Class: Mongo::Session

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
ClusterTime::Consumer, Loggable, Retryable
Defined in:
lib/mongo/session.rb,
lib/mongo/session/session_pool.rb,
lib/mongo/session/server_session.rb

Overview

Note:

Session objects are not thread-safe. An application may use a session from only one thread or process at a time.

A logical session representing a set of sequential operations executed by an application that are related in some way.

Since:

  • 2.5.0

Defined Under Namespace

Classes: ServerSession, SessionPool

Constant Summary collapse

MISMATCHED_CLUSTER_ERROR_MSG =

Error message indicating that the session was retrieved from a client with a different cluster than that of the client through which it is currently being used.

Since:

  • 2.5.0

'The configuration of the client used to create this session does not match that ' +
'of the client owning this operation. Please only use this session for operations through its parent ' +
'client.'.freeze
SESSION_ENDED_ERROR_MSG =

Error message describing that the session cannot be used because it has already been ended.

Since:

  • 2.5.0

'This session has ended and cannot be used. Please create a new one.'.freeze
SESSIONS_NOT_SUPPORTED =

Error message describing that sessions are not supported by the server version.

Since:

  • 2.5.0

'Sessions are not supported by the connected servers.'.freeze
NO_TRANSACTION_STATE =

The state of a session in which the last operation was not related to any transaction or no operations have yet occurred.

Since:

  • 2.6.0

:no_transaction
STARTING_TRANSACTION_STATE =

The state of a session in which a user has initiated a transaction but no operations within the transactions have occurred yet.

Since:

  • 2.6.0

:starting_transaction
TRANSACTION_IN_PROGRESS_STATE =

The state of a session in which a transaction has been started and at least one operation has occurred, but the transaction has not yet been committed or aborted.

Since:

  • 2.6.0

:transaction_in_progress
TRANSACTION_COMMITTED_STATE =

The state of a session in which the last operation executed was a transaction commit.

Since:

  • 2.6.0

:transaction_committed
TRANSACTION_ABORTED_STATE =

The state of a session in which the last operation executed was a transaction abort.

Since:

  • 2.6.0

:transaction_aborted
UNLABELED_WRITE_CONCERN_CODES =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Since:

  • 2.5.0

[
  79,  # UnknownReplWriteConcern
  100, # CannotSatisfyWriteConcern,
].freeze

Constants included from Loggable

Loggable::PREFIX

Instance Attribute Summary collapse

Attributes included from ClusterTime::Consumer

#cluster_time

Instance Method Summary collapse

Methods included from ClusterTime::Consumer

#advance_cluster_time

Methods included from Loggable

#log_debug, #log_error, #log_fatal, #log_info, #log_warn, #logger

Methods included from Retryable

#legacy_write_with_retry, #nro_write_with_retry, #read_with_one_retry, #read_with_retry, #read_with_retry_cursor, #write_with_retry

Constructor Details

#initialize(server_session, client, options = {}) ⇒ Session

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Note:

Applications should use Client#start_session to begin a session.

Initialize a Session.

Examples:

Session.new(server_session, client, options)

Parameters:

  • server_session (ServerSession)

    The server session this session is associated with.

  • client (Client)

    The client through which this session is created.

  • options (Hash) (defaults to: {})

    The options for this session.

Options Hash (options):

  • :causal_consistency (true|false)

    Whether to enable causal consistency for this session.

  • :default_transaction_options (Hash)

    Options to pass to start_transaction by default, can contain any of the options that start_transaction accepts.

  • :implicit (true|false)

    For internal driver use only - specifies whether the session is implicit.

  • :read_preference (Hash)

    The read preference options hash, with the following optional keys:

    • :mode – the read preference as a string or symbol; valid values are :primary, :primary_preferred, :secondary, :secondary_preferred and :nearest.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 59

def initialize(server_session, client, options = {})
  @server_session = server_session
  options = options.dup

  @client = client.use(:admin)
  @options = options.freeze
  @cluster_time = nil
  @state = NO_TRANSACTION_STATE
end

Instance Attribute Details

#clientClient (readonly)

Returns The client through which this session was created.

Returns:

  • (Client)

    The client through which this session was created.

Since:

  • 2.5.1



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# File 'lib/mongo/session.rb', line 77

def client
  @client
end

#operation_timeBSON::Timestamp (readonly)

Returns The latest seen operation time for this session.

Returns:

  • (BSON::Timestamp)

    The latest seen operation time for this session.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 86

def operation_time
  @operation_time
end

#optionsHash (readonly)

Returns The options for this session.

Returns:

  • (Hash)

    The options for this session.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 72

def options
  @options
end

#pinned_serverServer | nil (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns The server (which should be a mongos) that this session is pinned to, if any.

Returns:

  • (Server | nil)

    The server (which should be a mongos) that this session is pinned to, if any.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 206

def pinned_server
  @pinned_server
end

#recovery_tokenBSON::Document | nil

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns Recovery token for the sharded transaction being executed on this session, if any.

Returns:

  • (BSON::Document | nil)

    Recovery token for the sharded transaction being executed on this session, if any.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 212

def recovery_token
  @recovery_token
end

Instance Method Details

#abort_transactionObject

Abort the currently active transaction without making any changes to the database.

Examples:

Abort the transaction.

session.abort_transaction

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 602

def abort_transaction
  check_if_ended!
  check_if_no_transaction!

  if within_states?(TRANSACTION_COMMITTED_STATE)
    raise Mongo::Error::InvalidTransactionOperation.new(
      Mongo::Error::InvalidTransactionOperation.cannot_call_after_msg(
        :commitTransaction, :abortTransaction))
  end

  if within_states?(TRANSACTION_ABORTED_STATE)
    raise Mongo::Error::InvalidTransactionOperation.new(
      Mongo::Error::InvalidTransactionOperation.cannot_call_twice_msg(:abortTransaction))
  end

  begin
    unless starting_transaction?
      write_with_retry(self, txn_options[:write_concern], true) do |server, txn_num|
        Operation::Command.new(
          selector: { abortTransaction: 1 },
          db_name: 'admin',
          session: self,
          txn_num: txn_num
        ).execute(server)
      end
    end

    @state = TRANSACTION_ABORTED_STATE
  rescue Mongo::Error::InvalidTransactionOperation
    raise
  rescue Mongo::Error
    @state = TRANSACTION_ABORTED_STATE
  rescue Exception
    @state = TRANSACTION_ABORTED_STATE
    raise
  end

  # No official return value, but return true so that in interactive
  # use the method hints that it succeeded.
  true
end

#add_autocommit!(command) ⇒ Hash, BSON::Document

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Add the autocommit field to a command document if applicable.

Examples:

session.add_autocommit!(cmd)

Returns:

  • (Hash, BSON::Document)

    The command document.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 726

def add_autocommit!(command)
  command.tap do |c|
    c[:autocommit] = false if in_transaction?
  end
end

#add_id!(command) ⇒ Hash, BSON::Document

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Add this session's id to a command document.

Examples:

session.add_id!(cmd)

Returns:

  • (Hash, BSON::Document)

    The command document.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 741

def add_id!(command)
  command.merge!(lsid: session_id)
end

#add_start_transaction!(command) ⇒ Hash, BSON::Document

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Add the startTransaction field to a command document if applicable.

Examples:

session.add_start_transaction!(cmd)

Returns:

  • (Hash, BSON::Document)

    The command document.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 754

def add_start_transaction!(command)
  command.tap do |c|
    if starting_transaction?
      c[:startTransaction] = true
    end
  end
end

#add_txn_num!(command) ⇒ Hash, BSON::Document

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Add the transaction number to a command document if applicable.

Examples:

session.add_txn_num!(cmd)

Returns:

  • (Hash, BSON::Document)

    The command document.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 771

def add_txn_num!(command)
  command.tap do |c|
    c[:txnNumber] = BSON::Int64.new(@server_session.txn_num) if in_transaction?
  end
end

#add_txn_opts!(command, read) ⇒ Hash, BSON::Document

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Add the transactions options if applicable.

Examples:

session.add_txn_opts!(cmd)

Returns:

  • (Hash, BSON::Document)

    The command document.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 786

def add_txn_opts!(command, read)
  command.tap do |c|
    # The read concern should be added to any command that starts a transaction.
    if starting_transaction?
      # https://jira.mongodb.org/browse/SPEC-1161: transaction's
      # read concern overrides collection/database/client read concerns,
      # even if transaction's read concern is not set.
      # Read concern here is the one sent to the server and may
      # include afterClusterTime.
      if rc = c[:readConcern]
        rc = rc.dup
        rc.delete(:level)
      end
      if txn_read_concern
        if rc
          rc.update(txn_read_concern)
        else
          rc = txn_read_concern.dup
        end
      end
      if rc.nil? || rc.empty?
        c.delete(:readConcern)
      else
        c[:readConcern ] = Options::Mapper.transform_values_to_strings(rc)
      end
    end

    # We need to send the read concern level as a string rather than a symbol.
    if c[:readConcern]
      c[:readConcern] = Options::Mapper.transform_values_to_strings(c[:readConcern])
    end

    if c[:commitTransaction]
      if max_time_ms = txn_options[:max_commit_time_ms]
        c[:maxTimeMS] = max_time_ms
      end
    end

    # The write concern should be added to any abortTransaction or commitTransaction command.
    if (c[:abortTransaction] || c[:commitTransaction])
      if @already_committed
        wc = BSON::Document.new(c[:writeConcern] || txn_write_concern || {})
        wc.merge!(w: :majority)
        wc[:wtimeout] ||= 10000
        c[:writeConcern] = wc
      elsif txn_write_concern
        c[:writeConcern] ||= txn_write_concern
      end
    end

    # A non-numeric write concern w value needs to be sent as a string rather than a symbol.
    if c[:writeConcern] && c[:writeConcern][:w] && c[:writeConcern][:w].is_a?(Symbol)
      c[:writeConcern][:w] = c[:writeConcern][:w].to_s
    end
  end
end

#advance_operation_time(new_operation_time) ⇒ BSON::Timestamp

Advance the cached operation time for this session.

Examples:

Advance the operation time.

session.advance_operation_time(timestamp)

Parameters:

  • new_operation_time (BSON::Timestamp)

    The new operation time.

Returns:

  • (BSON::Timestamp)

    The max operation time, considering the current and new times.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 955

def advance_operation_time(new_operation_time)
  if @operation_time
    @operation_time = [ @operation_time, new_operation_time ].max
  else
    @operation_time = new_operation_time
  end
end

#clusterObject

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 79

def cluster
  @client.cluster
end

#commit_transaction(options = nil) ⇒ Object

Commit the currently active transaction on the session.

Examples:

Commits the transaction.

session.commit_transaction

Parameters:

  • options (Hash) (defaults to: nil)

    a customizable set of options

Options Hash (options):

  • :write_concern (nil | WriteConcern::Base)

    The write concern to use for this operation.

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 534

def commit_transaction(options=nil)
  check_if_ended!
  check_if_no_transaction!

  if within_states?(TRANSACTION_ABORTED_STATE)
    raise Mongo::Error::InvalidTransactionOperation.new(
      Mongo::Error::InvalidTransactionOperation.cannot_call_after_msg(
        :abortTransaction, :commitTransaction))
  end

  options ||= {}

  begin
    # If commitTransaction is called twice, we need to run the same commit
    # operation again, so we revert the session to the previous state.
    if within_states?(TRANSACTION_COMMITTED_STATE)
      @state = @last_commit_skipped ? STARTING_TRANSACTION_STATE : TRANSACTION_IN_PROGRESS_STATE
      @already_committed = true
    end

    if starting_transaction?
      @last_commit_skipped = true
    else
      @last_commit_skipped = false
      @committing_transaction = true

      write_concern = options[:write_concern] || txn_options[:write_concern]
      if write_concern && !write_concern.is_a?(WriteConcern::Base)
        write_concern = WriteConcern.get(write_concern)
      end
      write_with_retry(self, write_concern, true) do |server, txn_num, is_retry|
        if is_retry
          if write_concern
            wco = write_concern.options.merge(w: :majority)
            wco[:wtimeout] ||= 10000
            write_concern = WriteConcern.get(wco)
          else
            write_concern = WriteConcern.get(w: :majority, wtimeout: 10000)
          end
        end
        spec = {
          selector: { commitTransaction: 1 },
          db_name: 'admin',
          session: self,
          txn_num: txn_num,
          write_concern: write_concern,
        }
        Operation::Command.new(spec).execute(server)
      end
    end
  ensure
    @state = TRANSACTION_COMMITTED_STATE
    @committing_transaction = false
  end

  # No official return value, but return true so that in interactive
  # use the method hints that it succeeded.
  true
end

#committing_transaction?true | false

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns Whether the session is currently committing a transaction.

Returns:

  • (true | false)

    Whether the session is currently committing a transaction.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 665

def committing_transaction?
  !!@committing_transaction
end

#end_sessionnil

End this session.

If there is an in-progress transaction on this session, the transaction is aborted. The server session associated with this session is returned to the server session pool. Finally, this session is marked ended and is no longer usable.

If this session is already ended, this method does nothing.

Note that this method does not directly issue an endSessions command to this server, contrary to what its name might suggest.

Examples:

session.end_session

Returns:

  • (nil)

    Always nil.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 297

def end_session
  if !ended? && @client
    if within_states?(TRANSACTION_IN_PROGRESS_STATE)
      begin
        abort_transaction
      rescue Mongo::Error, Error::AuthError
      end
    end
    @client.cluster.session_pool.checkin(@server_session)
  end
ensure
  @server_session = nil
end

#ended?true, false

Whether this session has ended.

Examples:

session.ended?

Returns:

  • (true, false)

    Whether the session has ended.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 181

def ended?
  @server_session.nil?
end

#explicit?true, false

Is this session an explicit one (i.e. user-created).

Examples:

Is the session explicit?

session.explicit?

Returns:

  • (true, false)

    Whether this session is explicit.

Since:

  • 2.5.2



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# File 'lib/mongo/session.rb', line 116

def explicit?
  !implicit?
end

#implicit?true, false

Is this session an implicit one (not user-created).

Examples:

Is the session implicit?

session.implicit?

Returns:

  • (true, false)

    Whether this session is implicit.

Since:

  • 2.5.1



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# File 'lib/mongo/session.rb', line 104

def implicit?
  @implicit ||= !!(@options.key?(:implicit) && @options[:implicit] == true)
end

#in_transaction?true | false

Whether or not the session is currently in a transaction.

Examples:

Is the session in a transaction?

session.in_transaction?

Returns:

  • (true | false)

    Whether or not the session in a transaction.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 657

def in_transaction?
  within_states?(STARTING_TRANSACTION_STATE, TRANSACTION_IN_PROGRESS_STATE)
end

#inspectString

Get a formatted string for use in inspection.

Examples:

Inspect the session object.

session.inspect

Returns:

  • (String)

    The session inspection.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 275

def inspect
  "#<Mongo::Session:0x#{object_id} session_id=#{session_id} options=#{@options}>"
end

#next_txn_numInteger

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Increment and return the next transaction number.

Examples:

Get the next transaction number.

session.next_txn_num

Returns:

  • (Integer)

    The next transaction number.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 972

def next_txn_num
  if ended?
    raise Error::SessionEnded
  end

  @server_session.next_txn_num
end

#pin(server) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Pins this session to the specified server, which should be a mongos.

Parameters:

  • server (Server)

    The server to pin this session to.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 674

def pin(server)
  if server.nil?
    raise ArgumentError, 'Cannot pin to a nil server'
  end
  if Lint.enabled?
    unless server.mongos?
      raise Error::LintError, "Attempted to pin the session to server #{server.summary} which is not a mongos"
    end
  end
  @pinned_server = server
end

#process(result) ⇒ Operation::Result

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Process a response from the server that used this session.

Examples:

Process a response from the server.

session.process(result)

Parameters:

Returns:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 927

def process(result)
  unless implicit?
    set_operation_time(result)
    if cluster_time_doc = result.cluster_time
      advance_cluster_time(cluster_time_doc)
    end
  end
  @server_session.set_last_use!

  if doc = result.reply && result.reply.documents.first
    if doc[:recoveryToken]
      self.recovery_token = doc[:recoveryToken]
    end
  end

  result
end

#retry_reads?Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Whether reads executed with this session can be retried according to the modern retryable reads specification.

If this method returns true, the modern retryable reads have been requested by the application. If the server selected for a read operation supports modern retryable reads, they will be used for that particular operation. If the server selected for a read operation does not support modern retryable reads, the read will not be retried.

If this method returns false, legacy retryable reads have been requested by the application. Legacy retryable read logic will be used regardless of server version of the server(s) that the client is connected to. The number of read retries is given by :max_read_retries client option, which is 1 by default and can be set to 0 to disable legacy read retries.

Returns:

  • (Boolean)

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 136

def retry_reads?
  client.options[:retry_reads] != false
end

#retry_writes?true, false

Note:

Retryable writes are only available on server versions at least 3.6 and with sharded clusters or replica sets.

Will writes executed with this session be retried.

Examples:

Will writes be retried.

session.retry_writes?

Returns:

  • (true, false)

    If writes will be retried.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 151

def retry_writes?
  !!client.options[:retry_writes] && (cluster.replica_set? || cluster.sharded?)
end

#session_idBSON::Document

Get the server session id of this session, if the session was not ended. If the session was ended, returns nil.

Examples:

Get the session id.

session.session_id

Returns:

  • (BSON::Document)

    The server session id.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 194

def session_id
  if ended?
    raise Error::SessionEnded
  end

  @server_session.session_id
end

#start_transaction(options = nil) ⇒ Object

Places subsequent operations in this session into a new transaction.

Note that the transaction will not be started on the server until an operation is performed after start_transaction is called.

Examples:

Start a new transaction

session.start_transaction(options)

Parameters:

  • options (Hash) (defaults to: nil)

    The options for the transaction being started.

Options Hash (options):

  • :max_commit_time_ms (Integer)

    The maximum amount of time to allow a single commitTransaction command to run, in milliseconds.

  • read_concern (Hash)

    The read concern options hash, with the following optional keys:

    • :level – the read preference level as a symbol; valid values

      are *:local*, *:majority*, and *:snapshot*
      
  • :write_concern (Hash)

    The write concern options. Can be :w => Integer|String, :fsync => Boolean, :j => Boolean.

  • :read (Hash)

    The read preference options. The hash may have the following items:

    • :mode – read preference specified as a symbol; the only valid value is :primary.

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 479

def start_transaction(options = nil)
  if options
    Lint.validate_read_concern_option(options[:read_concern])

=begin
    # It would be handy to detect invalid read preferences here, but
    # some of the spec tests require later detection of invalid read prefs.
    # Maybe we can do this when lint mode is on.
    mode = options[:read] && options[:read][:mode].to_s
    if mode && mode != 'primary'
      raise Mongo::Error::InvalidTransactionOperation.new(
        "read preference in a transaction must be primary (requested: #{mode})"
      )
    end
=end
  end

  check_if_ended!

  if within_states?(STARTING_TRANSACTION_STATE, TRANSACTION_IN_PROGRESS_STATE)
    raise Mongo::Error::InvalidTransactionOperation.new(
      Mongo::Error::InvalidTransactionOperation::TRANSACTION_ALREADY_IN_PROGRESS)
  end

  unpin

  next_txn_num
  @txn_options = (@options[:default_transaction_options] || {}).merge(options || {})

  if txn_write_concern && !WriteConcern.get(txn_write_concern).acknowledged?
    raise Mongo::Error::InvalidTransactionOperation.new(
      Mongo::Error::InvalidTransactionOperation::UNACKNOWLEDGED_WRITE_CONCERN)
  end

  @state = STARTING_TRANSACTION_STATE
  @already_committed = false

  # This method has no explicit return value.
  # We could return nil here but true indicates to the user that the
  # operation succeeded. This is intended for interactive use.
  # Note that the return value is not documented.
  true
end

#starting_transaction?Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns:

  • (Boolean)

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 645

def starting_transaction?
  within_states?(STARTING_TRANSACTION_STATE)
end

#suppress_read_write_concern!(command) ⇒ Hash, BSON::Document

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Remove the read concern and/or write concern from the command if not applicable.

Examples:

session.suppress_read_write_concern!(cmd)

Returns:

  • (Hash, BSON::Document)

    The command document.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 852

def suppress_read_write_concern!(command)
  command.tap do |c|
    next unless in_transaction?

    c.delete(:readConcern) unless starting_transaction?
    c.delete(:writeConcern) unless c[:commitTransaction] || c[:abortTransaction]
  end
end

#txn_numInteger

Get the current transaction number.

Examples:

Get the current transaction number.

session.txn_num

Returns:

  • (Integer)

    The current transaction number.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 988

def txn_num
  if ended?
    raise Error::SessionEnded
  end

  @server_session.txn_num
end

#txn_optionsHash

on this session.

Returns:

  • (Hash)

    The options for the transaction currently being executed

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 92

def txn_options
  @txn_options or raise ArgumentError, "There is no active transaction"
end

#txn_read_preferenceHash

Get the read preference the session will use in the currently active transaction.

This is a driver style hash with underscore keys.

Examples:

Get the transaction's read preference

session.txn_read_preference

Returns:

  • (Hash)

    The read preference of the transaction.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 166

def txn_read_preference
  rp = txn_options[:read] ||
    @client.read_preference
  Mongo::Lint.validate_underscore_read_preference(rp)
  rp
end

#unpinObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Unpins this session from the pinned server, if the session was pinned.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 689

def unpin
  @pinned_server = nil
end

#unpin_maybe(error) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Unpins this session from the pinned server, if the session was pinned and the specified exception instance and the session's transaction state require it to be unpinned.

The exception instance should already have all of the labels set on it (both client- and server-side generated ones).

Parameters:

  • The (Error)

    exception instance to process.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 703

def unpin_maybe(error)
  if !within_states?(Session::NO_TRANSACTION_STATE) &&
    error.label?('TransientTransactionError')
  then
    unpin
  end

  if committing_transaction? &&
    error.label?('UnknownTransactionCommitResult')
  then
    unpin
  end
end

#update_state!Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Update the state of the session due to a (non-commit and non-abort) operation being run.

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 888

def update_state!
  case @state
  when STARTING_TRANSACTION_STATE
    @state = TRANSACTION_IN_PROGRESS_STATE
  when TRANSACTION_COMMITTED_STATE, TRANSACTION_ABORTED_STATE
    @state = NO_TRANSACTION_STATE
  end
end

#validate!(cluster) ⇒ nil

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Validate the session.

Examples:

session.validate!(cluster)

Parameters:

  • cluster (Cluster)

    The cluster the session is attempted to be used with.

Returns:

  • (nil)

    nil if the session is valid.

Raises:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 910

def validate!(cluster)
  check_matching_cluster!(cluster)
  check_if_ended!
  self
end

#validate_read_preference!(command) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Ensure that the read preference of a command primary.

Examples:

session.validate_read_preference!(command)

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 871

def validate_read_preference!(command)
  return unless in_transaction?
  return unless command['$readPreference']

  mode = command['$readPreference']['mode'] || command['$readPreference'][:mode]

  if mode && mode != 'primary'
    raise Mongo::Error::InvalidTransactionOperation.new(
      "read preference in a transaction must be primary (requested: #{mode})"
    )
  end
end

#with_transaction(options = nil) ⇒ Object

Note:

with_transaction contains a loop, therefore the if with_transaction itself is placed in a loop, its block should not call next or break to control the outer loop because this will instead affect the loop in with_transaction. The driver will warn and abort the transaction if it detects this situation.

Executes the provided block in a transaction, retrying as necessary.

Returns the return value of the block.

Exact number of retries and when they are performed are implementation details of the driver; the provided block should be idempotent, and should be prepared to be called more than once. The driver may retry the commit command within an active transaction or it may repeat the transaction and invoke the block again, depending on the error encountered if any. Note also that the retries may be executed against different servers.

Transactions cannot be nested - InvalidTransactionOperation will be raised if this method is called when the session already has an active transaction.

Exceptions raised by the block which are not derived from Mongo::Error stop processing, abort the transaction and are propagated out of with_transaction. Exceptions derived from Mongo::Error may be handled by with_transaction, resulting in retries of the process.

Currently, with_transaction will retry commits and block invocations until at least 120 seconds have passed since with_transaction started executing. This timeout is not configurable and may change in a future driver version.

Examples:

Execute a statement in a transaction

session.with_transaction(write_concern: {w: :majority}) do
  collection.update_one({ id: 3 }, { '$set' => { status: 'Inactive'} },
                        session: session)

end

Execute a statement in a transaction, limiting total time consumed

Timeout.timeout(5) do
  session.with_transaction(write_concern: {w: :majority}) do
    collection.update_one({ id: 3 }, { '$set' => { status: 'Inactive'} },
                          session: session)

  end
end

Parameters:

  • options (Hash) (defaults to: nil)

    The options for the transaction being started. These are the same options that start_transaction accepts.

Raises:

Since:

  • 2.7.0



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# File 'lib/mongo/session.rb', line 365

def with_transaction(options=nil)
  # Non-configurable 120 second timeout for the entire operation
  deadline = Time.now + 120
  transaction_in_progress = false
  loop do
    commit_options = {}
    if options
      commit_options[:write_concern] = options[:write_concern]
    end
    start_transaction(options)
    transaction_in_progress = true
    begin
      rv = yield self
    rescue Exception => e
      if within_states?(STARTING_TRANSACTION_STATE, TRANSACTION_IN_PROGRESS_STATE)
        abort_transaction
        transaction_in_progress = false
      end

      if Time.now >= deadline
        transaction_in_progress = false
        raise
      end

      if e.is_a?(Mongo::Error) && e.label?('TransientTransactionError')
        next
      end

      raise
    else
      if within_states?(TRANSACTION_ABORTED_STATE, NO_TRANSACTION_STATE, TRANSACTION_COMMITTED_STATE)
        transaction_in_progress = false
        return rv
      end

      begin
        commit_transaction(commit_options)
        transaction_in_progress = false
        return rv
      rescue Mongo::Error => e
        if e.label?('UnknownTransactionCommitResult')
          if Time.now >= deadline ||
            e.is_a?(Error::OperationFailure) && e.max_time_ms_expired?
          then
            transaction_in_progress = false
            raise
          end
          wc_options = case v = commit_options[:write_concern]
            when WriteConcern::Base
              v.options
            when nil
              {}
            else
              v
            end
          commit_options[:write_concern] = wc_options.merge(w: :majority)
          retry
        elsif e.label?('TransientTransactionError')
          if Time.now >= deadline
            transaction_in_progress = false
            raise
          end
          next
        else
          transaction_in_progress = false
          raise
        end
      rescue Error::AuthError
        transaction_in_progress = false
        raise
      end
    end
  end

  # No official return value, but return true so that in interactive
  # use the method hints that it succeeded.
  true
ensure
  if transaction_in_progress
    log_warn('with_transaction callback altered with_transaction loop, aborting transaction')
    begin
      abort_transaction
    rescue Error::OperationFailure, Error::InvalidTransactionOperation
    end
  end
end