busy             => params[:busy],
    :tag              => params[:tag],
    :max_workers      => params[:max_workers],
    :enabled_actions  => params[:enabled_actions]
  }
  host_attr = {:host => params[:host]}
  if (record = where(host_attr).first)
    record.update_attributes!(attrs)
    record
  else
    create!(attrs.merge(host_attr))
  end
end

Instance Method Details

#actions ⇒ Object

What Actions is this Node able to run?



71
72
73
 
# File 'lib/cloud_crowd/models/node_record.rb', line 71

def actions
  @actions ||= enabled_actions.split(',')
end

#active_model_serializer ⇒ Object 



122
 
# File 'lib/cloud_crowd/models/node_record.rb', line 122

def active_model_serializer; Serializer; end

#busy? ⇒ Boolean

Is this Node too busy for more work? Determined by number of workers, or the Node’s load average, as configured in config.yml.

Returns:

  • (Boolean) 


77
78
79
 
# File 'lib/cloud_crowd/models/node_record.rb', line 77

def busy?
  busy || (max_workers && work_units.count >= max_workers)
end

#display_status ⇒ Object

The printable status of the Node.



94
95
96
 
# File 'lib/cloud_crowd/models/node_record.rb', line 94

def display_status
  busy? ? 'busy' : 'available'
end

#node ⇒ Object

Keep a RestClient::Resource handy for contacting the Node, including HTTP authentication, if configured.



89
90
91
 
# File 'lib/cloud_crowd/models/node_record.rb', line 89

def node
  @node ||= RestClient::Resource.new(url, CloudCrowd.client_options)
end

#redistribute_work_units ⇒ Object (private)

When a Node exits, release its WorkUnits and redistribute them to others. Redistribute in a separate thread to avoid delaying shutdown.



132
133
134
 
# File 'lib/cloud_crowd/models/node_record.rb', line 132

def redistribute_work_units
  release_work_units
end

#release_work_units ⇒ Object

Release all of this Node’s WorkUnits for other nodes to take.



104
105
106
 
# File 'lib/cloud_crowd/models/node_record.rb', line 104

def release_work_units
  WorkUnit.where("node_record_id = #{id}").update_all('node_record_id = null, worker_pid = null')
end

#send_work_unit(unit) ⇒ Object

Dispatch a WorkUnit to this node. Places the node at back at the end of the rotation. If we fail to send the WorkUnit, we consider the node to be down, and remove this record, freeing up all of its checked-out work units. If the Node responds that it’s overloaded, we mark it as busy. Returns true if the WorkUnit was dispatched successfully.



53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
 
# File 'lib/cloud_crowd/models/node_record.rb', line 53

def send_work_unit(unit)
  result = node['/work'].post(:work_unit => unit.to_json)
  unit.assign_to(self, JSON.parse(result.body)['pid'])
  touch && true
rescue RestClient::RequestTimeout
  # The node's gone away.  Destroy it and it will check in when it comes back
  CloudCrowd.log "Node #{host} received RequestTimeout, removing it"
  destroy && false
rescue RestClient::RequestFailed => e
  raise e unless e.http_code == 503 && e.http_body == Node::OVERLOADED_MESSAGE
  update_attribute(:busy, true) && false
rescue RestClient::Exception, Errno::ECONNREFUSED, Timeout::Error, Errno::ECONNRESET=>e
  # Couldn't post to node, assume it's gone away.
  CloudCrowd.log "Node #{host} received #{e.class} #{e}, removing it"
  destroy && false
end

#to_json ⇒ Object 



124
125
126
 
# File 'lib/cloud_crowd/models/node_record.rb', line 124

def to_json
  Serializer.new(self).to_json
end

#url ⇒ Object

The URL at which this Node may be reached. TODO: Make sure that the host actually has externally accessible DNS.



83
84
85
 
# File 'lib/cloud_crowd/models/node_record.rb', line 83

def url
  @url ||= "http://#{host}"
end

#worker_pids ⇒ Object

A list of the process ids of the workers currently being run by the Node.



99
100
101
 
# File 'lib/cloud_crowd/models/node_record.rb', line 99

def worker_pids
  work_units.pluck('worker_pid')
end