Module: Activerecord::Mysql::Reconnect

Defined in:
lib/activerecord/mysql/reconnect/version.rb,
lib/activerecord/mysql/reconnect.rb

Defined Under Namespace

Modules: ExecuteWithReconnect, NewConnectionWithRetry, NullTransactionExt, ReconnectWithRetry

Constant Summary collapse

VERSION = 
'0.6.0'
DEFAULT_EXECUTION_TRIES = 
3
DEFAULT_EXECUTION_RETRY_WAIT = 
0.5
WITHOUT_RETRY_KEY = 
'activerecord-mysql-reconnect-without-retry'
HANDLE_ERROR = 
[
  ActiveRecord::StatementInvalid,
  Mysql2::Error,
  ActiveRecord::ConnectionNotEstablished
]
READ_SQL_REGEXP = 
/\A\s*(?:SELECT|SHOW|SET)\b/i
RETRY_MODES = 
[:r, :rw, :force]
DEFAULT_RETRY_MODE = 
:r
@@handle_r_error_messages = 
{
  lost_connection: 'Lost connection to MySQL server during query',
}
@@handle_rw_error_messages = 
{
  gone_away: 'MySQL server has gone away',
  server_shutdown: 'Server shutdown in progress',
  closed_connection: 'closed MySQL connection',
  cannot_connect: "Can't connect to MySQL server",
  interrupted: 'Query execution was interrupted',
  access_denied: 'Access denied for user',
  read_only: 'The MySQL server is running with the --read-only option',
  cannot_connect_to_local: "Can't connect to local MySQL server", # When running in local sandbox, or using a socket file
  unknown_host: 'Unknown MySQL server host', # For DNS blips
  lost_connection: "Lost connection to MySQL server at 'reading initial communication packet'",
  not_connected: "MySQL client is not connected",
  killed: 'Connection was killed',
}

Class Method Summary collapse

Class Method Details

.enable_retry ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 75

def enable_retry
  !!ActiveRecord::Base.enable_retry
end

.execution_retry_wait ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 70

def execution_retry_wait
  wait = ActiveRecord::Base.execution_retry_wait || DEFAULT_EXECUTION_RETRY_WAIT
  wait.kind_of?(BigDecimal) ? wait : BigDecimal(wait.to_s)
end

.execution_tries ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 66

def execution_tries
  ActiveRecord::Base.execution_tries || DEFAULT_EXECUTION_TRIES
end

.handle_r_error_messages ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 58

def handle_r_error_messages
  @@handle_r_error_messages
end

.handle_rw_error_messages ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 62

def handle_rw_error_messages
  @@handle_rw_error_messages
end

.logger ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 152

def logger
  if defined?(Rails)
    Rails.logger || ActiveRecord::Base.logger || Logger.new($stderr)
  else
    ActiveRecord::Base.logger || Logger.new($stderr)
  end
end

.retry_databases ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 115

def retry_databases
  @activerecord_mysql_reconnect_retry_databases || []
end

.retry_databases=(v) ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 91

def retry_databases=(v)
  v ||= []

  unless v.kind_of?(Array)
    v = [v]
  end

  @activerecord_mysql_reconnect_retry_databases = v.map do |database|
    if database.instance_of?(Symbol)
      database = Regexp.escape(database.to_s)
      [/.*/, /\A#{database}\z/]
    else
      host = '%'
      database = database.to_s

      if database =~ /:/
        host, database = database.split(':', 2)
      end

      [create_pattern_match_regex(host), create_pattern_match_regex(database)]
    end
  end
end

.retry_mode ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 87

def retry_mode
  @activerecord_mysql_reconnect_retry_mode || DEFAULT_RETRY_MODE
end

.retry_mode=(v) ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 79

def retry_mode=(v)
  unless RETRY_MODES.include?(v)
    raise "Invalid retry_mode. Please set one of the following: #{RETRY_MODES.map {|i| i.inspect }.join(', ')}"
  end

  @activerecord_mysql_reconnect_retry_mode = v
end

.retryable(opts) ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 119

def retryable(opts)
  block     = opts.fetch(:proc)
  on_error  = opts[:on_error]
  conn      = opts[:connection]
  sql       = opts[:sql]
  tries     = self.execution_tries
  retval    = nil

  retryable_loop(tries) do |n|
    begin
      retval = block.call
      break
    rescue => e
      if enable_retry and (tries.zero? or n < tries) and should_handle?(e, opts)
        on_error.call if on_error
        wait = self.execution_retry_wait * n

        logger.warn("MySQL server has gone away. Trying to reconnect in #{wait.to_f} seconds. (#{build_error_message(e, sql, conn)})")
        sleep(wait)
        next
      else
        if enable_retry and n > 1
          logger.warn("Query retry failed. (#{build_error_message(e, sql, conn)})")
        end

        raise e
      end
    end
  end

  return retval
end

.without_retry ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 160

def without_retry
  begin
    Thread.current[WITHOUT_RETRY_KEY] = true
    yield
  ensure
    Thread.current[WITHOUT_RETRY_KEY] = nil
  end
end

.without_retry? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/activerecord/mysql/reconnect.rb', line 169

def without_retry?
  !!Thread.current[WITHOUT_RETRY_KEY]
end