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 1.5.1

Elixir

# mix.exs                                                                                                   
   def deps do                                                          
     [{:observer_cli, "~> 1.5"}]
   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.

Escriptize

cd path/to/observer_cli/
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.
observer_cli TARGETNODE [TARGETCOOKIE REFRESHMS] to monitor remote node.

DEMO

Home Network System Ets Mnesia Application Document Process Port

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.

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_behaviour1, title => "XPlug",
      interval => 1500, shortcut => "X", sort_column => 3},
    #{module => observer_cli_plug_behaviour2, title => "YPlug",
      interval => 1600, shortcut => "Y", sort_column => 3}
  ]
}

Write observer_cli_plugin behaviour. observer_cli_plugin has 3 callbacks.

2.1 attributes.

-callback atributes(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 => 20},
            #{content => ets:info(xxx,size), width => 10},
            #{content => "Pool1 Size", width => 15},
            #{content => application:get_env(app,pool1_size), width => 30},
            #{content => "XYZ1 Process Mem", width => 18,
            #{content => {byte, element(2, erlang:process_info(xyz1, memory))}, width => 16}
        ],
        [
            #{content => "YYY Ets Size", width =>20},
            #{content => ets:info(yyy,size), width => 10},
            #{content => "Pool2 Size", width =>15},
            #{content => application:get_env(app,pool2_size), width => 30},
            #{content =>"XYZ2 Process Mem", width =>18},
            #{content => {byte, element(2, erlang:process_info(xyz2, memory))}, width => 16}
        ],
        [
            #{content => "ZZZ Ets Size", width =>20},
            #{content => ets:info(zzz,size), width => 10},
            #{content => "Pool3 Size", width =>15},
            #{content => application:get_env(app,pool3_size), width => 30},
            #{content => "XYZ3 Process Mem", width =>18},
            #{content => {byte, element(2, erlang:process_info(xyz3, memory))}, width => 16}
        ]
    ],
    NewState = PrevState,
    {Attrs, NewState}.

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

for example:

sheet_header() ->
    [
        #{title => "Pid", width => 25},
        #{title => "Status", width => 25},
        #{title => "Memory", width => 24, shortcut => "S"},
        #{title => "Reductions", width => 24, shortcut => "R"},
        #{title => "Message Queue Len", width => 25, shortcut => "Q"}
    ].

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

for example:

sheet_body(PrevState) ->
    Body =
      [begin
         [
             Pid,
             element(2, erlang:process_info(Pid, status)),
             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 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

1.5.2
- 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} 💻

License

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