1. docker
  2. Commit 305801f58f22c9a26bc05eaa800e399afb212fe3
Browse code

Disambiguate mirror -> other endpoint fallbacks from V2 -> V1

Signed-off-by: Jake Sanders <jsand@google.com>

Jake Sanders authored on 2017/11/15 09:06:17
Showing 4 changed files
distribution/errors.go
History View file @ 305801f
... ... 
@@ -126,21 +126,25 @@ func TranslatePullError(err error, ref reference.Named) error {
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 // continueOnError returns true if we should fallback to the next endpoint
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 // as a result of this error.
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-func continueOnError(err error) bool {
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+func continueOnError(err error, mirrorEndpoint bool) bool {
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 	switch v := err.(type) {
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 	case errcode.Errors:
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 		if len(v) == 0 {
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 			return true
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 		}
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-		return continueOnError(v[0])
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+		return continueOnError(v[0], mirrorEndpoint)
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 	case ErrNoSupport:
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-		return continueOnError(v.Err)
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+		return continueOnError(v.Err, mirrorEndpoint)
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 	case errcode.Error:
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-		return shouldV2Fallback(v)
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+		return mirrorEndpoint || shouldV2Fallback(v)
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 	case *client.UnexpectedHTTPResponseError:
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 		return true
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 	case ImageConfigPullError:
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-		return false
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+		// ImageConfigPullError only happens with v2 images, v1 fallback is
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+		// unnecessary.
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+		// Failures from a mirror endpoint should result in fallback to the
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+		// canonical repo.
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+		return mirrorEndpoint
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 	case error:
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 		return !strings.Contains(err.Error(), strings.ToLower(syscall.ESRCH.Error()))
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 	}
distribution/errors_test.go
History View file @ 305801f
147 151 
new file mode 100644
... ... 
@@ -0,0 +1,85 @@
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+package distribution
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+
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+import (
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+	"errors"
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+	"strings"
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+	"syscall"
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+	"testing"
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+
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+	"github.com/docker/distribution/registry/api/errcode"
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+	"github.com/docker/distribution/registry/api/v2"
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+	"github.com/docker/distribution/registry/client"
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+)
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+
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+var always_continue = []error{
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+	&client.UnexpectedHTTPResponseError{},
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+
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+	// Some errcode.Errors that don't disprove the existence of a V1 image
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+	errcode.Error{Code: errcode.ErrorCodeUnauthorized},
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+	errcode.Error{Code: v2.ErrorCodeManifestUnknown},
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+	errcode.Error{Code: v2.ErrorCodeNameUnknown},
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+
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+	errors.New("some totally unexpected error"),
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+}
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+
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+var continue_from_mirror_endpoint = []error{
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+	ImageConfigPullError{},
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+
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+	// Some other errcode.Error that doesn't indicate we should search for a V1 image.
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+	errcode.Error{Code: errcode.ErrorCodeTooManyRequests},
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+}
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+
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+var never_continue = []error{
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+	errors.New(strings.ToLower(syscall.ESRCH.Error())), // No such process
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+}
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+
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+func TestContinueOnError_NonMirrorEndpoint(t *testing.T) {
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+	for _, err := range always_continue {
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+		if !continueOnError(err, false) {
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+			t.Errorf("Should continue from non-mirror endpoint: %T: '%s'", err, err.Error())
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+		}
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+	}
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+
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+	for _, err := range continue_from_mirror_endpoint {
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+		if continueOnError(err, false) {
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+			t.Errorf("Should only continue from mirror endpoint: %T: '%s'", err, err.Error())
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+		}
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+	}
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+}
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+
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+func TestContinueOnError_MirrorEndpoint(t *testing.T) {
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+	errs := []error{}
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+	errs = append(errs, always_continue...)
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+	errs = append(errs, continue_from_mirror_endpoint...)
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+	for _, err := range errs {
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+		if !continueOnError(err, true) {
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+			t.Errorf("Should continue from mirror endpoint: %T: '%s'", err, err.Error())
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+		}
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+	}
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+}
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+
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+func TestContinueOnError_NeverContinue(t *testing.T) {
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+	for _, is_mirror_endpoint := range []bool{true, false} {
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+		for _, err := range never_continue {
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+			if continueOnError(err, is_mirror_endpoint) {
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+				t.Errorf("Should never continue: %T: '%s'", err, err.Error())
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+			}
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+		}
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+	}
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+}
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+
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+func TestContinueOnError_UnnestsErrors(t *testing.T) {
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+	// ContinueOnError should evaluate nested errcode.Errors.
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+
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+	// Assumes that v2.ErrorCodeNameUnknown is a continueable error code.
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+	err := errcode.Errors{errcode.Error{Code: v2.ErrorCodeNameUnknown}}
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+	if !continueOnError(err, false) {
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+		t.Fatal("ContinueOnError should unnest, base return value on errcode.Errors")
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+	}
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+
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+	// Assumes that errcode.ErrorCodeTooManyRequests is not a V1-fallback indication
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+	err = errcode.Errors{errcode.Error{Code: errcode.ErrorCodeTooManyRequests}}
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+	if continueOnError(err, false) {
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+		t.Fatal("ContinueOnError should unnest, base return value on errcode.Errors")
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+	}
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+}
distribution/pull_v2.go
History View file @ 305801f
... ... 
@@ -74,7 +74,7 @@ func (p *v2Puller) Pull(ctx context.Context, ref reference.Named, platform strin
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 		if _, ok := err.(fallbackError); ok {
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 			return err
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 		}
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-		if continueOnError(err) {
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+		if continueOnError(err, p.endpoint.Mirror) {
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 			return fallbackError{
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 				err:         err,
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 				confirmedV2: p.confirmedV2,
distribution/push_v2.go
History View file @ 305801f
... ... 
@@ -67,7 +67,7 @@ func (p *v2Pusher) Push(ctx context.Context) (err error) {
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 	}
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 	if err = p.pushV2Repository(ctx); err != nil {
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-		if continueOnError(err) {
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+		if continueOnError(err, p.endpoint.Mirror) {
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 			return fallbackError{
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 				err:         err,
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 				confirmedV2: p.pushState.confirmedV2,