Class: EventedMysql

Inherits:
EM::Connection
  • Object
show all
Defined in:
lib/em/mysql.rb,
lib/em/mysql.rb

Constant Summary collapse

DisconnectErrors = 
[
  'query: not connected',
  'MySQL server has gone away',
  'Lost connection to MySQL server during query'
]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(mysql, opts) ⇒ EventedMysql

Returns a new instance of EventedMysql.



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# File 'lib/em/mysql.rb', line 15

def initialize mysql, opts
  @mysql = mysql
  @fd = mysql.socket
  @opts = opts
  @current = nil
  @@queue ||= []
  @processing = false
  @connected = true

  log 'mysql connected'

  self.notify_readable = true
  EM.add_timer(0){ next_query }
end

Instance Attribute Details

#connected ⇒ Object (readonly)

Returns the value of attribute connected.



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# File 'lib/em/mysql.rb', line 29

def connected
  @connected
end

#opts ⇒ Object (readonly) Also known as: settings

Returns the value of attribute opts.



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# File 'lib/em/mysql.rb', line 29

def opts
  @opts
end

#processing ⇒ Object (readonly)

Returns the value of attribute processing.



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# File 'lib/em/mysql.rb', line 29

def processing
  @processing
end

Class Method Details

._connect(opts) ⇒ Object

stolen from sequel



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# File 'lib/em/mysql.rb', line 199

def self._connect opts
  opts = settings.merge(opts)

  conn = Mysql.init

  # set encoding _before_ connecting
  if charset = opts[:charset] || opts[:encoding]
    conn.options(Mysql::SET_CHARSET_NAME, charset)
  end

  conn.options(Mysql::OPT_LOCAL_INFILE, 'client')

  conn.real_connect(
    opts[:host] || 'localhost',
    opts[:user] || 'root',
    opts[:password],
    opts[:database],
    opts[:port],
    opts[:socket],
    0 +
    # XXX multi results require multiple callbacks to parse
    # Mysql::CLIENT_MULTI_RESULTS +
    # Mysql::CLIENT_MULTI_STATEMENTS +
    (opts[:compress] == false ? 0 : Mysql::CLIENT_COMPRESS)
  )
  
  # increase timeout so mysql server doesn't disconnect us
  # this is especially bad if we're disconnected while EM.attach is
  # still in progress, because by the time it gets to EM, the FD is
  # no longer valid, and it throws a c++ 'bad file descriptor' error
  # (do not use a timeout of -1 for unlimited, it does not work on mysqld > 5.0.60)
  conn.query("set @@wait_timeout = #{opts[:timeout] || 2592000}")

  # we handle reconnecting (and reattaching the new fd to EM)
  conn.reconnect = false

  # By default, MySQL 'where id is null' selects the last inserted id
  # Turn this off. http://dev.rubyonrails.org/ticket/6778
  conn.query("set SQL_AUTO_IS_NULL=0")

  # get results for queries
  conn.query_with_result = true

  conn
rescue Mysql::Error => e
  if cb = opts[:on_error]
    cb.call(e)
    nil
  else
    raise e
  end
end

.all(query, type = nil, &blk) ⇒ Object 



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# File 'lib/em/mysql.rb', line 276

def self.all query, type = nil, &blk
  responses = 0
  connection_pool.each do |c|
    c.execute(query, type) do
      responses += 1
      blk.call if blk and responses == @connection_pool.size
    end
  end
end

.connect(opts) ⇒ Object 



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# File 'lib/em/mysql.rb', line 184

def self.connect opts
  unless EM.respond_to?(:watch) and Mysql.method_defined?(:socket)
    raise RuntimeError, 'mysqlplus and EM.watch are required for EventedMysql'
  end
  
  if conn = _connect(opts)
    EM.watch conn.socket, self, conn, opts
  else
    EM.add_timer(5){ connect opts }
  end
end

.connection_pool ⇒ Object 



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# File 'lib/em/mysql.rb', line 286

def self.connection_pool
  @connection_pool ||= (1..settings[:connections]).map{ EventedMysql.connect(settings) }
  # p ['connpool', settings[:connections], @connection_pool.size]
  # (1..(settings[:connections]-@connection_pool.size)).each do
  #   @connection_pool << EventedMysql.connect(settings)
  # end unless settings[:connections] == @connection_pool.size
  # @connection_pool
end

.execute(query, type = nil, cblk = nil, eblk = nil, &blk) ⇒ Object 



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# File 'lib/em/mysql.rb', line 258

def self.execute query, type = nil, cblk = nil, eblk = nil, &blk
  unless nil#connection = connection_pool.find{|c| not c.processing and c.connected }
    @n ||= 0
    connection = connection_pool[@n]
    @n = 0 if (@n+=1) >= connection_pool.size
  end

  connection.execute(query, type, cblk, eblk, &blk)
end

.reset! ⇒ Object 



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# File 'lib/em/mysql.rb', line 295

def self.reset!
  @connection_pool.each do |c|
    c.close
  end
  @connection_pool = nil
end

.settings ⇒ Object 



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# File 'lib/em/mysql.rb', line 254

def self.settings
  @settings ||= { :connections => 4, :logging => false }
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/em/mysql.rb', line 162

def close
  @connected = false
  fd = detach
  log 'detached fd', fd
end

#execute(sql, response = nil, cblk = nil, eblk = nil, retries = 0, &blk) ⇒ Object 



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# File 'lib/em/mysql.rb', line 125

def execute sql, response = nil, cblk = nil, eblk = nil, retries = 0, &blk
  cblk ||= blk

  begin
    unless @processing or !@connected
      # begin
      #   log 'mysql ping', @mysql.ping
      #   # log 'mysql stat', @mysql.stat
      #   # log 'mysql errno', @mysql.errno
      # rescue
      #   log 'mysql ping failed'
      #   @@queue << [response, sql, blk]
      #   return close
      # end

      @processing = true

      log 'mysql sending', sql
      @mysql.send_query(sql)
    else
      @@queue << [response, sql, cblk, eblk, retries]
      return
    end
  rescue Mysql::Error => e
    log 'mysql error', e.message
    if DisconnectErrors.include? e.message
      @@queue << [response, sql, cblk, eblk, retries]
      return close
    else
      raise e
    end
  end

  log 'queuing', response, sql
  @current = [Time.now, response, sql, cblk, eblk, retries]
end

#notify_readable ⇒ Object 



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# File 'lib/em/mysql.rb', line 38

def notify_readable
  log 'readable'
  if item = @current
    @current = nil
    start, response, sql, cblk, eblk, retries = item
    log 'mysql response', Time.now-start, sql
    arg = case response
          when :raw
            result = @mysql.get_result
            @mysql.instance_variable_set('@cur_result', result)
            @mysql
          when :select
            ret = []
            result = @mysql.get_result
            result.each_hash{|h| ret << h }
            log 'mysql result', ret
            ret
          when :update
            result = @mysql.get_result
            @mysql.affected_rows
          when :insert
            result = @mysql.get_result
            @mysql.insert_id
          else
            result = @mysql.get_result
            log 'got a result??', result if result
            nil
          end

    @processing = false
    # result.free if result.is_a? Mysql::Result
    next_query
    cblk.call(arg) if cblk
  else
    log 'readable, but nothing queued?! probably an ERROR state'
    return close
  end
rescue Mysql::Error => e
  log 'mysql error', e.message
  if e.message =~ /Deadlock/ and retries < MAX_RETRIES_ON_DEADLOCKS
    @@queue << [response, sql, cblk, eblk, retries + 1]
    @processing = false
    next_query
  elsif DisconnectErrors.include? e.message
    @@queue << [response, sql, cblk, eblk, retries + 1]
    return close
  elsif cb = (eblk || @opts[:on_error])
    cb.call(e)
    @processing = false
    next_query
  else
    raise e
  end
# ensure
#   res.free if res.is_a? Mysql::Result
#   @processing = false
#   next_query
end

#unbind ⇒ Object 



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# File 'lib/em/mysql.rb', line 97

def unbind
  log 'mysql disconnect', $!, *($! ? $!.backtrace[0..5] : [])
  # cp = EventedMysql.instance_variable_get('@connection_pool') and cp.delete(self)
  @connected = false

  # XXX wait for the next tick until the current fd is removed completely from the reactor
  #
  # XXX in certain cases the new FD# (@mysql.socket) is the same as the old, since FDs are re-used
  # XXX without next_tick in these cases, unbind will get fired on the newly attached signature as well
  #
  # XXX do _NOT_ use EM.next_tick here. if a bunch of sockets disconnect at the same time, we want
  # XXX reconnects to happen after all the unbinds have been processed
  EM.add_timer(0) do
    log 'mysql reconnecting'
    @processing = false
    @mysql = EventedMysql._connect @opts
    @fd = @mysql.socket

    @signature = EM.attach_fd @mysql.socket, true
    EM.set_notify_readable @signature, true
    log 'mysql connected'
    EM.instance_variable_get('@conns')[@signature] = self
    @connected = true
    make_socket_blocking
    next_query
  end
end