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,
lib/mongo/session/server_session/dirtyable.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.'
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.'
SESSIONS_NOT_SUPPORTED =
Deprecated.

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

Since:

  • 2.5.0

'Sessions are not supported by the connected servers.'
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

#read_worker, #select_server, #with_overload_retry, #write_worker

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. This constructor is for internal driver use only.

Initialize a Session.

A session can be explicit or implicit. Lifetime of explicit sessions is managed by the application - applications explicitly create such sessions and explicitly end them. Implicit sessions are created automatically by the driver, and their lifetime is managed by the driver.

When an implicit session is created, it cannot have a server session associated with it. The server session will be checked out of the session pool when an operation using this session is actually executed. When an explicit session is created, it must reference a server session that is already allocated.

Parameters:

  • server_session (ServerSession | nil) —

    The server session this session is associated with. If the :implicit option is true, this must be nil.

  • 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_timeout_ms (Integer) —

    The timeoutMS value for the following operations executed on the session:

    • commitTransaction

    • abortTransaction

    • withTransaction

    • endSession

  • :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. If this is true, the server_session will be nil. This is done so that the server session is only checked out after the connection is checked out.

  • :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.

  • :snapshot (true | false) —

    Set up the session for snapshot reads.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 80

def initialize(server_session, client, options = {})
  if options[:causal_consistency] && options[:snapshot]
    raise ArgumentError, ':causal_consistency and :snapshot options cannot be both set on a session'
  end

  if options[:implicit]
    unless server_session.nil?
      raise ArgumentError, 'Implicit session cannot reference server session during construction'
    end
  elsif server_session.nil?
    raise ArgumentError, 'Explicit session must reference server session during construction'
  end

  @server_session = server_session
  options = options.dup

  # Implicit sessions only need the cluster and client options (never run
  # transactions), so avoid creating a Mongo::Client clone to prevent
  # memory leaks: use the original client directly instead.
  @client = options[:implicit] ? client : client.use(:admin)
  @cluster = @client.cluster
  @options = options.dup.freeze
  @cluster_time = nil
  @state = NO_TRANSACTION_STATE
  @with_transaction_deadline = nil
  @with_transaction_timeout_ms = nil
  @inside_with_transaction = false
end

Instance Attribute Details

#client ⇒ Client (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 117

def client
  @client
end

#cluster ⇒ Object (readonly)

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 119

def cluster
  @cluster
end

#operation_time ⇒ BSON::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 130

def operation_time
  @operation_time
end

#options ⇒ Hash (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 112

def options
  @options
end

#pinned_connection_global_id ⇒ Integer | 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 connection global id that this session is pinned to, if any.

Returns:

  • (Integer | nil) —

    The connection global id that this session is pinned to, if any.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 281

def pinned_connection_global_id
  @pinned_connection_global_id
end

#pinned_server ⇒ Server | 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 275

def pinned_server
  @pinned_server
end

#recovery_token ⇒ BSON::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 287

def recovery_token
  @recovery_token
end

#snapshot_timestamp ⇒ 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.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1270

def snapshot_timestamp
  @snapshot_timestamp
end

#with_transaction_deadline ⇒ Integer | 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 deadline for the current transaction, if any.

Returns:

  • (Integer | nil) —

    The deadline for the current transaction, if any.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1274

def with_transaction_deadline
  @with_transaction_deadline
end

Instance Method Details

#abort_transaction(options = nil) ⇒ Object

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

Examples:

Abort the transaction.

session.abort_transaction

Parameters:

  • options (Hash) (defaults to: nil) —

    a customizable set of options

Options Hash (options):

  • :timeout_ms (Integer) —

    The operation timeout in milliseconds. Must be a non-negative integer. An explicit value of 0 means infinite. The default value is unset which means the value is inherited from the client.

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 803

def abort_transaction(options = nil)
  QueryCache.clear

  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

  options ||= {}

  begin
    unless starting_transaction?
      @aborting_transaction = true
      context = Operation::Context.new(
        client: @client,
        session: self,
        operation_timeouts: operation_timeouts(options)
      )
      write_with_retry(txn_options[:write_concern],
                       ending_transaction: true, context: context) do |connection, txn_num, context|
        operation = Operation::Command.new(
          selector: { abortTransaction: 1 },
          db_name: 'admin',
          session: self,
          txn_num: txn_num
        )
        tracer.trace_operation(operation, context, op_name: 'abortTransaction') do
          operation.execute_with_connection(connection, context: context)
        end
      ensure
        unpin
      end
    end

    # Finish the transaction span before changing state
    tracer.finish_transaction_span(self)
    @state = TRANSACTION_ABORTED_STATE
  rescue Mongo::Error::InvalidTransactionOperation
    raise
  rescue Mongo::Error
    tracer.finish_transaction_span(self)
    @state = TRANSACTION_ABORTED_STATE
  rescue Exception
    tracer.finish_transaction_span(self)
    @state = TRANSACTION_ABORTED_STATE
    raise
  ensure
    @aborting_transaction = false
  end

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

#aborting_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 aborting a transaction.

Returns:

  • (true | false) —

    Whether the session is currently aborting a transaction.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 899

def aborting_transaction?
  !!@aborting_transaction
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 985

def add_autocommit!(command)
  command.tap do |c|
    c[:autocommit] = false if in_transaction?
  end
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 1000

def add_start_transaction!(command)
  command.tap do |c|
    c[:startTransaction] = true if starting_transaction?
  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 1015

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, context) ⇒ 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 1030

def add_txn_opts!(command, _read, context)
  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.
    c[:readConcern] = Options::Mapper.transform_values_to_strings(c[:readConcern]) if c[:readConcern]

    if c[:commitTransaction] && (max_time_ms = txn_options[:max_commit_time_ms])
      c[:maxTimeMS] = max_time_ms
    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] ||= 10_000
        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

    # Ignore wtimeout if csot
    c[:writeConcern]&.delete(:wtimeout) if context&.csot?

    # We must not send an empty (server default) write concern.
    c.delete(:writeConcern) if c[:writeConcern] && c[:writeConcern].empty?
  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 1209

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

  • :timeout_ms (Integer) —

    The operation timeout in milliseconds. Must be a non-negative integer. An explicit value of 0 means infinite. The default value is unset which means the value is inherited from the client.

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 717

def commit_transaction(options = nil)
  QueryCache.clear
  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]
      write_concern = WriteConcern.get(write_concern) if write_concern && !write_concern.is_a?(WriteConcern::Base)

      context = Operation::Context.new(
        client: @client,
        session: self,
        operation_timeouts: operation_timeouts(options)
      )
      write_with_retry(write_concern, ending_transaction: true,
                                      context: context) do |connection, txn_num, context|
        if context.retry? && !context.overload_only_retry?
          if write_concern
            wco = write_concern.options.merge(w: :majority)
            wco[:wtimeout] ||= 10_000
            write_concern = WriteConcern.get(wco)
          else
            write_concern = WriteConcern.get(w: :majority, wtimeout: 10_000)
          end
        end
        spec = {
          selector: { commitTransaction: 1 },
          db_name: 'admin',
          session: self,
          txn_num: txn_num,
          write_concern: write_concern,
        }
        operation = Operation::Command.new(spec)
        tracer.trace_operation(operation, context, op_name: 'commitTransaction') do
          operation.execute_with_connection(connection, context: context)
        end
      end
    end
    # Finish the transaction span before changing state
    tracer.finish_transaction_span(self)
  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 891

def committing_transaction?
  !!@committing_transaction
end

#dirty!(mark = true) ⇒ Object

Sets the dirty state to the given value for the underlying server session. If there is no server session, this does nothing.

Parameters:

  • mark (true | false) (defaults to: true) —

    whether to mark the server session as dirty, or not.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 139

def dirty!(mark = true)
  @server_session&.dirty!(mark)
end

#dirty? ⇒ true | false | 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 whether the underlying server session is dirty. If no server session exists for this session, returns nil.

Returns:

  • (true | false | nil) —

    whether the underlying server session is dirty. If no server session exists for this session, returns nil.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 147

def dirty?
  @server_session&.dirty?
end

#end_session ⇒ nil

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 374

def end_session
  if !ended? && @client
    if within_states?(TRANSACTION_IN_PROGRESS_STATE)
      begin
        abort_transaction
      rescue Mongo::Error, Error::AuthError
      end
    end
    # Release any pinned connection (e.g. after a committed transaction
    # in load-balanced mode).
    unpin if pinned_connection_global_id
    cluster.session_pool.checkin(@server_session) if @server_session
  end
ensure
  @server_session = nil
  @ended = true
  @client = 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 244

def ended?
  !!@ended
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 179

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 167

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 883

def in_transaction?
  within_states?(STARTING_TRANSACTION_STATE, TRANSACTION_IN_PROGRESS_STATE)
end

#inside_with_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 Whether we are currently inside a with_transaction block.

Returns:

  • (Boolean) —

    Whether we are currently inside a with_transaction block.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1278

def inside_with_transaction?
  @inside_with_transaction
end

#inspect ⇒ String

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 352

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

#materialize_if_needed ⇒ 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.

If not already set, populate a session objects’s server_session by checking out a session from the session pool.

Returns:

Raises:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1223

def materialize_if_needed
  raise Error::SessionEnded if ended?

  return unless implicit? && !@server_session

  @server_session = cluster.session_pool.checkout

  self
end

#materialized? ⇒ 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)

Raises:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1234

def materialized?
  raise Error::SessionEnded if ended?

  !@server_session.nil?
end

#next_txn_num ⇒ Integer

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.

Raises:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1249

def next_txn_num
  raise Error::SessionEnded if ended?

  @server_session.next_txn_num
end

#pin_to_connection(connection_global_id, connection: nil) ⇒ 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 connection.

this session to.

Parameters:

  • connection_global_id (Integer) —

    The global id of connection to pin

  • connection (Connection | nil) (defaults to: nil) —

    The connection object to pin to.

Raises:

  • (ArgumentError)

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 925

def pin_to_connection(connection_global_id, connection: nil)
  raise ArgumentError, 'Cannot pin to a nil connection id' if connection_global_id.nil?

  @pinned_connection_global_id = connection_global_id
  @pinned_connection = connection
end

#pin_to_server(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.

Raises:

  • (ArgumentError)

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 908

def pin_to_server(server)
  raise ArgumentError, 'Cannot pin to a nil server' if server.nil?

  if Lint.enabled? && !server.mongos?
    raise Error::LintError, "Attempted to pin the session to server #{server.summary} which is not a mongos"
  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 1183

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) && doc[:recoveryToken]
    self.recovery_token = doc[:recoveryToken]
  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 199

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

#retry_writes? ⇒ true, false

Note:

Retryable writes are only available with sharded clusters, replica sets, or load-balanced topologies.

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 214

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

#revert_to_starting_transaction! ⇒ 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.

Reverts the session state to STARTING_TRANSACTION_STATE. Called before retrying the first command in a transaction so that startTransaction: true is preserved on the retry.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1134

def revert_to_starting_transaction!
  return unless within_states?(TRANSACTION_IN_PROGRESS_STATE)

  @state = STARTING_TRANSACTION_STATE
end

#session_id ⇒ BSON::Document

Get the server session id of this session, if the session has not been ended. If the session had been ended, raises Error::SessionEnded.

Returns:

  • (BSON::Document) —

    The server session id.

Raises:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 256

def session_id
  raise Error::SessionEnded if ended?

  # An explicit session will always have a session_id, because during
  # construction a server session must be provided. An implicit session
  # will not have a session_id until materialized, thus calls to
  # session_id might fail. An application should not have an opportunity
  # to experience this failure because an implicit session shouldn't be
  # accessible to applications due to its lifetime being constrained to
  # operation execution, which is done entirely by the driver.
  raise Error::SessionNotMaterialized unless materialized?

  @server_session.session_id
end

#snapshot? ⇒ true | false

Returns Whether the session is configured for snapshot reads.

Returns:

  • (true | false) —

    Whether the session is configured for snapshot reads.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 123

def snapshot?
  !!options[:snapshot]
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. This option is deprecated, use :timeout_ms instead.

  • :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.

  • :timeout_ms (Integer) —

    The operation timeout in milliseconds. Must be a non-negative integer. An explicit value of 0 means infinite. The default value is unset which means the value is inherited from the client.

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 653

def start_transaction(options = nil)
  check_transactions_supported!

  if options
    Lint.validate_read_concern_option(options[:read_concern])

    #         # 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

  raise Mongo::Error::SnapshotSessionTransactionProhibited if snapshot?

  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
  tracer.start_transaction_span(self)

  # 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 871

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 1098

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_num ⇒ Integer

Get the current transaction number.

Examples:

Get the current transaction number.

session.txn_num

Returns:

  • (Integer) —

    The current transaction number.

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 1263

def txn_num
  raise Error::SessionEnded if ended?

  @server_session.txn_num
end

#txn_options ⇒ Hash

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 155

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

#txn_read_preference ⇒ Hash

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 229

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

#unpin(connection = nil) ⇒ 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 or connection, if the session was pinned.

Parameters:

  • connection (Connection | nil) (defaults to: nil) —

    Connection to unpin from.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 938

def unpin(connection = nil)
  @pinned_server = nil
  @pinned_connection_global_id = nil
  conn = connection || @pinned_connection
  if conn
    conn.unpin(:transaction)
    # Only check the connection back into the pool if nothing else
    # still holds a pin on it (e.g. an open cursor).
    unless conn.pinned?
      conn.connection_pool.check_in(conn)
    end
  end
  @pinned_connection = nil
end

#unpin_maybe(error, connection = nil) ⇒ 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 or connection, 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:

  • error (Error) —

    The exception instance to process.

  • connection (Connection | nil) (defaults to: nil) —

    Connection to unpin from.

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 964

def unpin_maybe(error, connection = nil)
  if !within_states?(Session::NO_TRANSACTION_STATE) &&
     error.label?('TransientTransactionError')
    unpin(connection)
  end

  if committing_transaction? &&
     error.label?('UnknownTransactionCommitResult')
    unpin(connection)
  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 1144

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!(client) ⇒ 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.

Validate the session for use by the specified client.

The session must not be ended and must have been created by a client with the same cluster as the client that the session is to be used with.

Parameters:

  • client (Client) —

    The client the session is to be used with.

Returns:

  • (Session) —

    self, if the session is valid.

Raises:

Since:

  • 2.5.0



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# File 'lib/mongo/session.rb', line 1166

def validate!(client)
  check_if_ended!
  check_matching_cluster!(client)
  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 is primary.

Examples:

session.validate_read_preference!(command)

Raises:

Since:

  • 2.6.0



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# File 'lib/mongo/session.rb', line 1117

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

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

  return unless mode && mode != 'primary'

  raise Mongo::Error::InvalidTransactionOperation.new(
    "read preference in a transaction must be primary (requested: #{mode})"
  )
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 447

def with_transaction(options = nil)
  @inside_with_transaction = true
  @with_transaction_timeout_ms = options&.dig(:timeout_ms) || @options[:default_timeout_ms] || @client.timeout_ms
  @with_transaction_deadline = calculate_with_transaction_deadline(options)
  deadline = if @with_transaction_deadline
               # CSOT enabled, so we have a customer defined deadline.
               @with_transaction_deadline
             else
               # CSOT not enabled, so we use the default deadline, 120 seconds.
               Utils.monotonic_time + 120
             end
  transaction_in_progress = false
  transaction_attempt = 0
  last_error = nil
  overload_error_count = 0
  overload_encountered = false

  loop do
    if transaction_attempt > 0
      if overload_encountered
        delay = @client.retry_policy.backoff_delay(overload_error_count)
        if backoff_would_exceed_deadline?(deadline, delay)
          make_timeout_error_from(last_error, 'CSOT timeout expired waiting to retry withTransaction')
        end
        raise(last_error) unless @client.retry_policy.should_retry_overload?(overload_error_count, delay)

        sleep(delay)
      else
        backoff = backoff_seconds_for_retry(transaction_attempt)
        if backoff_would_exceed_deadline?(deadline, backoff)
          make_timeout_error_from(last_error, 'CSOT timeout expired waiting to retry withTransaction')
        end

        sleep(backoff)
      end
    end

    commit_options = {}
    commit_options[:write_concern] = options[:write_concern] if options
    start_transaction(options)
    transaction_in_progress = true
    transaction_attempt += 1

    begin
      rv = yield self
    rescue Exception => e
      if within_states?(STARTING_TRANSACTION_STATE, TRANSACTION_IN_PROGRESS_STATE)
        log_warn("Aborting transaction due to #{e.class}: #{e}")
        # CSOT: if the deadline is already expired, clear it so that
        # abort_transaction uses a fresh timeout (not the expired deadline).
        # If the deadline is not yet expired, keep it so abort uses remaining time.
        @with_transaction_deadline = nil if @with_transaction_deadline && deadline_expired?(deadline)
        abort_transaction
        transaction_in_progress = false
      end

      if deadline_expired?(deadline)
        transaction_in_progress = false
        make_timeout_error_from(e, 'CSOT timeout expired during withTransaction callback')
      end

      if e.is_a?(Mongo::Error) && e.label?('TransientTransactionError')
        last_error = e
        if e.label?('SystemOverloadedError')
          overload_encountered = true
          overload_error_count += 1
        elsif overload_encountered
          overload_error_count += 1
        end
        next
      end

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

      # CSOT: if the timeout has expired before we can commit, abort the
      # transaction instead and raise a client-side timeout error.
      if @with_transaction_deadline && deadline_expired?(deadline)
        transaction_in_progress = false
        @with_transaction_deadline = nil
        abort_transaction
        raise Mongo::Error::TimeoutError, 'CSOT timeout expired before transaction could be committed'
      end

      begin
        commit_transaction(commit_options)
        transaction_in_progress = false
        return rv
      rescue Mongo::Error => e
        if e.label?('UnknownTransactionCommitResult')
          if deadline_expired?(deadline) ||
             (e.is_a?(Error::OperationFailure::Family) && e.max_time_ms_expired?)
            transaction_in_progress = false

            raise unless @with_transaction_timeout_ms && deadline_expired?(deadline)

            make_timeout_error_from(e, 'CSOT timeout expired during withTransaction commit')
          end

          if e.label?('SystemOverloadedError')
            overload_encountered = true
            overload_error_count += 1
          elsif overload_encountered
            overload_error_count += 1
          end

          if overload_encountered
            delay = @client.retry_policy.backoff_delay(overload_error_count)
            if backoff_would_exceed_deadline?(deadline, delay)
              transaction_in_progress = false
              make_timeout_error_from(e, 'CSOT timeout expired during withTransaction commit')
            end
            unless @client.retry_policy.should_retry_overload?(overload_error_count, delay)
              transaction_in_progress = false
              raise
            end
            sleep(delay)
          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 Utils.monotonic_time >= deadline
            transaction_in_progress = false
            make_timeout_error_from(e, 'CSOT timeout expired during withTransaction commit')
          end
          last_error = e
          if e.label?('SystemOverloadedError')
            overload_encountered = true
            overload_error_count += 1
          elsif overload_encountered
            overload_error_count += 1
          end
          @state = NO_TRANSACTION_STATE
          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 broke out of with_transaction loop, aborting transaction')
    begin
      abort_transaction
    rescue Error::OperationFailure::Family, Error::InvalidTransactionOperation
    end
  end
  @with_transaction_deadline = nil
  @with_transaction_timeout_ms = nil
  @inside_with_transaction = false
end