module Mongo::Retryable
Defines basic behavior around retrying operations.
@since 2.1.0
Public Instance Methods
Execute a read operation with a single retry.
@api private
@example Execute the read.
read_with_one_retry do ... end
@note This only retries read operations on socket errors.
@param [ Hash ] options Options. @param [ Proc ] block The block to execute.
@option options [ String ] :retry_message Message to log when retrying.
@return [ Result ] The result of the operation.
@since 2.2.6
# File lib/mongo/retryable.rb, line 84 def read_with_one_retry(options = nil) yield rescue Error::SocketError, Error::SocketTimeoutError => e retry_message = options && options[:retry_message] log_retry(e, message: retry_message) yield end
Execute a read operation with a retry.
@api private
@example Execute the read.
read_with_retry do ... end
@note This only retries read operations on socket errors.
@param [ Mongo::Session ] session The session that the operation is being run on. @param [ Proc ] block The block to execute.
@return [ Result ] The result of the operation.
@since 2.1.0
# File lib/mongo/retryable.rb, line 39 def read_with_retry(session = nil) attempt = 0 begin attempt += 1 yield rescue Error::SocketError, Error::SocketTimeoutError => e if attempt > cluster.max_read_retries || (session && session.in_transaction?) raise end log_retry(e) cluster.scan!(false) retry rescue Error::OperationFailure => e if cluster.sharded? && e.retryable? && !(session && session.in_transaction?) if attempt > cluster.max_read_retries raise end log_retry(e) sleep(cluster.read_retry_interval) retry else raise end end end
Implements write retrying functionality by yielding to the passed block one or more times.
If the session is provided (hence, the deployment supports sessions), and modern retry writes are enabled on the client, the modern retry logic is invoked. Otherwise the legacy retry logic is invoked.
If ending_transaction parameter is true, indicating that a transaction is being committed or aborted, the operation is executed exactly once. Note that, since transactions require sessions, this method will raise ArgumentError if ending_transaction is true and session is nil.
@api private
@example Execute the write.
write_with_retry do ... end
@note This only retries operations on not master failures, since it is
the only case we can be sure a partial write did not already occur.
@param [ nil | Session ] session Optional session to use with the operation. @param [ nil | Hash | WriteConcern::Base ] write_concern The write concern. @param [ true | false ] ending_transaction True if the write operation is abortTransaction or
commitTransaction, false otherwise.
@param [ Proc ] block The block to execute.
@yieldparam [ Server ] server The server to which the write should be sent. @yieldparam [ Integer ] txn_num Transaction number (NOT the ACID kind).
@return [ Result ] The result of the operation.
@since 2.1.0
# File lib/mongo/retryable.rb, line 126 def write_with_retry(session, write_concern, ending_transaction = false, &block) if ending_transaction && !session raise ArgumentError, 'Cannot end a transaction without a session' end unless ending_transaction || retry_write_allowed?(session, write_concern) return legacy_write_with_retry(nil, session, &block) end # If we are here, session is not nil. A session being nil would have # failed retry_write_allowed? check. server = cluster.next_primary unless ending_transaction || server.retry_writes? return legacy_write_with_retry(server, session, &block) end begin txn_num = session.in_transaction? ? session.txn_num : session.next_txn_num yield(server, txn_num, false) rescue Error::SocketError, Error::SocketTimeoutError => e if session.in_transaction? && !ending_transaction raise end retry_write(e, txn_num, &block) rescue Error::OperationFailure => e if (session.in_transaction? && !ending_transaction) || !e.write_retryable? raise end retry_write(e, txn_num, &block) end end
Private Instance Methods
# File lib/mongo/retryable.rb, line 196 def legacy_write_with_retry(server = nil, session = nil) # This is the pre-session retry logic, and is not subject to # current retryable write specifications. # In particular it does not retry on SocketError and SocketTimeoutError. attempt = 0 begin attempt += 1 yield(server || cluster.next_primary) rescue Error::OperationFailure => e server = nil if attempt > Cluster::MAX_WRITE_RETRIES raise end if e.write_retryable? && !(session && session.in_transaction?) log_retry(e) cluster.scan!(false) retry else raise end end end
Log a warning so that any application slow down is immediately obvious.
# File lib/mongo/retryable.rb, line 220 def log_retry(e, options = nil) message = if options && options[:message] options[:message] else "Retry" end Logger.logger.warn "#{message} due to: #{e.class.name} #{e.message}" end
# File lib/mongo/retryable.rb, line 177 def retry_write(original_error, txn_num, &block) # We do not request a scan of the cluster here, because error handling # for the error which triggered the retry should have updated the # server description and/or topology as necessary (specifically, # a socket error or a not master error should have marked the respective # server unknown). Here we just need to wait for server selection. server = cluster.next_primary raise original_error unless (server.retry_writes? && txn_num) log_retry(original_error) yield(server, txn_num, true) rescue Error::SocketError, Error::SocketTimeoutError => e raise e rescue Error::OperationFailure => e raise original_error unless e.write_retryable? raise e rescue raise original_error end
# File lib/mongo/retryable.rb, line 162 def retry_write_allowed?(session, write_concern) unless session && session.retry_writes? return false end if write_concern.nil? true else unless write_concern.is_a?(WriteConcern::Base) write_concern = WriteConcern.get(write_concern) end write_concern.acknowledged? end end