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moby--moby/distribution/errors.go
Aaron Lehmann 8f26fe4f59 Push/pull errors improvement and cleanup
Several improvements to error handling:

- Introduce ImageConfigPullError type, wrapping errors related to
  downloading the image configuration blob in schema2. This allows for a
  more descriptive error message to be seen by the end user.

- Change some logrus.Debugf calls that display errors to logrus.Errorf.
  Add log lines in the push/pull fallback cases to make sure the errors
  leading to the fallback are shown.

- Move error-related types and functions which are only used by the
  distribution package out of the registry package.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-02-11 16:28:56 -08:00

102 lines
2.8 KiB
Go

package distribution
import (
"net/url"
"strings"
"syscall"
"github.com/docker/distribution/registry/api/errcode"
"github.com/docker/distribution/registry/api/v2"
"github.com/docker/distribution/registry/client"
"github.com/docker/docker/distribution/xfer"
)
// ErrNoSupport is an error type used for errors indicating that an operation
// is not supported. It encapsulates a more specific error.
type ErrNoSupport struct{ Err error }
func (e ErrNoSupport) Error() string {
if e.Err == nil {
return "not supported"
}
return e.Err.Error()
}
// fallbackError wraps an error that can possibly allow fallback to a different
// endpoint.
type fallbackError struct {
// err is the error being wrapped.
err error
// confirmedV2 is set to true if it was confirmed that the registry
// supports the v2 protocol. This is used to limit fallbacks to the v1
// protocol.
confirmedV2 bool
}
// Error renders the FallbackError as a string.
func (f fallbackError) Error() string {
return f.err.Error()
}
// shouldV2Fallback returns true if this error is a reason to fall back to v1.
func shouldV2Fallback(err errcode.Error) bool {
switch err.Code {
case errcode.ErrorCodeUnauthorized, v2.ErrorCodeManifestUnknown, v2.ErrorCodeNameUnknown:
return true
}
return false
}
// continueOnError returns true if we should fallback to the next endpoint
// as a result of this error.
func continueOnError(err error) bool {
switch v := err.(type) {
case errcode.Errors:
if len(v) == 0 {
return true
}
return continueOnError(v[0])
case ErrNoSupport:
return continueOnError(v.Err)
case errcode.Error:
return shouldV2Fallback(v)
case *client.UnexpectedHTTPResponseError:
return true
case ImageConfigPullError:
return false
case error:
return !strings.Contains(err.Error(), strings.ToLower(syscall.ENOSPC.Error()))
}
// let's be nice and fallback if the error is a completely
// unexpected one.
// If new errors have to be handled in some way, please
// add them to the switch above.
return true
}
// retryOnError wraps the error in xfer.DoNotRetry if we should not retry the
// operation after this error.
func retryOnError(err error) error {
switch v := err.(type) {
case errcode.Errors:
return retryOnError(v[0])
case errcode.Error:
switch v.Code {
case errcode.ErrorCodeUnauthorized, errcode.ErrorCodeUnsupported, errcode.ErrorCodeDenied:
return xfer.DoNotRetry{Err: err}
}
case *url.Error:
return retryOnError(v.Err)
case *client.UnexpectedHTTPResponseError:
return xfer.DoNotRetry{Err: err}
case error:
if strings.Contains(err.Error(), strings.ToLower(syscall.ENOSPC.Error())) {
return xfer.DoNotRetry{Err: err}
}
}
// let's be nice and fallback if the error is a completely
// unexpected one.
// If new errors have to be handled in some way, please
// add them to the switch above.
return err
}