lifecycle

Documentation

Overview

Package lifecycle provides a life cycle manager abstracting the starting and stopping of processes by registered start or stop hooks.

The following features as supported:

• Start hooks can either be called synchronously or asynchronously.
• Start hooks can use the application context (hard shutdown) or background context (graceful shutdown).
• Stop hooks are synchronous and use a shutdown context with 10s timeout.
• Ordering of start and stop hooks.
• Any error from start hooks immediately triggers graceful shutdown.
• Closing application context triggers graceful shutdown.
• Any error from stop hooks immediately triggers hard shutdown.

Index

• type HookFunc
  • func (fn HookFunc) Call(ctx context.Context) error
• type HookFuncCtx
  • func (fn HookFuncCtx) Call(ctx context.Context) error
• type HookFuncErr
  • func (fn HookFuncErr) Call(context.Context) error
• type HookFuncMin
  • func (fn HookFuncMin) Call(context.Context) error
• type HookStartType
• type IHookFunc
• type Manager
  • func (m *Manager) RegisterStart(typ HookStartType, order OrderStart, fn IHookFunc)
  • func (m *Manager) RegisterStop(order OrderStop, fn IHookFunc)
  • func (m *Manager) Run(appCtx context.Context) error
• type OrderStart
  • func (i OrderStart) String() string
• type OrderStop
  • func (i OrderStop) String() string

Types

type HookFunc

type HookFunc func(ctx context.Context) error

HookFunc wraps a standard hook function (context and error) as a IHookFunc.

func (HookFunc) Call

func (fn HookFunc) Call(ctx context.Context) error

type HookFuncCtx

type HookFuncCtx func(ctx context.Context)

HookFuncCtx wraps a context (no error) hook function as a IHookFunc.

func (HookFuncCtx) Call

func (fn HookFuncCtx) Call(ctx context.Context) error

type HookFuncErr

type HookFuncErr func() error

HookFuncErr wraps an error (no context) hook function as a IHookFunc.

func (HookFuncErr) Call

func (fn HookFuncErr) Call(context.Context) error

type HookFuncMin

type HookFuncMin func()

HookFuncMin wraps a minimum (no context, no error) hook function as a IHookFunc.

func (HookFuncMin) Call

func (fn HookFuncMin) Call(context.Context) error

type HookStartType

type HookStartType int

HookStartType defines the type of start hook.

const (
	// AsyncAppCtx defines a start hook that will be called asynchronously (non-blocking)
	// with the application context. Using the application usually results in hard shutdown.
	AsyncAppCtx HookStartType = iota + 1

	// SyncBackground defines a start hook that wil be called synchronously (blocking)
	// with a fresh background context. Processes that support graceful shutdown can
	// associate this with a call to RegisterStop.
	SyncBackground

	// AsyncBackground defines a start hook that wil be called asynchronously (non-blocking)
	// with a fresh background context. Processes that support graceful shutdown can
	// associate this with a call to RegisterStop.
	AsyncBackground
)

type IHookFunc

type IHookFunc interface {
	Call(context.Context) error
}

IHookFunc is the life cycle hook function interface. Users will mostly wrap functions using one of the types below.

type Manager

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

Manager manages process life cycle by registered start and stop hooks.

func (*Manager) RegisterStart

func (m *Manager) RegisterStart(typ HookStartType, order OrderStart, fn IHookFunc)

RegisterStart registers a start hook. The type defines whether it is sync or async and which context is used. The order defines the order in which hooks are called.

func (*Manager) RegisterStop

func (m *Manager) RegisterStop(order OrderStop, fn IHookFunc)

RegisterStop registers a synchronous stop hook that will be called with the shutdown context that may timeout.

func (*Manager) Run

func (m *Manager) Run(appCtx context.Context) error

Run the lifecycle; start all hooks, waiting for shutdown, stop all hooks.

type OrderStart

type OrderStart int

OrderStart defines the order hooks are started.

const (
	StartAggSigDB OrderStart = iota
	StartRelay
	StartMonitoringAPI
	StartValidatorAPI
	StartP2PPing
	StartP2PConsensus
	StartSimulator
	StartScheduler
)

Global ordering of start hooks.

func (OrderStart) String

func (i OrderStart) String() string

type OrderStop

type OrderStop int

OrderStop defines the order hooks are stopped.

const (
	StopScheduler OrderStop = iota // High level components...
	StopRetryer
	StopDutyDB
	StopBeaconMock // Close this before validator API, since it can hold long-lived connections.
	StopValidatorAPI
	StopTracing // Low level services...
	StopP2PPeerDB
	StopP2PTCPNode
	StopP2PUDPNode
	StopMonitoringAPI
)

Global ordering of stop hooks; follows dependency tree from root to leaves.

func (OrderStop) String

func (i OrderStop) String() string