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sharedptr.go
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sharedptr.go
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// Copyright 2020 The searKing Author. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package resilience
import (
"context"
"fmt"
"strings"
"sync"
"time"
"github.com/searKing/golang/go/sync/atomic"
"github.com/sirupsen/logrus"
)
const (
// DefaultConnectTimeout is the default timeout to establish a connection to
// a ZooKeeper node.
DefaultResilienceConstructTimeout = 0
// DefaultSessionTimeout is the default timeout to keep the current
// ZooKeeper session alive during a temporary disconnect.
DefaultResilienceTaskMaxRetryDuration = 15 * time.Second
DefaultTaskRetryTimeout = 1 * time.Second
DefaultTaskRescheduleTimeout = 1 * time.Second
)
var (
ErrEmptyValue = fmt.Errorf("empty value")
ErrAlreadyShutdown = fmt.Errorf("already shutdown")
ErrNotReady = fmt.Errorf("not ready")
ErrAlreadyAddedTask = fmt.Errorf("task is already added")
)
type SharedPtr struct {
sp *sharedPtr
mu sync.Mutex
backgroundStopped atomic.Bool
WatchStopped atomic.Bool
}
func NewSharedPtr(ctx context.Context, new func() (Ptr, error), l logrus.FieldLogger) *SharedPtr {
return &SharedPtr{
sp: newSharedPtrSafe(ctx, new, l),
}
}
//
// The returned context is always non-nil; it defaults to the
// background context.
func (g *SharedPtr) Context() context.Context {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.Context()
}
func (g *SharedPtr) GetLogger() logrus.FieldLogger {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.GetLogger()
}
func (g *SharedPtr) InShutdown() bool {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.InShutdown()
}
func (g *SharedPtr) GetTaskById(id string) (task *Task, has bool) {
//g.mu.Lock()
//defer g.mu.Unlock()
return g.sp.GetTaskById(id)
}
func (g *SharedPtr) GetTasks() map[string]*Task {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.GetTasks()
}
func (g *SharedPtr) AddTask(task *Task) error {
if task == nil {
go g.GetLogger().WithError(ErrEmptyValue).
Error("task is nil to add, ignore it...")
return ErrEmptyValue
}
if task.Handle == nil {
go g.GetLogger().WithField("task", task.String()).WithError(ErrEmptyValue).
Error("task is nonsense to add, ignore it...")
return ErrEmptyValue
}
if g.InShutdown() {
go g.GetLogger().WithField("task", task.String()).
Error("resilience is shutdown already, ignore it...")
return ErrAlreadyShutdown
}
task.Ctx, task.CancelFn = context.WithCancel(g.Context())
if _, addedTask := g.GetTaskById(task.ID()); addedTask {
go g.GetLogger().WithField("task", task.String()).
Error("task is added already, ignore it...")
return ErrAlreadyAddedTask
}
go g.backgroundTask()
go func() {
go g.GetLogger().WithField("task", task.String()).Info("new task is adding...")
g.getTaskC() <- task
}()
return nil
}
func (g *SharedPtr) AddTaskFunc(taskType TaskType, handle func() error, descriptions ...string) error {
return g.AddTask(&Task{
Description: strings.Join(descriptions, ""),
Type: taskType,
Handle: handle,
RetryDuration: DefaultTaskRetryTimeout,
RepeatDuration: DefaultTaskRescheduleTimeout,
Ctx: g.Context(),
})
}
func (g *SharedPtr) AddTaskFuncAsConstruct(handle func() error, descriptions ...string) error {
return g.AddTaskFunc(TaskType{Construct: true}, handle, descriptions...)
}
func (g *SharedPtr) AddTaskFuncAsConstructRepeat(handle func() error, descriptions ...string) error {
return g.AddTaskFunc(TaskType{Construct: true, Repeat: true}, handle, descriptions...)
}
func (g *SharedPtr) AddTaskFuncAsRepeat(handle func() error, descriptions ...string) error {
return g.AddTaskFunc(TaskType{Repeat: true}, handle, descriptions...)
}
func (g *SharedPtr) AddTaskFuncAsRetry(handle func() error, descriptions ...string) error {
return g.AddTaskFunc(TaskType{Retry: true}, handle, descriptions...)
}
func (g *SharedPtr) RemoveTaskById(id string) {
g.mu.Lock()
defer g.mu.Unlock()
g.sp.RemoveTaskById(id, true)
return
}
func (g *SharedPtr) RemoveAllTask() {
g.mu.Lock()
defer g.mu.Unlock()
g.sp.RemoveAllTasks()
}
func (g *SharedPtr) TaskIds() []string {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.TaskIds()
}
func (g *SharedPtr) Watch() chan<- Event {
eventC := g.event()
go func() {
swapped := g.WatchStopped.CAS(false, true)
if !swapped {
return
}
defer func() {
g.WatchStopped.Store(false)
}()
L:
for {
select {
case <-g.Context().Done():
break L
case event, ok := <-eventC:
if !ok {
break L
}
switch event {
case EventNew, EventExpired:
if event == EventExpired {
g.resetPtr()
}
// New x
_, err := g.GetWithRetry()
if err != nil {
go g.GetLogger().WithField("event", event).WithError(err).Warn("handle event failed...")
continue
}
go g.GetLogger().WithField("event", event).Infof("handle event success...")
case EventClose:
g.resetPtr()
}
}
}
}()
return eventC
}
func (g *SharedPtr) Ready() error {
if g == nil {
return ErrEmptyValue
}
if g.InShutdown() {
return ErrAlreadyShutdown
}
x := g.Get()
if x != nil {
return x.Ready()
}
return ErrEmptyValue
}
// std::shared_ptr.get() until ptr is ready & std::shared_ptr.make_unique() if necessary
func (g *SharedPtr) GetUntilReady() (Ptr, error) {
err := Retry(g.Context(), g.GetLogger(), g.sp.TaskMaxRetryDuration, g.sp.ConstructTimeout, func() error {
x := g.Get()
if x != nil {
// check if x is ready
if err := x.Ready(); err != nil {
// until ready
return err
}
return nil
}
// New x
x, err := g.allocate()
if err != nil {
return err
}
if x == nil {
return ErrEmptyValue
}
return ErrNotReady
})
return g.Get(), err
}
// std::shared_ptr.get() & std::shared_ptr.make_unique() if necessary
func (g *SharedPtr) GetWithRetry() (Ptr, error) {
// if allocated, return now
if x := g.Get(); x != nil {
return x, nil
}
// New x
err := Retry(g.Context(), g.GetLogger(), g.sp.TaskMaxRetryDuration, g.sp.ConstructTimeout, func() error {
_, err := g.allocate()
return err
})
if err != nil {
return nil, err
}
return g.Get(), nil
}
// std::shared_ptr.release()
func (g *SharedPtr) Release() Ptr {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.Release()
}
// std::shared_ptr.reset()
func (g *SharedPtr) Reset() {
g.RemoveAllTask()
g.resetPtr()
}
// std::shared_ptr.get()
func (g *SharedPtr) Get() Ptr {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.Get()
}
// reset ptr and ready to start again
func (g *SharedPtr) resetPtr() {
x := g.Release()
if x != nil {
x.Close()
}
return
}
func (g *SharedPtr) allocate() (Ptr, error) {
g.mu.Lock()
defer g.mu.Unlock()
x := g.sp.Get()
if x != nil {
return x, nil
}
if g.sp.New == nil {
return nil, nil
}
x, err := g.sp.New()
if err != nil {
return g.sp.Get(), err
}
g.sp.Reset(x)
go g.backgroundTask()
g.recoveryTaskLocked()
return g.sp.Get(), nil
}
func (g *SharedPtr) recoveryTaskLocked() {
for _, t := range g.sp.SnapTasks() {
if t == nil {
continue
}
task := t.Clone()
select {
case <-g.sp.Context().Done():
return
case <-task.Context().Done():
continue
default:
}
if !task.Type.Drop {
task.State = TaskStateDormancy
}
if task.State == TaskStateDormancy {
task.State = TaskStateNew
go g.sp.GetLogger().WithField("task", task.String()).Info("recover task is adding...")
go func() {
g.sp.GetTaskC() <- task
}()
}
}
}
func (g *SharedPtr) backgroundTask() {
swapped := g.backgroundStopped.CAS(false, true)
if !swapped {
return
}
defer func() {
g.backgroundStopped.Store(false)
}()
L:
for {
select {
case <-g.Context().Done():
break L
case task, ok := <-g.getTaskC():
if !ok {
break L
}
if task == nil {
continue
}
if task.State != TaskStateNew {
go g.GetLogger().WithField("task", task.String()).
Warn("task is received with unexpected state, ignore duplicate schedule...")
continue
}
// verify whether task is duplicated
// store task
_, addedTask := g.GetTaskById(task.ID())
go g.GetLogger().WithField("task", task.String()).
Infof("task is received, try to schedule...")
if addedTask {
go g.GetLogger().WithField("task", task.String()).
Warn("task is added already, ignore duplicate schedule...")
continue
}
if task.Type.Construct {
if _, err := g.GetWithRetry(); err != nil {
go g.GetLogger().WithField("task", task.String()).
Warn("task is added but not scheduled, new has not been called yet...")
continue
}
} else {
if _, err := g.GetUntilReady(); err != nil {
go g.GetLogger().WithField("task", task.String()).
Warn("task is added but not scheduled, not ready yet...")
continue
}
}
addTask := func() {
g.mu.Lock()
defer g.mu.Unlock()
g.sp.AddTask(task)
}
deleteTask := func(cancel bool) {
g.mu.Lock()
defer g.mu.Unlock()
g.sp.RemoveTaskById(task.ID(), cancel)
}
// Handle task
addTask()
go func() {
if task.State != TaskStateNew {
return
}
task.State = TaskStateRunning
go g.GetLogger().WithField("task", task.String()).Info("task is running now...")
// execute the task and refresh the state
func() {
defer func() {
if r := recover(); r != nil {
task.State = TaskStateDoneErrorHappened
go g.GetLogger().WithField("task", task.String()).WithField("recovery", r).
Error("task is done failed...")
}
}()
if task.Handle == nil {
task.State = TaskStateDoneNormally
return
}
if err := task.Handle(); err != nil {
task.State = TaskStateDoneErrorHappened
go g.GetLogger().WithField("task", task.String()).WithError(err).
Warnf("task is done failed...")
return
}
go g.GetLogger().WithField("task", task.String()).
Info("task is done successfully...")
task.State = TaskStateDoneNormally
}()
// handle completed execution and refresh the state
func() {
waitBeforeRepeat := func() {
go g.GetLogger().WithField("task", task.String()).
Warnf("task is rescheduled to repeat in %s...", task.RepeatDuration)
<-time.After(task.RepeatDuration)
}
waitBeforeRetry := func() {
go g.GetLogger().WithField("task", task.String()).
Warnf("task is rescheduled to recover in %s...", task.RetryDuration)
<-time.After(task.RetryDuration)
}
select {
case <-task.Context().Done():
task.State = TaskStateDeath
return
default:
// Drop
if task.Type.Drop && !task.Type.Retry {
task.State = TaskStateDeath
return
}
if task.Type.Drop && task.Type.Retry {
if task.State == TaskStateDoneErrorHappened {
waitBeforeRetry()
task.State = TaskStateNew
return
}
task.State = TaskStateDeath
return
}
// Repeat
if task.Type.Repeat && !task.Type.Construct {
waitBeforeRepeat()
task.State = TaskStateNew
return
}
if task.Type.Repeat && task.Type.Construct {
go g.GetLogger().WithField("task", task.String()).
Warnf("task is rescheduled and restart all tasks...")
deleteTask(false) // don't recover this task, this task will be added later
g.resetPtr()
go func() {
_, _ = g.GetWithRetry()
}()
waitBeforeRepeat()
task.State = TaskStateNew
return
}
// Construct && !Drop && !Repeat
if task.Type.Construct {
//Retry
if task.Type.Retry && task.State == TaskStateDoneErrorHappened {
go g.GetLogger().WithField("task", task.String()).
Warnf("task is rescheduled and restart all tasks...")
deleteTask(false) // don't recover this task, this task will be added later
g.resetPtr()
go func() {
_, _ = g.GetWithRetry()
}()
waitBeforeRetry()
task.State = TaskStateNew
return
}
task.State = TaskStateDormancy
return
}
// !Dop && !Repeat && !Construct
if task.Type.Retry {
if task.State == TaskStateDoneErrorHappened {
go g.GetLogger().WithField("task", task.String()).
Warnf("task is rescheduled ...")
deleteTask(false) // don't recover this task, this task will be added later
waitBeforeRetry()
task.State = TaskStateNew
return
}
task.State = TaskStateDormancy
return
}
task.State = TaskStateDormancy
return
}
}()
// complete the task's life cycle
func() {
select {
case <-task.Context().Done():
go g.GetLogger().WithField("task", task.String()).
Info("task is canceled, go to death now...")
deleteTask(false) // canceled already
return
default:
switch task.State {
case TaskStateNew:
deleteTask(false)
if task.State == TaskStateRunning {
go g.GetLogger().WithField("task", task.String()).
Infof("task is rescheduled now...")
}
go g.GetLogger().WithField("task", task.String()).
Infof("task is rescheduled now...")
g.getTaskC() <- task
case TaskStateDormancy:
go g.GetLogger().WithField("task", task.String()).
Infof("task is done, go to dormancy...")
case TaskStateDeath:
go g.GetLogger().WithField("task", task.String()).
Infof("task is dead, go to death...")
deleteTask(true)
default:
go g.GetLogger().WithField("task", task.String()).
Info("task is with unexpect state, go to death now...")
deleteTask(true)
}
}
}()
}()
}
}
}
func (g *SharedPtr) getTaskC() chan *Task {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.GetTaskC()
}
func (g *SharedPtr) event() chan Event {
g.mu.Lock()
defer g.mu.Unlock()
return g.sp.Event()
}