Add push object

Split resolver to only return a name with separate methods
for getting a fetcher and pusher. Add implementation for
push.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

remotes/docker/pusher.go

@@ -0,0 +1,144 @@
+package docker
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"path"
+	"strings"
+
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/log"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+type dockerPusher struct {
+	*dockerBase
+	tag string
+}
+
+func (p dockerPusher) Push(ctx context.Context, desc ocispec.Descriptor, r io.Reader) error {
+	var (
+		isManifest bool
+		existCheck string
+	)
+
+	switch desc.MediaType {
+	case images.MediaTypeDockerSchema2Manifest, images.MediaTypeDockerSchema2ManifestList,
+		ocispec.MediaTypeImageManifest, ocispec.MediaTypeImageIndex:
+		isManifest = true
+		existCheck = path.Join("manifests", desc.Digest.String())
+	default:
+		existCheck = path.Join("blobs", desc.Digest.String())
+	}
+
+	req, err := http.NewRequest(http.MethodHead, p.url(existCheck), nil)
+	if err != nil {
+		return err
+	}
+
+	req.Header.Set("Accept", strings.Join([]string{desc.MediaType, `*`}, ", "))
+	resp, err := p.doRequestWithRetries(ctx, req, nil)
+	if err != nil {
+		if errors.Cause(err) != ErrInvalidAuthorization {
+			return err
+		}
+		log.G(ctx).WithError(err).Debugf("Unable to check existence, continuing with push")
+	} else {
+		if resp.StatusCode == http.StatusOK {
+			return nil
+		}
+		if resp.StatusCode != http.StatusNotFound {
+			// TODO: log error
+			return errors.Errorf("unexpected response: %s", resp.Status)
+		}
+	}
+
+	// TODO: Lookup related objects for cross repository push
+
+	if isManifest {
+		// Read all to use bytes.Reader for using GetBody
+		b, err := ioutil.ReadAll(r)
+		if err != nil {
+			return errors.Wrap(err, "failed to read manifest")
+		}
+		var putPath string
+		if p.tag != "" {
+			putPath = path.Join("manifests", p.tag)
+		} else {
+			putPath = path.Join("manifests", desc.Digest.String())
+		}
+
+		req, err := http.NewRequest(http.MethodPut, p.url(putPath), nil)
+		if err != nil {
+			return err
+		}
+		req.ContentLength = int64(len(b))
+		req.Body = ioutil.NopCloser(bytes.NewReader(b))
+		req.GetBody = func() (io.ReadCloser, error) {
+			return ioutil.NopCloser(bytes.NewReader(b)), nil
+		}
+		req.Header.Add("Content-Type", desc.MediaType)
+
+		resp, err := p.doRequestWithRetries(ctx, req, nil)
+		if err != nil {
+			return err
+		}
+		if resp.StatusCode != http.StatusCreated {
+			// TODO: log error
+			return errors.Errorf("unexpected response: %s", resp.Status)
+		}
+	} else {
+		// TODO: Do monolithic upload if size is small
+
+		// TODO: Turn multi-request blob uploader into ingester
+
+		// Start upload request
+		req, err := http.NewRequest(http.MethodPost, p.url("blobs", "uploads")+"/", nil)
+		if err != nil {
+			return err
+		}
+
+		resp, err := p.doRequestWithRetries(ctx, req, nil)
+		if err != nil {
+			return err
+		}
+		if resp.StatusCode != http.StatusAccepted {
+			// TODO: log error
+			return errors.Errorf("unexpected response: %s", resp.Status)
+		}
+
+		location := resp.Header.Get("Location")
+		// Support paths without host in location
+		if strings.HasPrefix(location, "/") {
+			u := p.base
+			u.Path = location
+			location = u.String()
+		}
+
+		// TODO: Support chunked upload
+		req, err = http.NewRequest(http.MethodPut, location, r)
+		if err != nil {
+			return err
+		}
+		q := req.URL.Query()
+		q.Add("digest", desc.Digest.String())
+		req.URL.RawQuery = q.Encode()
+		req.ContentLength = desc.Size
+
+		resp, err = p.doRequest(ctx, req)
+		if err != nil {
+			return err
+		}
+		if resp.StatusCode != http.StatusCreated {
+			// TODO: log error
+			return errors.Errorf("unexpected response: %s", resp.Status)
+		}
+
+	}
+
+	return nil
+}