* API: Add tag lookup to history command. Fixes #882

api_params.go

@@ -2,6 +2,7 @@ package docker
 
 type APIHistory struct {
 	ID        string `json:"Id"`
+	Tag       string `json:",omitempty"`
 	Created   int64
 	CreatedBy string `json:",omitempty"`
 }

commands.go

@@ -627,7 +627,7 @@ func (cli *DockerCli) CmdHistory(args ...string) error {
 	fmt.Fprintln(w, "ID\tCREATED\tCREATED BY")
 
 	for _, out := range outs {
-		fmt.Fprintf(w, "%s\t%s ago\t%s\n", out.ID, utils.HumanDuration(time.Now().Sub(time.Unix(out.Created, 0))), out.CreatedBy)
+		fmt.Fprintf(w, "%s (%s)\t%s ago\t%s\n", out.ID, out.Tag, utils.HumanDuration(time.Now().Sub(time.Unix(out.Created, 0))), out.CreatedBy)
 	}
 	w.Flush()
 	return nil

server.go

@@ -218,12 +218,26 @@ func (srv *Server) ImageHistory(name string) ([]APIHistory, error) {
 		return nil, err
 	}
 
+	lookupMap := make(map[string]string)
+	for name, repository := range srv.runtime.repositories.Repositories {
+		for tag, id := range repository {
+			// If the ID already has a reverse lookup, do not update it unless for "latest"
+			if _, exists := lookupMap[id]; exists {
+				if tag != "latest" {
+					continue
+				}
+			}
+			lookupMap[id] = name + ":" + tag
+		}
+	}
+
 	outs := []APIHistory{} //produce [] when empty instead of 'null'
 	err = image.WalkHistory(func(img *Image) error {
 		var out APIHistory
 		out.ID = srv.runtime.repositories.ImageName(img.ShortID())
 		out.Created = img.Created.Unix()
 		out.CreatedBy = strings.Join(img.ContainerConfig.Cmd, " ")
+		out.Tag = lookupMap[img.ID]
 		outs = append(outs, out)
 		return nil
 	})