gossipcache

package module
v0.4.0 Latest Latest
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 Go to latest Published: Apr 12, 2023 License: MIT Imports: 18 Imported by: 0

README

Gossip powered group cache library

Why not plain groupcache?

Manually managing the list of peers sucks

Why mailgun's groupcache?

We using mailgun's groupcache fork instead of Google's because they've added support for context.Context, go.mod, and explicit key removal and expiration.

See also

Documentation

Overview

Package gossipcache provides a Gossip powered groupcache

Index

Constants

View Source 
const (
	// DefaultCacheBasePath is the default Path under the CacheBaseURL for the groupcache
	DefaultCacheBasePath = "/_groupcache/"
	// DefaultCacheReplicas indicated the default number of replicas for the groupcache
	DefaultCacheReplicas = 50
)

Variables

This section is empty.

Functions

func InferCacheBaseURL added in v0.4.0 

func InferCacheBaseURL(cfg *memberlist.Config) (string, error)

InferCacheBaseURL produces a CacheBaseURL pointing to https on 443/tcp of Transport's AdveriseAddr

func NewGossipTransport added in v0.4.0 

func NewGossipTransport(conf *Config) (memberlist.Transport, *transport.Config, error)

NewGossipTransport creates a transport.Transport from a Config

func NewGossipTransportConfig added in v0.4.0 

func NewGossipTransportConfig(conf *Config) (*transport.Config, error)

NewGossipTransportConfig creates a transport.Config from a Config

func NewMemberlistLogger 

func NewMemberlistLogger(l slog.Logger) *log.Logger

NewMemberlistLogger creates a standard logger to consume memberlist logs

func PrepareCacheBaseURL added in v0.4.0 

func PrepareCacheBaseURL(s string) (string, error)

PrepareCacheBaseURL sanitises a CacheBaseURL value

func SetMemberlistLogger 

func SetMemberlistLogger(cfg *memberlist.Config, l slog.Logger) error

SetMemberlistLogger sets a memberlist.Config to use a given slog.Logger

Types

type Cluster 

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

Cluster implements a memberlist for GossipCache

func NewCluster 

func NewCluster(conf *memberlist.Config, options ...ClusterConfigOption) (*Cluster, error)

NewCluster creates a new memberlist cluster for GossipCache

func Prepare 

func Prepare(conf *memberlist.Config, options ...ClusterConfigOption) (
	*Cluster, *memberlist.Config, error)

Prepare prepares a Cluster to be created

func (*Cluster) Create 

func (cluster *Cluster) Create() error

Create finishes the creation the Cluster. Only to be used after calling Prepare()

type ClusterConfigOption 

type ClusterConfigOption func(*Cluster, *memberlist.Config) error

ClusterConfigOption is used to adjust the memberlist.Config before creating the cluster

func WithAddress 

func WithAddress(host string) ClusterConfigOption

WithAddress creates a configuration option to set a specific binding address

func WithAliveDelegate 

func WithAliveDelegate(handler func(*Cluster, *memberlist.Node) error) ClusterConfigOption

WithAliveDelegate sets a callback to be invoked when a message about a live node is received from the network. Returning a non-nil error prevents the node from being considered a peer

func WithConflictDelegate 

func WithConflictDelegate(handler func(*Cluster,
	*memberlist.Node, *memberlist.Node)) ClusterConfigOption

WithConflictDelegate sets a callback to receive notifications about an attempt to join with a name already in use

func WithDefaultLANConfig 

func WithDefaultLANConfig() ClusterConfigOption

WithDefaultLANConfig sets the cluster configuration to the default recommended by memberlist for local network environments

func WithDefaultLocalConfig 

func WithDefaultLocalConfig() ClusterConfigOption

WithDefaultLocalConfig sets the cluster configuration to the default recommended by memberlist for local loopback environments

func WithDefaultWANConfig 

func WithDefaultWANConfig() ClusterConfigOption

WithDefaultWANConfig sets the cluster configuration to the default recommended by memberlist for WAN environments

func WithDelegateProtocolVersion 

func WithDelegateProtocolVersion(version, min, max uint8) ClusterConfigOption

WithDelegateProtocolVersion sets the Protocol versions we handle

func WithEventDelegate 

func WithEventDelegate(handler func(*Cluster,
	*memberlist.Node, memberlist.NodeEventType)) ClusterConfigOption

WithEventDelegate sets a callback to receive notifications about members joining and leaving

func WithGetBroadcastDelegate 

func WithGetBroadcastDelegate(handler func(*Cluster, int, int) [][]byte) ClusterConfigOption

WithGetBroadcastDelegate sets a callback to retrieve a list of buffers to broadcast

func WithGossipAdvertise 

func WithGossipAdvertise(host string, port int16) ClusterConfigOption

WithGossipAdvertise creates a configuration option for the Node to advertise different address/port than the one it's locally bound to

func WithGossipKey 

func WithGossipKey(salt string, key []byte) ClusterConfigOption

WithGossipKey creates a configuration option for the cluster's encryption

func WithGossipKeyBase64 

func WithGossipKeyBase64(salt, key string) ClusterConfigOption

WithGossipKeyBase64 creates a configuration option for the cluster's encryption

func WithGossipLogger 

func WithGossipLogger(logger slog.Logger) ClusterConfigOption

WithGossipLogger creates a configuration option for the Node to use a given slog.Logger

func WithGossipPort 

func WithGossipPort(port int16) ClusterConfigOption

WithGossipPort creates a configuration option to set a specific TCP/UDP port for the Gossip Node

func WithLocalStateDelegate 

func WithLocalStateDelegate(handler func(*Cluster, bool) []byte) ClusterConfigOption

WithLocalStateDelegate sets a callback to send the LocalState to a remote. The 'join' boolean indicates this is for a join instead of a push/pull

func WithMergeDelegate 

func WithMergeDelegate(handler func(*Cluster, []*memberlist.Node) error) ClusterConfigOption

WithMergeDelegate sets a callback when a merge operation could take place. If the return value is non-nil, the merge is canceled.

func WithMergeRemoteStateDelegate 

func WithMergeRemoteStateDelegate(handler func(*Cluster, []byte, bool)) ClusterConfigOption

WithMergeRemoteStateDelegate sets a callback to receive the LocalState of a remote. The 'join' boolean indicates this is for a join instead of a push/pull

func WithNodeMetaDelegate 

func WithNodeMetaDelegate(handler func(cluster *Cluster, limit int) []byte) ClusterConfigOption

WithNodeMetaDelegate sets a callback to provide information about the current node

func WithNotifyMsgDelegate 

func WithNotifyMsgDelegate(handler func(cluster *Cluster, userData []byte)) ClusterConfigOption

WithNotifyMsgDelegate sets a callback for received user-data

func WithPingDelegate 

func WithPingDelegate(payload []byte,
	completed func(*Cluster, *memberlist.Node, time.Duration, []byte)) ClusterConfigOption

WithPingDelegate sets a callback to notify an observer how long it took for a ping message to complete a round trip.

It can also be used for writing arbitrary byte slices into ack messages

func WithTransport 

func WithTransport(transport memberlist.Transport) ClusterConfigOption

WithTransport creates a configuration option to set the cluster's transport

type ClusterDelegate 

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

ClusterDelegate hooks handlers into the Memberlist Cluster life cycle

func (*ClusterDelegate) AckPayload 

func (cd *ClusterDelegate) AckPayload() []byte

AckPayload is invoked when an ack is being sent; the returned bytes will be appended to the ack

func (*ClusterDelegate) GetBroadcasts 

func (cd *ClusterDelegate) GetBroadcasts(overhead, limit int) [][]byte

GetBroadcasts is called when user data messages can be broadcast.

func (*ClusterDelegate) LocalState 

func (cd *ClusterDelegate) LocalState(join bool) []byte

LocalState is used for a TCP Push/Pull

func (*ClusterDelegate) MergeRemoteState 

func (cd *ClusterDelegate) MergeRemoteState(buf []byte, join bool)

MergeRemoteState is invoked after a TCP Push/Pull

func (*ClusterDelegate) NodeMeta 

func (cd *ClusterDelegate) NodeMeta(limit int) []byte

NodeMeta is used to retrieve meta-data about the current node when broadcasting an alive message

func (*ClusterDelegate) NotifyAlive 

func (cd *ClusterDelegate) NotifyAlive(peer *memberlist.Node) error

NotifyAlive is invoked when a message about a live node is received from the network

func (*ClusterDelegate) NotifyConflict 

func (cd *ClusterDelegate) NotifyConflict(existing, other *memberlist.Node)

NotifyConflict is invoked when a name conflict is detected

func (*ClusterDelegate) NotifyJoin 

func (cd *ClusterDelegate) NotifyJoin(node *memberlist.Node)

NotifyJoin is invoked when a node is detected to have joined.

func (*ClusterDelegate) NotifyLeave 

func (cd *ClusterDelegate) NotifyLeave(node *memberlist.Node)

NotifyLeave is invoked when a node is detected to have left.

func (*ClusterDelegate) NotifyMerge 

func (cd *ClusterDelegate) NotifyMerge(peers []*memberlist.Node) error

NotifyMerge is invoked when a merge could take place.

func (*ClusterDelegate) NotifyMsg 

func (cd *ClusterDelegate) NotifyMsg(userData []byte)

NotifyMsg is called when a user-data message is received.

func (*ClusterDelegate) NotifyPingComplete 

func (cd *ClusterDelegate) NotifyPingComplete(peer *memberlist.Node,
	rtt time.Duration, payload []byte)

NotifyPingComplete is invoked when an ack for a ping is received

func (*ClusterDelegate) NotifyUpdate 

func (cd *ClusterDelegate) NotifyUpdate(node *memberlist.Node)

NotifyUpdate is invoked when a node is detected to have

type Config added in v0.4.0 

type Config struct {
	// Context
	Context context.Context

	// Logger is an optional logger to bind to memberlist and groupcache
	Logger slog.Logger

	// Transport is the Cluster's transport configuration
	Transport *transport.Config

	// Memberlist is the Cluster's configuration
	Memberlist *memberlist.Config

	// CacheReplicas is the number of replicas in the groupcache.
	// If zero or negative it will be set to DefaultCacheReplicas
	CacheReplicas int

	// CacheBaseURL is the base of the advertised URL for the groupcache.
	// Path and Query string components will be ignored
	CacheBaseURL string
	// CacheBasePath is the path under the CacheBaseURL where the groupcache
	// handler is mounted
	CacheBasePath string

	// ClientTLSConfig is the tls.Config to be used when connecting to other
	// nodes of the cluster when https scheme is used
	ClientTLSConfig *tls.Config
}

Config represents the configuration used to setup the GossipCache node

func (*Config) SetDefaults added in v0.4.0 

func (conf *Config) SetDefaults() error

SetDefaults populates Config with defaults, except for CacheBaseURL which we will attempt to populate after memberlist is prepared

type GossipCache added in v0.4.0 

type GossipCache struct {
	*groupcache.HTTPPool
}

GossipCache is a groupcache cluster managed using memberlist

Source Files

View all Source files

Directories

Path Synopsis
Package transport provides a memberlist.Transport implementation
 Package transport provides a memberlist.Transport implementation

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