cli: Add a hidden 'observe' subcommand

The observe subcommand executes Hubble's observe command. We are still
trying to figure out how to distribute Hubble's CLI. This is a short
term workaround so that people can use it to interact with Hubble in
the meantime.

Ref #9925

Signed-off-by: Michi Mutsuzaki <michi@isovalent.com>

cilium/cmd/observe.go

@@ -0,0 +1,23 @@
+// Copyright 2020 Authors of Cilium
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd
+
+import "github.com/cilium/hubble/cmd/observe"
+
+func init() {
+	cmd := observe.New()
+	cmd.Hidden = true
+	rootCmd.AddCommand(cmd)
+}