Add remote.WithContext (#744)

This allows passing a context.Context into any remote operations.

pkg/v1/remote/catalog.go

@@ -52,7 +52,11 @@ func CatalogPage(target name.Registry, last string, n int, options ...Option) ([
 	}
 
 	client := http.Client{Transport: tr}
-	resp, err := client.Get(uri.String())
+	req, err := http.NewRequest(http.MethodGet, uri.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := client.Do(req.WithContext(o.context))
 	if err != nil {
 		return nil, err
 	}
@@ -92,6 +96,11 @@ func Catalog(ctx context.Context, target name.Registry, options ...Option) ([]st
 
 	client := http.Client{Transport: tr}
 
+	// WithContext overrides the ctx passed directly.
+	if o.context != context.Background() {
+		ctx = o.context
+	}
+
 	var (
 		parsed   catalog
 		repoList []string

pkg/v1/remote/check.go

@@ -1,6 +1,7 @@
 package remote
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 
@@ -34,8 +35,9 @@ func CheckPushPermission(ref name.Reference, kc authn.Keychain, t http.RoundTrip
 	// authorize a push. Figure out how to return early here when we can,
 	// to avoid a roundtrip for spec-compliant registries.
 	w := writer{
-		repo:   ref.Context(),
-		client: &http.Client{Transport: tr},
+		repo:    ref.Context(),
+		client:  &http.Client{Transport: tr},
+		context: context.Background(),
 	}
 	loc, _, err := w.initiateUpload("", "")
 	if loc != "" {

pkg/v1/remote/delete.go

@@ -47,7 +47,7 @@ func Delete(ref name.Reference, options ...Option) error {
 		return err
 	}
 
-	resp, err := c.Do(req)
+	resp, err := c.Do(req.WithContext(o.context))
 	if err != nil {
 		return err
 	}

pkg/v1/remote/descriptor.go

@@ -16,6 +16,7 @@ package remote
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -168,10 +169,7 @@ func (d *Descriptor) ImageIndex() (v1.ImageIndex, error) {
 
 func (d *Descriptor) remoteImage() *remoteImage {
 	return &remoteImage{
-		fetcher: fetcher{
-			Ref:    d.Ref,
-			Client: d.Client,
-		},
+		fetcher:    d.fetcher,
 		manifest:   d.Manifest,
 		mediaType:  d.MediaType,
 		descriptor: &d.Descriptor,
@@ -180,10 +178,7 @@ func (d *Descriptor) remoteImage() *remoteImage {
 
 func (d *Descriptor) remoteIndex() *remoteIndex {
 	return &remoteIndex{
-		fetcher: fetcher{
-			Ref:    d.Ref,
-			Client: d.Client,
-		},
+		fetcher:    d.fetcher,
 		manifest:   d.Manifest,
 		mediaType:  d.MediaType,
 		descriptor: &d.Descriptor,
@@ -192,8 +187,9 @@ func (d *Descriptor) remoteIndex() *remoteIndex {
 
 // fetcher implements methods for reading from a registry.
 type fetcher struct {
-	Ref    name.Reference
-	Client *http.Client
+	Ref     name.Reference
+	Client  *http.Client
+	context context.Context
 }
 
 func makeFetcher(ref name.Reference, o *options) (*fetcher, error) {
@@ -202,8 +198,9 @@ func makeFetcher(ref name.Reference, o *options) (*fetcher, error) {
 		return nil, err
 	}
 	return &fetcher{
-		Ref:    ref,
-		Client: &http.Client{Transport: tr},
+		Ref:     ref,
+		Client:  &http.Client{Transport: tr},
+		context: o.context,
 	}, nil
 }
 
@@ -228,7 +225,7 @@ func (f *fetcher) fetchManifest(ref name.Reference, acceptable []types.MediaType
 	}
 	req.Header.Set("Accept", strings.Join(accept, ","))
 
-	resp, err := f.Client.Do(req)
+	resp, err := f.Client.Do(req.WithContext(f.context))
 	if err != nil {
 		return nil, nil, err
 	}
@@ -282,7 +279,12 @@ func (f *fetcher) fetchManifest(ref name.Reference, acceptable []types.MediaType
 
 func (f *fetcher) fetchBlob(h v1.Hash) (io.ReadCloser, error) {
 	u := f.url("blobs", h.String())
-	resp, err := f.Client.Get(u.String())
+	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := f.Client.Do(req.WithContext(f.context))
 	if err != nil {
 		return nil, err
 	}
@@ -297,7 +299,12 @@ func (f *fetcher) fetchBlob(h v1.Hash) (io.ReadCloser, error) {
 
 func (f *fetcher) headBlob(h v1.Hash) (*http.Response, error) {
 	u := f.url("blobs", h.String())
-	resp, err := f.Client.Head(u.String())
+	req, err := http.NewRequest(http.MethodHead, u.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := f.Client.Do(req.WithContext(f.context))
 	if err != nil {
 		return nil, err
 	}

pkg/v1/remote/image.go

@@ -156,7 +156,12 @@ func (rl *remoteImageLayer) Compressed() (io.ReadCloser, error) {
 	// TODO: Maybe we don't want to try pulling from the registry first?
 	var lastErr error
 	for _, u := range urls {
-		resp, err := rl.ri.Client.Get(u.String())
+		req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+		if err != nil {
+			return nil, err
+		}
+
+		resp, err := rl.ri.Client.Do(req.WithContext(rl.ri.context))
 		if err != nil {
 			lastErr = err
 			continue

pkg/v1/remote/image_test.go

@@ -16,6 +16,7 @@ package remote
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -178,8 +179,9 @@ func TestRawManifestDigests(t *testing.T) {
 
 			rmt := remoteImage{
 				fetcher: fetcher{
-					Ref:    ref,
-					Client: http.DefaultClient,
+					Ref:     ref,
+					Client:  http.DefaultClient,
+					context: context.Background(),
 				},
 			}
 
@@ -212,8 +214,9 @@ func TestRawManifestNotFound(t *testing.T) {
 
 	img := remoteImage{
 		fetcher: fetcher{
-			Ref:    mustNewTag(t, fmt.Sprintf("%s/%s:latest", u.Host, expectedRepo)),
-			Client: http.DefaultClient,
+			Ref:     mustNewTag(t, fmt.Sprintf("%s/%s:latest", u.Host, expectedRepo)),
+			Client:  http.DefaultClient,
+			context: context.Background(),
 		},
 	}
 
@@ -251,8 +254,9 @@ func TestRawConfigFileNotFound(t *testing.T) {
 
 	rmt := remoteImage{
 		fetcher: fetcher{
-			Ref:    mustNewTag(t, fmt.Sprintf("%s/%s:latest", u.Host, expectedRepo)),
-			Client: http.DefaultClient,
+			Ref:     mustNewTag(t, fmt.Sprintf("%s/%s:latest", u.Host, expectedRepo)),
+			Client:  http.DefaultClient,
+			context: context.Background(),
 		},
 	}
 
@@ -291,8 +295,9 @@ func TestAcceptHeaders(t *testing.T) {
 
 	rmt := &remoteImage{
 		fetcher: fetcher{
-			Ref:    mustNewTag(t, fmt.Sprintf("%s/%s:latest", u.Host, expectedRepo)),
-			Client: http.DefaultClient,
+			Ref:     mustNewTag(t, fmt.Sprintf("%s/%s:latest", u.Host, expectedRepo)),
+			Client:  http.DefaultClient,
+			context: context.Background(),
 		},
 	}
 	manifest, err := rmt.RawManifest()

pkg/v1/remote/index.go

@@ -180,8 +180,9 @@ func (r *remoteIndex) childDescriptor(child v1.Descriptor, platform v1.Platform)
 	}
 	return &Descriptor{
 		fetcher: fetcher{
-			Ref:    ref,
-			Client: r.Client,
+			Ref:     ref,
+			Client:  r.Client,
+			context: r.context,
 		},
 		Manifest:   manifest,
 		Descriptor: child,

pkg/v1/remote/index_test.go

@@ -16,6 +16,7 @@ package remote
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -140,8 +141,9 @@ func TestIndexRawManifestDigests(t *testing.T) {
 
 			rmt := remoteIndex{
 				fetcher: fetcher{
-					Ref:    ref,
-					Client: http.DefaultClient,
+					Ref:     ref,
+					Client:  http.DefaultClient,
+					context: context.Background(),
 				},
 			}
 

pkg/v1/remote/list.go

@@ -58,6 +58,13 @@ func ListWithContext(ctx context.Context, repo name.Repository, options ...Optio
 		RawQuery: "n=1000",
 	}
 
+	// This is lazy, but I want to make sure List(..., WithContext(ctx)) works
+	// without calling makeOptions() twice (which can have side effects).
+	// This means ListWithContext(ctx, ..., WithContext(ctx2)) prefers ctx2.
+	if o.context != context.Background() {
+		ctx = o.context
+	}
+
 	client := http.Client{Transport: tr}
 	tagList := []string{}
 	parsed := tags{}

pkg/v1/remote/options.go

@@ -15,6 +15,7 @@
 package remote
 
 import (
+	"context"
 	"net/http"
 
 	"github.com/google/go-containerregistry/pkg/authn"
@@ -31,13 +32,15 @@ type options struct {
 	keychain  authn.Keychain
 	transport http.RoundTripper
 	platform  v1.Platform
+	context   context.Context
 }
 
 func makeOptions(target authn.Resource, opts ...Option) (*options, error) {
 	o := &options{
 		auth:      authn.Anonymous,
 		transport: http.DefaultTransport,
 		platform:  defaultPlatform,
+		context:   context.Background(),
 	}
 
 	for _, option := range opts {
@@ -114,3 +117,17 @@ func WithPlatform(p v1.Platform) Option {
 		return nil
 	}
 }
+
+// WithContext is a functional option for setting the context in http requests
+// performed by a given function. Note that this context is used for _all_
+// http requests, not just the initial volley. E.g., for remote.Image, the
+// context will be set on http requests generated by subsequent calls to
+// RawConfigFile() and even methods on layers returned by Layers().
+//
+// The default context is context.Background().
+func WithContext(ctx context.Context) Option {
+	return func(o *options) error {
+		o.context = ctx
+		return nil
+	}
+}