Add verification for CNAB bundles (#17)

Add verification for CNAB bundles

Gopkg.toml

@@ -2,6 +2,15 @@
   name = "github.com/spf13/cobra"
   version = "0.0.4"
 
+[[constraint]]
+  name = "github.com/docker/cnab-to-oci"
+  source = "github.com/radu-matei/cnab-to-oci"
+  branch = "canonical"
+
+[[constraint]]
+  name = "github.com/docker/distribution"
+  revision = "83389a148052d74ac602f5f1d62f86ff2f3c4aa5"
+
 [prune]
   go-tests = true
   unused-packages = true

bundle.json

@@ -0,0 +1 @@
+{"description":"A short description of your bundle","invocationImages":[{"image":"cnab/helloworld:0.1.1","imageType":"docker","size":42}],"keywords":["helloworld","cnab","tutorial"],"maintainers":[{"email":"[email protected]","name":"Jane Doe","url":"https://example.com"}],"name":"helloworld","schemaVersion":"v1.0.0-WD","version":"0.1.1"}

cmd/list.go

@@ -11,10 +11,24 @@ type listCmd struct {
 }
 
 func newListCmd() *cobra.Command {
+	const listDesc = `
+Lists all targets for a given trust collection on a remote server.
+
+Example:
+$ signy list docker.io/library/alpine
+
+3.5     66952b313e51c3bd1987d7c4ddf5dba9bc0fb6e524eed2448fa660246b3e76ec
+3.8     04696b491e0cc3c58a75bace8941c14c924b9f313b03ce5029ebbc040ed9dcd9
+3.2     e9a2035f9d0d7cee1cdd445f5bfa0c5c646455ee26f14565dce23cf2d2de7570
+3.6     66790a2b79e1ea3e1dabac43990c54aca5d1ddf268d9a5a0285e4167c8b24475
+3.10    6a92cd1fcdc8d8cdec60f33dda4db2cb1fcdcacf3410a8e05b3741f44a9b5998
+3.9.4   7746df395af22f04212cd25a92c1d6dbc5a06a0ca9579a229ef43008d4d1302a
+`
 	list := listCmd{}
 	cmd := &cobra.Command{
-		Use:   "list",
-		Short: "Lists targets for a remote trusted collection",
+		Use:   "list [GUN]",
+		Short: "Lists all targets for a given remote collection on a trust server.",
+		Long:  listDesc,
 		Args:  cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			list.gun = args[0]

cmd/main.go

@@ -23,6 +23,7 @@ func init() {
 	rootCmd.AddCommand(
 		newListCmd(),
 		newSignCmd(),
+		newVerifyCmd(),
 	)
 
 	rootCmd.PersistentFlags().StringVarP(&trustServer, "server", "", "https://notary.docker.io", "The trust server used")