Class: LS4::LocationAwareMasterSelectService

Inherits:
Service show all
Defined in:
lib/ls4/service/master_select.rb

Instance Method Summary collapse

Methods inherited from Service

init

Methods included from EventBus::SingletonMixin

#ebus_bind!, #ebus_connect, extended

Methods included from EventBus::BusMixin

#ebus_all_slots, #ebus_disconnect!

Methods included from EventBus::DeclarerBase::Methods

#connect, #ebus_all_slots, #ebus_call_log, #ebus_call_slots, #ebus_signal_error, #ebus_signal_log, #ebus_signal_slots

Methods included from EventBus::DeclarerBase

#call_slot, #signal_slot

Constructor Details

#initialize ⇒ LocationAwareMasterSelectService

Returns a new instance of LocationAwareMasterSelectService.



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# File 'lib/ls4/service/master_select.rb', line 29

def initialize
  @map = {}  # { rsid => [nids] }
  @self_location = ConfigBus.self_location
end

Instance Method Details

#select_master(rsid, key) ⇒ Object 



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# File 'lib/ls4/service/master_select.rb', line 64

def select_master(rsid, key)
  loc_nodes = @map[rsid]
  unless loc_nodes
    raise "no such rsid: #{rsid}"
  end
  digest = Digest::MD5.digest(key)
  i = digest.unpack('C')[0]
  loc_nodes.map {|nodes| rotate(nodes, i) }.flatten
end

#select_master_static(rsid) ⇒ Object 



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# File 'lib/ls4/service/master_select.rb', line 74

def select_master_static(rsid)
  loc_nodes = @map[rsid]
  unless loc_nodes
    raise "no such rsid: #{rsid}"
  end
  loc_nodes.flatten
end

#update_nodes(nodes = nil) ⇒ Object 



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# File 'lib/ls4/service/master_select.rb', line 34

def update_nodes(nodes=nil)
  nodes ||= MembershipBus.get_all_nodes

  rsid_nodes = {}
  nodes.each {|node|
    node.rsids.each {|rsid|
      (rsid_nodes[rsid] ||= []) << node
    }
  }

  rsid_loc_nids = {}
  rsid_nodes.each_pair {|rsid,nodes|
    loc_grouped = nodes.group_by {|node| node.location }

    sorted = loc_grouped.to_a.sort_by {|loc,nodes| loc }
    if idx = sorted.find_index {|loc,nodes| loc == @self_location }
      sorted = rotate(sorted, idx)
    end

    loc_nids = sorted.map {|loc,nodes|
      nids = nodes.map {|node| node.nid }
      nids.sort
    }

    rsid_loc_nids[rsid] = loc_nids
  }

  @map = rsid_loc_nids
end