adding optional emission of some erlang vm stats

ChangeLog

@@ -1,3 +1,12 @@
+Version 5.5.0 (molinaro)
+  * vmstats can now be sent once a minute via mondemand when specified in the
+    application config file.  A program id is required so a minimal config
+    might be something like
+      { vmstats, [ { program_id, mondemand } ] }
+    in addition a context could be added via a context parameter with a
+    2-tuple list as an argument like
+      { vmstats, [ { program_id, mondemand }, {context, [{foo,bar}]} ] }
+
 Version 5.4.2 (molinaro)
   * problem with context deserialization
 

mondemand_dev.config

@@ -1,6 +1,7 @@
 [
   { mondemand, [
-      { lwes_channel, { 1, [ { "127.0.0.1", 20602 } ] } } %,
+      { lwes_channel, { 1, [ { "127.0.0.1", 20602 } ] } },
+      { vmstats, [ { program_id, mondemand } ] }
 %      { lwes_channel, { 2, [{"127.0.0.1",20602}, {"172.16.107.128", 20602}] } } %,
 %      { config_file, "mondemand.conf" }
 %      { send_interval, 5 }

src/mondemand.app.src

@@ -1,7 +1,7 @@
 { application, mondemand,
   [
    { description, "Erlang Mondemand Bindings." },
-   { vsn, "5.4.2" },
+   { vsn, "5.5.0" },
    { modules, [] },
    { registered, [mondemand,mondemand_sup]},
    { applications, [kernel,stdlib,lwes]},

src/mondemand.erl

@@ -250,6 +250,17 @@ send_stats (ProgId, Context, Stats) ->
   send_event (Event).
 
 flush () ->
+  case application:get_env (mondemand, vmstats) of
+    {ok, L} when is_list (L) ->
+      case proplists:get_value (program_id, L) of
+        undefined -> ok;
+        ProgId ->
+          Context = proplists:get_value (context, L, []),
+          VmStats = mondemand_vmstats:to_mondemand (),
+          send_stats (ProgId, Context, VmStats)
+      end;
+    _ -> ok
+  end,
   mondemand_statdb:flush (1, fun flush_one/1).
 
 reset_stats () ->

src/mondemand_sup.erl

@@ -23,16 +23,20 @@ init([]) ->
 
   VMStatsChild =
     case application:get_env (mondemand, vmstats) of
-      {ok, true} ->
-        [
-          { mondemand_vmstats,
-           {mondemand_vmstats, start_link, []},
-           permanent,
-           2000,
-           worker,
-           [mondemand_vmstats]
-          }
-          ];
+      {ok, L} when is_list (L) ->
+        case proplists:get_value (program_id, L) of
+          undefined -> [];
+          _ ->
+            [
+              { mondemand_vmstats,
+               {mondemand_vmstats, start_link, []},
+               permanent,
+               2000,
+               worker,
+               [mondemand_vmstats]
+              }
+            ]
+        end;
       _ ->
         []
     end,