kvdbsync

Documentation

Overview

Package kvdbsync implements the key-value data store client and server that satisfythe datasync API. The datasync API contains the Data Broker & KeyValProtoWatcher APIs, which are basically facades in front of different key-value or SQL stores.

A key-value store is used as a transport channel between a remote client and the agent(server). It stores data/configuration for multiple agents (servers). Therefore, a client only needs to know the address of the key-value store but not the addresses of individual agents. The client can write data/configuration independently of the agent's (server's) lifecycle.

The Data KeyValProtoWatcher is used during regular operation to efficiently propagate data/configuration changes from the key & value store to the agents (servers). Upon receiving a data change event, the watcher makes an incremental update to its data. When data resynchronization (RESYNC) is triggered, then the Data Broker is used to read all particular keys & values from the key-value store. Reading all particular keys & values is a more reliable but less efficient data synchronization method.

Index

• type ChangeWatchResp
  • func NewChangeWatchResp(delegate keyval.ProtoWatchResp, prevVal datasync.LazyValue) *ChangeWatchResp
  • func (ev *ChangeWatchResp) GetChangeType() datasync.PutDel
  • func (ev *ChangeWatchResp) GetKey() string
  • func (ev *ChangeWatchResp) GetPrevValue(prevVal proto.Message) (exists bool, err error)
  • func (ev *ChangeWatchResp) GetRevision() (rev int64)
  • func (ev *ChangeWatchResp) GetValue(val proto.Message) (err error)
• type Deps
• type Iterator
  • func NewIterator(delegate keyval.ProtoKeyValIterator) *Iterator
  • func (it *Iterator) GetNext() (kv datasync.KeyVal, stop bool)
• type Plugin
  • func (plugin *Plugin) AfterInit() error
  • func (plugin *Plugin) Close() error
  • func (plugin *Plugin) Init() error
  • func (plugin *Plugin) Put(key string, data proto.Message, opts ...datasync.PutOption) error
  • func (plugin *Plugin) String() string
  • func (plugin *Plugin) Watch(resyncName string, changeChan chan datasync.ChangeEvent, ...) (datasync.WatchRegistration, error)

Types

type ChangeWatchResp

type ChangeWatchResp struct {
	*syncbase.DoneChannel
	// contains filtered or unexported fields
}

ChangeWatchResp is a structure that adapts the BytesWatchResp to the datasync api.

func NewChangeWatchResp

func NewChangeWatchResp(delegate keyval.ProtoWatchResp, prevVal datasync.LazyValue) *ChangeWatchResp

NewChangeWatchResp creates a new instance of ChangeWatchResp.

func (*ChangeWatchResp) GetChangeType

func (ev *ChangeWatchResp) GetChangeType() datasync.PutDel

GetChangeType - see the comment in implemented interface datasync.ChangeEvent

func (*ChangeWatchResp) GetKey

func (ev *ChangeWatchResp) GetKey() string

GetKey returns the key associated with the change

func (*ChangeWatchResp) GetPrevValue

func (ev *ChangeWatchResp) GetPrevValue(prevVal proto.Message) (exists bool, err error)

GetPrevValue delegates to WatchResp. For description of parameter and output values see the comment in implemented interface datasync.ChangeEvent

func (*ChangeWatchResp) GetRevision

func (ev *ChangeWatchResp) GetRevision() (rev int64)

GetRevision returns revision associated with the change.

func (*ChangeWatchResp) GetValue

func (ev *ChangeWatchResp) GetValue(val proto.Message) (err error)

GetValue delegates to WatchResp. For description of parameter and output values see the comment in implemented interface datasync.ChangeEvent

type Deps

type Deps struct {
	localdeps.PluginInfraDeps                      // inject
	ResyncOrch                resync.Subscriber    // inject
	KvPlugin                  keyval.KvProtoPlugin // inject
}

Deps is here to group injected dependencies of plugin to not mix with other plugin fields.

type Iterator

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

Iterator adapts the db_proto.KeyValIterator to the datasync.KeyValIterator

func NewIterator

func NewIterator(delegate keyval.ProtoKeyValIterator) *Iterator

NewIterator creates a new instance of Iterator.

func (*Iterator) GetNext

func (it *Iterator) GetNext() (kv datasync.KeyVal, stop bool)

GetNext just delegate GetNext

type Plugin

type Plugin struct {
	Deps // inject
	// contains filtered or unexported fields
}

Plugin dbsync implements Plugin interface

func (*Plugin) AfterInit

func (plugin *Plugin) AfterInit() error

AfterInit uses provided connection to build new transport watcher

func (*Plugin) Close

func (plugin *Plugin) Close() error

Close resources

func (*Plugin) Init

func (plugin *Plugin) Init() error

Init does nothing

func (*Plugin) Put

func (plugin *Plugin) Put(key string, data proto.Message, opts ...datasync.PutOption) error

Put to ETCD or any other data transport (from other Agent Plugins)

func (*Plugin) String

func (plugin *Plugin) String() string

String returns if set Deps.PluginName or "kvdbsync" otherwise

func (*Plugin) Watch

func (plugin *Plugin) Watch(resyncName string, changeChan chan datasync.ChangeEvent,
	resyncChan chan datasync.ResyncEvent, keyPrefixes ...string) (datasync.WatchRegistration, error)

Watch using ETCD or any other Key Val data store.