Observer CLI integration

Makefile

@@ -1,5 +1,7 @@
 PROJECT = rabbitmq_cli
 
+dep_observer_cli = git https://github.com/zhongwencool/observer_cli 1.4.4
+
 BUILD_DEPS = rabbit_common
 DEPS = observer_cli
 TEST_DEPS = amqp_client rabbit

lib/rabbitmq/cli/diagnostics/commands/observer_command.ex

@@ -0,0 +1,58 @@
+## The contents of this file are subject to the Mozilla Public License
+## Version 1.1 (the "License"); you may not use this file except in
+## compliance with the License. You may obtain a copy of the License
+## at https://www.mozilla.org/MPL/
+##
+## Software distributed under the License is distributed on an "AS IS"
+## basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+## the License for the specific language governing rights and
+## limitations under the License.
+##
+## The Original Code is RabbitMQ.
+##
+## The Initial Developer of the Original Code is GoPivotal, Inc.
+## Copyright (c) 2007-2019 Pivotal Software, Inc.  All rights reserved.
+
+defmodule RabbitMQ.CLI.Diagnostics.Commands.ObserverCommand do
+  @behaviour RabbitMQ.CLI.CommandBehaviour
+  use RabbitMQ.CLI.DefaultOutput
+
+  def switches(), do: [interval: :integer]
+  def aliases(), do: [i: :interval]
+
+  def merge_defaults(args, opts) do
+    {args, Map.merge(%{interval: 5}, opts)}
+  end
+
+
+  use RabbitMQ.CLI.Core.AcceptsNoPositionalArguments
+  use RabbitMQ.CLI.Core.RequiresRabbitAppRunning
+
+  def run([], %{node: node_name, interval: interval}) do
+    case :observer_cli.start(node_name, [{:interval, interval * 1000}]) do
+      # See zhongwencool/observer_cli#54
+      {:badrpc, _} = err   -> err
+      {:error, _} = err    -> err
+      {:error, _, _} = err -> err
+      :ok   -> {:ok, "Disconnected from #{node_name}."}
+      :quit -> {:ok, "Disconnected from #{node_name}."}
+      other -> other
+    end
+  end
+
+  def help_section(), do: :observability_and_health_checks
+
+  def description(), do: "Starts a CLI observer interface on the target node"
+
+  def usage, do: "observer [--interval <seconds>]"
+
+  def usage_additional() do
+    [
+      ["--interval <seconds>", "Update interval to use, in seconds"]
+    ]
+  end
+
+  def banner(_, %{node: node_name}) do
+    "Starting a CLI observer interface on node #{node_name}..."
+  end
+end

mix.exs

@@ -89,18 +89,19 @@ defmodule RabbitMQCtl.MixfileBase do
       {:json, "~> 1.2.0"},
       {:csv, "~> 2.0.0"},
       {:stdout_formatter, "~> 0.2.3"},
+      {:observer_cli, "~> 1.4.4"},
 
       {:amqp, "~> 1.2.0", only: :test},
       {:dialyxir, "~> 0.5", only: :test, runtime: false},
-      {:temp, "~> 0.4", only: :test},
+      {:temp, "~> 0.4", only: :test}
     ]
 
     rabbitmq_deps = case System.get_env("DEPS_DIR") do
       nil ->
         # rabbitmq_cli is built as a standalone Elixir application.
         [
           {:rabbit_common, "~> 3.7.0"},
-          {:amqp_client, "~> 3.7.0", only: :test},
+          {:amqp_client, "~> 3.7.0", only: :test}
         ]
       deps_dir ->
         # rabbitmq_cli is built as part of RabbitMQ.

test/diagnostics/observer_command_test.exs

@@ -0,0 +1,53 @@
+## The contents of this file are subject to the Mozilla Public License
+## Version 1.1 (the "License"); you may not use this file except in
+## compliance with the License. You may obtain a copy of the License
+## at https://www.mozilla.org/MPL/
+##
+## Software distributed under the License is distributed on an "AS IS"
+## basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+## the License for the specific language governing rights and
+## limitations under the License.
+##
+## The Original Code is RabbitMQ.
+##
+## The Initial Developer of the Original Code is GoPivotal, Inc.
+## Copyright (c) 2007-2019 Pivotal Software, Inc.  All rights reserved.
+
+
+defmodule ObserverCommandTest do
+  use ExUnit.Case
+  import TestHelper
+
+  @command RabbitMQ.CLI.Diagnostics.Commands.ObserverCommand
+
+  setup_all do
+    RabbitMQ.CLI.Core.Distribution.start()
+
+    :ok
+  end
+
+  setup context do
+    {:ok, opts: %{
+        node: get_rabbit_hostname(),
+        interval: 5,
+        timeout: context[:test_timeout] || 15000
+      }}
+  end
+
+  test "merge_defaults: injects a default interval of 5s" do
+    assert @command.merge_defaults([], %{}) == {[], %{interval: 5}}
+  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
+
+  @tag test_timeout: 3000
+  test "run: targeting an unreachable node throws a badrpc", context do
+    assert match?({:badrpc, _}, @command.run([], %{node: :jake@thedog, interval: 5}))
+  end
+end

test/test_helper.exs

@@ -14,6 +14,7 @@
 ## Copyright (c) 2007-2019 Pivotal Software, Inc.  All rights reserved.
 
 
+ExUnit.configure(exclude: [disabled: true])
 ExUnit.start()
 
 defmodule TestHelper do