1## This Source Code Form is subject to the terms of the Mozilla Public
2## License, v. 2.0. If a copy of the MPL was not distributed with this
3## file, You can obtain one at https://mozilla.org/MPL/2.0/.
4##
5## Copyright (c) 2019-2021 VMware, Inc. or its affiliates.  All rights reserved.
6
7defmodule RabbitMQ.CLI.Diagnostics.Commands.LogTailCommand do
8  @moduledoc """
9  Displays standard log file location on the target node
10  """
11  @behaviour RabbitMQ.CLI.CommandBehaviour
12
13  alias RabbitMQ.CLI.Core.LogFiles
14
15  def switches, do: [number: :integer, timeout: :integer]
16  def aliases, do: ['N': :number, t: :timeout]
17
18  def merge_defaults(args, opts) do
19    {args, Map.merge(%{number: 50}, opts)}
20  end
21  use RabbitMQ.CLI.Core.AcceptsNoPositionalArguments
22
23  def run([], %{node: node_name, timeout: timeout, number: n}) do
24    case LogFiles.get_default_log_location(node_name, timeout) do
25      {:ok, file} ->
26        :rabbit_misc.rpc_call(node_name,
27                              :rabbit_log_tail, :tail_n_lines, [file, n],
28                              timeout)
29      error -> error
30    end
31  end
32
33  use RabbitMQ.CLI.DefaultOutput
34
35  def help_section(), do: :observability_and_health_checks
36
37  def description(), do: "Prints the last N lines of the log on the node"
38
39  def usage, do: "log_tail [--number|-N <number>]"
40
41  def usage_additional do
42    [
43      ["<number>", "number of lines to print. Defaults to 50"]
44    ]
45  end
46
47  def banner([], %{node: node_name, number: n}) do
48    "Last #{n} log lines on node #{node_name} ..."
49  end
50end
51