topology

package
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Published: Jan 9, 2024 License: Apache-2.0 Imports: 37 Imported by: 0

Documentation

Overview

Package topology contains types that handles the discovery, monitoring, and selection of servers. This package is designed to expose enough inner workings of service discovery and monitoring to allow low level applications to have fine grained control, while hiding most of the detailed implementation of the algorithms.

Example (ClusterMonitoring)
package main

import (
	"log"

	"go.mongodb.org/mongo-driver/x/mongo/driver/topology"
)

func main() {
	topo, err := topology.New(nil)
	if err != nil {
		log.Fatalf("could not create topology: %v", err)
	}
	err = topo.Connect()
	if err != nil {
		log.Fatalf("could not create topology: %v", err)
	}

	sub, err := topo.Subscribe()
	if err != nil {
		log.Fatalf("could not subscribe to topology: %v", err)
	}

	for desc := range sub.Updates {
		log.Printf("%#v", desc)
	}
}
Output:

Index

Examples

Constants

This section is empty.

Variables

View Source
var (
	// MinSupportedMongoDBVersion is the version string for the lowest MongoDB version supported by the driver.
	MinSupportedMongoDBVersion = "3.6"

	// SupportedWireVersions is the range of wire versions supported by the driver.
	SupportedWireVersions = description.NewVersionRange(6, 21)
)
View Source
var (
	// ErrServerClosed occurs when an attempt to Get a connection is made after
	// the server has been closed.
	ErrServerClosed = errors.New("server is closed")
	// ErrServerConnected occurs when at attempt to Connect is made after a server
	// has already been connected.
	ErrServerConnected = errors.New("server is connected")
)
View Source
var ErrConnectionClosed = ConnectionError{ConnectionID: "<closed>", /* contains filtered or unexported fields */}

ErrConnectionClosed is returned from an attempt to use an already closed connection.

View Source
var ErrPoolClosed = PoolError("attempted to check out a connection from closed connection pool")

ErrPoolClosed is returned when attempting to check out a connection from a closed pool.

View Source
var ErrPoolNotPaused = PoolError("only a paused pool can be marked ready")

ErrPoolNotPaused is returned when attempting to mark a connection pool "ready" that is not currently "paused".

View Source
var ErrServerSelectionTimeout = errors.New("server selection timeout")

ErrServerSelectionTimeout is returned from server selection when the server selection process took longer than allowed by the timeout.

View Source
var ErrSubscribeAfterClosed = errors.New("cannot subscribe after closeConnection")

ErrSubscribeAfterClosed is returned when a user attempts to subscribe to a closed Server or Topology.

View Source
var ErrTopologyClosed = errors.New("topology is closed")

ErrTopologyClosed is returned when a user attempts to call a method on a closed Topology.

View Source
var ErrTopologyConnected = errors.New("topology is connected or connecting")

ErrTopologyConnected is returned whena user attempts to Connect to an already connected Topology.

View Source
var ErrWrongPool = PoolError("connection does not belong to this pool")

ErrWrongPool is return when a connection is returned to a pool it doesn't belong to.

Functions

func ConvertToDriverAPIOptions

func ConvertToDriverAPIOptions(s *options.ServerAPIOptions) *driver.ServerAPIOptions

ConvertToDriverAPIOptions converts a options.ServerAPIOptions instance to a driver.ServerAPIOptions.

func ServerAPIFromServerOptions

func ServerAPIFromServerOptions(opts []ServerOption) *driver.ServerAPIOptions

ServerAPIFromServerOptions will return the server API options if they have been functionally set on the ServerOption slice.

Types

type Config

type Config struct {
	Mode                   MonitorMode
	ReplicaSetName         string
	SeedList               []string
	ServerOpts             []ServerOption
	URI                    string
	ServerSelectionTimeout time.Duration
	ServerMonitor          *event.ServerMonitor
	SRVMaxHosts            int
	SRVServiceName         string
	LoadBalanced           bool
	// contains filtered or unexported fields
}

Config is used to construct a topology.

func NewConfig

func NewConfig(co *options.ClientOptions, clock *session.ClusterClock) (*Config, error)

NewConfig will translate data from client options into a topology config for building non-default deployments. Server and topology options are not honored if a custom deployment is used.

type Connection

type Connection struct {
	// contains filtered or unexported fields
}

Connection implements the driver.Connection interface to allow reading and writing wire messages and the driver.Expirable interface to allow expiring. It wraps an underlying topology.connection to make it more goroutine-safe and nil-safe.

func (*Connection) Address

func (c *Connection) Address() address.Address

Address returns the address of this connection.

func (*Connection) Alive

func (c *Connection) Alive() bool

Alive returns if the connection is still alive.

func (*Connection) Close

func (c *Connection) Close() error

Close returns this connection to the connection pool. This method may not closeConnection the underlying socket.

func (*Connection) CompressWireMessage

func (c *Connection) CompressWireMessage(src, dst []byte) ([]byte, error)

CompressWireMessage handles compressing the provided wire message using the underlying connection's compressor. The dst parameter will be overwritten with the new wire message. If there is no compressor set on the underlying connection, then no compression will be performed.

func (*Connection) Description

func (c *Connection) Description() description.Server

Description returns the server description of the server this connection is connected to.

func (*Connection) DriverConnectionID

func (c *Connection) DriverConnectionID() uint64

DriverConnectionID returns the driver connection ID. TODO(GODRIVER-2824): change return type to int64.

func (*Connection) Expire

func (c *Connection) Expire() error

Expire closes this connection and will closeConnection the underlying socket.

func (*Connection) ID

func (c *Connection) ID() string

ID returns the ID of this connection.

func (*Connection) LocalAddress

func (c *Connection) LocalAddress() address.Address

LocalAddress returns the local address of the connection

func (*Connection) PinToCursor

func (c *Connection) PinToCursor() error

PinToCursor updates this connection to reflect that it is pinned to a cursor.

func (*Connection) PinToTransaction

func (c *Connection) PinToTransaction() error

PinToTransaction updates this connection to reflect that it is pinned to a transaction.

func (*Connection) ReadWireMessage

func (c *Connection) ReadWireMessage(ctx context.Context) ([]byte, error)

ReadWireMessage handles reading a wire message from the underlying connection. The dst parameter will be overwritten with the new wire message.

func (*Connection) ServerConnectionID

func (c *Connection) ServerConnectionID() *int64

ServerConnectionID returns the server connection ID of this connection.

func (*Connection) Stale

func (c *Connection) Stale() bool

Stale returns if the connection is stale.

func (*Connection) UnpinFromCursor

func (c *Connection) UnpinFromCursor() error

UnpinFromCursor updates this connection to reflect that it is no longer pinned to a cursor.

func (*Connection) UnpinFromTransaction

func (c *Connection) UnpinFromTransaction() error

UnpinFromTransaction updates this connection to reflect that it is no longer pinned to a transaction.

func (*Connection) WriteWireMessage

func (c *Connection) WriteWireMessage(ctx context.Context, wm []byte) error

WriteWireMessage handles writing a wire message to the underlying connection.

type ConnectionError

type ConnectionError struct {
	ConnectionID string
	Wrapped      error
	// contains filtered or unexported fields
}

ConnectionError represents a connection error.

func (ConnectionError) Error

func (e ConnectionError) Error() string

Error implements the error interface.

func (ConnectionError) Unwrap

func (e ConnectionError) Unwrap() error

Unwrap returns the underlying error.

type ConnectionOption

type ConnectionOption func(*connectionConfig)

ConnectionOption is used to configure a connection.

func WithCompressors

func WithCompressors(fn func([]string) []string) ConnectionOption

WithCompressors sets the compressors that can be used for communication.

func WithConnectTimeout

func WithConnectTimeout(fn func(time.Duration) time.Duration) ConnectionOption

WithConnectTimeout configures the maximum amount of time a dial will wait for a Connect to complete. The default is 30 seconds.

func WithConnectionLoadBalanced

func WithConnectionLoadBalanced(fn func(bool) bool) ConnectionOption

WithConnectionLoadBalanced specifies whether or not the connection is to a server behind a load balancer.

func WithDialer

func WithDialer(fn func(Dialer) Dialer) ConnectionOption

WithDialer configures the Dialer to use when making a new connection to MongoDB.

func WithDisableOCSPEndpointCheck

func WithDisableOCSPEndpointCheck(fn func(bool) bool) ConnectionOption

WithDisableOCSPEndpointCheck specifies whether or the driver should perform non-stapled OCSP verification. If set to true, the driver will only check stapled responses and will continue the connection without reaching out to OCSP responders.

func WithHTTPClient

func WithHTTPClient(fn func(*http.Client) *http.Client) ConnectionOption

WithHTTPClient configures the HTTP client for a connection.

func WithHandshaker

func WithHandshaker(fn func(Handshaker) Handshaker) ConnectionOption

WithHandshaker configures the Handshaker that wll be used to initialize newly dialed connections.

func WithIdleTimeout

func WithIdleTimeout(fn func(time.Duration) time.Duration) ConnectionOption

WithIdleTimeout configures the maximum idle time to allow for a connection.

func WithMonitor

WithMonitor configures a event for command monitoring.

func WithOCSPCache

func WithOCSPCache(fn func(ocsp.Cache) ocsp.Cache) ConnectionOption

WithOCSPCache specifies a cache to use for OCSP verification.

func WithReadTimeout

func WithReadTimeout(fn func(time.Duration) time.Duration) ConnectionOption

WithReadTimeout configures the maximum read time for a connection.

func WithTLSConfig

func WithTLSConfig(fn func(*tls.Config) *tls.Config) ConnectionOption

WithTLSConfig configures the TLS options for a connection.

func WithWriteTimeout

func WithWriteTimeout(fn func(time.Duration) time.Duration) ConnectionOption

WithWriteTimeout configures the maximum write time for a connection.

func WithZlibLevel

func WithZlibLevel(fn func(*int) *int) ConnectionOption

WithZlibLevel sets the zLib compression level.

func WithZstdLevel

func WithZstdLevel(fn func(*int) *int) ConnectionOption

WithZstdLevel sets the zstd compression level.

type Dialer

type Dialer interface {
	DialContext(ctx context.Context, network, address string) (net.Conn, error)
}

Dialer is used to make network connections.

var DefaultDialer Dialer = &net.Dialer{}

DefaultDialer is the Dialer implementation that is used by this package. Changing this will also change the Dialer used for this package. This should only be changed why all of the connections being made need to use a different Dialer. Most of the time, using a WithDialer option is more appropriate than changing this variable.

type DialerFunc

type DialerFunc func(ctx context.Context, network, address string) (net.Conn, error)

DialerFunc is a type implemented by functions that can be used as a Dialer.

func (DialerFunc) DialContext

func (df DialerFunc) DialContext(ctx context.Context, network, address string) (net.Conn, error)

DialContext implements the Dialer interface.

type Handshaker

type Handshaker = driver.Handshaker

Handshaker is the interface implemented by types that can perform a MongoDB handshake over a provided driver.Connection. This is used during connection initialization. Implementations must be goroutine safe.

type MonitorMode

type MonitorMode uint8

MonitorMode represents the way in which a server is monitored.

const (
	AutomaticMode MonitorMode = iota
	SingleMode
)

These constants are the available monitoring modes.

type PoolError

type PoolError string

PoolError is an error returned from a Pool method.

func (PoolError) Error

func (pe PoolError) Error() string

type SelectedServer

type SelectedServer struct {
	*Server

	Kind description.TopologyKind
}

SelectedServer represents a specific server that was selected during server selection. It contains the kind of the topology it was selected from.

func (*SelectedServer) Description

func (ss *SelectedServer) Description() description.SelectedServer

Description returns a description of the server as of the last heartbeat.

type Server

type Server struct {
	// contains filtered or unexported fields
}

Server is a single server within a topology.

func ConnectServer

func ConnectServer(
	addr address.Address,
	updateCallback updateTopologyCallback,
	topologyID primitive.ObjectID,
	opts ...ServerOption,
) (*Server, error)

ConnectServer creates a new Server and then initializes it using the Connect method.

func NewServer

func NewServer(addr address.Address, topologyID primitive.ObjectID, opts ...ServerOption) *Server

NewServer creates a new server. The mongodb server at the address will be monitored on an internal monitoring goroutine.

func (*Server) Connect

func (s *Server) Connect(updateCallback updateTopologyCallback) error

Connect initializes the Server by starting background monitoring goroutines. This method must be called before a Server can be used.

func (*Server) Connection

func (s *Server) Connection(ctx context.Context) (driver.Connection, error)

Connection gets a connection to the server.

func (*Server) Description

func (s *Server) Description() description.Server

Description returns a description of the server as of the last heartbeat.

func (*Server) Disconnect

func (s *Server) Disconnect(ctx context.Context) error

Disconnect closes sockets to the server referenced by this Server. Subscriptions to this Server will be closed. Disconnect will shutdown any monitoring goroutines, closeConnection the idle connection pool, and will wait until all the in use connections have been returned to the connection pool and are closed before returning. If the context expires via cancellation, deadline, or timeout before the in use connections have been returned, the in use connections will be closed, resulting in the failure of any in flight read or write operations. If this method returns with no errors, all connections associated with this Server have been closed.

func (*Server) OperationCount

func (s *Server) OperationCount() int64

OperationCount returns the current number of in-progress operations for this server.

func (*Server) ProcessError

func (s *Server) ProcessError(err error, conn driver.Connection) driver.ProcessErrorResult

ProcessError handles SDAM error handling and implements driver.ErrorProcessor.

func (*Server) ProcessHandshakeError

func (s *Server) ProcessHandshakeError(err error, startingGenerationNumber uint64, serviceID *primitive.ObjectID)

ProcessHandshakeError implements SDAM error handling for errors that occur before a connection finishes handshaking.

func (*Server) RTTMonitor

func (s *Server) RTTMonitor() driver.RTTMonitor

RTTMonitor returns this server's round-trip-time monitor.

func (*Server) RequestImmediateCheck

func (s *Server) RequestImmediateCheck()

RequestImmediateCheck will cause the server to send a heartbeat immediately instead of waiting for the heartbeat timeout.

func (*Server) SelectedDescription

func (s *Server) SelectedDescription() description.SelectedServer

SelectedDescription returns a description.SelectedServer with a Kind of Single. This can be used when performing tasks like monitoring a batch of servers and you want to run one off commands against those servers.

func (*Server) String

func (s *Server) String() string

String implements the Stringer interface.

func (*Server) Subscribe

func (s *Server) Subscribe() (*ServerSubscription, error)

Subscribe returns a ServerSubscription which has a channel on which all updated server descriptions will be sent. The channel will have a buffer size of one, and will be pre-populated with the current description.

type ServerOption

type ServerOption func(*serverConfig)

ServerOption configures a server.

func WithClock

func WithClock(fn func(clock *session.ClusterClock) *session.ClusterClock) ServerOption

WithClock configures the ClusterClock for the server to use.

func WithCompressionOptions

func WithCompressionOptions(fn func(...string) []string) ServerOption

WithCompressionOptions configures the server's compressors.

func WithConnectionOptions

func WithConnectionOptions(fn func(...ConnectionOption) []ConnectionOption) ServerOption

WithConnectionOptions configures the server's connections.

func WithConnectionPoolMaintainInterval

func WithConnectionPoolMaintainInterval(fn func(time.Duration) time.Duration) ServerOption

WithConnectionPoolMaintainInterval configures the interval that the background connection pool maintenance goroutine runs.

func WithConnectionPoolMaxIdleTime

func WithConnectionPoolMaxIdleTime(fn func(time.Duration) time.Duration) ServerOption

WithConnectionPoolMaxIdleTime configures the maximum time that a connection can remain idle in the connection pool before being removed. If connectionPoolMaxIdleTime is 0, then no idle time is set and connections will not be removed because of their age

func WithConnectionPoolMonitor

func WithConnectionPoolMonitor(fn func(*event.PoolMonitor) *event.PoolMonitor) ServerOption

WithConnectionPoolMonitor configures the monitor for all connection pool actions

func WithHeartbeatInterval

func WithHeartbeatInterval(fn func(time.Duration) time.Duration) ServerOption

WithHeartbeatInterval configures a server's heartbeat interval.

func WithHeartbeatTimeout

func WithHeartbeatTimeout(fn func(time.Duration) time.Duration) ServerOption

WithHeartbeatTimeout configures how long to wait for a heartbeat socket to connection.

func WithMaxConnecting

func WithMaxConnecting(fn func(uint64) uint64) ServerOption

WithMaxConnecting configures the maximum number of connections a connection pool may establish simultaneously. If maxConnecting is 0, the default value of 2 is used.

func WithMaxConnections

func WithMaxConnections(fn func(uint64) uint64) ServerOption

WithMaxConnections configures the maximum number of connections to allow for a given server. If max is 0, then maximum connection pool size is not limited.

func WithMinConnections

func WithMinConnections(fn func(uint64) uint64) ServerOption

WithMinConnections configures the minimum number of connections to allow for a given server. If min is 0, then there is no lower limit to the number of connections.

func WithRegistry

func WithRegistry(fn func(*bsoncodec.Registry) *bsoncodec.Registry) ServerOption

WithRegistry configures the registry for the server to use when creating cursors.

func WithServerAPI

func WithServerAPI(fn func(serverAPI *driver.ServerAPIOptions) *driver.ServerAPIOptions) ServerOption

WithServerAPI configures the server API options for the server to use.

func WithServerAppName

func WithServerAppName(fn func(string) string) ServerOption

WithServerAppName configures the server's application name.

func WithServerLoadBalanced

func WithServerLoadBalanced(fn func(bool) bool) ServerOption

WithServerLoadBalanced specifies whether or not the server is behind a load balancer.

func WithServerMonitor

func WithServerMonitor(fn func(*event.ServerMonitor) *event.ServerMonitor) ServerOption

WithServerMonitor configures the monitor for all SDAM events for a server

type ServerSelectionError

type ServerSelectionError struct {
	Desc    description.Topology
	Wrapped error
}

ServerSelectionError represents a Server Selection error.

func (ServerSelectionError) Error

func (e ServerSelectionError) Error() string

Error implements the error interface.

func (ServerSelectionError) Unwrap

func (e ServerSelectionError) Unwrap() error

Unwrap returns the underlying error.

type ServerSubscription

type ServerSubscription struct {
	C <-chan description.Server
	// contains filtered or unexported fields
}

ServerSubscription represents a subscription to the description.Server updates for a specific server.

func (*ServerSubscription) Unsubscribe

func (ss *ServerSubscription) Unsubscribe() error

Unsubscribe unsubscribes this ServerSubscription from updates and closes the subscription channel.

type Topology

type Topology struct {
	// contains filtered or unexported fields
}

Topology represents a MongoDB deployment.

func New

func New(cfg *Config) (*Topology, error)

New creates a new topology. A "nil" config is interpreted as the default configuration.

func (*Topology) Connect

func (t *Topology) Connect() error

Connect initializes a Topology and starts the monitoring process. This function must be called to properly monitor the topology.

func (*Topology) Description

func (t *Topology) Description() description.Topology

Description returns a description of the topology.

func (*Topology) Disconnect

func (t *Topology) Disconnect(ctx context.Context) error

Disconnect closes the topology. It stops the monitoring thread and closes all open subscriptions.

func (*Topology) FindServer

func (t *Topology) FindServer(selected description.Server) (*SelectedServer, error)

FindServer will attempt to find a server that fits the given server description. This method will return nil, nil if a matching server could not be found.

func (*Topology) Kind

func (t *Topology) Kind() description.TopologyKind

Kind returns the topology kind of this Topology.

func (*Topology) RequestImmediateCheck

func (t *Topology) RequestImmediateCheck()

RequestImmediateCheck will send heartbeats to all the servers in the topology right away, instead of waiting for the heartbeat timeout.

func (*Topology) SelectServer

func (t *Topology) SelectServer(ctx context.Context, ss description.ServerSelector) (driver.Server, error)

SelectServer selects a server with given a selector. SelectServer complies with the server selection spec, and will time out after serverSelectionTimeout or when the parent context is done.

func (*Topology) String

func (t *Topology) String() string

String implements the Stringer interface

func (*Topology) Subscribe

func (t *Topology) Subscribe() (*driver.Subscription, error)

Subscribe returns a Subscription on which all updated description.Topologys will be sent. The channel of the subscription will have a buffer size of one, and will be pre-populated with the current description.Topology. Subscribe implements the driver.Subscriber interface.

func (*Topology) Unsubscribe

func (t *Topology) Unsubscribe(sub *driver.Subscription) error

Unsubscribe unsubscribes the given subscription from the topology and closes the subscription channel. Unsubscribe implements the driver.Subscriber interface.

type WaitQueueTimeoutError

type WaitQueueTimeoutError struct {
	Wrapped error
	// contains filtered or unexported fields
}

WaitQueueTimeoutError represents a timeout when requesting a connection from the pool

func (WaitQueueTimeoutError) Error

func (w WaitQueueTimeoutError) Error() string

Error implements the error interface.

func (WaitQueueTimeoutError) Unwrap

func (w WaitQueueTimeoutError) Unwrap() error

Unwrap returns the underlying error.

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