Move httputils error helpers to errdefs package

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

errdefs/http_helpers.go

@@ -0,0 +1,172 @@
+package errdefs // import "github.com/docker/docker/errdefs"
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/docker/distribution/registry/api/errcode"
+	"github.com/sirupsen/logrus"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// GetHTTPErrorStatusCode retrieves status code from error message.
+func GetHTTPErrorStatusCode(err error) int {
+	if err == nil {
+		logrus.WithFields(logrus.Fields{"error": err}).Error("unexpected HTTP error handling")
+		return http.StatusInternalServerError
+	}
+
+	var statusCode int
+
+	// Stop right there
+	// Are you sure you should be adding a new error class here? Do one of the existing ones work?
+
+	// Note that the below functions are already checking the error causal chain for matches.
+	switch {
+	case IsNotFound(err):
+		statusCode = http.StatusNotFound
+	case IsInvalidParameter(err):
+		statusCode = http.StatusBadRequest
+	case IsConflict(err) || IsAlreadyExists(err):
+		statusCode = http.StatusConflict
+	case IsUnauthorized(err):
+		statusCode = http.StatusUnauthorized
+	case IsUnavailable(err):
+		statusCode = http.StatusServiceUnavailable
+	case IsForbidden(err):
+		statusCode = http.StatusForbidden
+	case IsNotModified(err):
+		statusCode = http.StatusNotModified
+	case IsNotImplemented(err):
+		statusCode = http.StatusNotImplemented
+	case IsSystem(err) || IsUnknown(err) || IsDataLoss(err) || IsDeadline(err) || IsCancelled(err):
+		statusCode = http.StatusInternalServerError
+	default:
+		statusCode = statusCodeFromGRPCError(err)
+		if statusCode != http.StatusInternalServerError {
+			return statusCode
+		}
+		statusCode = statusCodeFromDistributionError(err)
+		if statusCode != http.StatusInternalServerError {
+			return statusCode
+		}
+		if e, ok := err.(causer); ok {
+			return GetHTTPErrorStatusCode(e.Cause())
+		}
+
+		logrus.WithFields(logrus.Fields{
+			"module":     "api",
+			"error_type": fmt.Sprintf("%T", err),
+		}).Debugf("FIXME: Got an API for which error does not match any expected type!!!: %+v", err)
+	}
+
+	if statusCode == 0 {
+		statusCode = http.StatusInternalServerError
+	}
+
+	return statusCode
+}
+
+// FromStatusCode creates an errdef error, based on the provided HTTP status-code
+func FromStatusCode(err error, statusCode int) error {
+	if err == nil {
+		return err
+	}
+	switch statusCode {
+	case http.StatusNotFound:
+		err = NotFound(err)
+	case http.StatusBadRequest:
+		err = InvalidParameter(err)
+	case http.StatusConflict:
+		err = Conflict(err)
+	case http.StatusUnauthorized:
+		err = Unauthorized(err)
+	case http.StatusServiceUnavailable:
+		err = Unavailable(err)
+	case http.StatusForbidden:
+		err = Forbidden(err)
+	case http.StatusNotModified:
+		err = NotModified(err)
+	case http.StatusNotImplemented:
+		err = NotImplemented(err)
+	case http.StatusInternalServerError:
+		if !IsSystem(err) && !IsUnknown(err) && !IsDataLoss(err) && !IsDeadline(err) && !IsCancelled(err) {
+			err = System(err)
+		}
+	default:
+		logrus.WithFields(logrus.Fields{
+			"module":      "api",
+			"status_code": fmt.Sprintf("%d", statusCode),
+		}).Debugf("FIXME: Got an status-code for which error does not match any expected type!!!: %d", statusCode)
+
+		switch {
+		case statusCode >= 200 && statusCode < 400:
+			// it's a client error
+		case statusCode >= 400 && statusCode < 500:
+			err = InvalidParameter(err)
+		case statusCode >= 500 && statusCode < 600:
+			err = System(err)
+		default:
+			err = Unknown(err)
+		}
+	}
+	return err
+}
+
+// statusCodeFromGRPCError returns status code according to gRPC error
+func statusCodeFromGRPCError(err error) int {
+	switch status.Code(err) {
+	case codes.InvalidArgument: // code 3
+		return http.StatusBadRequest
+	case codes.NotFound: // code 5
+		return http.StatusNotFound
+	case codes.AlreadyExists: // code 6
+		return http.StatusConflict
+	case codes.PermissionDenied: // code 7
+		return http.StatusForbidden
+	case codes.FailedPrecondition: // code 9
+		return http.StatusBadRequest
+	case codes.Unauthenticated: // code 16
+		return http.StatusUnauthorized
+	case codes.OutOfRange: // code 11
+		return http.StatusBadRequest
+	case codes.Unimplemented: // code 12
+		return http.StatusNotImplemented
+	case codes.Unavailable: // code 14
+		return http.StatusServiceUnavailable
+	default:
+		if e, ok := err.(causer); ok {
+			return statusCodeFromGRPCError(e.Cause())
+		}
+		// codes.Canceled(1)
+		// codes.Unknown(2)
+		// codes.DeadlineExceeded(4)
+		// codes.ResourceExhausted(8)
+		// codes.Aborted(10)
+		// codes.Internal(13)
+		// codes.DataLoss(15)
+		return http.StatusInternalServerError
+	}
+}
+
+// statusCodeFromDistributionError returns status code according to registry errcode
+// code is loosely based on errcode.ServeJSON() in docker/distribution
+func statusCodeFromDistributionError(err error) int {
+	switch errs := err.(type) {
+	case errcode.Errors:
+		if len(errs) < 1 {
+			return http.StatusInternalServerError
+		}
+		if _, ok := errs[0].(errcode.ErrorCoder); ok {
+			return statusCodeFromDistributionError(errs[0])
+		}
+	case errcode.ErrorCoder:
+		return errs.ErrorCode().Descriptor().HTTPStatusCode
+	default:
+		if e, ok := err.(causer); ok {
+			return statusCodeFromDistributionError(e.Cause())
+		}
+	}
+	return http.StatusInternalServerError
+}

errdefs/http_helpers_test.go

@@ -0,0 +1,92 @@
+package errdefs
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+
+	"gotest.tools/assert"
+)
+
+func TestFromStatusCode(t *testing.T) {
+	testErr := fmt.Errorf("some error occurred")
+
+	testCases := []struct {
+		err    error
+		status int
+		check  func(error) bool
+	}{
+		{
+			err:    testErr,
+			status: http.StatusNotFound,
+			check:  IsNotFound,
+		},
+		{
+			err:    testErr,
+			status: http.StatusBadRequest,
+			check:  IsInvalidParameter,
+		},
+		{
+			err:    testErr,
+			status: http.StatusConflict,
+			check:  IsConflict,
+		},
+		{
+			err:    testErr,
+			status: http.StatusUnauthorized,
+			check:  IsUnauthorized,
+		},
+		{
+			err:    testErr,
+			status: http.StatusServiceUnavailable,
+			check:  IsUnavailable,
+		},
+		{
+			err:    testErr,
+			status: http.StatusForbidden,
+			check:  IsForbidden,
+		},
+		{
+			err:    testErr,
+			status: http.StatusNotModified,
+			check:  IsNotModified,
+		},
+		{
+			err:    testErr,
+			status: http.StatusNotImplemented,
+			check:  IsNotImplemented,
+		},
+		{
+			err:    testErr,
+			status: http.StatusInternalServerError,
+			check:  IsSystem,
+		},
+		{
+			err:    Unknown(testErr),
+			status: http.StatusInternalServerError,
+			check:  IsUnknown,
+		},
+		{
+			err:    DataLoss(testErr),
+			status: http.StatusInternalServerError,
+			check:  IsDataLoss,
+		},
+		{
+			err:    Deadline(testErr),
+			status: http.StatusInternalServerError,
+			check:  IsDeadline,
+		},
+		{
+			err:    Cancelled(testErr),
+			status: http.StatusInternalServerError,
+			check:  IsCancelled,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(http.StatusText(tc.status), func(t *testing.T) {
+			err := FromStatusCode(tc.err, tc.status)
+			assert.Check(t, tc.check(err), "unexpected error-type %T", err)
+		})
+	}
+}