 Documentation
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      Documentation
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    Overview ¶
Package zk is a native Go client library for the ZooKeeper orchestration service.
Index ¶
- Constants
- Variables
- func FLWRuok(servers []string, timeout time.Duration) []bool
- func FormatServers(servers []string) []string
- func StartTracer(listenAddr, serverAddr string)
- type ACL
- type CheckVersionRequest
- type Conn
- func (c *Conn) AddAuth(scheme string, auth []byte) error
- func (c *Conn) Children(path string) ([]string, *Stat, error)
- func (c *Conn) ChildrenW(path string) ([]string, *Stat, <-chan Event, error)
- func (c *Conn) Close()
- func (c *Conn) Create(path string, data []byte, flags int32, acl []ACL) (string, error)
- func (c *Conn) CreateProtectedEphemeralSequential(path string, data []byte, acl []ACL) (string, error)
- func (c *Conn) Delete(path string, version int32) error
- func (c *Conn) Exists(path string) (bool, *Stat, error)
- func (c *Conn) ExistsW(path string) (bool, *Stat, <-chan Event, error)
- func (c *Conn) Get(path string) ([]byte, *Stat, error)
- func (c *Conn) GetACL(path string) ([]ACL, *Stat, error)
- func (c *Conn) GetW(path string) ([]byte, *Stat, <-chan Event, error)
- func (c *Conn) Multi(ops ...interface{}) ([]MultiResponse, error)
- func (c *Conn) Set(path string, data []byte, version int32) (*Stat, error)
- func (c *Conn) SetACL(path string, acl []ACL, version int32) (*Stat, error)
- func (c *Conn) SetLogger(l Logger)
- func (c *Conn) State() State
- func (c *Conn) Sync(path string) (string, error)
 
- type CreateRequest
- type DeleteRequest
- type Dialer
- type ErrCode
- type ErrMissingServerConfigField
- type Event
- type EventType
- type Lock
- type Logger
- type Mode
- type MultiResponse
- type PathVersionRequest
- type Server
- type ServerClient
- type ServerClients
- type ServerConfig
- type ServerConfigServer
- type ServerStats
- type SetDataRequest
- type Stat
- type State
- type TestCluster
- type TestServer
Constants ¶
const ( EventNodeCreated = EventType(1) EventNodeDeleted = EventType(2) EventNodeDataChanged = EventType(3) EventNodeChildrenChanged = EventType(4) EventSession = EventType(-1) EventNotWatching = EventType(-2) )
const ( StateUnknown = State(-1) StateDisconnected = State(0) StateConnecting = State(1) StateAuthFailed = State(4) StateConnectedReadOnly = State(5) StateSaslAuthenticated = State(6) StateExpired = State(-112) StateConnected = State(100) StateHasSession = State(101) )
const ( FlagEphemeral = 1 FlagSequence = 2 )
const ( PermRead = 1 << iota PermWrite PermCreate PermDelete PermAdmin PermAll = 0x1f )
Constants for ACL permissions
const ( DefaultServerTickTime = 2000 DefaultServerInitLimit = 10 DefaultServerSyncLimit = 5 DefaultServerAutoPurgeSnapRetainCount = 3 DefaultPeerPort = 2888 DefaultLeaderElectionPort = 3888 )
const (
	DefaultPort = 2181
)
    Variables ¶
var ( ErrConnectionClosed = errors.New("zk: connection closed") ErrUnknown = errors.New("zk: unknown error") ErrAPIError = errors.New("zk: api error") ErrNoNode = errors.New("zk: node does not exist") ErrNoAuth = errors.New("zk: not authenticated") ErrBadVersion = errors.New("zk: version conflict") ErrNoChildrenForEphemerals = errors.New("zk: ephemeral nodes may not have children") ErrNodeExists = errors.New("zk: node already exists") ErrNotEmpty = errors.New("zk: node has children") ErrSessionExpired = errors.New("zk: session has been expired by the server") ErrInvalidACL = errors.New("zk: invalid ACL specified") ErrAuthFailed = errors.New("zk: client authentication failed") ErrClosing = errors.New("zk: zookeeper is closing") ErrNothing = errors.New("zk: no server responsees to process") ErrSessionMoved = errors.New("zk: session moved to another server, so operation is ignored") )
var ( // ErrDeadlock is returned by Lock when trying to lock twice without unlocking first ErrDeadlock = errors.New("zk: trying to acquire a lock twice") // ErrNotLocked is returned by Unlock when trying to release a lock that has not first be acquired. ErrNotLocked = errors.New("zk: not locked") )
var ( ErrUnhandledFieldType = errors.New("zk: unhandled field type") ErrPtrExpected = errors.New("zk: encode/decode expect a non-nil pointer to struct") ErrShortBuffer = errors.New("zk: buffer too small") )
ErrInvalidPath indicates that an operation was being attempted on an invalid path. (e.g. empty path)
ErrNoServer indicates that an operation cannot be completed because attempts to connect to all servers in the list failed.
Functions ¶
func FLWRuok ¶
FLWRuok is a FourLetterWord helper function. In particular, this function pulls the ruok output from each server.
func FormatServers ¶
FormatServers takes a slice of addresses, and makes sure they are in a format that resembles <addr>:<port>. If the server has no port provided, the DefaultPort constant is added to the end.
Types ¶
type ACL ¶
func AuthACL ¶
AuthACL produces an ACL list containing a single ACL which uses the provided permissions, with the scheme "auth", and ID "", which is used by ZooKeeper to represent any authenticated user.
type CheckVersionRequest ¶
type CheckVersionRequest PathVersionRequest
type Conn ¶
type Conn struct {
	// contains filtered or unexported fields
}
    func Connect ¶
Connect establishes a new connection to a pool of zookeeper servers using the default net.Dialer. See ConnectWithDialer for further information about session timeout.
func ConnectWithDialer ¶
func ConnectWithDialer(servers []string, sessionTimeout time.Duration, dialer Dialer) (*Conn, <-chan Event, error)
ConnectWithDialer establishes a new connection to a pool of zookeeper servers. The provided session timeout sets the amount of time for which a session is considered valid after losing connection to a server. Within the session timeout it's possible to reestablish a connection to a different server and keep the same session. This is means any ephemeral nodes and watches are maintained.
func (*Conn) ChildrenW ¶
func (*Conn) Create ¶
func (*Conn) CreateProtectedEphemeralSequential ¶
func (c *Conn) CreateProtectedEphemeralSequential(path string, data []byte, acl []ACL) (string, error)
CreateProtectedEphemeralSequential fixes a race condition if the server crashes after it creates the node. On reconnect the session may still be valid so the ephemeral node still exists. Therefore, on reconnect we need to check if a node with a GUID generated on create exists.
func (*Conn) GetW ¶
GetW returns the contents of a znode and sets a watch
func (*Conn) Multi ¶
func (c *Conn) Multi(ops ...interface{}) ([]MultiResponse, error)
Multi executes multiple ZooKeeper operations or none of them. The provided ops must be one of *CreateRequest, *DeleteRequest, *SetDataRequest, or *CheckVersionRequest.
func (*Conn) SetLogger ¶ added in v1.0.8
SetLogger sets the logger to be used for printing errors. Logger is an interface provided by this package.
func (*Conn) State ¶
States returns the current state of the connection.
type DeleteRequest ¶
type DeleteRequest PathVersionRequest
type ErrMissingServerConfigField ¶
type ErrMissingServerConfigField string
func (ErrMissingServerConfigField) Error ¶
func (e ErrMissingServerConfigField) Error() string
type Event ¶
type Lock ¶
type Lock struct {
	// contains filtered or unexported fields
}
    Lock is a mutual exclusion lock.
func NewLock ¶
NewLock creates a new lock instance using the provided connection, path, and acl. The path must be a node that is only used by this lock. A lock instances starts unlocked until Lock() is called.
func (*Lock) Lock ¶
Lock attempts to acquire the lock. It will wait to return until the lock is acquired or an error occurs. If this instance already has the lock then ErrDeadlock is returned.
type Logger ¶ added in v1.0.8
type Logger interface {
	Printf(string, ...interface{})
}
    Logger is an interface that can be implemented to provide custom log output.
var DefaultLogger Logger = defaultLogger{}
    DefaultLogger uses the stdlib log package for logging.
type Server ¶
type ServerClient ¶
type ServerClient struct {
	Queued        int64
	Received      int64
	Sent          int64
	SessionID     int64
	Lcxid         int64
	Lzxid         int64
	Timeout       int32
	LastLatency   int32
	MinLatency    int32
	AvgLatency    int32
	MaxLatency    int32
	Established   time.Time
	LastResponse  time.Time
	Addr          string
	LastOperation string // maybe?
	Error         error
}
    ServerClient is the information for a single Zookeeper client and its session. This is used to parse/extract the output fo the `cons` command.
type ServerClients ¶
type ServerClients struct {
	Clients []*ServerClient
	Error   error
}
    ServerClients is a struct for the FLWCons() function. It's used to provide the list of Clients.
This is needed because FLWCons() takes multiple servers.
func FLWCons ¶
func FLWCons(servers []string, timeout time.Duration) ([]*ServerClients, bool)
FLWCons is a FourLetterWord helper function. In particular, this function pulls the ruok output from each server.
As with FLWSrvr, the boolean value indicates whether one of the requests had an issue. The Clients struct has an Error value that can be checked.
type ServerConfig ¶
type ServerConfig struct {
	TickTime                 int    // Number of milliseconds of each tick
	InitLimit                int    // Number of ticks that the initial synchronization phase can take
	SyncLimit                int    // Number of ticks that can pass between sending a request and getting an acknowledgement
	DataDir                  string // Direcrory where the snapshot is stored
	ClientPort               int    // Port at which clients will connect
	AutoPurgeSnapRetainCount int    // Number of snapshots to retain in dataDir
	AutoPurgePurgeInterval   int    // Purge task internal in hours (0 to disable auto purge)
	Servers                  []ServerConfigServer
}
    func (ServerConfig) Marshall ¶
func (sc ServerConfig) Marshall(w io.Writer) error
type ServerConfigServer ¶
type ServerStats ¶
type ServerStats struct {
	Sent        int64
	Received    int64
	NodeCount   int64
	MinLatency  int64
	AvgLatency  int64
	MaxLatency  int64
	Connections int64
	Outstanding int64
	Epoch       int32
	Counter     int32
	BuildTime   time.Time
	Mode        Mode
	Version     string
	Error       error
}
    ServerStats is the information pulled from the Zookeeper `stat` command.
func FLWSrvr ¶
func FLWSrvr(servers []string, timeout time.Duration) ([]*ServerStats, bool)
FLWSrvr is a FourLetterWord helper function. In particular, this function pulls the srvr output from the zookeeper instances and parses the output. A slice of *ServerStats structs are returned as well as a boolean value to indicate whether this function processed successfully.
If the boolean value is false there was a problem. If the *ServerStats slice is empty or nil, then the error happened before we started to obtain 'srvr' values. Otherwise, one of the servers had an issue and the "Error" value in the struct should be inspected to determine which server had the issue.
type Stat ¶
type Stat struct {
	Czxid          int64 // The zxid of the change that caused this znode to be created.
	Mzxid          int64 // The zxid of the change that last modified this znode.
	Ctime          int64 // The time in milliseconds from epoch when this znode was created.
	Mtime          int64 // The time in milliseconds from epoch when this znode was last modified.
	Version        int32 // The number of changes to the data of this znode.
	Cversion       int32 // The number of changes to the children of this znode.
	Aversion       int32 // The number of changes to the ACL of this znode.
	EphemeralOwner int64 // The session id of the owner of this znode if the znode is an ephemeral node. If it is not an ephemeral node, it will be zero.
	DataLength     int32 // The length of the data field of this znode.
	NumChildren    int32 // The number of children of this znode.
	Pzxid          int64 // last modified children
}
    type TestCluster ¶
type TestCluster struct {
	Path    string
	Servers []TestServer
}
    func StartTestCluster ¶
func StartTestCluster(size int, stdout, stderr io.Writer) (*TestCluster, error)
func (*TestCluster) Connect ¶
func (ts *TestCluster) Connect(idx int) (*Conn, error)
func (*TestCluster) ConnectAll ¶
func (ts *TestCluster) ConnectAll() (*Conn, <-chan Event, error)
func (*TestCluster) ConnectAllTimeout ¶
func (*TestCluster) Stop ¶
func (ts *TestCluster) Stop() error
       Source Files
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      Source Files
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- conn.go
- constants.go
- flw.go
- lock.go
- server_help.go
- server_java.go
- structs.go
- tracer.go
- util.go