Generalise threshold checks on process attributes

This commit generalises the logic that checks for process
attributes and moves it to weatherreport_utils. This is
groundwork for the following commit which will add a check
for processes by memory usage by re-using the generalised code.

We also take the opportunity to rename fold_processes to
something that is more descriptive and also correct.

BugzID: 32875

2 files changed, 37 insertions, 26 deletions

diff --git a/src/weatherreport/src/weatherreport_check_message_queues.erl b/src/weatherreport/src/weatherreport_check_message_queues.erl
index 3633ae3f1..ae99ff4dc 100644
--- a/src/weatherreport/src/weatherreport_check_message_queues.erl
+++ b/src/weatherreport/src/weatherreport_check_message_queues.erl
@@ -41,35 +41,17 @@ description() ->
 valid() ->
     weatherreport_node:can_connect().
 
-fold_processes([], Acc, _Opts) ->
-    Acc;
-fold_processes([{Pid, MBoxSize, Info} | T], Acc, Opts) when MBoxSize < ?THRESHOLD ->
-    Message = {info, {mbox_ok, {Pid, MBoxSize, Info}}},
-    fold_processes(T, [Message | Acc], Opts);
-fold_processes([{Pid, MBoxSize, Info} | T], Acc, Opts) ->
-    Message = case proplists:get_value(expert, Opts) of
-        true ->
-            Pinfo = weatherreport_node:local_command(recon, info, [Pid]),
-            {warning, {mbox_large, {Pid, MBoxSize, Info, Pinfo}}};
-        _ ->
-            {warning, {mbox_large, {Pid, MBoxSize, Info}}}
-    end,
-    fold_processes(T, [Message | Acc], Opts).
-
 -spec check(list()) -> [{atom(), term()}].
 check(Opts) ->
-    Processes = weatherreport_node:local_command(
-        recon,
-        proc_count,
-        [message_queue_len, 10]
-    ),
-    fold_processes(Processes, [], Opts).
+    weatherreport_util:check_proc_count(
+        message_queue_len,
+        ?THRESHOLD,
+        Opts).
 
 -spec format(term()) -> {io:format(), [term()]}.
-format({mbox_large, {Pid, MBoxSize, Info, Pinfo}}) ->
+format({high, {Pid, MBoxSize, Info, Pinfo}}) ->
     {"Process ~w has excessive mailbox size of ~w: ~w ~w", [Pid, MBoxSize, Info, Pinfo]};
-format({mbox_large, {Pid, MBoxSize, Info}}) ->
+format({high, {Pid, MBoxSize, Info}}) ->
     {"Process ~w has excessive mailbox size of ~w: ~w", [Pid, MBoxSize, Info]};
-format({mbox_ok, {Pid, MBoxSize, Info}}) ->
+format({ok, {Pid, MBoxSize, Info}}) ->
     {"Process ~w has mailbox size of ~w: ~w", [Pid, MBoxSize, Info]}.
-
diff --git a/src/weatherreport/src/weatherreport_util.erl b/src/weatherreport/src/weatherreport_util.erl
index a7957922f..ab5370812 100644
--- a/src/weatherreport/src/weatherreport_util.erl
+++ b/src/weatherreport/src/weatherreport_util.erl
@@ -33,7 +33,8 @@
          log/3,log/4,
          binary_to_float/1,
          should_log/1,
-         flush_stdout/0]).
+         flush_stdout/0,
+         check_proc_count/3]).
 
 %% @doc Converts a check module name into a short name that can be
 %% used to refer to a check on the command line.  For example,
@@ -113,3 +114,31 @@ should_log(Level) ->
 
 flush_stdout() ->
     timer:sleep(1000).
+
+%% @doc Utility function to check processes based on an attribute returned
+%% by recon:proc_count/2.
+-spec check_proc_count(atom(), integer(), list()) -> [{atom(), term()}].
+check_proc_count(Key, Threshold, Opts) ->
+    Processes = weatherreport_node:local_command(recon, proc_count, [Key, 10]),
+    procs_to_messages(Processes, Threshold, [], Opts).
+
+%% @doc Utility function to convert the list of process info returned by
+%% recon:proc_count/2 into a list of diagnostic messages.
+-spec procs_to_messages(list(), integer(), list(), list()) -> [{atom(), term()}].
+procs_to_messages([], _Threshold, Acc, _Opts) ->
+    Acc;
+procs_to_messages([{Pid, Value, Info} | T], Threshold, Acc, Opts) ->
+    Level = case Value > Threshold of
+        true -> warning;
+        _ -> info
+    end,
+    Message = case {Level, proplists:get_value(expert, Opts)} of
+        {warning, true} ->
+            Pinfo = weatherreport_node:local_command(recon, info, [Pid]),
+            {warning, {high, {Pid, Value, Info, Pinfo}}};
+        {warning, _} ->
+            {warning, {high, {Pid, Value, Info}}};
+        {info, _} ->
+            {info, {ok, {Pid, Value, Info}}}
+    end,
+    procs_to_messages(T, Threshold, [Message | Acc], Opts).