拉取镜像manifest

    acceptMediaTypes := []string{schema1.MediaTypeManifest, schema2.MediaTypeManifest}
    digest, mediaType, payload, err := m.srcClient.PullManifest(tag, acceptMediaTypes)

tag 就是 reference PullManifest实现

func (r *Repository) PullManifest(reference string, acceptMediaTypes []string) (digest, mediaType string, payload []byte, err error) {
    req, err := http.NewRequest("GET", buildManifestURL(r.Endpoint.String(), r.Name, reference), nil)
    if err != nil {
        return
    }

    for _, mediaType := range acceptMediaTypes {
        req.Header.Add(http.CanonicalHeaderKey("Accept"), mediaType)
    }

    resp, err := r.client.Do(req)
    if err != nil {
        err = parseError(err)
        return
    }

    defer resp.Body.Close()
    b, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return
    }

    if resp.StatusCode == http.StatusOK {
        digest = resp.Header.Get(http.CanonicalHeaderKey("Docker-Content-Digest"))
        mediaType = resp.Header.Get(http.CanonicalHeaderKey("Content-Type"))
        payload = b
        return
    }

    err = &registry_error.Error{
        StatusCode: resp.StatusCode,
        Detail:     string(b),
    }

    return
}

返回的头里面包含digest、mediaType和mainfest内容b。解析出来，

判读blob是否存在

for _, blob := range blobs {
        exist, ok := m.blobsExistence[blob]
        if !ok {
            exist, err = m.dstClient.BlobExist(blob)
            if err != nil {
                m.logger.Errorf("an error occurred while checking existence of blob %s of %s:%s on %s: %v", blob, name, tag, m.dstURL, err)
                return "", err
            }
            m.blobsExistence[blob] = exist
        }

        if !exist {
            m.blobs = append(m.blobs, blob)
        } else {
            m.logger.Infof("blob %s of %s:%s already exists in %s", blob, name, tag, m.dstURL)
        }
    }

拉取并上传不存在的blob

func (r *Repository) PullBlob(digest string) (size int64, data io.ReadCloser, err error) {
    req, err := http.NewRequest("GET", buildBlobURL(r.Endpoint.String(), r.Name, digest), nil)
    if err != nil {
        return
    }

    resp, err := r.client.Do(req)
    if err != nil {
        err = parseError(err)
        return
    }

    if resp.StatusCode == http.StatusOK {
        contengLength := resp.Header.Get(http.CanonicalHeaderKey("Content-Length"))
        size, err = strconv.ParseInt(contengLength, 10, 64)
        if err != nil {
            return
        }
        data = resp.Body
        return
    }
    // can not close the connect if the status code is 200
    defer resp.Body.Close()

    b, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return
    }

    err = &registry_error.Error{
        StatusCode: resp.StatusCode,
        Detail:     string(b),
    }

    return
}

上传blob层

func (r *Repository) PushBlob(digest string, size int64, data io.Reader) error {
    location, _, err := r.initiateBlobUpload(r.Name)
    if err != nil {
        return err
    }
    return r.monolithicBlobUpload(location, digest, size, data)
}

func (r *Repository) monolithicBlobUpload(location, digest string, size int64, data io.Reader) error {
    req, err := http.NewRequest("PUT", buildMonolithicBlobUploadURL(location, digest), data)
    if err != nil {
        return err
    }

    resp, err := r.client.Do(req)
    if err != nil {
        return parseError(err)
    }

    defer resp.Body.Close()

    if resp.StatusCode == http.StatusCreated {
        return nil
    }

    b, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return err
    }

    return &registry_error.Error{
        StatusCode: resp.StatusCode,
        Detail:     string(b),
    }
}

上传manifest

func (r *Repository) PushManifest(reference, mediaType string, payload []byte) (digest string, err error) {
    req, err := http.NewRequest("PUT", buildManifestURL(r.Endpoint.String(), r.Name, reference),
        bytes.NewReader(payload))
    if err != nil {
        return
    }
    req.Header.Set(http.CanonicalHeaderKey("Content-Type"), mediaType)

    resp, err := r.client.Do(req)
    if err != nil {
        err = parseError(err)
        return
    }

    defer resp.Body.Close()

    if resp.StatusCode == http.StatusCreated {
        digest = resp.Header.Get(http.CanonicalHeaderKey("Docker-Content-Digest"))
        return
    }

    b, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return
    }

    err = &registry_error.Error{
        StatusCode: resp.StatusCode,
        Detail:     string(b),
    }

    return
}