---

observer_cli

Visualize Erlang/Elixir Nodes On The Command Line base on recon. Document in detail.

Goal

• Provide a high-performance tool usable both in development and production settings.
• Focus on important and detailed information about real-time running system.
• Keep minimal consumption.

---

Installation

Erlang

%% rebar.config
{deps, [observer_cli]}
%% erlang.mk
dep_observer_cli = hex 1.7.4

Elixir

# mix.exs
   def deps do
     [{:observer_cli, "~> 1.7"}]
   end

---

How-To

Try in local shell.

%% rebar3 project
rebar3 shell
1> observer_cli:start().
%% mix project
iex -S mix
iex(1)> :observer_cli.start

Monitor remote node

%% rebar3 project
rebar3 shell --name 'observer_cli@127.0.0.1'
1> observer_cli:start('target@host', 'magic_cookie').
%% mix project
iex --name "observer_cli@127.0.0.1" -S mix
iex(1)> :observer_cli.start(:'target@host', :'magic_cookie')

❗ ensure observer_cli application been loaded on target node.

Try in Elixir 1.9.x release

%% create elixir release
mix release
%% rpc current node
_build/dev/rel/example/bin/example rpc ":observer_cli.start"

❗ ensure observer_cli application been loaded on current node.

Escriptize

1. cd path/to/observer_cli/
2. rebar3 escriptize to generate an escript executable containing the project's and its dependencies' BEAM files. Place script(_build/default/bin/observer_cli) anywhere in your path and use observer_cli command.
3. observer_cli TARGETNODE [TARGETCOOKIE REFRESHMS] to monitor remote node.

---

DEMO

How to write your own plugin?

If you need to customize some of your internal metrics and integrate it into observer_ci, you only need to write a observer_cli_plugin behaviour in a few simple steps to get a nice presentation.

1. Configure observer_cli，tell observer_cli how to find your plugin.

%% module       - Specific module implements plugin behavior. It's mandatory.
%% title        - Menu title. It's mandatory.
%% shortcut     - Switch plugin by shortcut. It's mandatory.
%% interval     - Refresh interval ms. It's optional. default is 1500ms.
%% sort_column  - Sort the sheet by this index. It's optional default is 2.

{plugins,
  [
    #{module => observer_cli_plug_behaviour_x, title => "XPlug",
      interval => 1600, shortcut => "X", sort_column => 3},
    #{module => observer_cli_plug_behaviour_y, title => "YPlug",
      interval =>2000, shortcut => "Y", sort_column => 3}
  ]
}

The main view is HOME by default(observer_cli:start()). If you want to plugin view as main view, DO:your_cli:start().

% your_cli.erl
start() -> observer_cli:start_plugin().

2. Write observer_cli_plugin behaviour. observer_cli_plugin has 3 callbacks.

2.1 attributes.

-callback attributes(PrevState) -> {[Rows], NewState} when
    Rows :: #{content => string()|integer()|{byte, pos_integer()},
              width => pos_integer(), color => binary()}.

for example:

attributes(PrevState) ->
  Attrs = [
    [
      #{content => "XXX Ets Size", width => 15},
      #{content => 122, width => 10},
      #{content => "Memory Capcity", width => 15},
      #{content => {percent, 0.12}, width => 16},
      #{content => "XYZ1 Process Mem", width => 19},
      #{content => {byte, 1023 * 1203}, width => 19}
    ],
    [
      #{content => "YYY Ets Size", width => 15},
      #{content => 43, width => 10},
      #{content => "Disk Capcity", width => 15},
      #{content => {percent, 0.23}, width => 16},
      #{content => "XYZ2 Process Mem", width => 19},
      #{content => {byte, 2034 * 220}, width => 19}
    ],
    [
      #{content => "ZZZ Ets Size", width => 15},
      #{content => 108, width => 10},
      #{content => "Volume Capcity", width => 15},
      #{content => {percent, 0.101}, width => 16},
      #{content => "XYZ3 Process Mem", width => 19},
      #{content => {byte, 12823}, width => 19}
    ]
  ],
  NewState = PrevState,
  {Attrs, NewState}.

|Home(H)|XPlug(X)|YPlug(Y)| | 0Days 3:34:50 |
|XXX Ets Size | 122 | Memory Capcity | 12.00% | XYZ1 Process Mem | 1.1737 MB |
|YYY Ets Size | 43 | Disk Capcity | 23.00% | XYZ2 Process Mem | 436.9922 KB |
|ZZZ Ets Size | 108 | Volume Capcity | 10.10% | XYZ3 Process Mem | 12.5225 KB |

-callback sheet_header() -> [SheetHeader] when
    SheetHeader :: #{title => string(), width => pos_integer(), shortcut => string()}.

for example:

sheet_header() ->
  [
    #{title => "Pid", width => 15},
    #{title => "Register", width => 20},
    #{title => "Memory", width => 20, shortcut => "S"},
    #{title => "Reductions", width => 23, shortcut => "R"},
    #{title => "Message Queue Len", width => 23, shortcut => "Q"}
  ].

|No |Pid |Register |Memory(S) |Reductions(R) |Message Queue Len(Q) |

-callback sheet_body(PrevState) -> {[SheetBody], NewState} when
    PrevState :: any(),
    SheetBody :: list(),
    NewState :: any().

for example:

sheet_body(PrevState) ->
  Body = [
    begin
      Register =
        case erlang:process_info(Pid, registered_name) of
          [] -> [];
          {_, Name} -> Name
        end,
      [
        Pid,
        Register,
        {byte, element(2, erlang:process_info(Pid, memory))},
        element(2, erlang:process_info(Pid, reductions)),
        element(2, erlang:process_info(Pid, message_queue_len))
      ]
    end
    || Pid <- erlang:processes()
  ],
  NewState = PrevState,
  {Body, NewState}.

Support {byte, 1024*10} to 10.0000 KB; {percent, 0.12} to 12.00%.

|No |Pid |Register |Memory(S) |Reductions(R) |Message Queue Len(Q) |
|1 |<0.242.0> | | 4.5020 MB | 26544288 | 0 |
|2 | <0.206.0> | | 1.2824 MB | 13357885 | 0 |
|3 | <0.10.0> | erl_prim_loader | 1.0634 MB | 10046775 | 0 |
|4 | <0.434.0> | | 419.1719 KB | 10503690 | 0 |
|5 | <0.44.0> | application_contro | 416.6250 KB | 153598 | 0 |
|6 | <0.50.0> | code_server | 416.4219 KB | 301045 | 0 |
|7 | <0.9.0> | rebar_agent | 136.7031 KB | 1337603 | 0 |
|8 | <0.207.0> | | 99.3125 KB | 9629 | 0 |
|9 | <0.58.0> | file_server_2 | 41.3359 KB | 34303 | 0 |
|10 | <0.209.0> | | 27.3438 KB | 31210 | 0 |
|11 | <0.0.0> | init | 25.8516 KB | 8485 | 0 |
|refresh: 1600ms q(quit) Positive Number(set refresh interval time ms) F/B(forward/back) Current pages is 1 |

Support F/B to page up/down.

A more specific plugin can collect linux system information such as kernel vsn, loadavg, disk, memory usage, cpu utilization, IO statistics.

---

Changelog

• 1.7.5

  • Fix crash when mnesia table with external copies. Which mnesia:table_info(TabName, storage_type) returns tuple {ext, _, _}

• 1.7.4

  • fix crash when ets:info/1 return undefined.

• 1.7.3

  • fix system pane exception by ps command.

• 1.7.2

  • Fix error when inspecting process that monitors via {RegName, Node}.

• 1.7.1

  • application view show starting/loading/startPfalse/loaded/started application.
  • fixed badarg when staring by rpc and stop by ctrl+c.
  • fixed mix.exe version error

• 1.7.0

  • application view support reductions/memory/process_count sort
  • plugin support {byte, 1024} to 10.0000 KB
  • plugin support {percent, 0.1234 to 12.34%
  • plugin support dig deep process view.

• 1.6.2

  • fixed crash when ps command not found on windows.

• 1.6.1

  • remove precise opt version

• 1.6.0

  • hidden schedule usage default
  • format by erlformat
  • add ps -o pcpu,pmem,rss,vsz information
  • remove recon_alloc:memory/1 from HOME(too much cpu usage)

• 1.5.4

  • Bump Recon to 2.5.1 for otp23 alloc compat.

• 1.5.2

  • Use erlang:system_info(otp_release) when can't find OTP_VERSION file for the full version.

• 1.5.1

  • Hide mnesia tab when it's not started
  • Show specific erl version such as '22.0.5'

• 1.5.0

  • Bump Recon to 2.5.0

• 1.4.5

  • Include a minimal mix.exs build file
  • Make sure EXIT message has been clear

• 1.4.4

  • Make sure connection errors can be handled

• 1.4.3

  • Bump Recon to 2.4.0

• 1.4.2

  • Hidden schedule process bar when core > 100.
  • Allow to compile escript w/ inet6 based distribution.
  • Rewrite plugin callback, rename kv_label/0 to attributes/1.

• 1.4.1

  • Fixed ets view memory usage wrong.
  • mnesia view memory usage According to bytes.

• 1.4.0

  • Support write your own plugin.

• 1.3.4

  • View(ets mnesia) support page down/up; support sort by memory or size.
  • Fixed pause crash.
  • Make refresh interval configurable.

• 1.3.3

  • fixed io:format(Format,Args) Format not support iolist OTP R21

• 1.3.2

  • Make sure all observer_cli process exit when quit.
  • Upgrade recon to 2.3.6

• 1.3.1

  • Add atom limit/count in home.
  • Escript support short name and long name.
  • Fixed store process not exit.
  • Upgrade recon to 2.3.5

• 1.3.0

  • Rewrite Network/Process view.
  • Support PageDown/PageUp for top n list.
  • Escript auto load observer_cli when it's not load on target node.

• 1.2.2

  • fix schedule number >= 32 display wrong.
  • improve memory(byte/kilobyte/megabyte/gigabyte) unit.

• 1.2.1

  • fixed autosize not work.
  • try best to make color adjust all platform.

• 1.2.0

  • add application GUI.
  • Rearrange GUI and optimize render.
  • Always automatically adapt to the window size.

• 1.1.0

  • Support escript, observer_cli <TARGETNODE> <COOKIE>

• 1.0.9

  • Upgrade rebar3 to 3.3.3 for publish hex repo.

---

Contributors

zhongwencool 💻	Dimitrios Zorbas 💻	taotao 💻	Trevor Brown 💻	Zaiming Shi 💻

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License

See the LICENSE file for license rights and limitations (MIT).