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Merge pull request #612 from stevvooe/simplify-resolution-flow

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cmd/dist, remotes: simplify resolution flow
This commit is contained in:
Michael Crosby 2017-03-09 12:41:12 -08:00 committed by GitHub
commit 0e0ae74b82
6 changed files with 593 additions and 201 deletions
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74
cmd/dist/fetch.go vendored
View file

@ -46,8 +46,7 @@ Most of this is experimental and there are few leaps to make this work.`,
Action: func(clicontext *cli.Context) error {
var (
ctx = background
locator = clicontext.Args().First()
object = clicontext.Args().Get(1)
ref = clicontext.Args().First()
)
conn, err := connectGRPC(clicontext)
@ -59,11 +58,7 @@ Most of this is experimental and there are few leaps to make this work.`,
if err != nil {
return err
}
fetcher, err := resolver.Resolve(ctx, locator)
if err != nil {
return err
}
ctx = withJobsContext(ctx)
ingester := contentservice.NewIngesterFromClient(contentapi.NewContentClient(conn))
cs, err := resolveContentStore(clicontext)
@ -73,10 +68,17 @@ Most of this is experimental and there are few leaps to make this work.`,
eg, ctx := errgroup.WithContext(ctx)
ctx = withJobsContext(ctx)
resolved := make(chan struct{})
eg.Go(func() error {
return fetchManifest(ctx, ingester, fetcher, object)
addJob(ctx, ref)
name, desc, fetcher, err := resolver.Resolve(ctx, ref)
if err != nil {
return err
}
log.G(ctx).WithField("image", name).Debug("fetching")
close(resolved)
return dispatch(ctx, ingester, fetcher, desc)
})
errs := make(chan error)
@ -96,8 +98,7 @@ Most of this is experimental and there are few leaps to make this work.`,
case <-ticker.C:
fw.Flush()
tw := tabwriter.NewWriter(fw, 1, 8, 1, '\t', 0)
// fmt.Fprintln(tw, "REF\tSIZE\tAGE")
tw := tabwriter.NewWriter(fw, 1, 8, 1, ' ', 0)
var total int64
js := getJobs(ctx)
@ -137,10 +138,20 @@ Most of this is experimental and there are few leaps to make this work.`,
if _, ok := activeSeen[j]; ok {
continue
}
status := "done"
if j == ref {
select {
case <-resolved:
status = "resolved"
default:
status = "resolving"
}
}
statuses[j] = statusInfo{
Ref: j,
Status: "done", // for now!
Status: status, // for now!
}
}
@ -151,21 +162,27 @@ Most of this is experimental and there are few leaps to make this work.`,
switch status.Status {
case "downloading":
bar := progress.Bar(float64(status.Offset) / float64(status.Total))
fmt.Fprintf(tw, "%s:\t%s\t%40r\t%8.8s/%s\n",
fmt.Fprintf(tw, "%s:\t%s\t%40r\t%8.8s/%s\t\n",
status.Ref,
status.Status,
bar,
progress.Bytes(status.Offset), progress.Bytes(status.Total))
case "done":
case "resolving":
bar := progress.Bar(0.0)
fmt.Fprintf(tw, "%s:\t%s\t%40r\t\n",
status.Ref,
status.Status,
bar)
default:
bar := progress.Bar(1.0)
fmt.Fprintf(tw, "%s:\t%s\t%40r\n",
fmt.Fprintf(tw, "%s:\t%s\t%40r\t\n",
status.Ref,
status.Status,
bar)
}
}
fmt.Fprintf(tw, "elapsed: %-4.1fs\ttotal: %7.6v\t(%v)\n",
fmt.Fprintf(tw, "elapsed: %-4.1fs\ttotal: %7.6v\t(%v)\t\n",
time.Since(start).Seconds(),
// TODO(stevvooe): These calculations are actually way off.
// Need to account for previously downloaded data. These
@ -250,14 +267,11 @@ func (j *jobs) jobs() []string {
return jobs
}
func fetchManifest(ctx context.Context, ingester content.Ingester, fetcher remotes.Fetcher, object string, hints ...string) error {
const manifestMediaType = "application/vnd.docker.distribution.manifest.v2+json"
hints = append(hints, "mediatype:"+manifestMediaType)
ref := "manifest-" + object
func fetchManifest(ctx context.Context, ingester content.Ingester, fetcher remotes.Fetcher, desc ocispec.Descriptor) error {
ref := "manifest-" + desc.Digest.String()
addJob(ctx, ref)
rc, err := fetcher.Fetch(ctx, object, hints...)
rc, err := fetcher.Fetch(ctx, desc)
if err != nil {
return err
}
@ -291,18 +305,10 @@ func fetchManifest(ctx context.Context, ingester content.Ingester, fetcher remot
}
func fetch(ctx context.Context, ingester content.Ingester, fetcher remotes.Fetcher, desc ocispec.Descriptor) error {
var (
hints []string
object = desc.Digest.String()
)
if desc.MediaType != "" {
hints = append(hints, "mediatype:"+desc.MediaType)
}
ref := "fetch-" + object
ref := "fetch-" + desc.Digest.String()
addJob(ctx, ref)
log.G(ctx).Debug("fetch")
rc, err := fetcher.Fetch(ctx, object, hints...)
rc, err := fetcher.Fetch(ctx, desc)
if err != nil {
log.G(ctx).WithError(err).Error("fetch error")
return err
@ -328,7 +334,7 @@ func dispatch(ctx context.Context, ingester content.Ingester, fetcher remotes.Fe
switch desc.MediaType {
case MediaTypeDockerSchema2Manifest, ocispec.MediaTypeImageManifest:
eg.Go(func() error {
return fetchManifest(ctx, ingester, fetcher, desc.Digest.String(), "mediatype:"+desc.MediaType)
return fetchManifest(ctx, ingester, fetcher, desc)
})
case MediaTypeDockerSchema2ManifestList, ocispec.MediaTypeImageIndex:
return fmt.Errorf("%v not yet supported", desc.MediaType)

285
cmd/dist/fetchobject.go vendored
View file

@ -10,10 +10,12 @@ import (
"net/url"
"os"
"path"
"strconv"
"strings"
"github.com/Sirupsen/logrus"
"github.com/docker/containerd/log"
"github.com/docker/containerd/reference"
"github.com/docker/containerd/remotes"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
@ -47,8 +49,7 @@ var fetchObjectCommand = cli.Command{
var (
ctx = background
timeout = context.Duration("timeout")
locator = context.Args().First()
args = context.Args().Tail()
ref = context.Args().First()
)
if timeout > 0 {
@ -57,35 +58,21 @@ var fetchObjectCommand = cli.Command{
defer cancel()
}
if locator == "" {
return errors.New("containerd: remote required")
}
if len(args) < 1 {
return errors.New("containerd: object required")
}
object := args[0]
hints := args[1:]
resolver, err := getResolver(ctx)
if err != nil {
return err
}
remote, err := resolver.Resolve(ctx, locator)
ctx = log.WithLogger(ctx, log.G(ctx).WithField("ref", ref))
log.G(ctx).Infof("resolving")
_, desc, fetcher, err := resolver.Resolve(ctx, ref)
if err != nil {
return err
}
ctx = log.WithLogger(ctx, log.G(ctx).WithFields(
logrus.Fields{
"remote": locator,
"object": object,
}))
log.G(ctx).Infof("fetching")
rc, err := remote.Fetch(ctx, object, hints...)
rc, err := fetcher.Fetch(ctx, desc)
if err != nil {
return err
}
@ -99,73 +86,50 @@ var fetchObjectCommand = cli.Command{
},
}
// getResolver prepares the resolver from the environment and options.
func getResolver(ctx contextpkg.Context) (remotes.Resolver, error) {
return newDockerResolver(), nil
}
// NOTE(stevvooe): Most of the code below this point is prototype code to
// demonstrate a very simplified docker.io fetcher. We have a lot of hard coded
// values but we leave many of the details down to the fetcher, creating a lot
// of room for ways to fetch content.
// getResolver prepares the resolver from the environment and options.
func getResolver(ctx contextpkg.Context) (remotes.Resolver, error) {
return remotes.ResolverFunc(func(ctx contextpkg.Context, locator string) (remotes.Fetcher, error) {
if !strings.HasPrefix(locator, "docker.io") && !strings.HasPrefix(locator, "localhost:5000") {
return nil, errors.Errorf("unsupported locator: %q", locator)
type dockerFetcher struct {
base url.URL
token string
}
var (
base = url.URL{
Scheme: "https",
Host: "registry-1.docker.io",
}
prefix = strings.TrimPrefix(locator, "docker.io/")
)
if strings.HasPrefix(locator, "localhost:5000") {
base.Scheme = "http"
base.Host = "localhost:5000"
prefix = strings.TrimPrefix(locator, "localhost:5000/")
func (r *dockerFetcher) url(ps ...string) string {
url := r.base
url.Path = path.Join(url.Path, path.Join(ps...))
return url.String()
}
token, err := getToken(ctx, "repository:"+prefix+":pull")
if err != nil {
return nil, err
}
return remotes.FetcherFunc(func(ctx contextpkg.Context, object string, hints ...string) (io.ReadCloser, error) {
func (r *dockerFetcher) Fetch(ctx contextpkg.Context, desc ocispec.Descriptor) (io.ReadCloser, error) {
ctx = log.WithLogger(ctx, log.G(ctx).WithFields(
logrus.Fields{
"prefix": prefix, // or repo?
"base": base.String(),
"hints": hints,
"base": r.base.String(),
"digest": desc.Digest,
},
))
if _, err := digest.Parse(object); err != nil {
// in this case, we are seeking a manifest by a tag. Let's add some hints.
hints = append(hints, "mediatype:"+MediaTypeDockerSchema2Manifest)
hints = append(hints, "mediatype:"+MediaTypeDockerSchema2ManifestList)
hints = append(hints, "mediatype:"+ocispec.MediaTypeImageManifest)
hints = append(hints, "mediatype:"+ocispec.MediaTypeImageIndex)
}
paths, err := getV2URLPaths(prefix, object, hints...)
paths, err := getV2URLPaths(desc)
if err != nil {
return nil, err
}
for _, path := range paths {
url := base
url.Path = path
log.G(ctx).WithField("url", url).Debug("fetch content")
u := r.url(path)
req, err := http.NewRequest(http.MethodGet, url.String(), nil)
req, err := http.NewRequest(http.MethodGet, u, nil)
if err != nil {
return nil, err
}
req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
req.Header.Set("Accept", strings.Join(remotes.HintValues("mediatype", hints...), ", "))
resp, err := ctxhttp.Do(ctx, http.DefaultClient, req)
req.Header.Set("Accept", strings.Join([]string{desc.MediaType, `*`}, ", "))
resp, err := r.doRequest(ctx, req)
if err != nil {
return nil, err
}
@ -175,15 +139,164 @@ func getResolver(ctx contextpkg.Context) (remotes.Resolver, error) {
continue // try one of the other urls.
}
resp.Body.Close()
return nil, errors.Errorf("unexpected status code %v: %v", url, resp.Status)
return nil, errors.Errorf("unexpected status code %v: %v", u, resp.Status)
}
return resp.Body, nil
}
return nil, errors.New("not found")
}), nil
}), nil
}
func (r *dockerFetcher) doRequest(ctx contextpkg.Context, req *http.Request) (*http.Response, error) {
ctx = log.WithLogger(ctx, log.G(ctx).WithField("url", req.URL.String()))
log.G(ctx).WithField("request.headers", req.Header).Debug("fetch content")
if r.token != "" {
req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", r.token))
}
resp, err := ctxhttp.Do(ctx, http.DefaultClient, req)
if err != nil {
return nil, err
}
log.G(ctx).WithFields(logrus.Fields{
"status": resp.Status,
"response.headers": resp.Header,
}).Debug("fetch response received")
return resp, err
}
type dockerResolver struct{}
var _ remotes.Resolver = &dockerResolver{}
func newDockerResolver() remotes.Resolver {
return &dockerResolver{}
}
func (r *dockerResolver) Resolve(ctx contextpkg.Context, ref string) (string, ocispec.Descriptor, remotes.Fetcher, error) {
refspec, err := reference.Parse(ref)
if err != nil {
return "", ocispec.Descriptor{}, nil, err
}
var (
base url.URL
token string
)
switch refspec.Hostname() {
case "docker.io":
base.Scheme = "https"
base.Host = "registry-1.docker.io"
prefix := strings.TrimPrefix(refspec.Locator, "docker.io/")
base.Path = path.Join("/v2", prefix)
token, err = getToken(ctx, "repository:"+prefix+":pull")
if err != nil {
return "", ocispec.Descriptor{}, nil, err
}
case "localhost:5000":
base.Scheme = "http"
base.Host = "localhost:5000"
base.Path = path.Join("/v2", strings.TrimPrefix(refspec.Locator, "localhost:5000/"))
default:
return "", ocispec.Descriptor{}, nil, errors.Errorf("unsupported locator: %q", refspec.Locator)
}
fetcher := &dockerFetcher{
base: base,
token: token,
}
var (
urls []string
dgst = refspec.Digest()
)
if dgst != "" {
if err := dgst.Validate(); err != nil {
// need to fail here, since we can't actually resolve the invalid
// digest.
return "", ocispec.Descriptor{}, nil, err
}
// turns out, we have a valid digest, make a url.
urls = append(urls, fetcher.url("manifests", dgst.String()))
} else {
urls = append(urls, fetcher.url("manifests", refspec.Object))
}
// fallback to blobs on not found.
urls = append(urls, fetcher.url("blobs", dgst.String()))
for _, u := range urls {
req, err := http.NewRequest(http.MethodHead, u, nil)
if err != nil {
return "", ocispec.Descriptor{}, nil, err
}
// set headers for all the types we support for resolution.
req.Header.Set("Accept", strings.Join([]string{
MediaTypeDockerSchema2Manifest,
MediaTypeDockerSchema2ManifestList,
ocispec.MediaTypeImageManifest,
ocispec.MediaTypeImageIndex, "*"}, ", "))
log.G(ctx).Debug("resolving")
resp, err := fetcher.doRequest(ctx, req)
if err != nil {
return "", ocispec.Descriptor{}, nil, err
}
resp.Body.Close() // don't care about body contents.
if resp.StatusCode > 299 {
if resp.StatusCode == http.StatusNotFound {
continue
}
return "", ocispec.Descriptor{}, nil, errors.Errorf("unexpected status code %v: %v", u, resp.Status)
}
// this is the only point at which we trust the registry. we use the
// content headers to assemble a descriptor for the name. when this becomes
// more robust, we mostly get this information from a secure trust store.
dgstHeader := digest.Digest(resp.Header.Get("Docker-Content-Digest"))
if dgstHeader != "" {
if err := dgstHeader.Validate(); err != nil {
if err == nil {
return "", ocispec.Descriptor{}, nil, errors.Errorf("%q in header not a valid digest", dgstHeader)
}
return "", ocispec.Descriptor{}, nil, errors.Wrapf(err, "%q in header not a valid digest", dgstHeader)
}
dgst = dgstHeader
}
if dgst == "" {
return "", ocispec.Descriptor{}, nil, errors.Wrapf(err, "could not resolve digest for %v", ref)
}
var (
size int64
sizeHeader = resp.Header.Get("Content-Length")
)
size, err = strconv.ParseInt(sizeHeader, 10, 64)
if err != nil || size < 0 {
return "", ocispec.Descriptor{}, nil, errors.Wrapf(err, "%q in header not a valid size", sizeHeader)
}
desc := ocispec.Descriptor{
Digest: dgst,
MediaType: resp.Header.Get("Content-Type"), // need to strip disposition?
Size: size,
}
log.G(ctx).WithField("desc.digest", desc.Digest).Debug("resolved")
return ref, desc, fetcher, nil
}
return "", ocispec.Descriptor{}, nil, errors.Errorf("%v not found", ref)
}
func getToken(ctx contextpkg.Context, scopes ...string) (string, error) {
@ -232,39 +345,17 @@ func getToken(ctx contextpkg.Context, scopes ...string) (string, error) {
// getV2URLPaths generates the candidate urls paths for the object based on the
// set of hints and the provided object id. URLs are returned in the order of
// most to least likely succeed.
func getV2URLPaths(prefix, object string, hints ...string) ([]string, error) {
func getV2URLPaths(desc ocispec.Descriptor) ([]string, error) {
var urls []string
// TODO(stevvooe): We can probably define a higher-level "type" hint to
// avoid having to do extra round trips to resolve content, as well as
// avoid the tedium of providing media types.
if remotes.HintExists("mediatype", MediaTypeDockerSchema2Manifest, hints...) ||
remotes.HintExists("mediatype", MediaTypeDockerSchema2ManifestList, hints...) ||
remotes.HintExists("mediatype", ocispec.MediaTypeImageManifest, hints...) ||
remotes.HintExists("mediatype", ocispec.MediaTypeImageIndex, hints...) {
// fast path out if we know we are getting a manifest. Arguably, we
// should fallback to blobs, just in case.
urls = append(urls, path.Join("/v2", prefix, "manifests", object))
switch desc.MediaType {
case MediaTypeDockerSchema2Manifest, MediaTypeDockerSchema2ManifestList,
ocispec.MediaTypeImageManifest, ocispec.MediaTypeImageIndex:
urls = append(urls, path.Join("manifests", desc.Digest.String()))
}
// we have a digest, use blob or manifest path, depending on hints, may
// need to try both.
urls = append(urls, path.Join("/v2", prefix, "blobs", object))
// always fallback to attempting to get the object out of the blobs store.
urls = append(urls, path.Join("blobs", desc.Digest.String()))
// probably a take, so we go through the manifests endpoint
urls = append(urls, path.Join("/v2", prefix, "manifests", object))
var (
noduplicates []string
seen = map[string]struct{}{}
)
for _, u := range urls {
if _, ok := seen[u]; !ok {
seen[u] = struct{}{}
noduplicates = append(noduplicates, u)
}
}
return noduplicates, nil
return urls, nil
}

139
reference/reference.go Normal file
View file

@ -0,0 +1,139 @@
package reference
import (
"errors"
"fmt"
"net/url"
"path"
"regexp"
"strings"
digest "github.com/opencontainers/go-digest"
)
var (
ErrInvalid = errors.New("invalid reference")
ErrObjectRequired = errors.New("object required")
ErrHostnameRequired = errors.New("hostname required")
)
// Spec defines the main components of a reference specification.
//
// A reference specification is a schema-less URI parsed into common
// components. The two main components, locator and object, are required to be
// supported by remotes. It represents a superset of the naming define in
// docker's reference schema. It aims to be compatible but not prescriptive.
//
// While the interpretation of the components, locator and object, are up to
// the remote, we define a few common parts, accessible via helper methods.
//
// The first is the hostname, which is part of the locator. This doesn't need
// to map to a physical resource, but it must parse as a hostname. We refer to
// this as the namespace.
//
// The other component is the digest, which may be a part of the object
// identifier, always prefixed with an '@'. If present, the remote may use the
// digest portion directly or resolve it against a prefix. If the object
type Spec struct {
// Locator is the host and path portion of the specification. The host
// portion may refer to an actual host or just a namespace of related
// images.
//
// Typically, the locator may used to resolve the remote to fetch specific
// resources.
Locator string
// Object contains the identifier for the remote resource. Classically,
// this is a tag but can refer to anything in a remote. By convention, any
// portion that may be a partial or whole digest will be preceeded by an
// `@`. Anything preceeding the `@` will be referred to as the "tag".
//
// In practice, we will see this broken down into the following formats:
//
// 1. <tag>
// 2. <tag>@<digest spec>
// 3. @<digest spec>
//
// We define the tag to be anything except '@' and ':'. <digest spec> may
// be a full valid digest or shortened version, possibly with elided
// algorithm.
Object string
}
var splitRe = regexp.MustCompile(`[:@]`)
// Parse parses the string into a structured ref.
func Parse(s string) (Spec, error) {
u, err := url.Parse("dummy://" + s)
if err != nil {
return Spec{}, err
}
if u.Scheme != "dummy" {
return Spec{}, ErrInvalid
}
if u.Host == "" {
return Spec{}, ErrHostnameRequired
}
parts := splitRe.Split(u.Path, 2)
if len(parts) < 2 {
return Spec{}, ErrObjectRequired
}
// This allows us to retain the @ to signify digests or shortend digests in
// the object.
object := u.Path[len(parts[0]):]
if object[:1] == ":" {
object = object[1:]
}
return Spec{
Locator: path.Join(u.Host, parts[0]),
Object: object,
}, nil
}
// Hostname returns the hostname portion of the locator.
//
// Remotes are not required to directly access the resources at this host. This
// method is provided for convenience.
func (r Spec) Hostname() string {
i := strings.Index(r.Locator, "/")
if i < 0 {
i = len(r.Locator) + 1
}
return r.Locator[:i]
}
// Digest returns the digest portion of the reference spec. This may be a
// partial or invalid digest, which may be used to lookup a complete digest.
func (r Spec) Digest() digest.Digest {
_, dgst := SplitObject(r.Object)
return dgst
}
// String returns the normalized string for the ref.
func (r Spec) String() string {
if r.Object[:1] == "@" {
return fmt.Sprintf("%v%v", r.Locator, r.Object)
}
return fmt.Sprintf("%v:%v", r.Locator, r.Object)
}
// SplitObject provides two parts of the object spec, delimiited by an `@`
// symbol.
//
// Either may be empty and it is the callers job to validate them
// appropriately.
func SplitObject(obj string) (tag string, dgst digest.Digest) {
parts := strings.SplitAfterN(obj, "@", 2)
if len(parts) < 2 {
return parts[0], ""
} else {
return parts[0], digest.Digest(parts[1])
}
}

179
reference/reference_test.go Normal file
View file

@ -0,0 +1,179 @@
package reference
import (
"testing"
digest "github.com/opencontainers/go-digest"
)
func TestReferenceParser(t *testing.T) {
for _, testcase := range []struct {
Skip bool
Name string
Input string
Normalized string
Digest digest.Digest
Hostname string
Expected Spec
Err error
}{
{
Name: "Basic",
Input: "docker.io/library/redis:foo?fooo=asdf",
Normalized: "docker.io/library/redis:foo",
Hostname: "docker.io",
Expected: Spec{
Locator: "docker.io/library/redis",
Object: "foo",
},
},
{
Name: "BasicWithDigest",
Input: "docker.io/library/redis:foo@sha256:abcdef?fooo=asdf",
Normalized: "docker.io/library/redis:foo@sha256:abcdef",
Hostname: "docker.io",
Digest: "sha256:abcdef",
Expected: Spec{
Locator: "docker.io/library/redis",
Object: "foo@sha256:abcdef",
},
},
{
Name: "DigestOnly",
Input: "docker.io/library/redis@sha256:abcdef?fooo=asdf",
Expected: Spec{
Locator: "docker.io/library/redis",
Object: "@sha256:abcdef",
},
Hostname: "docker.io",
Normalized: "docker.io/library/redis@sha256:abcdef",
Digest: "sha256:abcdef",
},
{
Name: "AtShortDigest",
Input: "docker.io/library/redis:obj@abcdef?fooo=asdf",
Normalized: "docker.io/library/redis:obj@abcdef",
Hostname: "docker.io",
Digest: "abcdef",
Expected: Spec{
Locator: "docker.io/library/redis",
Object: "obj@abcdef",
},
},
{
Name: "HostWithPort",
Input: "localhost:5000/library/redis:obj@abcdef?fooo=asdf",
Normalized: "localhost:5000/library/redis:obj@abcdef",
Hostname: "localhost:5000",
Digest: "abcdef",
Expected: Spec{
Locator: "localhost:5000/library/redis",
Object: "obj@abcdef",
},
},
{
Name: "HostnameRequired",
Input: "/docker.io/library/redis:obj@abcdef?fooo=asdf",
Err: ErrHostnameRequired,
},
{
Name: "ErrObjectRequired",
Input: "docker.io/library/redis?fooo=asdf",
Err: ErrObjectRequired,
},
{
Name: "Subdomain",
Input: "sub-dom1.foo.com/bar/baz/quux:latest",
Hostname: "sub-dom1.foo.com",
Expected: Spec{
Locator: "sub-dom1.foo.com/bar/baz/quux",
Object: "latest",
},
},
{
Name: "SubdomainWithLongTag",
Input: "sub-dom1.foo.com/bar/baz/quux:some-long-tag",
Hostname: "sub-dom1.foo.com",
Expected: Spec{
Locator: "sub-dom1.foo.com/bar/baz/quux",
Object: "some-long-tag",
},
},
{
Name: "AGCRAppears",
Input: "b.gcr.io/test.example.com/my-app:test.example.com",
Hostname: "b.gcr.io",
Expected: Spec{
Locator: "b.gcr.io/test.example.com/my-app",
Object: "test.example.com",
},
},
{
Name: "Punycode",
Input: "xn--n3h.com/myimage:xn--n3h.com", // ☃.com in punycode
Hostname: "xn--n3h.com",
Expected: Spec{
Locator: "xn--n3h.com/myimage",
Object: "xn--n3h.com",
},
},
{
Name: "PunycodeWithDigest",
Input: "xn--7o8h.com/myimage:xn--7o8h.com@sha512:fffffff",
Hostname: "xn--7o8h.com",
Digest: "sha512:fffffff",
Expected: Spec{
Locator: "xn--7o8h.com/myimage",
Object: "xn--7o8h.com@sha512:fffffff",
},
},
{
Skip: true, // TODO(stevvooe): Implement this case.
Name: "SchemeDefined",
Input: "http://xn--7o8h.com/myimage:xn--7o8h.com@sha512:fffffff",
Hostname: "xn--7o8h.com",
Digest: "sha512:fffffff",
Err: ErrInvalid,
},
} {
t.Run(testcase.Name, func(t *testing.T) {
if testcase.Skip {
t.Skip("testcase disabled")
return
}
ref, err := Parse(testcase.Input)
if err != testcase.Err {
if testcase.Err != nil {
t.Fatalf("expected error %v for %q, got %v, %#v", testcase.Err, testcase.Input, err, ref)
} else {
t.Fatalf("unexpected error %v", err)
}
} else if testcase.Err != nil {
return
}
if ref != testcase.Expected {
t.Fatalf("%#v != %#v", ref, testcase.Expected)
}
if testcase.Normalized == "" {
testcase.Normalized = testcase.Input
}
if ref.String() != testcase.Normalized {
t.Fatalf("normalization failed: %v != %v", ref.String(), testcase.Normalized)
}
if ref.Digest() != testcase.Digest {
t.Fatalf("digest extraction failed: %v != %v", ref.Digest(), testcase.Digest)
}
if ref.Hostname() != testcase.Hostname {
t.Fatalf("unexpected hostname: %v != %v", ref.Hostname(), testcase.Hostname)
}
})
}
}

41
remotes/remote.go
View file

@ -1,41 +0,0 @@
package remotes
import (
"context"
"io"
)
type Fetcher interface {
// Fetch the resource identified by id. The id is opaque to the remote, but
// may typically be a tag or a digest.
//
// Hints are provided to give instruction on how the resource may be
// fetched. They may provide information about the expected type or size.
// They may be protocol specific or help a protocol to identify the most
// efficient fetch methodology.
//
// Hints are the format of `<type>:<content>` where `<type>` is the type
// of the hint and `<content>` can be pretty much anything. For example, a
// media type hint would be the following:
//
// mediatype:application/vnd.docker.distribution.manifest.v2+json
//
// The following hint names are must be honored across all remote
// implementations:
//
// size: specify the expected size in bytes
// mediatype: specify the expected mediatype
//
// The caller should never expect the hints to be honored and should
// validate that returned content is as expected. They are only provided to
// help the remote retrieve the content.
Fetch(ctx context.Context, id string, hints ...string) (io.ReadCloser, error)
}
// FetcherFunc allows package users to implement a Fetcher with just a
// function.
type FetcherFunc func(context.Context, string, ...string) (io.ReadCloser, error)
func (fn FetcherFunc) Fetch(ctx context.Context, object string, hints ...string) (io.ReadCloser, error) {
return fn(ctx, object, hints...)
}

38
remotes/resolver.go
View file

@ -1,19 +1,37 @@
package remotes
import "context"
import (
"context"
"io"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
// Resolver provides a remote based on a locator.
type Resolver interface {
// Resolve returns a remote from the locator.
// Resolve attempts to resolve the reference into a name and descriptor.
//
// A locator is a scheme-less URI representing the remote. Structurally, it
// has a host and path. The "host" can be used to directly reference a
// specific host or be matched against a specific handler.
Resolve(ctx context.Context, locator string) (Fetcher, error)
// The argument `ref` should be a scheme-less URI representing the remote.
// Structurally, it has a host and path. The "host" can be used to directly
// reference a specific host or be matched against a specific handler.
//
// The returned name should be used to identify the referenced entity.
// Dependending on the remote namespace, this may be immutable or mutable.
// While the name may differ from ref, it should itself be a valid ref.
//
// If the resolution fails, an error will be returned.
Resolve(ctx context.Context, ref string) (name string, desc ocispec.Descriptor, fetcher Fetcher, err error)
}
type ResolverFunc func(context.Context, string) (Fetcher, error)
func (fn ResolverFunc) Resolve(ctx context.Context, locator string) (Fetcher, error) {
return fn(ctx, locator)
type Fetcher interface {
// Fetch the resource identified by the descriptor.
Fetch(ctx context.Context, desc ocispec.Descriptor) (io.ReadCloser, error)
}
// FetcherFunc allows package users to implement a Fetcher with just a
// function.
type FetcherFunc func(ctx context.Context, desc ocispec.Descriptor) (io.ReadCloser, error)
func (fn FetcherFunc) Fetch(ctx context.Context, desc ocispec.Descriptor) (io.ReadCloser, error) {
return fn(ctx, desc)
}