retry_task.go

// Copyright 2018 Changkun Ou. All rights reserved.
// Use of this source code is governed by a MIT
// license that can be found in the LICENSE file.

package tests

import (
	"fmt"
	"sync/atomic"
	"time"
	"unsafe"
)

// RetryTask implements task.Interface However it has no
// export field, which is not able to be scheduled by sched
type RetryTask struct {
	RetryCount int64
	MaxRetry   int64
	id         string
	execution  time.Time
}

// NewRetryTask creates a task
func NewRetryTask(id string, e time.Time, maxRetry int64) *RetryTask {
	return &RetryTask{
		RetryCount: 0,
		MaxRetry:   maxRetry,
		id:         id,
		execution:  e,
	}
}

// GetID get task id
func (t *RetryTask) GetID() (id string) {
	id = t.id
	return
}

// GetExecution get execution time
func (t *RetryTask) GetExecution() (execute time.Time) {
	execute = t.execution
	return
}

// GetTimeout get timeout of execution
func (t *RetryTask) GetTimeout() (executeTimeout time.Duration) {
	return time.Millisecond
}

// GetRetryTime get retry execution duration
func (t *RetryTask) GetRetryTime() time.Time {
	return time.Now().UTC().Add(time.Millisecond * 100)
}

// SetID sets the id of a task
func (t *RetryTask) SetID(id string) {
	t.id = id
}

// IsValidID check id is valid
func (t *RetryTask) IsValidID() bool {
	return true
}

// SetExecution sets the execution time of a task
func (t *RetryTask) SetExecution(current time.Time) time.Time {
	var ptr = unsafe.Pointer(&t.execution)
	var old unsafe.Pointer
	// spin lock
	for {
		old = atomic.LoadPointer(&ptr)
		if atomic.CompareAndSwapPointer(&ptr, old, unsafe.Pointer(&current)) {
			return *((*time.Time)(old))
		}
	}
}

// Execute is the actual execution block
func (t *RetryTask) Execute() (result interface{}, retry bool, fail error) {
	if t.RetryCount > t.MaxRetry {
		O.SetLast(time.Now().UTC())
		return fmt.Sprintf(
			"retry task %s, retry count: %d, tollerance: %v, last.",
			t.id, t.RetryCount, time.Now().UTC().Sub(t.GetExecution())), false, nil

	}
	O.Push(t.id)
	if O.IsFirstZero() {
		O.SetFirst(time.Now().UTC())
	}
	atomic.AddInt64(&t.RetryCount, 1)
	return fmt.Sprintf(
		"retry task %s, retry count: %d. tollerance: %v",
		t.id, t.RetryCount, time.Now().UTC().Sub(t.GetExecution())), true, nil
}