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em_db.rb
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em_db.rb
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require 'eventmachine'
module Tarantool
class EMDB < DB
IPROTO_CONNECTION_TYPE = :em_callback
INITIAL = Object.new.freeze
class Curry1 < Struct.new(:obj, :arg)
def call
obj.call arg
end
end
class FeedResponse < Struct.new(:response)
def call(result)
if Exception === result
response.cb.call result
else
response.call_callback(result)
end
end
end
def _send_request(shard_numbers, read_write, response)
if @closed
exc = ::IProto::Disconnected.new("Tarantool is closed")
if EM.reactor_running?
EM.next_tick Curry1.new(response.cb, exc)
else
response.cb.call exc
end
else
feed = FeedResponse.new(response)
shard_numbers = shard_numbers[0] if Array === shard_numbers && shard_numbers.size == 1
if Array === shard_numbers
_send_to_several_shards(shard_numbers, read_write, response, feed)
else
_send_to_one_shard(shard_numbers, read_write, response, feed)
end
end
end
def _send_to_one_shard(shard_number, read_write, response, feed)
if (replicas = _shard(shard_number)).size == 1
replicas[0].send_request(response.request_type, response.body, OneReplica.new(response, feed))
elsif read_write == :read
replicas = replicas.shuffle if @replica_strategy == :round_robin
EM.next_tick OneShardRead.new(replicas, response, feed)
else
EM.next_tick OneShardWrite.new(replicas, response, feed)
end
end
class OneReplica
include ParseIProto
def initialize(response, feed)
@response = response
@feed = feed
end
def call(result)
if Exception === (result = _parse_iproto(result))
@feed.call result
else
@feed.call @response.parse_response(result)
end
end
end
class OneShardRead
include ParseIProto
def initialize(replicas, response, feed)
@replicas = replicas
@i = -1
@response = response
@feed = feed
end
def call(result=INITIAL)
result = _parse_iproto(result) unless result == INITIAL
case result
when INITIAL, ::IProto::ConnectionError
begin
if (@i += 1) >= @replicas.size
EM.next_tick Curry1.new(@feed, ConnectionError.new("no available connections"))
return
end
end until (repl = @replicas[@i]).could_be_connected?
repl.send_request(@response.request_type, @response.body, self)
when Exception
@feed.call result
else
@feed.call @response.parse_response(result)
end
end
end
class OneShardWrite
include ParseIProto
def initialize(replicas, response, feed)
@replicas_origin = replicas
@replicas = replicas.dup
@i = replicas.size
@response = response
@feed = feed
end
def rotate!
if @i > 0
@i -= 1
@replicas.rotate!
end
end
def call(result=INITIAL)
result = _parse_iproto(result) unless result == INITIAL
case result
when INITIAL, ::IProto::ConnectionError, ::Tarantool::NonMaster
rotate! if Exception === result
rotate! until @i <= 0 || (repl = @replicas[0]).could_be_connected?
if @i <= 0
EM.next_tick Curry1.new(@feed, NoMasterError.new("no available master connections"))
return
end
repl.send_request(@response.request_type, @response.body, self)
when Exception
@feed.call result
else
@replicas_origin.replace @replicas
@feed.call @response.parse_response(result)
end
end
end
class Concatter
def initialize(count, feed)
@result = []
@count = count
@feed = feed
end
def call(array)
if @count > 0
case array
when Array
@result.concat array
when Exception
@result = array
@count = 1
else
@result << array
end
if (@count -= 1) == 0
if Array === @result && Integer === @result.first
@feed.call @result.inject(0){|s, i| s + i}
else
@feed.call @result
end
end
end
end
end
class ConcatterReplace
def initialize(count, feed)
@result = []
@count = count
@feed = feed
end
def call(array)
if @count > 0
case array
when Array
@result.concat array
when ::Tarantool::TupleDoesntExists
@result << array
when Exception
@result = array
@count = 1
else
@result << array
end
if (@count -= 1) == 0
if Exception === @result
@feed.call @result
elsif @result.all?{|r| ::Tarantool::TupleDoesntExists === r}
@feed.call @result.first
else
@result.delete_if{|r| ::Tarantool::TupleDoesntExists === r}
if Integer === @result.first
@feed.call @result.inject(0){|s, i| s + i}
else
@feed.call @result
end
end
end
end
end
end
def _send_to_several_shards(shard_numbers, read_write, response, feed)
concat = read_write != :replace ? Concatter.new(shard_numbers.size, feed) :
ConcatterReplace.new(shard_numbers.size, feed)
for shard in shard_numbers
_send_to_one_shard(shard, read_write, response, concat)
end
end
end
end