Inspect remote images

Added new flag to `docker inspect` command:

    $ docker inspect --remote <imageName>[:<tag>]...

Which inspects remote images. If a short name is given, all additional
registries will be queried until a match is found. Additional `[:TAG]`
suffix may further specify desired `<image>`.

This allows for remote inspection without downloading image layers.

Signed-off-by: Michal Minar <miminar@redhat.com>

api/client/inspect.go

@@ -5,11 +5,15 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"net/http"
+	"net/url"
 	"strings"
 	"text/template"
 
 	"github.com/docker/docker/api/types"
 	flag "github.com/docker/docker/pkg/mflag"
+	"github.com/docker/docker/pkg/parsers"
+	"github.com/docker/docker/registry"
 )
 
 // CmdInspect displays low-level information on one or more containers or images.
@@ -18,6 +22,7 @@ import (
 func (cli *DockerCli) CmdInspect(args ...string) error {
 	cmd := cli.Subcmd("inspect", "CONTAINER|IMAGE [CONTAINER|IMAGE...]", "Return low-level information on a container or image", true)
 	tmplStr := cmd.String([]string{"f", "#format", "-format"}, "", "Format the output using the given go template")
+	remote := cmd.Bool([]string{"r", "-remote"}, false, "Inspect remote images")
 	cmd.Require(flag.Min, 1)
 
 	cmd.ParseFlags(args, true)
@@ -37,20 +42,46 @@ func (cli *DockerCli) CmdInspect(args ...string) error {
 	isImage := false
 
 	for _, name := range cmd.Args() {
-		obj, _, err := readBody(cli.call("GET", "/containers/"+name+"/json", nil, nil))
-		if err != nil {
-			obj, _, err = readBody(cli.call("GET", "/images/"+name+"/json", nil, nil))
+		var (
+			err        error
+			stream     io.ReadCloser
+			statusCode int
+		)
+		if !*remote {
+			stream, statusCode, err = cli.call("GET", "/containers/"+name+"/json", nil, nil)
+		}
+		if *remote || err != nil {
+			if *remote {
+				taglessRemote, _ := parsers.ParseRepositoryTag(name)
+				// Resolve the Repository name from fqn to RepositoryInfo
+				repoInfo, err := registry.ParseRepositoryInfo(taglessRemote)
+				if err != nil {
+					return err
+				}
+				v := url.Values{}
+				v.Set("remote", "1")
+				stream, statusCode, err = cli.clientRequestAttemptLogin("GET", "/images/"+name+"/json?"+v.Encode(), nil, nil, repoInfo.Index, "inspect")
+			} else {
+				stream, statusCode, err = cli.call("GET", "/images/"+name+"/json", nil, nil)
+			}
 			isImage = true
-			if err != nil {
-				if strings.Contains(err.Error(), "No such") {
-					fmt.Fprintf(cli.err, "Error: No such image or container: %s\n", name)
-				} else {
+			if err != nil || statusCode != http.StatusOK {
+				if (err != nil && strings.Contains(err.Error(), "No such")) || statusCode == http.StatusNotFound {
+					if *remote {
+						fmt.Fprintf(cli.err, "Error: No such image: %s\n", name)
+					} else {
+						fmt.Fprintf(cli.err, "Error: No such image or container: %s\n", name)
+					}
+				} else if err != nil {
 					fmt.Fprintf(cli.err, "%s", err)
+				} else {
+					fmt.Fprintf(cli.err, "Image lookup failed with status %d (%s)\n", statusCode, http.StatusText(statusCode))
 				}
 				status = 1
 				continue
 			}
 		}
+		obj, _, err := readBody(stream, statusCode, err)
 
 		if tmpl == nil {
 			if err = json.Indent(indented, obj, "", "    "); err != nil {
@@ -63,13 +94,24 @@ func (cli *DockerCli) CmdInspect(args ...string) error {
 			dec := json.NewDecoder(rdr)
 
 			if isImage {
-				inspPtr := types.ImageInspect{}
-				if err := dec.Decode(&inspPtr); err != nil {
-					fmt.Fprintf(cli.err, "%s\n", err)
-					status = 1
-					continue
+				if *remote {
+					inspPtr := types.RemoteImageInspect{}
+					if err := dec.Decode(&inspPtr); err != nil {
+						fmt.Fprintf(cli.err, "%s\n", err)
+						status = 1
+						continue
+					}
+					err = tmpl.Execute(cli.out, inspPtr)
+				} else {
+					inspPtr := types.ImageInspect{}
+					if err := dec.Decode(&inspPtr); err != nil {
+						fmt.Fprintf(cli.err, "%s\n", err)
+						status = 1
+						continue
+					}
+					err = tmpl.Execute(cli.out, inspPtr)
 				}
-				if err := tmpl.Execute(cli.out, inspPtr); err != nil {
+				if err != nil {
 					rdr.Seek(0, 0)
 					var raw interface{}
 					if err := dec.Decode(&raw); err != nil {

api/server/server.go

@@ -1163,12 +1163,43 @@ func (s *Server) getImagesByName(version version.Version, w http.ResponseWriter,
 		return fmt.Errorf("Missing parameter")
 	}
 
-	imageInspect, err := s.daemon.Repositories().Lookup(vars["name"])
-	if err != nil {
-		return err
-	}
+	name := vars["name"]
+
+	if boolValue(r, "remote") {
+		authEncoded := r.Header.Get("X-Registry-Auth")
+		authConfig := &cliconfig.AuthConfig{}
+		if authEncoded != "" {
+			authJson := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authEncoded))
+			if err := json.NewDecoder(authJson).Decode(authConfig); err != nil {
+				// for a pull it is not an error if no auth was given
+				// to increase compatibility with the existing api it is defaulting to be empty
+				authConfig = &cliconfig.AuthConfig{}
+			}
+		}
 
-	return writeJSON(w, http.StatusOK, imageInspect)
+		image, tag := parsers.ParseRepositoryTag(name)
+		metaHeaders := map[string][]string{}
+		for k, v := range r.Header {
+			if strings.HasPrefix(k, "X-Meta-") {
+				metaHeaders[k] = v
+			}
+		}
+		lookupRemoteConfig := &graph.LookupRemoteConfig{
+			MetaHeaders: metaHeaders,
+			AuthConfig:  authConfig,
+		}
+		imageInspect, err := s.daemon.Repositories().LookupRemote(image, tag, lookupRemoteConfig)
+		if err != nil {
+			return err
+		}
+		return writeJSON(w, http.StatusOK, imageInspect)
+	} else {
+		imageInspect, err := s.daemon.Repositories().Lookup(name)
+		if err != nil {
+			return err
+		}
+		return writeJSON(w, http.StatusOK, imageInspect)
+	}
 }
 
 func (s *Server) postBuild(version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

api/types/types.go

@@ -92,6 +92,22 @@ type ImageInspect struct {
 	VirtualSize     int64
 }
 
+type RemoteImageInspect struct {
+	ImageInspect
+	Registry string
+	Digest   string
+	Tag      string
+}
+
+type LegacyImage struct {
+	ID          string `json:"Id"`
+	Repository  string
+	Tag         string
+	Created     int
+	Size        int
+	VirtualSize int
+}
+
 // GET  "/containers/json"
 type Port struct {
 	IP          string

contrib/completion/fish/docker.fish

@@ -207,6 +207,7 @@ complete -c docker -f -n '__fish_docker_no_subcommand' -a info -d 'Display syste
 complete -c docker -f -n '__fish_docker_no_subcommand' -a inspect -d 'Return low-level information on a container or image'
 complete -c docker -A -f -n '__fish_seen_subcommand_from inspect' -s f -l format -d 'Format the output using the given go template.'
 complete -c docker -A -f -n '__fish_seen_subcommand_from inspect' -l help -d 'Print usage'
+complete -c docker -A -f -n '__fish_seen_subcommand_from inspect' -s r -l remote -d 'Inspect remote images'
 complete -c docker -A -f -n '__fish_seen_subcommand_from inspect' -a '(__fish_print_docker_images)' -d "Image"
 complete -c docker -A -f -n '__fish_seen_subcommand_from inspect' -a '(__fish_print_docker_containers all)' -d "Container"
 

docs/man/docker-inspect.1.md

@@ -8,6 +8,7 @@ docker-inspect - Return low-level information on a container or image
 **docker inspect**
 [**--help**]
 [**-f**|**--format**[=*FORMAT*]]
+[**-r**|**--remote**[=*false*]]
 CONTAINER|IMAGE [CONTAINER|IMAGE...]
 
 # DESCRIPTION
@@ -24,6 +25,13 @@ each result.
 **-f**, **--format**=""
     Format the output using the given go template.
 
+**-r**, **--remote**=*true*|*false*
+	Inspect remote images.
+
+	Image name can be suffixed with [:TAG]. If short name is given, all
+additional registries will be searched until a match is found. The default is
+*false*.
+
 # EXAMPLES
 
 ## Getting information on a container