errors.go

/*
   Copyright The containerd Authors.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

// Package errdefs defines the common errors used throughout containerd
// packages.
//
// Use with fmt.Errorf to add context to an error.
//
// To detect an error class, use the IsXXX functions to tell whether an error
// is of a certain type.
package errdefs

import (
	"context"
	"errors"
)

// Definitions of common error types used throughout containerd. All containerd
// errors returned by most packages will map into one of these errors classes.
// Packages should return errors of these types when they want to instruct a
// client to take a particular action.
//
// These errors map closely to grpc errors.
var (
	ErrUnknown            = errUnknown{}
	ErrInvalidArgument    = errInvalidArgument{}
	ErrNotFound           = errNotFound{}
	ErrAlreadyExists      = errAlreadyExists{}
	ErrPermissionDenied   = errPermissionDenied{}
	ErrResourceExhausted  = errResourceExhausted{}
	ErrFailedPrecondition = errFailedPrecondition{}
	ErrConflict           = errConflict{}
	ErrNotModified        = errNotModified{}
	ErrAborted            = errAborted{}
	ErrOutOfRange         = errOutOfRange{}
	ErrNotImplemented     = errNotImplemented{}
	ErrInternal           = errInternal{}
	ErrUnavailable        = errUnavailable{}
	ErrDataLoss           = errDataLoss{}
	ErrUnauthenticated    = errUnauthorized{}
)

// cancelled maps to Moby's "ErrCancelled"
type cancelled interface {
	Cancelled()
}

// IsCanceled returns true if the error is due to `context.Canceled`.
func IsCanceled(err error) bool {
	return errors.Is(err, context.Canceled) || isInterface[cancelled](err)
}

type errUnknown struct{}

func (errUnknown) Error() string { return "unknown" }

func (errUnknown) Unknown() {}

// unknown maps to Moby's "ErrUnknown"
type unknown interface {
	Unknown()
}

// IsUnknown returns true if the error is due to an unknown error,
// unhandled condition or unexpected response.
func IsUnknown(err error) bool {
	return errors.Is(err, errUnknown{}) || isInterface[unknown](err)
}

type errInvalidArgument struct{}

func (errInvalidArgument) Error() string { return "invalid argument" }

func (errInvalidArgument) InvalidParameter() {}

// invalidParameter maps to Moby's "ErrInvalidParameter"
type invalidParameter interface {
	InvalidParameter()
}

// IsInvalidArgument returns true if the error is due to an invalid argument
func IsInvalidArgument(err error) bool {
	return errors.Is(err, ErrInvalidArgument) || isInterface[invalidParameter](err)
}

// deadlineExceed maps to Moby's "ErrDeadline"
type deadlineExceeded interface {
	DeadlineExceeded()
}

// IsDeadlineExceeded returns true if the error is due to
// `context.DeadlineExceeded`.
func IsDeadlineExceeded(err error) bool {
	return errors.Is(err, context.DeadlineExceeded) || isInterface[deadlineExceeded](err)
}

type errNotFound struct{}

func (errNotFound) Error() string { return "not found" }

func (errNotFound) NotFound() {}

// notFound maps to Moby's "ErrNotFound"
type notFound interface {
	NotFound()
}

// IsNotFound returns true if the error is due to a missing object
func IsNotFound(err error) bool {
	return errors.Is(err, ErrNotFound) || isInterface[notFound](err)
}

type errAlreadyExists struct{}

func (errAlreadyExists) Error() string { return "already exists" }

// IsAlreadyExists returns true if the error is due to an already existing
// metadata item
func IsAlreadyExists(err error) bool {
	return errors.Is(err, ErrAlreadyExists)
}

type errPermissionDenied struct{}

func (errPermissionDenied) Error() string { return "permission denied" }

// forbidden maps to Moby's "ErrForbidden"
type forbidden interface {
	Forbidden()
}

// IsPermissionDenied returns true if the error is due to permission denied
// or forbidden (403) response
func IsPermissionDenied(err error) bool {
	return errors.Is(err, ErrPermissionDenied) || isInterface[forbidden](err)
}

type errResourceExhausted struct{}

func (errResourceExhausted) Error() string { return "resource exhausted" }

// IsResourceExhausted returns true if the error is due to
// a lack of resources or too many attempts.
func IsResourceExhausted(err error) bool {
	return errors.Is(err, errResourceExhausted{})
}

type errFailedPrecondition struct{}

func (e errFailedPrecondition) Error() string { return "failed precondition" }

// IsFailedPrecondition returns true if an operation could not proceed due to
// the lack of a particular condition
func IsFailedPrecondition(err error) bool {
	return errors.Is(err, errFailedPrecondition{})
}

type errConflict struct{}

func (errConflict) Error() string { return "conflict" }

func (errConflict) Conflict() {}

// conflict maps to Moby's "ErrConflict"
type conflict interface {
	Conflict()
}

// IsConflict returns true if an operation could not proceed due to
// a conflict.
func IsConflict(err error) bool {
	return errors.Is(err, errConflict{}) || isInterface[conflict](err)
}

type errNotModified struct{}

func (errNotModified) Error() string { return "not modified" }

func (errNotModified) NotModified() {}

// notModified maps to Moby's "ErrNotModified"
type notModified interface {
	NotModified()
}

// IsNotModified returns true if an operation could not proceed due
// to an object not modified from a previous state.
func IsNotModified(err error) bool {
	return errors.Is(err, errNotModified{}) || isInterface[notModified](err)
}

type errAborted struct{}

func (errAborted) Error() string { return "aborted" }

// IsAborted returns true if an operation was aborted.
func IsAborted(err error) bool {
	return errors.Is(err, errAborted{})
}

type errOutOfRange struct{}

func (errOutOfRange) Error() string { return "out of range" }

// IsOutOfRange returns true if an operation could not proceed due
// to data being out of the expected range.
func IsOutOfRange(err error) bool {
	return errors.Is(err, errOutOfRange{})
}

type errNotImplemented struct{}

func (errNotImplemented) Error() string { return "not implemented" }

func (errNotImplemented) NotImplemented() {}

// notImplemented maps to Moby's "ErrNotImplemented"
type notImplemented interface {
	NotImplemented()
}

// IsNotImplemented returns true if the error is due to not being implemented
func IsNotImplemented(err error) bool {
	return errors.Is(err, errNotImplemented{}) || isInterface[notImplemented](err)
}

type errInternal struct{}

func (errInternal) Error() string { return "internal" }

func (errInternal) System() {}

// system maps to Moby's "ErrSystem"
type system interface {
	System()
}

// IsInternal returns true if the error returns to an internal or system error
func IsInternal(err error) bool {
	return errors.Is(err, errInternal{}) || isInterface[system](err)
}

type errUnavailable struct{}

func (errUnavailable) Error() string { return "unavailable" }

func (errUnavailable) Unavailable() {}

// unavailable maps to Moby's "ErrUnavailable"
type unavailable interface {
	Unavailable()
}

// IsUnavailable returns true if the error is due to a resource being unavailable
func IsUnavailable(err error) bool {
	return errors.Is(err, errUnavailable{}) || isInterface[unavailable](err)
}

type errDataLoss struct{}

func (errDataLoss) Error() string { return "data loss" }

func (errDataLoss) DataLoss() {}

// dataLoss maps to Moby's "ErrDataLoss"
type dataLoss interface {
	DataLoss()
}

// IsDataLoss returns true if data during an operation was lost or corrupted
func IsDataLoss(err error) bool {
	return errors.Is(err, errDataLoss{}) || isInterface[dataLoss](err)
}

type errUnauthorized struct{}

func (errUnauthorized) Error() string { return "unauthorized" }

func (errUnauthorized) Unauthorized() {}

// unauthorized maps to Moby's "ErrUnauthorized"
type unauthorized interface {
	Unauthorized()
}

// IsUnauthorized returns true if the error indicates that the user was
// unauthenticated or unauthorized.
func IsUnauthorized(err error) bool {
	return errors.Is(err, errUnauthorized{}) || isInterface[unauthorized](err)
}

func isInterface[T any](err error) bool {
	for {
		switch x := err.(type) {
		case T:
			return true
		case interface{ Unwrap() error }:
			err = x.Unwrap()
			if err == nil {
				return false
			}
		case interface{ Unwrap() []error }:
			for _, err := range x.Unwrap() {
				if isInterface[T](err) {
					return true
				}
			}
			return false
		default:
			return false
		}
	}
}