Merge pull request #117 from imtutta/feature/extend_plugin

feat: extend plugin behaviour to customize the view of body's items

Author: zhongwencool

docs/plugin.md

@@ -157,4 +157,35 @@ Support `{byte, 1024*10}` to ` 10.0000 KB`; `{percent, 0.12}` to `12.00%`.
 
 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.
+[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.
+
+3. Handler: specific per-item behavior
+
+By default, once you select a row, it will show the process information in `observer_cli_process` view. This is done 
+by looking for a `pid` in the row, so the first one found will be used and passed to the `observer_cli_process` view.
+
+To customize this behavior, you can implement your own handler. The handler is a tuple with a function and a module. 
+The function is a predicate that will be used to filter all row's items and, if the resulting list in not empty, the 
+`Handler:start/3` function will be called. The signature is the same of `observer_cli_process:start/3`.
+
+The new configuration will look like this:
+
+```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.
+%% handler      - Specific handler implements per-item behavior. It's optional, default is `{fun is_pid/1,observer_cli_process}`.`
+
+{plugins,
+  [
+    #{module => observer_cli_plug_behaviour_x, title => "XPlug",
+      interval => 1600, shortcut => "X", sort_column => 3,
+      handler => {fun is_pid/1, observer_cli_plug_item_behaviour_x}},
+    #{module => observer_cli_plug_behaviour_y, title => "YPlug",
+      interval =>2000, shortcut => "Y", sort_column => 3,
+      handler => {fun is_binary/1, observer_cli_plug_item_behaviour_y}},
+  ]
+}
+```

src/observer_cli_plugin.erl

@@ -95,17 +95,19 @@ manager(ChildPid, SheetCache, ViewOpts) ->
             observer_cli_lib:exit_processes([ChildPid]),
             start(ViewOpts#view_opts{plug = PlugOpts#plug{plugs = NewPlugs}});
         {jump, CurRow} ->
+            CurPlugs = maps:get(CurIndex, Plugs),
+            {Filter, Handler} = maps:get(handler, CurPlugs, {fun is_pid/1, observer_cli_process}),
             case ets:lookup(SheetCache, CurRow) of
                 [{CurRow, Items}] ->
-                    case [I || I <- Items, is_pid(I)] of
-                        [ChoosePid | _] ->
+                    case [I || I <- Items, Filter(I)] of
+                        [ChooseItem | _] ->
                             observer_cli_lib:exit_processes([ChildPid]),
                             ets:delete(SheetCache),
                             NewPlugs = update_plugins(CurIndex, Plugs, #{cur_row => CurRow}),
                             NewViewOpts = ViewOpts#view_opts{
                                 plug = PlugOpts#plug{plugs = NewPlugs}
                             },
-                            observer_cli_process:start(plugin, ChoosePid, NewViewOpts);
+                            Handler:start(plugin, ChooseItem, NewViewOpts);
                         [] ->
                             manager(ChildPid, SheetCache, ViewOpts)
                     end;
@@ -114,14 +116,15 @@ manager(ChildPid, SheetCache, ViewOpts) ->
             end;
         jump ->
             CurPlugs = maps:get(CurIndex, Plugs),
-            CurRow = maps:get(cur_row, CurPlugs),
+            CurRow = maps:get(cur_row, CurPlugs, observer_cli_process),
+            {Filter, Handler} = maps:get(handler, CurPlugs, {fun is_pid/1, observer_cli_process}),
             case ets:lookup(SheetCache, CurRow) of
                 [{CurRow, Items}] ->
-                    case [I || I <- Items, is_pid(I)] of
-                        [ChoosePid | _] ->
+                    case [I || I <- Items, Filter(I)] of
+                        [ChooseItem | _] ->
                             observer_cli_lib:exit_processes([ChildPid]),
                             ets:delete(SheetCache),
-                            observer_cli_process:start(plugin, ChoosePid, ViewOpts);
+                            Handler:start(plugin, ChooseItem, ViewOpts);
                         [] ->
                             manager(ChildPid, SheetCache, ViewOpts)
                     end;