Class: ContentShard

Inherits:
Object show all
Defined in:
lib/adhd/models/content_shard.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(nodesv, this_shardv) ⇒ ContentShard

Returns a new instance of ContentShard.



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# File 'lib/adhd/models/content_shard.rb', line 6

def initialize(nodesv, this_shardv)
  @nodes = nodesv
  @this_shard = this_shardv

  # Work out the rest
  @our_node = nodesv.our_node
  @this_shard_db = nodesv.our_node.get_content_db(this_shardv.shard_db_name)

  @last_sync_seq = 0 # @this_shard_db.info['update_seq']
end

Instance Attribute Details

#nodes ⇒ Object

Returns the value of attribute nodes.



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# File 'lib/adhd/models/content_shard.rb', line 4

def nodes
  @nodes
end

#our_node ⇒ Object

Returns the value of attribute our_node.



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# File 'lib/adhd/models/content_shard.rb', line 4

def our_node
  @our_node
end

#this_shard ⇒ Object

Returns the value of attribute this_shard.



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# File 'lib/adhd/models/content_shard.rb', line 4

def this_shard
  @this_shard
end

#this_shard_db ⇒ Object

Returns the value of attribute this_shard_db.



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# File 'lib/adhd/models/content_shard.rb', line 4

def this_shard_db
  @this_shard_db
end

Instance Method Details

#in_shard?(internal_id) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/adhd/models/content_shard.rb', line 17

def in_shard?(internal_id)
   internal_id >= this_shard.range_start && internal_id < this_shard.range_end
end

#sync ⇒ Object 



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# File 'lib/adhd/models/content_shard.rb', line 29

def sync
  # A Shard only pushes with the master of the shard
  # or the node with the highest is_storage value alive
  # Shard masters ensure changes are pushed to all

  # NOTE: This method needs serious refactoring
  # No need to update
  return false if @this_shard_db.info['update_seq'] == @last_sync_seq

  # Are we the shard master?
  am_master = (our_node.name == this_shard.master_node)

  if !am_master
    master_node = Node.by_name(:key => this_shard.master_node).first
    remote_db = master_node.get_content_db(this_shard.shard_db_name)
    bool_to = @our_node.replicate_to(this_shard_db, master_node, remote_db)
    if bool_to
      @last_sync_seq = @this_shard_db.info['update_seq']
      return true
    end
  end

  # Either we are the master or the master has failed -- we replicate with
  # all nodes or the first available aside us and master
  all_good = true
  this_shard.node_list.each do |node_name|
    # Do not sync with ourselves
    next if (@our_node.name == node_name)
  
     # Push all changes to the other nodes
     remote_node = Node.by_name(:key =>  node_name).first
     remote_db = remote_node.get_content_db(this_shard.shard_db_name)
     bool_to = @our_node.replicate_to(this_shard_db, remote_node, remote_db)
     all_good &= bool_to
     if !am_master && bool_to
       # NOTE: How to build skynet, Note 2
       #       We are doing some "gonzo" replication, here. Our master is
       #       clearly down so we find the second best node; we push our
       #       changes to this node, and now also *replicate from*
       #       that node.
       @our_node.replicate_from(this_shard_db, remote_node, remote_db)
       @last_sync_seq = @this_shard_db.info['update_seq']
       break
     end
  end
  if all_good
    @last_sync_seq = @this_shard_db.info['update_seq']
    return true
  else
    return false
  end
end

#write_doc(content_doc) ⇒ Object 



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# File 'lib/adhd/models/content_shard.rb', line 21

def write_doc(content_doc)
  # Write a content document to this shard
  # Make sure it is in this shard
  if in_shard? content_doc.internal_id
    this_shard_db.save_doc(content_doc)
  end
end