Restore riaknostic output to console

When riaknostic became part of Riak instead of a separate app, its
output (through lager) ended up in the node's console.log instead of
being output by 'riak-admin diag'. Among other things, this broke the
riaknostic_rt riak test. This adds a layer on top of lager, so messages
can be directed to the console again, simply by using io:format. This
way, messages are sent to the group_leader instead of the user process,
which is what the lager backend does. When riaknostic is invoked through
RPC by riak-admin, the caller becomes the group leader and picks up
those messages. I wish there was a cleaner way to do this leveraging
something in lager, but I couldn't find any.

src/riaknostic.erl

@@ -129,7 +129,6 @@ run(InputChecks) ->
                 [] ->
                     io:format("No diagnostic messages to report.~n");
                 _ ->
-                    io:format("Check ~s for diagnostic output.~n",[proplists:get_value(lager_file_backend,gen_event:which_handlers(lager_event))]),
                     lists:foreach(fun riaknostic_check:print/1, SortedMessages)
             end
     end.

src/riaknostic_check.erl

@@ -94,7 +94,9 @@ modules() ->
 print({Level, Mod, Data}) ->
     case Mod:format(Data) of
         {Format, Terms} ->
-            lager:log(Level, self(), Format, Terms);
+            riaknostic_util:log(Level, Format, Terms);
         String ->
-            lager:log(Level, self(), String)
+            riaknostic_util:log(Level, String)
     end.
+
+

src/riaknostic_node.erl

@@ -60,7 +60,7 @@ local_command(Module, Function, Args) ->
 %% @see can_connect/0
 -spec local_command(Module::atom(), Function::atom(), Args::[term()], Timeout::integer()) -> term().
 local_command(Module, Function, Args, Timeout) ->
-    lager:debug("Local RPC: ~p:~p(~p) [~p]", [Module, Function, Args, Timeout]),
+    riaknostic_util:log(debug, "Local RPC: ~p:~p(~p) [~p]", [Module, Function, Args, Timeout]),
     rpc:call(nodename(), Module, Function, Args, Timeout).
 
 %% @doc Calls the given 0-arity module and function on all members of
@@ -86,7 +86,7 @@ cluster_command(Module, Function, Args) ->
 %% @see can_connect/0
 -spec cluster_command(Module::atom(), Function::atom(), Args::[term()], Timeout::integer()) -> term().
 cluster_command(Module, Function, Args, Timeout) ->
-    lager:debug("Cluster RPC: ~p:~p(~p) [~p]", [Module, Function, Args, Timeout]),
+    riaknostic_util:log(debug, "Cluster RPC: ~p:~p(~p) [~p]", [Module, Function, Args, Timeout]),
     Stats = stats(),
     {ring_members, RingMembers} = lists:keyfind(ring_members, 1, Stats),
     rpc:multicall(RingMembers, Module, Function, Args, Timeout).
@@ -106,7 +106,7 @@ can_connect() ->
     case is_connected() of
         true -> true;
         false ->
-            lager:debug("Not connected to the local Riak node, trying to connect. alive:~p connect_failed:~p", [is_alive(), connect_failed()]),
+            riaknostic_util:log(debug, "Not connected to the local Riak node, trying to connect. alive:~p connect_failed:~p", [is_alive(), connect_failed()]),
             maybe_connect()
     end.
 
@@ -149,7 +149,7 @@ try_connect() ->
     case {net_kernel:hidden_connect_node(TargetNode), net_adm:ping(TargetNode)} of
         {true, pong} ->
             application:set_env(riaknostic, connect_failed, false),
-            lager:debug("Connected to local Riak node ~p.", [TargetNode]),
+            riaknostic_util:log(debug, "Connected to local Riak node ~p.", [TargetNode]),
             true;
         _ ->
             application:set_env(riaknostic, connect_failed, true),
@@ -165,7 +165,7 @@ connect_failed() ->
     end.
 
 start_net() ->
-    lager:debug("Starting distributed Erlang."),
+    riaknostic_util:log(debug, "Starting distributed Erlang."),
     {Type, RiakName} = riaknostic_config:node_name(),
     ThisNode = append_node_suffix(RiakName, "_diag"),
     {ok, _} = net_kernel:start([ThisNode, Type]),
@@ -198,7 +198,7 @@ has_stats() ->
     end.
 
 fetch_stats() ->
-    lager:debug("Fetching local riak_kv_status."),
+    riaknostic_util:log(debug, "Fetching local riak_kv_status."),
     case local_command(riak_kv_status, statistics) of
         [] -> [];
         PList ->

src/riaknostic_util.erl

@@ -25,6 +25,7 @@
 -module(riaknostic_util).
 -export([short_name/1,
          run_command/1,
+         log/2,log/3,
          binary_to_float/1]).
 
 %% @doc Converts a check module name into a short name that can be
@@ -38,14 +39,14 @@ short_name(Mod) when is_atom(Mod) ->
 %% redirected to stdout so its output will be included.
 -spec run_command(Command::iodata()) -> StdOut::iodata().
 run_command(Command) ->
-    lager:debug("Running shell command: ~s", [Command]),
+    riaknostic_util:log(debug, "Running shell command: ~s", [Command]),
     Port = erlang:open_port({spawn,Command},[exit_status, stderr_to_stdout]),
     do_read(Port, []).
 
 do_read(Port, Acc) ->
     receive
         {Port, {data, StdOut}} ->
-            lager:debug("Shell command output: ~n~s~n",[StdOut]),
+            riaknostic_util:log(debug, "Shell command output: ~n~s~n",[StdOut]),
             do_read(Port, Acc ++ StdOut);
         {Port, {exit_status, _}} -> 
             %%port_close(Port),
@@ -60,3 +61,29 @@ do_read(Port, Acc) ->
 -spec binary_to_float(binary()) -> float().
 binary_to_float(Bin) ->
     list_to_float(binary_to_list(Bin)).
+
+log(Level, Format, Terms) ->
+    case should_log(Level) of
+        true ->
+            io:format(lists:concat(["[", Level, "] ", Format, "~n"]), Terms);
+        false ->
+            ok
+    end,
+    lager:log(Level, self(), Format, Terms).
+
+log(Level, String) ->
+    case should_log(Level) of
+        true ->
+            io:format(lists:concat(["[", Level, "] ", String, "~n"]));
+        false ->
+            ok
+    end,
+    lager:log(Level, self(), String).
+
+should_log(Level) ->
+    AppLevel = case application:get_env(riaknostic, log_level) of
+        undefined -> info;
+        {ok, L0} -> L0
+    end,
+    lager_util:level_to_num(AppLevel) >= lager_util:level_to_num(Level).
+