Move NewClient and AppContext to commands pkg

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

cmd/ctr/commands/client.go

@@ -0,0 +1,40 @@
+package commands
+
+import (
+	gocontext "context"
+
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/namespaces"
+	"github.com/urfave/cli"
+)
+
+// AppContext returns the context for a command. Should only be called once per
+// command, near the start.
+//
+// This will ensure the namespace is picked up and set the timeout, if one is
+// defined.
+func AppContext(context *cli.Context) (gocontext.Context, gocontext.CancelFunc) {
+	var (
+		ctx       = gocontext.Background()
+		timeout   = context.GlobalDuration("timeout")
+		namespace = context.GlobalString("namespace")
+		cancel    gocontext.CancelFunc
+	)
+	ctx = namespaces.WithNamespace(ctx, namespace)
+	if timeout > 0 {
+		ctx, cancel = gocontext.WithTimeout(ctx, timeout)
+	} else {
+		ctx, cancel = gocontext.WithCancel(ctx)
+	}
+	return ctx, cancel
+}
+
+// NewClient returns a new containerd client
+func NewClient(context *cli.Context) (*containerd.Client, gocontext.Context, gocontext.CancelFunc, error) {
+	client, err := containerd.New(context.GlobalString("address"))
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	ctx, cancel := AppContext(context)
+	return client, ctx, cancel, nil
+}