Add context show command

Signed-off-by: Christopher Crone <christopher.crone@docker.com>

cli/cmd/context/context.go

@@ -46,6 +46,7 @@ func Command(opts *cliopts.GlobalOpts) *cobra.Command {
 		createCommand(),
 		listCommand(),
 		removeCommand(),
+		showCommand(opts),
 		useCommand(opts),
 		login.Command(),
 	)

cli/cmd/context/show.go

@@ -0,0 +1,63 @@
+/*
+	Copyright (c) 2020 Docker Inc.
+
+	Permission is hereby granted, free of charge, to any person
+	obtaining a copy of this software and associated documentation
+	files (the "Software"), to deal in the Software without
+	restriction, including without limitation the rights to use, copy,
+	modify, merge, publish, distribute, sublicense, and/or sell copies
+	of the Software, and to permit persons to whom the Software is
+	furnished to do so, subject to the following conditions:
+
+	The above copyright notice and this permission notice shall be
+	included in all copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+	EXPRESS OR IMPLIED,
+	INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+	IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+	HOLDERS BE LIABLE FOR ANY CLAIM,
+	DAMAGES OR OTHER LIABILITY,
+	WHETHER IN AN ACTION OF CONTRACT,
+	TORT OR OTHERWISE,
+	ARISING FROM, OUT OF OR IN CONNECTION WITH
+	THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+package context
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	cliopts "github.com/docker/api/cli/options"
+	apicontext "github.com/docker/api/context"
+	"github.com/docker/api/context/store"
+)
+
+func showCommand(opts *cliopts.GlobalOpts) *cobra.Command {
+	return &cobra.Command{
+		Use:   "show",
+		Short: "Print the current context",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return runShow(cmd.Context(), opts)
+		},
+	}
+}
+
+func runShow(ctx context.Context, opts *cliopts.GlobalOpts) error {
+	s := store.ContextStore(ctx)
+	name := apicontext.CurrentContext(ctx)
+	// Match behavior of existing CLI
+	if name != store.DefaultContextName {
+		if _, err := s.Get(name, nil); err != nil {
+			return err
+		}
+	}
+	fmt.Println(name)
+	return nil
+}

tests/e2e/e2e.go

@@ -21,7 +21,9 @@ func main() {
 
 	It("should be initialized with default context", func() {
 		NewDockerCommand("context", "use", "default").ExecOrDie()
-		output := NewCommand("docker", "context", "ls").ExecOrDie()
+		output := NewDockerCommand("context", "show").ExecOrDie()
+		Expect(output).To(ContainSubstring("default"))
+		output = NewCommand("docker", "context", "ls").ExecOrDie()
 		Expect(output).To(Not(ContainSubstring("test-example")))
 		Expect(output).To(ContainSubstring("default *"))
 	})
@@ -59,6 +61,8 @@ func main() {
 		Expect(currentContext).To(ContainSubstring("test-example"))
 		output := NewCommand("docker", "context", "ls").ExecOrDie()
 		Expect(output).To(ContainSubstring("test-example *"))
+		output = NewDockerCommand("context", "show").ExecOrDie()
+		Expect(output).To(ContainSubstring("test-example"))
 	})
 
 	It("can run ps command", func() {