Unknown is an unknown server or topology kind.
const Unknown = 0
SelectedServer augments the Server type by also including the TopologyKind of the topology that includes the server. This type should be used to track the state of a server that was selected to perform an operation.
type SelectedServer struct {
Server
Kind TopologyKind
}
Server contains information about a node in a cluster. This is created from hello command responses. If the value of the Kind field is LoadBalancer, only the Addr and Kind fields will be set. All other fields will be set to the zero value of the field's type.
type Server struct {
Addr address.Address
Arbiters []string
AverageRTT time.Duration
AverageRTTSet bool
Compression []string // compression methods returned by server
CanonicalAddr address.Address
ElectionID primitive.ObjectID
HeartbeatInterval time.Duration
HelloOK bool
Hosts []string
IsCryptd bool
LastError error
LastUpdateTime time.Time
LastWriteTime time.Time
MaxBatchCount uint32
MaxDocumentSize uint32
MaxMessageSize uint32
Members []address.Address
Passives []string
Passive bool
Primary address.Address
ReadOnly bool
ServiceID *primitive.ObjectID // Only set for servers that are deployed behind a load balancer.
// Deprecated: Use SessionTimeoutMinutesPtr instead.
SessionTimeoutMinutes uint32
SessionTimeoutMinutesPtr *int64
SetName string
SetVersion uint32
Tags tag.Set
TopologyVersion *TopologyVersion
Kind ServerKind
WireVersion *VersionRange
}
func NewDefaultServer(addr address.Address) Server
NewDefaultServer creates a new unknown server description with the given address.
func NewServer(addr address.Address, response bson.Raw) Server
NewServer creates a new server description from the given hello command response.
func NewServerFromError(addr address.Address, err error, tv *TopologyVersion) Server
NewServerFromError creates a new unknown server description with the given parameters.
func (s Server) DataBearing() bool
DataBearing returns true if the server is a data bearing server.
func (s Server) Equal(other Server) bool
Equal compares two server descriptions and returns true if they are equal
func (s Server) LoadBalanced() bool
LoadBalanced returns true if the server is a load balancer or is behind a load balancer.
func (s Server) SetAverageRTT(rtt time.Duration) Server
SetAverageRTT sets the average round trip time for this server description.
func (s Server) String() string
String implements the Stringer interface
ServerKind represents the type of a single server in a topology.
type ServerKind uint32
These constants are the possible types of servers.
const (
Standalone ServerKind = 1
RSMember ServerKind = 2
RSPrimary ServerKind = 4 + RSMember
RSSecondary ServerKind = 8 + RSMember
RSArbiter ServerKind = 16 + RSMember
RSGhost ServerKind = 32 + RSMember
Mongos ServerKind = 256
LoadBalancer ServerKind = 512
)
func (kind ServerKind) String() string
String returns a stringified version of the kind or "Unknown" if the kind is invalid.
ServerSelector is an interface implemented by types that can perform server selection given a topology description and list of candidate servers. The selector should filter the provided candidates list and return a subset that matches some criteria.
type ServerSelector interface {
SelectServer(Topology, []Server) ([]Server, error)
}
func CompositeSelector(selectors []ServerSelector) ServerSelector
CompositeSelector combines multiple selectors into a single selector by applying them in order to the candidates list.
For example, if the initial candidates list is [s0, s1, s2, s3] and two selectors are provided where the first matches s0 and s1 and the second matches s1 and s2, the following would occur during server selection:
1. firstSelector([s0, s1, s2, s3]) -> [s0, s1] 2. secondSelector([s0, s1]) -> [s1]
The final list of candidates returned by the composite selector would be [s1].
func LatencySelector(latency time.Duration) ServerSelector
LatencySelector creates a ServerSelector which selects servers based on their average RTT values.
func OutputAggregateSelector(rp *readpref.ReadPref) ServerSelector
OutputAggregateSelector selects servers based on the provided read preference given that the underlying operation is aggregate with an output stage.
func ReadPrefSelector(rp *readpref.ReadPref) ServerSelector
ReadPrefSelector selects servers based on the provided read preference.
func WriteSelector() ServerSelector
WriteSelector selects all the writable servers.
ServerSelectorFunc is a function that can be used as a ServerSelector.
type ServerSelectorFunc func(Topology, []Server) ([]Server, error)
func (ssf ServerSelectorFunc) SelectServer(t Topology, s []Server) ([]Server, error)
SelectServer implements the ServerSelector interface.
Topology contains information about a MongoDB cluster.
type Topology struct {
Servers []Server
SetName string
Kind TopologyKind
// Deprecated: Use SessionTimeoutMinutesPtr instead.
SessionTimeoutMinutes uint32
SessionTimeoutMinutesPtr *int64
CompatibilityErr error
}
func (t Topology) Equal(other Topology) bool
Equal compares two topology descriptions and returns true if they are equal.
func (t Topology) HasReadableServer(mode readpref.Mode) bool
HasReadableServer returns true if the topology contains a server suitable for reading.
If the Topology's kind is Single or Sharded, the mode parameter is ignored and the function contains true if any of the servers in the Topology are of a known type.
For replica sets, the function returns true if the cluster contains a server that matches the provided read preference mode.
func (t Topology) HasWritableServer() bool
HasWritableServer returns true if a topology has a server available for writing.
If the Topology's kind is Single or Sharded, this function returns true if any of the servers in the Topology are of a known type.
For replica sets, the function returns true if the replica set contains a primary.
func (t Topology) String() string
String implements the Stringer interface.
TopologyKind represents a specific topology configuration.
type TopologyKind uint32
These constants are the available topology configurations.
const (
Single TopologyKind = 1
ReplicaSet TopologyKind = 2
ReplicaSetNoPrimary TopologyKind = 4 + ReplicaSet
ReplicaSetWithPrimary TopologyKind = 8 + ReplicaSet
Sharded TopologyKind = 256
LoadBalanced TopologyKind = 512
)
func (kind TopologyKind) String() string
String implements the fmt.Stringer interface.
TopologyVersion represents a software version.
type TopologyVersion struct {
ProcessID primitive.ObjectID
Counter int64
}
func NewTopologyVersion(doc bson.Raw) (*TopologyVersion, error)
NewTopologyVersion creates a TopologyVersion based on doc
func (tv *TopologyVersion) CompareToIncoming(responseTV *TopologyVersion) int
CompareToIncoming compares the receiver, which represents the currently known TopologyVersion for a server, to an incoming TopologyVersion extracted from a server command response.
This returns -1 if the receiver version is less than the response, 0 if the versions are equal, and 1 if the receiver version is greater than the response. This comparison is not commutative.
VersionRange represents a range of versions.
type VersionRange struct {
Min int32
Max int32
}
func NewVersionRange(min, max int32) VersionRange
NewVersionRange creates a new VersionRange given a min and a max.
func (vr *VersionRange) Equals(other *VersionRange) bool
Equals returns a bool indicating whether the supplied VersionRange is equal.
func (vr VersionRange) Includes(v int32) bool
Includes returns a bool indicating whether the supplied integer is included in the range.
func (vr VersionRange) String() string
String implements the fmt.Stringer interface.