Move remotes to core/remotes

Signed-off-by: Derek McGowan <derek@mcg.dev>

core/remotes/errors/errors.go

@@ -0,0 +1,55 @@
+/*
+   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 errors
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+)
+
+var _ error = ErrUnexpectedStatus{}
+
+// ErrUnexpectedStatus is returned if a registry API request returned with unexpected HTTP status
+type ErrUnexpectedStatus struct {
+	Status                    string
+	StatusCode                int
+	Body                      []byte
+	RequestURL, RequestMethod string
+}
+
+func (e ErrUnexpectedStatus) Error() string {
+	return fmt.Sprintf("unexpected status from %s request to %s: %s", e.RequestMethod, e.RequestURL, e.Status)
+}
+
+// NewUnexpectedStatusErr creates an ErrUnexpectedStatus from HTTP response
+func NewUnexpectedStatusErr(resp *http.Response) error {
+	var b []byte
+	if resp.Body != nil {
+		b, _ = io.ReadAll(io.LimitReader(resp.Body, 64000)) // 64KB
+	}
+	err := ErrUnexpectedStatus{
+		Body:          b,
+		Status:        resp.Status,
+		StatusCode:    resp.StatusCode,
+		RequestMethod: resp.Request.Method,
+	}
+	if resp.Request.URL != nil {
+		err.RequestURL = resp.Request.URL.String()
+	}
+	return err
+}