init

pkg/filesystem/chunk/backoff/backoff.go

@@ -0,0 +1,74 @@
+package backoff
+
+import (
+	"errors"
+	"fmt"
+	"github.com/cloudreve/Cloudreve/v3/pkg/util"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+// Backoff used for retry sleep backoff
+type Backoff interface {
+	Next(err error) bool
+	Reset()
+}
+
+// ConstantBackoff implements Backoff interface with constant sleep time. If the error
+// is retryable and with `RetryAfter` defined, the `RetryAfter` will be used as sleep duration.
+type ConstantBackoff struct {
+	Sleep time.Duration
+	Max   int
+
+	tried int
+}
+
+func (c *ConstantBackoff) Next(err error) bool {
+	c.tried++
+	if c.tried > c.Max {
+		return false
+	}
+
+	var e *RetryableError
+	if errors.As(err, &e) && e.RetryAfter > 0 {
+		util.Log().Warning("Retryable error %q occurs in backoff, will sleep after %s.", e, e.RetryAfter)
+		time.Sleep(e.RetryAfter)
+	} else {
+		time.Sleep(c.Sleep)
+	}
+
+	return true
+}
+
+func (c *ConstantBackoff) Reset() {
+	c.tried = 0
+}
+
+type RetryableError struct {
+	Err        error
+	RetryAfter time.Duration
+}
+
+// NewRetryableErrorFromHeader constructs a new RetryableError from http response header
+// and existing error.
+func NewRetryableErrorFromHeader(err error, header http.Header) *RetryableError {
+	retryAfter := header.Get("retry-after")
+	if retryAfter == "" {
+		retryAfter = "0"
+	}
+
+	res := &RetryableError{
+		Err: err,
+	}
+
+	if retryAfterSecond, err := strconv.ParseInt(retryAfter, 10, 64); err == nil {
+		res.RetryAfter = time.Duration(retryAfterSecond) * time.Second
+	}
+
+	return res
+}
+
+func (e *RetryableError) Error() string {
+	return fmt.Sprintf("retryable error with retry-after=%s: %s", e.RetryAfter, e.Err)
+}