detector

Documentation

Overview

The detector package houses implementation of master detectors. The default implementation is the zookeeper master detector. It uses zookeeper to detect the lead Mesos master during startup/failover.

Index

• Variables
• func CreateMasterInfo(pid *upid.UPID) *mesos.MasterInfo
• func Register(prefix string, f PluginFactory) error
• type AllMasters
• type Master
  • func New(spec string, options ...Option) (m Master, err error)
• type MasterChanged
• type OnMasterChanged
  • func (f OnMasterChanged) OnMasterChanged(mi *mesos.MasterInfo)
• type Option
• type PluginFactory
  • func MatchingPlugin(spec string) (PluginFactory, bool)
• type Standalone
  • func NewStandalone(mi *mesos.MasterInfo) *Standalone
  • func (s *Standalone) Cancel()
  • func (s *Standalone) Detect(o MasterChanged) error
  • func (s *Standalone) Done() <-chan struct{}
  • func (s *Standalone) String() string

Variables

var (

	// ErrEmptySpec is the error for when no master is provided
	ErrEmptySpec = errors.New("empty master specification")
)

Functions

func CreateMasterInfo

func CreateMasterInfo(pid *upid.UPID) *mesos.MasterInfo

Super-useful utility func that attempts to build a mesos.MasterInfo from a upid.UPID specification. An attempt is made to determine the IP address of the UPID's Host and any errors during such resolution will result in a nil returned result. A nil result is also returned upon errors parsing the Port specification of the UPID.

TODO(jdef) make this a func of upid.UPID so that callers can invoke somePid.MasterInfo()?

func Register

func Register(prefix string, f PluginFactory) error

associates a plugin implementation with a Master specification prefix. packages that provide plugins are expected to invoke this func within their init() implementation. schedulers that wish to support plugins may anonymously import ("_") a package the auto-registers said plugins.

Types

type AllMasters

type AllMasters interface {
	// UpdatedMasters is invoked upon a change in the membership of mesos
	// masters, and is useful to clients that wish to know the entire set
	// of Mesos masters currently running.
	UpdatedMasters([]*mesos.MasterInfo)
}

AllMasters defines an optional interface that, if implemented by the same struct as implements MasterChanged, will receive an additional callbacks independently of leadership changes. it's possible that, as a result of a leadership change, both the OnMasterChanged and UpdatedMasters callbacks would be invoked.

**NOTE:** Detector implementations are not required to support this optional interface. Please RTFM of the detector implementation that you want to use.

type Master

type Master interface {
	// Detect new master election. Every time a new master is elected, the
	// detector will alert the observer. The first call to Detect is expected
	// to kickstart any background detection processing (and not before then).
	// If detection startup fails, or the listener cannot be added, then an
	// error is returned.
	Detect(MasterChanged) error

	// returns a chan that, when closed, indicates the detector has terminated
	Done() <-chan struct{}

	// cancel the detector. it's ok to call this multiple times, or even if
	// Detect() hasn't been invoked yet.
	Cancel()
}

An abstraction of a Master detector which can be used to detect the leading master from a group.

func New

func New(spec string, options ...Option) (m Master, err error)

Create a new detector given the provided specification. Examples are:

• file://{path_to_local_file}
• {ipaddress}:{port}
• master@{ip_address}:{port}
• master({id})@{ip_address}:{port}

Support for the file:// prefix is intentionally hardcoded so that it may not be inadvertently overridden by a custom plugin implementation. Custom plugins are supported via the Register and MatchingPlugin funcs.

Furthermore it is expected that master detectors returned from this func are not yet running and will only begin to spawn requisite background processing upon, or some time after, the first invocation of their Detect.

type MasterChanged

type MasterChanged interface {
	// Invoked when the master changes
	OnMasterChanged(*mesos.MasterInfo)
}

type OnMasterChanged

type OnMasterChanged func(*mesos.MasterInfo)

func/interface adapter

func (OnMasterChanged) OnMasterChanged

func (f OnMasterChanged) OnMasterChanged(mi *mesos.MasterInfo)

type Option

type Option func(interface{}) Option

functional option type for detectors

type PluginFactory

type PluginFactory func(string, ...Option) (Master, error)

func MatchingPlugin

func MatchingPlugin(spec string) (PluginFactory, bool)

type Standalone

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

func NewStandalone

func NewStandalone(mi *mesos.MasterInfo) *Standalone

Create a new stand alone master detector.

func (*Standalone) Cancel

func (s *Standalone) Cancel()

func (*Standalone) Detect

func (s *Standalone) Detect(o MasterChanged) error

Detecting the new master.

func (*Standalone) Done

func (s *Standalone) Done() <-chan struct{}

func (*Standalone) String

func (s *Standalone) String() string