From 6cb8f01a74c400366b9b474826c5eb6bd779cc9f Mon Sep 17 00:00:00 2001
From: Gordon <1432970085@qq.com>
Date: Mon, 15 Aug 2022 17:59:52 +0800
Subject: [PATCH] retry function

---
 pkg/tools/retry/retry.go   | 184 +++++++++++++++++++++++++++++++++++++
 pkg/tools/retry/stratey.go |  56 +++++++++++
 2 files changed, 240 insertions(+)
 create mode 100644 pkg/tools/retry/retry.go
 create mode 100644 pkg/tools/retry/stratey.go

diff --git a/pkg/tools/retry/retry.go b/pkg/tools/retry/retry.go
new file mode 100644
index 000000000..8877dd0a5
--- /dev/null
+++ b/pkg/tools/retry/retry.go
@@ -0,0 +1,184 @@
+package retry
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"runtime/debug"
+	"time"
+)
+
+var (
+	ErrorAbort                 = errors.New("stop retry")
+	ErrorTimeout               = errors.New("retry timeout")
+	ErrorContextDeadlineExceed = errors.New("context deadline exceeded")
+	ErrorEmptyRetryFunc        = errors.New("empty retry function")
+	ErrorTimeFormat            = errors.New("time out err")
+)
+
+type RetriesFunc func() error
+type Option func(c *Config)
+type HookFunc func()
+type RetriesChecker func(err error) (needRetry bool)
+type Config struct {
+	MaxRetryTimes int
+	Timeout       time.Duration
+	RetryChecker  RetriesChecker
+	Strategy      Strategy
+	RecoverPanic  bool
+	BeforeTry     HookFunc
+	AfterTry      HookFunc
+}
+
+var (
+	DefaultMaxRetryTimes = 3
+	DefaultTimeout       = time.Minute
+	DefaultInterval      = time.Second * 2
+	DefaultRetryChecker  = func(err error) bool {
+		return !errors.Is(err, ErrorAbort) // not abort error, should continue retry
+	}
+)
+
+func newDefaultConfig() *Config {
+	return &Config{
+		MaxRetryTimes: DefaultMaxRetryTimes,
+		RetryChecker:  DefaultRetryChecker,
+		Timeout:       DefaultTimeout,
+		Strategy:      NewLinear(DefaultInterval),
+		BeforeTry:     func() {},
+		AfterTry:      func() {},
+	}
+}
+
+func WithTimeout(timeout time.Duration) Option {
+	return func(c *Config) {
+		c.Timeout = timeout
+	}
+}
+
+func WithMaxRetryTimes(times int) Option {
+	return func(c *Config) {
+		c.MaxRetryTimes = times
+	}
+}
+
+func WithRecoverPanic() Option {
+	return func(c *Config) {
+		c.RecoverPanic = true
+	}
+}
+
+func WithBeforeHook(hook HookFunc) Option {
+	return func(c *Config) {
+		c.BeforeTry = hook
+	}
+}
+
+func WithAfterHook(hook HookFunc) Option {
+	return func(c *Config) {
+		c.AfterTry = hook
+	}
+}
+
+func WithRetryChecker(checker RetriesChecker) Option {
+	return func(c *Config) {
+		c.RetryChecker = checker
+	}
+}
+
+func WithBackOffStrategy(s BackoffStrategy, duration time.Duration) Option {
+	return func(c *Config) {
+		switch s {
+		case StrategyConstant:
+			c.Strategy = NewConstant(duration)
+		case StrategyLinear:
+			c.Strategy = NewLinear(duration)
+		case StrategyFibonacci:
+			c.Strategy = NewFibonacci(duration)
+		}
+	}
+}
+
+func WithCustomStrategy(s Strategy) Option {
+	return func(c *Config) {
+		c.Strategy = s
+	}
+}
+
+func Do(ctx context.Context, fn RetriesFunc, opts ...Option) error {
+	if fn == nil {
+		return ErrorEmptyRetryFunc
+	}
+	var (
+		abort         = make(chan struct{}, 1) // caller choose to abort retry
+		run           = make(chan error, 1)
+		panicInfoChan = make(chan string, 1)
+
+		timer  *time.Timer
+		runErr error
+	)
+	config := newDefaultConfig()
+	for _, o := range opts {
+		o(config)
+	}
+	if config.Timeout > 0 {
+		timer = time.NewTimer(config.Timeout)
+	} else {
+		return ErrorTimeFormat
+	}
+	go func() {
+		var err error
+		defer func() {
+			if e := recover(); e == nil {
+				return
+			} else {
+				panicInfoChan <- fmt.Sprintf("retry function panic has occured, err=%v, stack:%s", e, string(debug.Stack()))
+			}
+		}()
+		for i := 0; i < config.MaxRetryTimes; i++ {
+			config.BeforeTry()
+			err = fn()
+			config.AfterTry()
+			if err == nil {
+				run <- nil
+				return
+			}
+			// check whether to retry
+			if config.RetryChecker != nil {
+				needRetry := config.RetryChecker(err)
+				if !needRetry {
+					abort <- struct{}{}
+					return
+				}
+			}
+			if config.Strategy != nil {
+				interval := config.Strategy.Sleep(i + 1)
+				<-time.After(interval)
+			}
+		}
+		run <- err
+	}()
+	select {
+	case <-ctx.Done():
+		// context deadline exceed
+		return ErrorContextDeadlineExceed
+	case <-timer.C:
+		// timeout
+		return ErrorTimeout
+	case <-abort:
+		// caller abort
+		return ErrorAbort
+	case msg := <-panicInfoChan:
+		// panic occurred
+		if !config.RecoverPanic {
+			panic(msg)
+		}
+		runErr = fmt.Errorf("panic occurred=%s", msg)
+	case e := <-run:
+		// normal run
+		if e != nil {
+			runErr = fmt.Errorf("retry failed, err=%w", e)
+		}
+	}
+	return runErr
+}
diff --git a/pkg/tools/retry/stratey.go b/pkg/tools/retry/stratey.go
new file mode 100644
index 000000000..e045684e8
--- /dev/null
+++ b/pkg/tools/retry/stratey.go
@@ -0,0 +1,56 @@
+package retry
+
+import "time"
+
+type BackoffStrategy int
+
+const (
+	StrategyConstant BackoffStrategy = iota
+	StrategyLinear
+	StrategyFibonacci
+)
+
+type Strategy interface {
+	Sleep(times int) time.Duration
+}
+type Constant struct {
+	startInterval time.Duration
+}
+
+func NewConstant(d time.Duration) *Constant {
+	return &Constant{startInterval: d}
+}
+
+type Linear struct {
+	startInterval time.Duration
+}
+
+func NewLinear(d time.Duration) *Linear {
+	return &Linear{startInterval: d}
+}
+
+type Fibonacci struct {
+	startInterval time.Duration
+}
+
+func NewFibonacci(d time.Duration) *Fibonacci {
+	return &Fibonacci{startInterval: d}
+}
+
+func (c *Constant) Sleep(_ int) time.Duration {
+	return c.startInterval
+}
+func (l *Linear) Sleep(times int) time.Duration {
+	return l.startInterval * time.Duration(times)
+
+}
+func (f *Fibonacci) Sleep(times int) time.Duration {
+	return f.startInterval * time.Duration(fibonacciNumber(times))
+
+}
+func fibonacciNumber(n int) int {
+	if n == 0 || n == 1 {
+		return n
+	}
+	return fibonacciNumber(n-1) + fibonacciNumber(n-2)
+}