rclone/fs/fserrors/error.go

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// Package fserrors provides errors and error handling
package fserrors
import (
"fmt"
"io"
"net/http"
"strings"
"time"
"github.com/rclone/rclone/lib/errors"
)
// Retrier is an optional interface for error as to whether the
// operation should be retried at a high level.
//
// This should be returned from Update or Put methods as required
type Retrier interface {
error
Retry() bool
}
// retryError is a type of error
type retryError string
// Error interface
func (r retryError) Error() string {
return string(r)
}
// Retry interface
func (r retryError) Retry() bool {
return true
}
// Check interface
var _ Retrier = retryError("")
// RetryErrorf makes an error which indicates it would like to be retried
func RetryErrorf(format string, a ...interface{}) error {
return retryError(fmt.Sprintf(format, a...))
}
// wrappedRetryError is an error wrapped so it will satisfy the
// Retrier interface and return true
type wrappedRetryError struct {
error
}
// Retry interface
func (err wrappedRetryError) Retry() bool {
return true
}
// Check interface
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var _ Retrier = wrappedRetryError{error(nil)}
// RetryError makes an error which indicates it would like to be retried
func RetryError(err error) error {
if err == nil {
err = errors.New("needs retry")
}
return wrappedRetryError{err}
}
func (err wrappedRetryError) Cause() error {
return err.error
}
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// IsRetryError returns true if err conforms to the Retry interface
// and calling the Retry method returns true.
func IsRetryError(err error) (isRetry bool) {
errors.Walk(err, func(err error) bool {
if r, ok := err.(Retrier); ok {
isRetry = r.Retry()
return true
}
return false
})
return
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}
// Fataler is an optional interface for error as to whether the
// operation should cause the entire operation to finish immediately.
//
// This should be returned from Update or Put methods as required
type Fataler interface {
error
Fatal() bool
}
// wrappedFatalError is an error wrapped so it will satisfy the
// Retrier interface and return true
type wrappedFatalError struct {
error
}
// Fatal interface
func (err wrappedFatalError) Fatal() bool {
return true
}
// Check interface
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var _ Fataler = wrappedFatalError{error(nil)}
// FatalError makes an error which indicates it is a fatal error and
// the sync should stop.
func FatalError(err error) error {
if err == nil {
err = errors.New("fatal error")
}
return wrappedFatalError{err}
}
func (err wrappedFatalError) Cause() error {
return err.error
}
// IsFatalError returns true if err conforms to the Fatal interface
// and calling the Fatal method returns true.
func IsFatalError(err error) (isFatal bool) {
errors.Walk(err, func(err error) bool {
if r, ok := err.(Fataler); ok {
isFatal = r.Fatal()
return true
}
return false
})
return
}
// NoRetrier is an optional interface for error as to whether the
// operation should not be retried at a high level.
//
// If only NoRetry errors are returned in a sync then the sync won't
// be retried.
//
// This should be returned from Update or Put methods as required
type NoRetrier interface {
error
NoRetry() bool
}
// wrappedNoRetryError is an error wrapped so it will satisfy the
// Retrier interface and return true
type wrappedNoRetryError struct {
error
}
// NoRetry interface
func (err wrappedNoRetryError) NoRetry() bool {
return true
}
// Check interface
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var _ NoRetrier = wrappedNoRetryError{error(nil)}
// NoRetryError makes an error which indicates the sync shouldn't be
// retried.
func NoRetryError(err error) error {
return wrappedNoRetryError{err}
}
func (err wrappedNoRetryError) Cause() error {
return err.error
}
// IsNoRetryError returns true if err conforms to the NoRetry
// interface and calling the NoRetry method returns true.
func IsNoRetryError(err error) (isNoRetry bool) {
errors.Walk(err, func(err error) bool {
if r, ok := err.(NoRetrier); ok {
isNoRetry = r.NoRetry()
return true
}
return false
})
return
}
// NoLowLevelRetrier is an optional interface for error as to whether
// the operation should not be retried at a low level.
//
// NoLowLevelRetry errors won't be retried by low level retry loops.
type NoLowLevelRetrier interface {
error
NoLowLevelRetry() bool
}
// wrappedNoLowLevelRetryError is an error wrapped so it will satisfy the
// NoLowLevelRetrier interface and return true
type wrappedNoLowLevelRetryError struct {
error
}
// NoLowLevelRetry interface
func (err wrappedNoLowLevelRetryError) NoLowLevelRetry() bool {
return true
}
// Check interface
var _ NoLowLevelRetrier = wrappedNoLowLevelRetryError{error(nil)}
// NoLowLevelRetryError makes an error which indicates the sync
// shouldn't be low level retried.
func NoLowLevelRetryError(err error) error {
return wrappedNoLowLevelRetryError{err}
}
// Cause returns the underlying error
func (err wrappedNoLowLevelRetryError) Cause() error {
return err.error
}
// IsNoLowLevelRetryError returns true if err conforms to the NoLowLevelRetry
// interface and calling the NoLowLevelRetry method returns true.
func IsNoLowLevelRetryError(err error) (isNoLowLevelRetry bool) {
errors.Walk(err, func(err error) bool {
if r, ok := err.(NoLowLevelRetrier); ok {
isNoLowLevelRetry = r.NoLowLevelRetry()
return true
}
return false
})
return
}
// RetryAfter is an optional interface for error as to whether the
// operation should be retried after a given delay
//
// This should be returned from Update or Put methods as required and
// will cause the entire sync to be retried after a delay.
type RetryAfter interface {
error
RetryAfter() time.Time
}
// ErrorRetryAfter is an error which expresses a time that should be
// waited for until trying again
type ErrorRetryAfter time.Time
// NewErrorRetryAfter returns an ErrorRetryAfter with the given
// duration as an endpoint
func NewErrorRetryAfter(d time.Duration) ErrorRetryAfter {
return ErrorRetryAfter(time.Now().Add(d))
}
// Error returns the textual version of the error
func (e ErrorRetryAfter) Error() string {
return fmt.Sprintf("try again after %v (%v)", time.Time(e).Format(time.RFC3339Nano), time.Time(e).Sub(time.Now()))
}
// RetryAfter returns the time the operation should be retried at or
// after
func (e ErrorRetryAfter) RetryAfter() time.Time {
return time.Time(e)
}
// Check interface
var _ RetryAfter = ErrorRetryAfter{}
// RetryAfterErrorTime returns the time that the RetryAfter error
// indicates or a Zero time.Time
func RetryAfterErrorTime(err error) (retryAfter time.Time) {
errors.Walk(err, func(err error) bool {
if r, ok := err.(RetryAfter); ok {
retryAfter = r.RetryAfter()
return true
}
return false
})
return
}
// IsRetryAfterError returns true if err is an ErrorRetryAfter
func IsRetryAfterError(err error) bool {
return !RetryAfterErrorTime(err).IsZero()
}
// CountableError is an optional interface for error. It stores a boolean
// which signifies if the error has already been counted or not
type CountableError interface {
error
Count()
IsCounted() bool
}
// wrappedFatalError is an error wrapped so it will satisfy the
// Retrier interface and return true
type wrappedCountableError struct {
error
isCounted bool
}
// CountableError interface
func (err *wrappedCountableError) Count() {
err.isCounted = true
}
// CountableError interface
func (err *wrappedCountableError) IsCounted() bool {
return err.isCounted
}
func (err *wrappedCountableError) Cause() error {
return err.error
}
// IsCounted returns true if err conforms to the CountableError interface
// and has already been counted
func IsCounted(err error) bool {
if r, ok := err.(CountableError); ok {
return r.IsCounted()
}
return false
}
// Count sets the isCounted variable on the error if it conforms to the
// CountableError interface
func Count(err error) {
if r, ok := err.(CountableError); ok {
r.Count()
}
}
// Check interface
var _ CountableError = &wrappedCountableError{error: error(nil)}
// FsError makes an error which can keep a record that it is already counted
// or not
func FsError(err error) error {
if err == nil {
err = errors.New("countable error")
}
return &wrappedCountableError{error: err}
}
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// Cause is a souped up errors.Cause which can unwrap some standard
// library errors too. It returns true if any of the intermediate
// errors had a Timeout() or Temporary() method which returned true.
func Cause(cause error) (retriable bool, err error) {
errors.Walk(cause, func(c error) bool {
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// Check for net error Timeout()
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if x, ok := c.(interface {
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Timeout() bool
}); ok && x.Timeout() {
retriable = true
}
// Check for net error Temporary()
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if x, ok := c.(interface {
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Temporary() bool
}); ok && x.Temporary() {
retriable = true
}
err = c
return false
})
return
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}
// retriableErrorStrings is a list of phrases which when we find it
// in an an error, we know it is a networking error which should be
// retried.
//
// This is incredibly ugly - if only errors.Cause worked for all
// errors and all errors were exported from the stdlib.
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var retriableErrorStrings = []string{
"use of closed network connection", // internal/poll/fd.go
"unexpected EOF reading trailer", // net/http/transfer.go
"transport connection broken", // net/http/transport.go
"http: ContentLength=", // net/http/transfer.go
"server closed idle connection", // net/http/transport.go
"bad record MAC", // crypto/tls/alert.go
"stream error:", // src/net/http/h2_bundle.go
}
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// Errors which indicate networking errors which should be retried
//
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// These are added to in retriable_errors*.go
var retriableErrors = []error{
io.EOF,
io.ErrUnexpectedEOF,
}
// ShouldRetry looks at an error and tries to work out if retrying the
// operation that caused it would be a good idea. It returns true if
// the error implements Timeout() or Temporary() or if the error
// indicates a premature closing of the connection.
func ShouldRetry(err error) bool {
if err == nil {
return false
}
// If error has been marked to NoLowLevelRetry then don't retry
if IsNoLowLevelRetryError(err) {
return false
}
// Find root cause if available
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retriable, err := Cause(err)
if retriable {
return true
}
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// Check if it is a retriable error
for _, retriableErr := range retriableErrors {
if err == retriableErr {
return true
}
}
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// Check error strings (yuch!) too
errString := err.Error()
for _, phrase := range retriableErrorStrings {
if strings.Contains(errString, phrase) {
return true
}
}
return false
}
// ShouldRetryHTTP returns a boolean as to whether this resp deserves.
// It checks to see if the HTTP response code is in the slice
// retryErrorCodes.
func ShouldRetryHTTP(resp *http.Response, retryErrorCodes []int) bool {
if resp == nil {
return false
}
for _, e := range retryErrorCodes {
if resp.StatusCode == e {
return true
}
}
return false
}
type causer interface {
Cause() error
}
var (
_ causer = wrappedRetryError{}
_ causer = wrappedFatalError{}
_ causer = wrappedNoRetryError{}
)