Add docker context inspect command relying on classic docker

cli/dockerclassic/exec.go

@@ -0,0 +1,36 @@
+package dockerclassic
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+
+	apicontext "github.com/docker/api/context"
+	"github.com/docker/api/context/store"
+)
+
+// Exec will delegate the cli command to docker-classic
+func Exec(ctx context.Context) {
+	currentContext := apicontext.CurrentContext(ctx)
+	s := store.ContextStore(ctx)
+
+	_, err := s.Get(currentContext)
+	// Only run original docker command if the current context is not
+	// ours.
+	if err != nil {
+		cmd := exec.CommandContext(ctx, "docker-classic", os.Args[1:]...)
+		cmd.Stdin = os.Stdin
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		if err := cmd.Run(); err != nil {
+			if exiterr, ok := err.(*exec.ExitError); ok {
+				fmt.Fprintln(os.Stderr, exiterr.Error())
+				os.Exit(exiterr.ExitCode())
+			}
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		os.Exit(0)
+	}
+}