e43b5ce5e5
This is possible now that we no longer support go1.12 and brings rclone into line with standard practices in the Go world. This also removes errors.New and errors.Errorf from lib/errors and prefers the stdlib errors package over lib/errors.
466 lines
12 KiB
Go
466 lines
12 KiB
Go
// Package fserrors provides errors and error handling
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package fserrors
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net/http"
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"strings"
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"time"
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liberrors "github.com/rclone/rclone/lib/errors"
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)
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// Must be satisfied for errors.Is/errors.As/Errors.Unwrap
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type unwrapper interface {
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Unwrap() error
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}
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// Retrier is an optional interface for error as to whether the
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// operation should be retried at a high level.
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//
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// This should be returned from Update or Put methods as required
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type Retrier interface {
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error
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Retry() bool
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}
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// retryError is a type of error
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type retryError string
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// Error interface
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func (r retryError) Error() string {
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return string(r)
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}
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// Retry interface
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func (r retryError) Retry() bool {
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return true
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}
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// Check interfaces
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var _ Retrier = retryError("")
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// RetryErrorf makes an error which indicates it would like to be retried
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func RetryErrorf(format string, a ...interface{}) error {
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return retryError(fmt.Sprintf(format, a...))
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}
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// wrappedRetryError is an error wrapped so it will satisfy the
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// Retrier interface and return true
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type wrappedRetryError struct {
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error
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}
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// Retry interface
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func (err wrappedRetryError) Retry() bool {
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return true
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}
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// Check interfaces
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var _ Retrier = wrappedRetryError{error(nil)}
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var _ unwrapper = wrappedRetryError{}
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// RetryError makes an error which indicates it would like to be retried
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func RetryError(err error) error {
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if err == nil {
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err = errors.New("needs retry")
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}
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return wrappedRetryError{err}
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}
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func (err wrappedRetryError) Unwrap() error {
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return err.error
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}
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// IsRetryError returns true if err conforms to the Retry interface
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// and calling the Retry method returns true.
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func IsRetryError(err error) (isRetry bool) {
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liberrors.Walk(err, func(err error) bool {
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if r, ok := err.(Retrier); ok {
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isRetry = r.Retry()
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return true
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}
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return false
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})
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return
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}
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// Fataler is an optional interface for error as to whether the
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// operation should cause the entire operation to finish immediately.
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//
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// This should be returned from Update or Put methods as required
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type Fataler interface {
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error
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Fatal() bool
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}
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// wrappedFatalError is an error wrapped so it will satisfy the
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// Retrier interface and return true
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type wrappedFatalError struct {
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error
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}
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// Fatal interface
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func (err wrappedFatalError) Fatal() bool {
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return true
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}
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// Check interfaces
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var _ Fataler = wrappedFatalError{error(nil)}
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var _ unwrapper = wrappedFatalError{}
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// FatalError makes an error which indicates it is a fatal error and
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// the sync should stop.
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func FatalError(err error) error {
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if err == nil {
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err = errors.New("fatal error")
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}
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return wrappedFatalError{err}
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}
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func (err wrappedFatalError) Unwrap() error {
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return err.error
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}
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// IsFatalError returns true if err conforms to the Fatal interface
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// and calling the Fatal method returns true.
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func IsFatalError(err error) (isFatal bool) {
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liberrors.Walk(err, func(err error) bool {
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if r, ok := err.(Fataler); ok {
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isFatal = r.Fatal()
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return true
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}
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return false
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})
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return
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}
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// NoRetrier is an optional interface for error as to whether the
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// operation should not be retried at a high level.
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//
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// If only NoRetry errors are returned in a sync then the sync won't
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// be retried.
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//
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// This should be returned from Update or Put methods as required
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type NoRetrier interface {
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error
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NoRetry() bool
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}
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// wrappedNoRetryError is an error wrapped so it will satisfy the
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// Retrier interface and return true
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type wrappedNoRetryError struct {
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error
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}
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// NoRetry interface
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func (err wrappedNoRetryError) NoRetry() bool {
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return true
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}
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// Check interfaces
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var _ NoRetrier = wrappedNoRetryError{error(nil)}
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var _ unwrapper = wrappedNoRetryError{}
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// NoRetryError makes an error which indicates the sync shouldn't be
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// retried.
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func NoRetryError(err error) error {
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return wrappedNoRetryError{err}
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}
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func (err wrappedNoRetryError) Unwrap() error {
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return err.error
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}
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// IsNoRetryError returns true if err conforms to the NoRetry
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// interface and calling the NoRetry method returns true.
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func IsNoRetryError(err error) (isNoRetry bool) {
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liberrors.Walk(err, func(err error) bool {
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if r, ok := err.(NoRetrier); ok {
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isNoRetry = r.NoRetry()
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return true
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}
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return false
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})
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return
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}
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// NoLowLevelRetrier is an optional interface for error as to whether
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// the operation should not be retried at a low level.
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//
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// NoLowLevelRetry errors won't be retried by low level retry loops.
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type NoLowLevelRetrier interface {
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error
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NoLowLevelRetry() bool
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}
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// wrappedNoLowLevelRetryError is an error wrapped so it will satisfy the
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// NoLowLevelRetrier interface and return true
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type wrappedNoLowLevelRetryError struct {
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error
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}
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// NoLowLevelRetry interface
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func (err wrappedNoLowLevelRetryError) NoLowLevelRetry() bool {
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return true
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}
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// Check interfaces
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var _ NoLowLevelRetrier = wrappedNoLowLevelRetryError{error(nil)}
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var _ unwrapper = wrappedNoLowLevelRetryError{}
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// NoLowLevelRetryError makes an error which indicates the sync
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// shouldn't be low level retried.
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func NoLowLevelRetryError(err error) error {
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return wrappedNoLowLevelRetryError{err}
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}
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// Unwrap returns the underlying error
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func (err wrappedNoLowLevelRetryError) Unwrap() error {
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return err.error
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}
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// IsNoLowLevelRetryError returns true if err conforms to the NoLowLevelRetry
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// interface and calling the NoLowLevelRetry method returns true.
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func IsNoLowLevelRetryError(err error) (isNoLowLevelRetry bool) {
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liberrors.Walk(err, func(err error) bool {
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if r, ok := err.(NoLowLevelRetrier); ok {
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isNoLowLevelRetry = r.NoLowLevelRetry()
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return true
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}
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return false
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})
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return
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}
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// RetryAfter is an optional interface for error as to whether the
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// operation should be retried after a given delay
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//
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// This should be returned from Update or Put methods as required and
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// will cause the entire sync to be retried after a delay.
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type RetryAfter interface {
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error
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RetryAfter() time.Time
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}
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// ErrorRetryAfter is an error which expresses a time that should be
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// waited for until trying again
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type ErrorRetryAfter time.Time
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// NewErrorRetryAfter returns an ErrorRetryAfter with the given
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// duration as an endpoint
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func NewErrorRetryAfter(d time.Duration) ErrorRetryAfter {
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return ErrorRetryAfter(time.Now().Add(d))
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}
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// Error returns the textual version of the error
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func (e ErrorRetryAfter) Error() string {
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return fmt.Sprintf("try again after %v (%v)", time.Time(e).Format(time.RFC3339Nano), time.Time(e).Sub(time.Now()))
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}
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// RetryAfter returns the time the operation should be retried at or
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// after
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func (e ErrorRetryAfter) RetryAfter() time.Time {
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return time.Time(e)
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}
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// Check interfaces
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var _ RetryAfter = ErrorRetryAfter{}
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// RetryAfterErrorTime returns the time that the RetryAfter error
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// indicates or a Zero time.Time
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func RetryAfterErrorTime(err error) (retryAfter time.Time) {
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liberrors.Walk(err, func(err error) bool {
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if r, ok := err.(RetryAfter); ok {
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retryAfter = r.RetryAfter()
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return true
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}
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return false
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})
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return
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}
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// IsRetryAfterError returns true if err is an ErrorRetryAfter
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func IsRetryAfterError(err error) bool {
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return !RetryAfterErrorTime(err).IsZero()
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}
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// CountableError is an optional interface for error. It stores a boolean
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// which signifies if the error has already been counted or not
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type CountableError interface {
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error
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Count()
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IsCounted() bool
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}
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// wrappedFatalError is an error wrapped so it will satisfy the
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// Retrier interface and return true
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type wrappedCountableError struct {
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error
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isCounted bool
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}
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// CountableError interface
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func (err *wrappedCountableError) Count() {
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err.isCounted = true
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}
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// CountableError interface
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func (err *wrappedCountableError) IsCounted() bool {
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return err.isCounted
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}
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func (err wrappedCountableError) Unwrap() error {
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return err.error
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}
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// IsCounted returns true if err conforms to the CountableError interface
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// and has already been counted
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func IsCounted(err error) bool {
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if r, ok := err.(CountableError); ok {
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return r.IsCounted()
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}
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return false
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}
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// Count sets the isCounted variable on the error if it conforms to the
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// CountableError interface
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func Count(err error) {
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if r, ok := err.(CountableError); ok {
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r.Count()
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}
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}
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// Check interface
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var _ CountableError = &wrappedCountableError{error: error(nil)}
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var _ unwrapper = wrappedCountableError{}
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// FsError makes an error which can keep a record that it is already counted
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// or not
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func FsError(err error) error {
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if err == nil {
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err = errors.New("countable error")
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}
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return &wrappedCountableError{error: err}
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}
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// Cause is a souped up errors.Cause which can unwrap some standard
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// library errors too. It returns true if any of the intermediate
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// errors had a Timeout() or Temporary() method which returned true.
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func Cause(cause error) (retriable bool, err error) {
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liberrors.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
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}); ok && x.Timeout() {
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retriable = true
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}
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// Check for net error Temporary()
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if x, ok := c.(interface {
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Temporary() bool
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}); ok && x.Temporary() {
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retriable = true
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}
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err = c
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return false
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})
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return
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}
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// retriableErrorStrings is a list of phrases which when we find it
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// in an error, we know it is a networking error which should be
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// retried.
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//
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// This is incredibly ugly - if only errors.Cause worked for all
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// errors and all errors were exported from the stdlib.
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var retriableErrorStrings = []string{
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"use of closed network connection", // internal/poll/fd.go
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"unexpected EOF reading trailer", // net/http/transfer.go
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"transport connection broken", // net/http/transport.go
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"http: ContentLength=", // net/http/transfer.go
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"server closed idle connection", // net/http/transport.go
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"bad record MAC", // crypto/tls/alert.go
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"stream error:", // net/http/h2_bundle.go
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"tls: use of closed connection", // crypto/tls/conn.go
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}
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// Errors which indicate networking errors which should be retried
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//
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// These are added to in retriable_errors*.go
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var retriableErrors = []error{
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io.EOF,
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io.ErrUnexpectedEOF,
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}
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// ShouldRetry looks at an error and tries to work out if retrying the
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// operation that caused it would be a good idea. It returns true if
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// the error implements Timeout() or Temporary() or if the error
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// indicates a premature closing of the connection.
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func ShouldRetry(err error) bool {
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if err == nil {
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return false
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}
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// If error has been marked to NoLowLevelRetry then don't retry
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if IsNoLowLevelRetryError(err) {
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return false
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}
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// Find root cause if available
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retriable, err := Cause(err)
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if retriable {
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return true
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}
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// Check if it is a retriable error
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for _, retriableErr := range retriableErrors {
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if err == retriableErr {
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return true
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}
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}
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// Check error strings (yuch!) too
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errString := err.Error()
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for _, phrase := range retriableErrorStrings {
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if strings.Contains(errString, phrase) {
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return true
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}
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}
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return false
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}
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// ShouldRetryHTTP returns a boolean as to whether this resp deserves.
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// It checks to see if the HTTP response code is in the slice
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// retryErrorCodes.
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func ShouldRetryHTTP(resp *http.Response, retryErrorCodes []int) bool {
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if resp == nil {
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return false
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}
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for _, e := range retryErrorCodes {
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if resp.StatusCode == e {
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return true
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}
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}
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return false
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}
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// ContextError checks to see if ctx is in error.
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//
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// If it is in error then it overwrites *perr with the context error
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// if *perr was nil and returns true.
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//
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// Otherwise it returns false.
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func ContextError(ctx context.Context, perr *error) bool {
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if ctxErr := ctx.Err(); ctxErr != nil {
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if *perr == nil {
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*perr = ctxErr
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}
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return true
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}
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return false
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}
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