class Mongo::Server::ConnectionPool
Represents a connection pool for server connections.
@since 2.0.0, largely rewritten in 2.9.0
Constants
- DEFAULT_MAX_SIZE
The default max size for the connection pool.
@since 2.9.0
- DEFAULT_MIN_SIZE
The default min size for the connection pool.
@since 2.9.0
- DEFAULT_WAIT_TIMEOUT
The default timeout, in seconds, to wait for a connection.
This timeout applies while in flow threads are waiting for background threads to establish connections (and hence they must connect, handshake and auth in the allotted time).
It is currently set to 10 seconds. The default connect timeout is 10 seconds by itself, but setting large timeouts can get applications in trouble if their requests get timed out by the reverse proxy, thus anything over 15 seconds is potentially dangerous.
@since 2.9.0
Attributes
@api private
@api private
@return [ Hash ] options The pool options.
Condition variable broadcast when the size of the pool changes to wake up the populator
@api private
@api private
Public Class Methods
Finalize the connection pool for garbage collection.
@param [ List<Mongo::Connection> ] available_connections The available connections. @param [ List<Mongo::Connection> ] pending_connections The pending connections. @param [ Populator ] populator The populator.
@return [ Proc ] The Finalizer.
# File lib/mongo/server/connection_pool.rb, line 786 def self.finalize(available_connections, pending_connections, populator) proc do available_connections.each do |connection| connection.disconnect!(reason: :pool_closed) end available_connections.clear pending_connections.each do |connection| connection.disconnect!(reason: :pool_closed) end pending_connections.clear # Finalizer does not close checked out connections. # Those would have to be garbage collected on their own # and that should close them. end end
Create the new connection pool.
@param [ Server ] server The server which this connection pool is for. @param [ Hash ] options The connection pool options.
@option options [ Integer ] :max_size The maximum pool size. Setting
this option to zero creates an unlimited connection pool.
@option options [ Integer ] :max_pool_size Deprecated.
The maximum pool size. If max_size is also given, max_size and max_pool_size must be identical.
@option options [ Integer ] :min_size The minimum pool size. @option options [ Integer ] :min_pool_size Deprecated.
The minimum pool size. If min_size is also given, min_size and min_pool_size must be identical.
@option options [ Float ] :wait_timeout The time to wait, in
seconds, for a free connection.
@option options [ Float ] :wait_queue_timeout Deprecated.
Alias for :wait_timeout. If both wait_timeout and wait_queue_timeout are given, their values must be identical.
@option options [ Float ] :max_idle_time The time, in seconds,
after which idle connections should be closed by the pool.
@option options [ true, false ] :populator_io For internal driver
use only. Set to false to prevent the populator threads from being created and started in the server's connection pool. It is intended for use in tests that also turn off monitoring_io, unless the populator is explicitly needed. If monitoring_io is off, but the populator_io is on, the populator needs to be manually closed at the end of the test, since a cluster without monitoring is considered not connected, and thus will not clean up the connection pool populator threads on close.
Note: Additionally, options for connections created by this pool should
be included in the options passed here, and they will be forwarded to any connections created by the pool.
@since 2.0.0, API changed in 2.9.0
# File lib/mongo/server/connection_pool.rb, line 91 def initialize(server, options = {}) unless server.is_a?(Server) raise ArgumentError, 'First argument must be a Server instance' end options = options.dup if options[:min_size] && options[:min_pool_size] && options[:min_size] != options[:min_pool_size] raise ArgumentError, "Min size #{options[:min_size]} is not identical to min pool size #{options[:min_pool_size]}" end if options[:max_size] && options[:max_pool_size] && options[:max_size] != options[:max_pool_size] raise ArgumentError, "Max size #{options[:max_size]} is not identical to max pool size #{options[:max_pool_size]}" end if options[:wait_timeout] && options[:wait_queue_timeout] && options[:wait_timeout] != options[:wait_queue_timeout] raise ArgumentError, "Wait timeout #{options[:wait_timeout]} is not identical to wait queue timeout #{options[:wait_queue_timeout]}" end options[:min_size] ||= options[:min_pool_size] options.delete(:min_pool_size) options[:max_size] ||= options[:max_pool_size] options.delete(:max_pool_size) if options[:min_size] && options[:max_size] && (options[:max_size] != 0 && options[:min_size] > options[:max_size]) then raise ArgumentError, "Cannot have min size #{options[:min_size]} exceed max size #{options[:max_size]}" end if options[:wait_queue_timeout] options[:wait_timeout] ||= options[:wait_queue_timeout] end options.delete(:wait_queue_timeout) @server = server @options = options.freeze @generation_manager = GenerationManager.new(server: server) @ready = false @closed = false # A connection owned by this pool should be either in the # available connections array (which is used as a stack) # or in the checked out connections set. @available_connections = available_connections = [] @checked_out_connections = Set.new @pending_connections = Set.new @interrupt_connections = [] # Mutex used for synchronizing access to @available_connections and # @checked_out_connections. The pool object is thread-safe, thus # all methods that retrieve or modify instance variables generally # must do so under this lock. @lock = Mutex.new # Background thread reponsible for maintaining the size of # the pool to at least min_size @populator = Populator.new(self, options) @populate_semaphore = Semaphore.new # Condition variable to enforce the first check in check_out: max_pool_size. # This condition variable should be signaled when the number of # unavailable connections decreases (pending + pending_connections + # available_connections). @size_cv = Mongo::ConditionVariable.new(@lock) # This represents the number of threads that have made it past the size_cv # gate but have not acquired a connection to add to the pending_connections # set. @connection_requests = 0 # Condition variable to enforce the second check in check_out: max_connecting. # Thei condition variable should be signaled when the number of pending # connections decreases. @max_connecting_cv = Mongo::ConditionVariable.new(@lock) @max_connecting = options.fetch(:max_connecting, 2) ObjectSpace.define_finalizer(self, self.class.finalize(@available_connections, @pending_connections, @populator)) publish_cmap_event( Monitoring::Event::Cmap::PoolCreated.new(@server.address, options, self) ) end
Public Instance Methods
Number of available connections in the pool.
@return [ Integer ] Number of available connections.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 273 def available_count raise_if_closed! @lock.synchronize do @available_connections.length end end
Check a connection back into the pool.
The connection must have been previously created by this pool.
@param [ Mongo::Server::Connection ] connection The connection.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 378 def check_in(connection) check_invariants @lock.synchronize do do_check_in(connection) end ensure check_invariants end
Checks a connection out of the pool.
If there are active connections in the pool, the most recently used connection is returned. Otherwise if the connection pool size is less than the max size, creates a new connection and returns it. Otherwise waits up to the wait timeout and raises Timeout::Error if there are still no active connections and the pool is at max size.
The returned connection counts toward the pool's max size. When the caller is finished using the connection, the connection should be checked back in via the #check_in method.
@return [ Mongo::Server::Connection ] The checked out connection. @raise [ Error::PoolClosedError ] If the pool has been closed. @raise [ Timeout::Error ] If the connection pool is at maximum size
and remains so for longer than the wait timeout.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 344 def check_out(connection_global_id: nil) check_invariants publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckOutStarted.new(@server.address) ) raise_if_pool_closed! raise_if_pool_paused_locked! connection = retrieve_and_connect_connection(connection_global_id) publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckedOut.new(@server.address, connection.id, self), ) if Lint.enabled? unless connection.connected? raise Error::LintError, "Connection pool for #{address} checked out a disconnected connection #{connection.generation}:#{connection.id}" end end connection ensure check_invariants end
Closes all idle connections in the pool and schedules currently checked out connections to be closed when they are checked back into the pool. The pool is paused, it will not create new connections in background and it will fail checkout requests until marked ready.
@option options [ true | false ] :lazy If true, do not close any of
the idle connections and instead let them be closed during a subsequent check out operation. Defaults to false.
@option options [ true | false ] :interrupt_in_use_connections If true,
close all checked out connections immediately. If it is false, do not close any of the checked out connections. Defaults to true.
@option options [ Object ] :service_id Clear connections with
the specified service id only.
@return [ true ] true.
@since 2.1.0
# File lib/mongo/server/connection_pool.rb, line 496 def clear(options = nil) raise_if_closed! if Lint.enabled? && !@server.unknown? raise Error::LintError, "Attempting to clear pool for server #{@server.summary} which is known" end do_clear(options) end
Marks the pool closed, closes all idle connections in the pool and schedules currently checked out connections to be closed when they are checked back into the pool. If force option is true, checked out connections are also closed. Attempts to use the pool after it is closed will raise Error::PoolClosedError.
@option options [ true | false ] :force Also close all checked out
connections.
@option options [ true | false ] :stay_ready For internal driver use
only. Whether or not to mark the pool as closed.
@return [ true ] Always true.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 620 def close(options = nil) return if closed? options ||= {} stop_populator @lock.synchronize do until @available_connections.empty? connection = @available_connections.pop connection.disconnect!(reason: :pool_closed) end if options[:force] until @checked_out_connections.empty? connection = @checked_out_connections.take(1).first connection.disconnect!(reason: :pool_closed) @checked_out_connections.delete(connection) end end unless options && options[:stay_ready] # mark pool as closed before releasing lock so # no connections can be created, checked in, or checked out @closed = true @ready = false end @max_connecting_cv.broadcast @size_cv.broadcast end publish_cmap_event( Monitoring::Event::Cmap::PoolClosed.new(@server.address, self) ) true end
Close sockets that have been open for longer than the max idle time,
if the option is set.
@since 2.5.0
# File lib/mongo/server/connection_pool.rb, line 707 def close_idle_sockets return if closed? return unless max_idle_time @lock.synchronize do i = 0 while i < @available_connections.length connection = @available_connections[i] if last_checkin = connection.last_checkin if (Time.now - last_checkin) > max_idle_time connection.disconnect!(reason: :idle) @available_connections.delete_at(i) @populate_semaphore.signal next end end i += 1 end end end
Whether the pool has been closed.
@return [ true | false ] Whether the pool is closed.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 286 def closed? !!@closed end
Disconnects the pool.
Does everything that clear
does, except if the pool is closed
this method does nothing but clear
would raise
PoolClosedError.
@since 2.1.0 @api private
# File lib/mongo/server/connection_pool.rb, line 513 def disconnect!(options = nil) do_clear(options) rescue Error::PoolClosedError # The "disconnected" state is between closed and paused. # When we are trying to disconnect the pool, permit the pool to be # already closed. end
Executes the check in after having already acquired the lock.
@param [ Mongo::Server::Connection ] connection The connection.
# File lib/mongo/server/connection_pool.rb, line 391 def do_check_in(connection) # When a connection is interrupted it is checked back into the pool # and closed. The operation that was using the connection before it was # interrupted will attempt to check it back into the pool, and we # should ignore it since its already been closed and removed from the pool. return if connection.closed? && connection.interrupted? unless connection.connection_pool == self raise ArgumentError, "Trying to check in a connection which was not checked out by this pool: #{connection} checked out from pool #{connection.connection_pool} (for #{self})" end unless @checked_out_connections.include?(connection) raise ArgumentError, "Trying to check in a connection which is not currently checked out by this pool: #{connection} (for #{self})" end # Note: if an event handler raises, resource will not be signaled. # This means threads waiting for a connection to free up when # the pool is at max size may time out. # Threads that begin waiting after this method completes (with # the exception) should be fine. @checked_out_connections.delete(connection) @size_cv.signal publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckedIn.new(@server.address, connection.id, self) ) if connection.interrupted? connection.disconnect!(reason: :stale) return end if connection.error? connection.disconnect!(reason: :error) return end if closed? connection.disconnect!(reason: :pool_closed) return end if connection.closed? # Connection was closed - for example, because it experienced # a network error. Nothing else needs to be done here. @populate_semaphore.signal elsif connection.generation != generation(service_id: connection.service_id) && !connection.pinned? # If connection is marked as pinned, it is used by a transaction # or a series of cursor operations in a load balanced setup. # In this case connection should not be disconnected until # unpinned. connection.disconnect!(reason: :stale) @populate_semaphore.signal else connection.record_checkin! @available_connections << connection @max_connecting_cv.signal end end
# File lib/mongo/server/connection_pool.rb, line 521 def do_clear(options = nil) check_invariants service_id = options && options[:service_id] @lock.synchronize do # Generation must be bumped before emitting pool cleared event. @generation_manager.bump(service_id: service_id) unless options && options[:lazy] close_available_connections(service_id) end if options && options[:interrupt_in_use_connections] schedule_for_interruption(@checked_out_connections, service_id) schedule_for_interruption(@pending_connections, service_id) end if @ready publish_cmap_event( Monitoring::Event::Cmap::PoolCleared.new( @server.address, service_id: service_id, interrupt_in_use_connections: options&.[](:interrupt_in_use_connections) ) ) # Only pause the connection pool if the server was marked unknown, # otherwise, allow the retry to be attempted with a ready pool. do_pause if !@server.load_balancer? && @server.unknown? end # Broadcast here to cause all of the threads waiting on the max # connecting to break out of the wait loop and error. @max_connecting_cv.broadcast # Broadcast here to cause all of the threads waiting on the pool size # to break out of the wait loop and error. @size_cv.broadcast end # "Schedule the background thread" after clearing. This is responsible # for cleaning up stale threads, and interrupting in use connections. @populate_semaphore.signal true ensure check_invariants end
Mark the connection pool as paused without acquiring the lock.
@api private
# File lib/mongo/server/connection_pool.rb, line 469 def do_pause if Lint.enabled? && !@server.unknown? raise Error::LintError, "Attempting to pause pool for server #{@server.summary} which is known" end return if !@ready @ready = false end
Get a pretty printed string inspection for the pool.
@example Inspect the pool.
pool.inspect
@return [ String ] The pool inspection.
@since 2.0.0
# File lib/mongo/server/connection_pool.rb, line 667 def inspect if closed? "#<Mongo::Server::ConnectionPool:0x#{object_id} min_size=#{min_size} max_size=#{max_size} " + "wait_timeout=#{wait_timeout} closed>" elsif !ready? "#<Mongo::Server::ConnectionPool:0x#{object_id} min_size=#{min_size} max_size=#{max_size} " + "wait_timeout=#{wait_timeout} paused>" else "#<Mongo::Server::ConnectionPool:0x#{object_id} min_size=#{min_size} max_size=#{max_size} " + "wait_timeout=#{wait_timeout} current_size=#{size} available=#{available_count}>" end end
The maximum seconds a socket can remain idle since it has been checked in to the pool, if set.
@return [ Float | nil ] The max socket idle time in seconds.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 210 def max_idle_time @max_idle_time ||= options[:max_idle_time] end
Get the maximum size of the connection pool.
@return [ Integer ] The maximum size of the connection pool.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 182 def max_size @max_size ||= options[:max_size] || [DEFAULT_MAX_SIZE, min_size].max end
Get the minimum size of the connection pool.
@return [ Integer ] The minimum size of the connection pool.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 191 def min_size @min_size ||= options[:min_size] || DEFAULT_MIN_SIZE end
Mark the connection pool as paused.
# File lib/mongo/server/connection_pool.rb, line 454 def pause raise_if_closed! check_invariants @lock.synchronize do do_pause end ensure check_invariants end
A connection pool is paused if it is not closed and it is not ready.
@return [ true | false ] whether the connection pool is paused.
@raise [ Error::PoolClosedError ] If the pool has been closed.
# File lib/mongo/server/connection_pool.rb, line 228 def paused? raise_if_closed! @lock.synchronize do !@ready end end
This method does three things:
-
Creates and adds a connection to the pool, if the pool's size is below min_size. Retries once if a socket-related error is encountered during this process and raises if a second error or a non socket-related error occurs.
-
Removes stale connections from the connection pool.
-
Interrupts connections marked for interruption.
Used by the pool populator background thread.
@return [ true | false ] Whether this method should be called again
to create more connections.
@raise [ Error::AuthError, Error ] The second socket-related error raised if a retry occured, or the non socket-related error
@api private
# File lib/mongo/server/connection_pool.rb, line 765 def populate return false if closed? begin return create_and_add_connection rescue Error::SocketError, Error::SocketTimeoutError => e # an error was encountered while connecting the connection, # ignore this first error and try again. log_warn("Populator failed to connect a connection for #{address}: #{e.class}: #{e}. It will retry.") end return create_and_add_connection end
Instructs the pool to create and return connections.
# File lib/mongo/server/connection_pool.rb, line 569 def ready raise_if_closed! # TODO: Add this back in RUBY-3174. # if Lint.enabled? # unless @server.connected? # raise Error::LintError, "Attempting to ready a pool for server #{@server.summary} which is disconnected" # end # end @lock.synchronize do return if @ready @ready = true end # Note that the CMAP spec demands serialization of CMAP events for a # pool. In order to implement this, event publication must be done into # a queue which is synchronized, instead of subscribers being invoked # from the trigger method like this one here inline. On MRI, assuming # the threads yield to others when they stop having work to do, it is # likely that the events would in practice always be published in the # required order. JRuby, being truly concurrent with OS threads, # would not offers such a guarantee. publish_cmap_event( Monitoring::Event::Cmap::PoolReady.new(@server.address, options, self) ) if options.fetch(:populator_io, true) if @populator.running? @populate_semaphore.signal else @populator.run! end end end
Whether the pool is ready.
@return [ true | false ] Whether the pool is ready.
# File lib/mongo/server/connection_pool.rb, line 293 def ready? @lock.synchronize do @ready end end
Size of the connection pool.
Includes available and checked out connections.
@return [ Integer ] Size of the connection pool.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 243 def size raise_if_closed! @lock.synchronize do unsynchronized_size end end
Stop the background populator thread and clean up any connections created which have not been connected yet.
Used when closing the pool or when terminating the bg thread for testing purposes. In the latter case, this method must be called before the pool is used, to ensure no connections in pending_connections were created in-flow by the #check_out method.
@api private
# File lib/mongo/server/connection_pool.rb, line 737 def stop_populator @populator.stop! @lock.synchronize do # If stop_populator is called while populate is running, there may be # connections waiting to be connected, connections which have not yet # been moved to available_connections, or connections moved to available_connections # but not deleted from pending_connections. These should be cleaned up. clear_pending_connections end end
@note This method is experimental and subject to change.
@api experimental @since 2.11.0
# File lib/mongo/server/connection_pool.rb, line 303 def summary @lock.synchronize do state = if closed? 'closed' elsif !@ready 'paused' else 'ready' end "#<ConnectionPool size=#{unsynchronized_size} (#{min_size}-#{max_size}) " + "used=#{@checked_out_connections.length} avail=#{@available_connections.length} pending=#{@pending_connections.length} #{state}>" end end
The time to wait, in seconds, for a connection to become available.
@return [ Float ] The queue wait timeout.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 200 def wait_timeout @wait_timeout ||= options[:wait_timeout] || DEFAULT_WAIT_TIMEOUT end
Yield the block to a connection, while handling check in/check out logic.
@example Execute with a connection.
pool.with_connection do |connection| connection.read end
@return [ Object ] The result of the block.
@since 2.0.0
# File lib/mongo/server/connection_pool.rb, line 690 def with_connection(connection_global_id: nil) raise_if_closed! connection = check_out(connection_global_id: connection_global_id) yield(connection) rescue Error::SocketError, Error::SocketTimeoutError, Error::ConnectionPerished => e maybe_raise_pool_cleared!(connection, e) ensure if connection check_in(connection) end end
Private Instance Methods
# File lib/mongo/server/connection_pool.rb, line 983 def check_invariants return unless Lint.enabled? # Server summary calls pool summary which requires pool lock -> deadlock. # Obtain the server summary ahead of time. server_summary = @server.summary @lock.synchronize do @available_connections.each do |connection| if connection.closed? raise Error::LintError, "Available connection is closed: #{connection} for #{server_summary}" end end @pending_connections.each do |connection| if connection.closed? raise Error::LintError, "Pending connection is closed: #{connection} for #{server_summary}" end end end end
Clear and disconnect the pending connections.
# File lib/mongo/server/connection_pool.rb, line 1047 def clear_pending_connections until @pending_connections.empty? connection = @pending_connections.take(1).first connection.disconnect! @pending_connections.delete(connection) end end
Close the available connections.
@param [ Array<Connection> ] connections A list of connections. @param [ Object ] service_id The service id.
# File lib/mongo/server/connection_pool.rb, line 1009 def close_available_connections(service_id) if @server.load_balancer? && service_id loop do conn = @available_connections.detect do |conn| conn.service_id == service_id && conn.generation < @generation_manager.generation(service_id: service_id) end if conn @available_connections.delete(conn) conn.disconnect!(reason: :stale, interrupted: true) @populate_semaphore.signal else break end end else @available_connections.delete_if do |conn| if conn.generation < @generation_manager.generation(service_id: service_id) conn.disconnect!(reason: :stale, interrupted: true) @populate_semaphore.signal true end end end end
Attempts to connect (handshake and auth) the connection. If an error is encountered, closes the connection and raises the error.
# File lib/mongo/server/connection_pool.rb, line 967 def connect_connection(connection) begin connection.connect! rescue Exception connection.disconnect!(reason: :error) raise end rescue Error::SocketError, Error::SocketTimeoutError => exc @server.unknown!( generation: exc.generation, service_id: exc.service_id, stop_push_monitor: true, ) raise end
Checks whether a connection is stale.
@param [ Mongo::Server::Connection ] connection The connection to check.
@return [ true | false ] Whether the connection is stale.
# File lib/mongo/server/connection_pool.rb, line 930 def connection_stale_unlocked?(connection) connection.generation != generation_unlocked(service_id: connection.service_id) && !connection.pinned? end
Create a connection, connect it, and add it to the pool. Also check for stale and interruptable connections and deal with them.
@return [ true | false ] True if a connection was created and
added to the pool, false otherwise
@raise [ Mongo::Error ] An error encountered during connection connect
# File lib/mongo/server/connection_pool.rb, line 845 def create_and_add_connection connection = nil @lock.synchronize do if !closed? && @ready && (unsynchronized_size + @connection_requests) < min_size && @pending_connections.length < @max_connecting then connection = create_connection @pending_connections << connection else return true if remove_interrupted_connections return true if remove_stale_connection return false end end begin connect_connection(connection) rescue Exception @lock.synchronize do @pending_connections.delete(connection) @max_connecting_cv.signal @size_cv.signal end raise end @lock.synchronize do @available_connections << connection @pending_connections.delete(connection) @max_connecting_cv.signal @size_cv.signal end true end
# File lib/mongo/server/connection_pool.rb, line 825 def create_connection r, _ = @generation_manager.pipe_fds(service_id: server.description.service_id) opts = options.merge( connection_pool: self, pipe: r # Do not pass app metadata - this will be retrieved by the connection # based on the auth needs. ) unless @server.load_balancer? opts[:generation] = generation end Connection.new(@server, opts) end
Retrieves a connection if one is available, otherwise we create a new one. If no connection exists and the pool is at max size, wait until a connection is checked back into the pool.
@param [ Float ] deadline The deadline to get the connection. @param [ Integer ] pid The current process id. @param [ Integer ] connection_global_id The global id for the
connection to check out.
@return [ Mongo::Server::Connection ] The checked out connection.
@raise [ Error::PoolClosedError ] If the pool has been closed. @raise [ Timeout::Error ] If the connection pool is at maximum size
and remains so for longer than the wait timeout.
# File lib/mongo/server/connection_pool.rb, line 1182 def get_connection(deadline, pid, connection_global_id) if connection = next_available_connection(connection_global_id) unless valid_available_connection?(connection, pid, connection_global_id) return nil end # If the connection is connected, it's not considered a # "pending connection". The pending_connections list represents # the set of connections that are awaiting connection. unless connection.connected? @connection_requests -= 1 @pending_connections << connection end return connection elsif connection_global_id && @server.load_balancer? # A particular connection is requested, but it is not available. # If it is nether available not checked out, we should stop here. @checked_out_connections.detect do |conn| conn.global_id == connection_global_id end.tap do |conn| if conn.nil? publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckOutFailed.new( @server.address, Monitoring::Event::Cmap::ConnectionCheckOutFailed::CONNECTION_ERROR ), ) raise Error::MissingConnection.new end end # We need a particular connection, and if it is not available # we can wait for an in-progress operation to return # such a connection to the pool. nil else connection = create_connection @connection_requests -= 1 @pending_connections << connection return connection end end
If the connection was interrupted, raise a pool cleared error. If it wasn't interrupted raise the original error.
@param [ Connection ] The connection. @param [ Mongo::Error ] The original error.
@raise [ Mongo::Error | Mongo::Error::PoolClearedError ] A PoolClearedError
if the connection was interrupted, the original error if not.
# File lib/mongo/server/connection_pool.rb, line 954 def maybe_raise_pool_cleared!(connection, e) if connection&.interrupted? err = Error::PoolClearedError.new(connection.server.address, connection.server.pool_internal).tap do |err| e.labels.each { |l| err.add_label(l) } end raise err else raise e end end
Returns the next available connection, optionally with given global id. If no suitable connections are available, returns nil.
# File lib/mongo/server/connection_pool.rb, line 809 def next_available_connection(connection_global_id) raise_unless_locked! if @server.load_balancer? && connection_global_id conn = @available_connections.detect do |conn| conn.global_id == connection_global_id end if conn @available_connections.delete(conn) end conn else @available_connections.pop end end
The lock should be acquired when calling this method.
# File lib/mongo/server/connection_pool.rb, line 1056 def raise_check_out_timeout!(connection_global_id) raise_unless_locked! publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckOutFailed.new( @server.address, Monitoring::Event::Cmap::ConnectionCheckOutFailed::TIMEOUT, ), ) connection_global_id_msg = if connection_global_id " for connection #{connection_global_id}" else '' end msg = "Timed out attempting to check out a connection " + "from pool for #{@server.address}#{connection_global_id_msg} after #{wait_timeout} sec. " + "Connections in pool: #{@available_connections.length} available, " + "#{@checked_out_connections.length} checked out, " + "#{@pending_connections.length + @connection_requests} pending " + "(max size: #{max_size})" raise Error::ConnectionCheckOutTimeout.new(msg, address: @server.address) end
# File lib/mongo/server/connection_pool.rb, line 1081 def raise_check_out_timeout_locked!(connection_global_id) @lock.synchronize do raise_check_out_timeout!(connection_global_id) end end
Asserts that the pool has not been closed.
@raise [ Error::PoolClosedError ] If the pool has been closed.
@since 2.9.0
# File lib/mongo/server/connection_pool.rb, line 940 def raise_if_closed! if closed? raise Error::PoolClosedError.new(@server.address, self) end end
The lock should be acquired when calling this method.
# File lib/mongo/server/connection_pool.rb, line 1122 def raise_if_not_ready! raise_unless_locked! raise_if_pool_closed! raise_if_pool_paused! end
# File lib/mongo/server/connection_pool.rb, line 1087 def raise_if_pool_closed! if closed? publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckOutFailed.new( @server.address, Monitoring::Event::Cmap::ConnectionCheckOutFailed::POOL_CLOSED ), ) raise Error::PoolClosedError.new(@server.address, self) end end
# File lib/mongo/server/connection_pool.rb, line 1099 def raise_if_pool_paused! raise_unless_locked! if !@ready publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckOutFailed.new( @server.address, # CMAP spec decided to conflate pool paused with all the other # possible non-timeout errors. Monitoring::Event::Cmap::ConnectionCheckOutFailed::CONNECTION_ERROR, ), ) raise Error::PoolPausedError.new(@server.address, self) end end
# File lib/mongo/server/connection_pool.rb, line 1115 def raise_if_pool_paused_locked! @lock.synchronize do raise_if_pool_paused! end end
# File lib/mongo/server/connection_pool.rb, line 1128 def raise_unless_locked! unless @lock.owned? raise ArgumentError, "the lock must be owned when calling this method" end end
Interrupt connections scheduled for interruption.
# File lib/mongo/server/connection_pool.rb, line 893 def remove_interrupted_connections return false if @interrupt_connections.empty? gens = Set.new while conn = @interrupt_connections.pop if @checked_out_connections.include?(conn) # If the connection has been checked out, mark it as interrupted and it will # be disconnected on check in. conn.interrupted! do_check_in(conn) elsif @pending_connections.include?(conn) # If the connection is pending, disconnect with the interrupted flag. conn.disconnect!(reason: :stale, interrupted: true) @pending_connections.delete(conn) end gens << [ conn.generation, conn.service_id ] end # Close the write side of the pipe. Pending connections might be # hanging on the Kernel#select call, so in order to interrupt that, # we also listen for the read side of the pipe in Kernel#select and # close the write side of the pipe here, which will cause select to # wake up and raise an IOError now that the socket is closed. # The read side of the pipe will be scheduled for closing on the next # generation bump. gens.each do |gen, service_id| @generation_manager.remove_pipe_fds(gen, service_id: service_id) end true end
Removes and disconnects all stale available connections.
# File lib/mongo/server/connection_pool.rb, line 884 def remove_stale_connection if conn = @available_connections.detect(&method(:connection_stale_unlocked?)) conn.disconnect!(reason: :stale) @available_connections.delete(conn) return true end end
Retrieves a connection and connects it.
@param [ Integer ] connection_global_id The global id for the
connection to check out.
@return [ Mongo::Server::Connection ] The checked out connection.
@raise [ Error::PoolClosedError ] If the pool has been closed. @raise [ Timeout::Error ] If the connection pool is at maximum size
and remains so for longer than the wait timeout.
# File lib/mongo/server/connection_pool.rb, line 1234 def retrieve_and_connect_connection(connection_global_id) deadline = Utils.monotonic_time + wait_timeout connection = nil @lock.synchronize do # The first gate to checking out a connection. Make sure the number of # unavailable connections is less than the max pool size. until max_size == 0 || unavailable_connections < max_size wait = deadline - Utils.monotonic_time raise_check_out_timeout!(connection_global_id) if wait <= 0 @size_cv.wait(wait) raise_if_not_ready! end @connection_requests += 1 while connection.nil? # The second gate to checking out a connection. Make sure 1) there # exists an available connection and 2) we are under max_connecting. until @available_connections.any? || @pending_connections.length < @max_connecting wait = deadline - Utils.monotonic_time raise_check_out_timeout!(connection_global_id) if wait <= 0 @max_connecting_cv.wait(wait) raise_if_not_ready! end connection = get_connection(deadline, Process.pid, connection_global_id) wait = deadline - Utils.monotonic_time raise_check_out_timeout!(connection_global_id) if connection.nil? && wait <= 0 end end begin connect_connection(connection) rescue Exception # Handshake or authentication failed @lock.synchronize do if @pending_connections.include?(connection) @pending_connections.delete(connection) else @connection_requests -= 1 end @max_connecting_cv.signal @size_cv.signal end @populate_semaphore.signal publish_cmap_event( Monitoring::Event::Cmap::ConnectionCheckOutFailed.new( @server.address, Monitoring::Event::Cmap::ConnectionCheckOutFailed::CONNECTION_ERROR ), ) raise end @lock.synchronize do @checked_out_connections << connection if @pending_connections.include?(connection) @pending_connections.delete(connection) else @connection_requests -= 1 end @max_connecting_cv.signal # no need to signal size_cv here since the number of unavailable # connections is unchanged. end connection end
Schedule connections of previous generations for interruption.
@param [ Array<Connection> ] connections A list of connections. @param [ Object ] service_id The service id.
# File lib/mongo/server/connection_pool.rb, line 1039 def schedule_for_interruption(connections, service_id) @interrupt_connections += connections.select do |conn| (!server.load_balancer? || conn.service_id == service_id) && conn.generation < @generation_manager.generation(service_id: service_id) end end
Returns the size of the connection pool without acquiring the lock. This method should only be used by other pool methods when they are already holding the lock as Ruby does not allow a thread holding a lock to acquire this lock again.
# File lib/mongo/server/connection_pool.rb, line 255 def unsynchronized_size @available_connections.length + @checked_out_connections.length + @pending_connections.length end
# File lib/mongo/server/connection_pool.rb, line 1134 def valid_available_connection?(connection, pid, connection_global_id) if connection.pid != pid log_warn("Detected PID change - Mongo client should have been reconnected (old pid #{connection.pid}, new pid #{pid}") connection.disconnect!(reason: :stale) @populate_semaphore.signal return false end if !connection.pinned? # If connection is marked as pinned, it is used by a transaction # or a series of cursor operations in a load balanced setup. # In this case connection should not be disconnected until # unpinned. if connection.generation != generation( service_id: connection.service_id ) # Stale connections should be disconnected in the clear # method, but if any don't, check again here connection.disconnect!(reason: :stale) @populate_semaphore.signal return false end if max_idle_time && connection.last_checkin && Time.now - connection.last_checkin > max_idle_time then connection.disconnect!(reason: :idle) @populate_semaphore.signal return false end end true end