Class: Querrel::Querreller

Inherits:
Object
  • Object
show all
Defined in:
lib/querrel/querreller.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dbs, options = {}) ⇒ Querreller

Returns a new instance of Querreller.



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# File 'lib/querrel/querreller.rb', line 7

def initialize(dbs, options = {})
  @connection_resolver = ConnectionResolver.new(dbs, options[:db_names])
end

Instance Attribute Details

#connection_resolver ⇒ Object

Returns the value of attribute connection_resolver.



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# File 'lib/querrel/querreller.rb', line 5

def connection_resolver
  @connection_resolver
end

Instance Method Details

#map(scope, options = {}, &blk) ⇒ Object 



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# File 'lib/querrel/querreller.rb', line 16

def map(scope, options = {}, &blk)
  if options.key?(:on)
    resolver = ConnectionResolver.new(dbs, !!options[:db_names])
    dbs = resolver.configurations.keys
  else
    resolver = @connection_resolver
    dbs = @connection_resolver.configurations.keys
  end

  query_model = scope.model
  results = {}

  threads = []
  dbs.each do |db|
    threads << Thread.new do
      con_spec = retrieve_connection_spec(db, resolver)
      dynamic_class_name = "TempModel#{Thread.current.object_id}"
      dynamic_class = Class.new(query_model)
      dynamic_class.send(:define_singleton_method, :name) { dynamic_class_name }

      begin
        dynamic_class.establish_connection(con_spec.config)
        local_scope = dynamic_class.all.merge(scope)
        results[db] = if block_given?
          res = yield(local_scope)
          res.to_a.each(&:readonly!) if res.is_a?(ActiveRecord::Relation)
          res
        else
          local_scope.to_a.each(&:readonly!)
        end
      ensure
        dynamic_class.connection_pool.release_connection
      end
    end
  end
  threads.each(&:join)

  results
end

#query(scope, options = {}, &blk) ⇒ Object 



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# File 'lib/querrel/querreller.rb', line 11

def query(scope, options = {}, &blk)
  buckets = map(scope, options, &blk)
  reduce(buckets)
end

#reduce(buckets) ⇒ Object 



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# File 'lib/querrel/querreller.rb', line 56

def reduce(buckets)
  buckets.flat_map{ |db, results| results }
end

#retrieve_connection_spec(db, resolver) ⇒ Object 



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# File 'lib/querrel/querreller.rb', line 60

def retrieve_connection_spec(db, resolver)
  resolver.spec(db.to_sym)
end

#while_connected_to(db, resolver, &b) ⇒ Object 



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# File 'lib/querrel/querreller.rb', line 64

def while_connected_to(db, resolver, &b)
  conf = resolver.spec(db.to_sym)
  pool = ActiveRecord::ConnectionAdapters::ConnectionPool.new(conf)
  pool.with_connection(&b)
ensure
  pool.disconnect!
end