### 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.
```erlang
%% 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}
]
}
```
2. Write observer_cli_plugin behaviour.
observer_cli_plugin has 3 callbacks.
2.1 attributes.
```erlang
-callback atributes(PrevState) -> {[Rows], NewState} when
Rows :: #{content => string()|integer()|{byte, pos_integer()},
width => pos_integer(), color => binary()}.
```
for example:
```erlang
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}.
```
```erlang
-callback sheet_header() -> [SheetHeader] when
SheetHeader :: #{title => string(), width => pos_integer(), shortcut => string()}.
```
for example:
```erlang
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"}
].
```
```erlang
-callback sheet_body(PrevState) -> {[SheetBody], NewState} when
PrevState :: any(),
SheetBody :: list(),
NewState :: any().
```
for example:
```erlang
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](https://github.com/zhongwencool/os_stats) 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](https://github.com/ferd/recon/commit/e0c3614334589e375f8b1492f404e4b764fe35e7)
- 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 
zhongwencool](https://tried.cc)
[💻](https://github.com/zhongwencool/observer_cli/commits?author=zhongwencool) | [
Dimitrios Zorbas](https://github.com/Zorbash)
[💻](https://github.com/zhongwencool/observer_cli/commits?author=Zorbash) | [
taotao](https://github.com/redink)
[💻](https://github.com/zhongwencool/observer_cli/commits?author=redink) | [
Trevor Brown](https://github.com/Stratus3D)
[💻](https://github.com/zhongwencool/observer_cli/commits?author=Stratus3D) | [
Zaiming Shi](https://github.com/zmstone)
[💻](https://github.com/zhongwencool/observer_cli/commits?author=zmstone) | | :---: | :---: | :---: | :---: | :---: | -------------------- ### License See the [LICENSE](https://github.com/zhongwencool/observer_cli/blob/master/LICENSE) file for license rights and limitations (MIT).