Merge pull request #2860 from rabbitmq/cli-remote_shell

Add rabbitmq-diagnostics remote_shell

deps/rabbitmq_cli/lib/rabbitmq/cli/diagnostics/commands/remote_shell_command.ex

@@ -0,0 +1,35 @@
+## This Source Code Form is subject to the terms of the Mozilla Public
+## License, v. 2.0. If a copy of the MPL was not distributed with this
+## file, You can obtain one at https://mozilla.org/MPL/2.0/.
+##
+## Copyright (c) 2007-2021 VMware, Inc. or its affiliates.  All rights reserved.
+
+defmodule RabbitMQ.CLI.Diagnostics.Commands.RemoteShellCommand do
+  @behaviour RabbitMQ.CLI.CommandBehaviour
+
+  use RabbitMQ.CLI.Core.MergesNoDefaults
+  use RabbitMQ.CLI.Core.AcceptsNoPositionalArguments
+
+  def run([], %{node: node_name}) do
+    _ = Supervisor.terminate_child(:kernel_sup, :user)
+    Process.flag(:trap_exit, true)
+    user_drv = :user_drv.start(['tty_sl -c -e', {node_name, :shell, :start, []}])
+    Process.link(user_drv)
+    receive do
+        {'EXIT', user_drv, _} ->
+            {:ok, "Disconnected from #{node_name}."}
+    end
+  end
+
+  use RabbitMQ.CLI.DefaultOutput
+
+  def help_section(), do: :observability_and_health_checks
+
+  def description(), do: "Starts an interactive Erlang shell on the target node"
+
+  def usage, do: "remote_shell"
+
+  def banner(_, %{node: node_name}) do
+    "Starting an interactive Erlang shell on node #{node_name}... Press 'Ctrl+G' then 'q' to exit."
+  end
+end

deps/rabbitmq_cli/test/diagnostics/remote_shell_command_test.exs

@@ -0,0 +1,40 @@
+## This Source Code Form is subject to the terms of the Mozilla Public
+## License, v. 2.0. If a copy of the MPL was not distributed with this
+## file, You can obtain one at https://mozilla.org/MPL/2.0/.
+##
+## Copyright (c) 2007-2020 VMware, Inc. or its affiliates.  All rights reserved.
+
+
+defmodule RemoteShellCommandTest do
+  use ExUnit.Case, async: false
+  import TestHelper
+
+  @command RabbitMQ.CLI.Diagnostics.Commands.RemoteShellCommand
+
+  setup_all do
+    RabbitMQ.CLI.Core.Distribution.start()
+
+    :ok
+  end
+
+  setup context do
+    {:ok, opts: %{
+        node: get_rabbit_hostname(),
+        timeout: context[:test_timeout] || 15000
+      }}
+  end
+
+  test "merge_defaults: nothing to do" do
+    assert @command.merge_defaults([], %{}) == {[], %{}}
+  end
+
+  test "validate: treats positional arguments as a failure" do
+    assert @command.validate(["extra-arg"], %{}) == {:validation_failure, :too_many_args}
+  end
+
+  test "validate: treats empty positional arguments and default switches as a success" do
+    assert @command.validate([], %{}) == :ok
+  end
+
+  # Unreachable nodes will leave the remote_shell open with an error.
+end