dispatcher

Documentation

Index

• Constants
• Variables
• type Cluster
• type Config
  • func DefaultConfig() *Config
• type Dispatcher
  • func New(cluster Cluster, c *Config) *Dispatcher
  • func (d *Dispatcher) Heartbeat(ctx context.Context, r *api.HeartbeatRequest) (*api.HeartbeatResponse, error)
  • func (d *Dispatcher) NodeCount() int
  • func (d *Dispatcher) Run(ctx context.Context) error
  • func (d *Dispatcher) Session(r *api.SessionRequest, stream api.Dispatcher_SessionServer) error
  • func (d *Dispatcher) Stop() error
  • func (d *Dispatcher) Tasks(r *api.TasksRequest, stream api.Dispatcher_TasksServer) error
  • func (d *Dispatcher) UpdateTaskStatus(ctx context.Context, r *api.UpdateTaskStatusRequest) (*api.UpdateTaskStatusResponse, error)

Constants

const (
	// DefaultHeartBeatPeriod is used for setting default value in cluster config
	// and in case if cluster config is missing.
	DefaultHeartBeatPeriod = 5 * time.Second
)

Variables

var (
	// ErrNodeAlreadyRegistered returned if node with same ID was already
	// registered with this dispatcher.
	ErrNodeAlreadyRegistered = errors.New("node already registered")
	// ErrNodeNotRegistered returned if node with such ID wasn't registered
	// with this dispatcher.
	ErrNodeNotRegistered = errors.New("node not registered")
	// ErrSessionInvalid returned when the session in use is no longer valid.
	// The node should re-register and start a new session.
	ErrSessionInvalid = errors.New("session invalid")
	// ErrNodeNotFound returned when the Node doesn't exist in raft.
	ErrNodeNotFound = errors.New("node not found")
)

Types

type Cluster

type Cluster interface {
	GetMemberlist() map[uint64]*api.RaftMember
	MemoryStore() *store.MemoryStore
}

Cluster is interface which represent raft cluster. mananger/state/raft.Node is implenents it. This interface needed only for easier unit-testing.

type Config

type Config struct {
	// Addr configures the address the dispatcher reports to agents.
	Addr             string
	HeartbeatPeriod  time.Duration
	HeartbeatEpsilon time.Duration
	// RateLimitPeriod specifies how often node with same ID can try to register
	// new session.
	RateLimitPeriod       time.Duration
	GracePeriodMultiplier int
}

Config is configuration for Dispatcher. For default you should use DefautConfig.

func DefaultConfig

func DefaultConfig() *Config

DefaultConfig returns default config for Dispatcher.

type Dispatcher

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

Dispatcher is responsible for dispatching tasks and tracking agent health.

func New

func New(cluster Cluster, c *Config) *Dispatcher

New returns Dispatcher with cluster interface(usually raft.Node). NOTE: each handler which does something with raft must add to Dispatcher.wg

func (*Dispatcher) Heartbeat

func (d *Dispatcher) Heartbeat(ctx context.Context, r *api.HeartbeatRequest) (*api.HeartbeatResponse, error)

Heartbeat is heartbeat method for nodes. It returns new TTL in response. Node should send new heartbeat earlier than now + TTL, otherwise it will be deregistered from dispatcher and its status will be updated to NodeStatus_DOWN

func (*Dispatcher) NodeCount

func (d *Dispatcher) NodeCount() int

NodeCount returns number of nodes which connected to this dispatcher.

func (*Dispatcher) Run

func (d *Dispatcher) Run(ctx context.Context) error

Run runs dispatcher tasks which should be run on leader dispatcher. Dispatcher can be stopped with cancelling ctx or calling Stop().

func (*Dispatcher) Session

func (d *Dispatcher) Session(r *api.SessionRequest, stream api.Dispatcher_SessionServer) error

Session is a stream which controls agent connection. Each message contains list of backup Managers with weights. Also there is a special boolean field Disconnect which if true indicates that node should reconnect to another Manager immediately.

func (*Dispatcher) Stop

func (d *Dispatcher) Stop() error

Stop stops dispatcher and closes all grpc streams.

func (*Dispatcher) Tasks

func (d *Dispatcher) Tasks(r *api.TasksRequest, stream api.Dispatcher_TasksServer) error

Tasks is a stream of tasks state for node. Each message contains full list of tasks which should be run on node, if task is not present in that list, it should be terminated.

func (*Dispatcher) UpdateTaskStatus

func (d *Dispatcher) UpdateTaskStatus(ctx context.Context, r *api.UpdateTaskStatusRequest) (*api.UpdateTaskStatusResponse, error)

UpdateTaskStatus updates status of task. Node should send such updates on every status change of its tasks.