Module: Activerecord::Mysql::Reconnect

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

Constant Summary collapse

VERSION = 
'0.3.1'
DEFAULT_EXECUTION_TRIES = 
3
DEFAULT_EXECUTION_RETRY_WAIT = 
0.5
WITHOUT_RETRY_KEY = 
'activerecord-mysql-reconnect-without-retry'
RETRYABLE_TRANSACTION_KEY = 
'activerecord-mysql-reconnect-transaction-retry'
HANDLE_ERROR = 
[
  ActiveRecord::StatementInvalid,
  Mysql2::Error,
]
HANDLE_R_ERROR_MESSAGES = 
[
  'Lost connection to MySQL server during query',
]
HANDLE_RW_ERROR_MESSAGES = 
[
  'MySQL server has gone away',
  'Server shutdown in progress',
  'closed MySQL connection',
  "Can't connect to MySQL server",
  'Query execution was interrupted',
  'Access denied for user',
]
HANDLE_ERROR_MESSAGES = 
HANDLE_R_ERROR_MESSAGES + HANDLE_RW_ERROR_MESSAGES
READ_SQL_REGEXP = 
/\A\s*(?:SELECT|SHOW|SET)\b/i
RETRY_MODES = 
[:r, :rw, :force]
DEFAULT_RETRY_MODE = 
:r

Class Method Summary collapse

Class Method Details

.enable_retry ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 61

def enable_retry
  !!ActiveRecord::Base.enable_retry
end

.execution_retry_wait ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 57

def execution_retry_wait
  ActiveRecord::Base.execution_retry_wait || DEFAULT_EXECUTION_RETRY_WAIT
end

.execution_tries ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 53

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

.logger ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 111

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

.retry_mode ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 73

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 65

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 77

def retryable(opts)
  block     = opts.fetch(:proc)
  on_error  = opts[:on_error]
  conn      = opts[:connection]
  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

        opt_msgs = ["cause: #{e} [#{e.class}]"]

        if conn and conn.kind_of?(Mysql2::Client)
          opt_msgs << 'connection: ' + [:host, :database, :username].map {|k| "#{k}=#{conn.query_options[k]}" }.join(";")
        end

        logger.warn("MySQL server has gone away. Trying to reconnect in #{wait} seconds. (#{opt_msgs.join(', ')})")
        sleep(wait)
        next
      else
        raise e
      end
    end
  end

  return retval
end

.retryable_transaction ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 132

def retryable_transaction
  begin
    Thread.current[RETRYABLE_TRANSACTION_KEY] = []

    ActiveRecord::Base.transaction do
      yield
    end
  ensure
    Thread.current[RETRYABLE_TRANSACTION_KEY] = nil
  end
end

.retryable_transaction_buffer ⇒ Object 



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# File 'lib/activerecord/mysql/reconnect.rb', line 144

def retryable_transaction_buffer
  Thread.current[RETRYABLE_TRANSACTION_KEY]
end

.without_retry ⇒ Object 



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

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 128

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