// Get issues a HEAD request for a Manifest against its named endpoint in order
// to construct a descriptor for the tag. If the registry doesn't support HEADing
// a manifest, fallback to GET.
func (t *tags) Get(ctx context.Context, tag string) (distribution.Descriptor, error) {
ref, err := reference.WithTag(t.name, tag)
if err != nil {
return distribution.Descriptor{}, err
}
u, err := t.ub.BuildManifestURL(ref)
if err != nil {
return distribution.Descriptor{}, err
}
req, err := http.NewRequest("HEAD", u, nil)
if err != nil {
return distribution.Descriptor{}, err
}
for _, t := range distribution.ManifestMediaTypes() {
req.Header.Add("Accept", t)
}
var attempts int
resp, err := t.client.Do(req)
check:
if err != nil {
return distribution.Descriptor{}, err
}
defer resp.Body.Close()
switch {
case resp.StatusCode >= 200 && resp.StatusCode < 400:
return descriptorFromResponse(resp)
case resp.StatusCode == http.StatusMethodNotAllowed:
req, err = http.NewRequest("GET", u, nil)
if err != nil {
return distribution.Descriptor{}, err
}
for _, t := range distribution.ManifestMediaTypes() {
req.Header.Add("Accept", t)
}
resp, err = t.client.Do(req)
attempts++
if attempts > 1 {
return distribution.Descriptor{}, err
}
goto check
default:
return distribution.Descriptor{}, HandleErrorResponse(resp)
}
}
// Get issues a HEAD request for a Manifest against its named endpoint in order
// to construct a descriptor for the tag. If the registry doesn't support HEADing
// a manifest, fallback to GET.
func (t *tags) Get(ctx context.Context, tag string) (distribution.Descriptor, error) {
ref, err := reference.WithTag(t.name, tag)
if err != nil {
return distribution.Descriptor{}, err
}
u, err := t.ub.BuildManifestURL(ref)
if err != nil {
return distribution.Descriptor{}, err
}
newRequest := func(method string) (*http.Response, error) {
req, err := http.NewRequest(method, u, nil)
if err != nil {
return nil, err
}
for _, t := range distribution.ManifestMediaTypes() {
req.Header.Add("Accept", t)
}
resp, err := t.client.Do(req)
return resp, err
}
resp, err := newRequest("HEAD")
if err != nil {
return distribution.Descriptor{}, err
}
defer resp.Body.Close()
switch {
case resp.StatusCode >= 200 && resp.StatusCode < 400:
return descriptorFromResponse(resp)
default:
// if the response is an error - there will be no body to decode.
// Issue a GET request:
// - for data from a server that does not handle HEAD
// - to get error details in case of a failure
resp, err = newRequest("GET")
if err != nil {
return distribution.Descriptor{}, err
}
defer resp.Body.Close()
if resp.StatusCode >= 200 && resp.StatusCode < 400 {
return descriptorFromResponse(resp)
}
return distribution.Descriptor{}, HandleErrorResponse(resp)
}
}
func (r *registry) getRequest(u, etag string) (req *http.Request, err error) {
req, err = http.NewRequest("GET", u, nil)
if err != nil {
return nil, err
}
for _, t := range distribution.ManifestMediaTypes() {
req.Header.Add("Accept", t)
}
if etag != "" {
req.Header.Set("If-None-Match", etag)
}
return req, nil
}
func (ms *manifests) Get(ctx context.Context, dgst digest.Digest, options ...distribution.ManifestServiceOption) (distribution.Manifest, error) {
var (
digestOrTag string
ref reference.Named
err error
contentDgst *digest.Digest
)
for _, option := range options {
if opt, ok := option.(distribution.WithTagOption); ok {
digestOrTag = opt.Tag
ref, err = reference.WithTag(ms.name, opt.Tag)
if err != nil {
return nil, err
}
} else if opt, ok := option.(contentDigestOption); ok {
contentDgst = opt.digest
} else {
err := option.Apply(ms)
if err != nil {
return nil, err
}
}
}
if digestOrTag == "" {
digestOrTag = dgst.String()
ref, err = reference.WithDigest(ms.name, dgst)
if err != nil {
return nil, err
}
}
u, err := ms.ub.BuildManifestURL(ref)
if err != nil {
return nil, err
}
req, err := http.NewRequest("GET", u, nil)
if err != nil {
return nil, err
}
for _, t := range distribution.ManifestMediaTypes() {
req.Header.Add("Accept", t)
}
if _, ok := ms.etags[digestOrTag]; ok {
req.Header.Set("If-None-Match", ms.etags[digestOrTag])
}
resp, err := ms.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode == http.StatusNotModified {
return nil, distribution.ErrManifestNotModified
} else if SuccessStatus(resp.StatusCode) {
if contentDgst != nil {
dgst, err := digest.ParseDigest(resp.Header.Get("Docker-Content-Digest"))
if err == nil {
*contentDgst = dgst
}
}
mt := resp.Header.Get("Content-Type")
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
m, _, err := distribution.UnmarshalManifest(mt, body)
if err != nil {
return nil, err
}
return m, nil
}
return nil, HandleErrorResponse(resp)
}
func (ms *manifests) Get(ctx context.Context, dgst digest.Digest, options ...distribution.ManifestServiceOption) (distribution.Manifest, error) {
var tag string
for _, option := range options {
if opt, ok := option.(withTagOption); ok {
tag = opt.tag
} else {
err := option.Apply(ms)
if err != nil {
return nil, err
}
}
}
var ref string
if tag != "" {
ref = tag
} else {
ref = dgst.String()
}
u, err := ms.ub.BuildManifestURL(ms.name, ref)
if err != nil {
return nil, err
}
req, err := http.NewRequest("GET", u, nil)
if err != nil {
return nil, err
}
for _, t := range distribution.ManifestMediaTypes() {
req.Header.Add("Accept", t)
}
if _, ok := ms.etags[ref]; ok {
req.Header.Set("If-None-Match", ms.etags[ref])
}
resp, err := ms.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode == http.StatusNotModified {
return nil, distribution.ErrManifestNotModified
} else if SuccessStatus(resp.StatusCode) {
mt := resp.Header.Get("Content-Type")
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
m, _, err := distribution.UnmarshalManifest(mt, body)
if err != nil {
return nil, err
}
return m, nil
}
return nil, HandleErrorResponse(resp)
}