More gross structural work; now has log levels and broken out log level control

9 files changed, 417 insertions, 147 deletions

diff --git a/ebin/rebar.app b/ebin/rebar.app
index f779b81..2127297 100644
--- a/ebin/rebar.app
+++ b/ebin/rebar.app
@@ -11,10 +11,14 @@
                   stdlib, 
                   sasl]},
   {env, [
+         %% Default log level
+         {log_level, error},
+         
          %% Key/value list of base/default configuration used by
          %% rebar_config during initialization
          {default_config, [
-                           {app_modules, [ rebar_erlc_compiler ]}
+                           {app_modules, [ rebar_erlc_compiler,
+                                           rebar_app_installer ]}
                            ]}
         ]}
 ]}.
diff --git a/include/rebar.hrl b/include/rebar.hrl
index fba5885..35de9f5 100644
--- a/include/rebar.hrl
+++ b/include/rebar.hrl
@@ -1,8 +1,14 @@
 
 -record(global_state, { working_dir }).
 
+-define(FAIL, throw({error, failed})).
+
 -define(CONSOLE(Str, Args), io:format(Str, Args)).
--define(WARN(Str, Args), io:format("WARN: " ++ Str, Args)).
 
--define(FAIL, throw({error, failed})).
+-define(DEBUG(Str, Args), rebar_log:log(debug, Str, Args)).
+-define(INFO(Str, Args), rebar_log:log(info, Str, Args)).
+-define(WARN(Str, Args), rebar_log:log(warn, Str, Args)).
+-define(ERROR(Str, Args), rebar_log:log(error, Str, Args)).
+
+-define(FMT(Str, Args), lists:flatten(io_lib:format(Str, Args))).
 
diff --git a/priv/rebar b/priv/rebar
index a9e229f..198f20d 100755
--- a/priv/rebar
+++ b/priv/rebar
@@ -28,138 +28,5 @@
 
 -include_lib("rebar/include/rebar.hrl").
 
-main(Commands) ->
-    %% Pre-load the rebar app so that we get default configuration
-    application:load(rebar),
-    
-    %% From the current working directory, search recursively and find
-    %% all the application and release directories. We always terminate the
-    %% recursion at an application or release directory.
-    Cwd = rebar_utils:get_cwd(),
-    case target_type(Cwd) of
-        undefined ->
-            Targets = find_targets(Cwd);
-        {Type, Filename} ->
-            Targets = [{Type, Cwd, Filename}]
-    end,
-
-    %% Prefix all the app targets to the code path so that inter-app compilation
-    %% works properly
-    update_code_path(Targets),
-
-    %% Finally, apply the specified command to each target
-    apply_commands(Targets, Commands);
-main(_) ->
-    io:format("usage: rebar <command>...\n").
-
-
-%%
-%% Recursively find all the targets starting at a root directory
-%%
-find_targets(Root) ->
-    {ok, Files} = file:list_dir(Root),
-    find_targets(Files, Root, [], 1).
-
-find_targets([], _Root, Acc, _Depth) ->
-    Acc;
-find_targets(_Files, _Root, Acc, 10) ->
-    Acc;
-find_targets([F | Rest], Root, Acc, Depth) ->
-    AbsName = filename:join([Root, F]),
-    case target_type(AbsName) of
-        undefined ->
-            case filelib:is_dir(AbsName) of
-                true ->
-                    {ok, SubFiles} = file:list_dir(AbsName),
-                    Acc2 = find_targets(SubFiles, AbsName, Acc, Depth+1);
-                false ->
-                    Acc2 = Acc
-            end;
-        {Type, Filename} ->
-            Acc2 = [{Type, AbsName, Filename} | Acc]
-    end,
-    find_targets(Rest, Root, Acc2, Depth).
-
-%%
-%% Determine the target type of a given file: app, rel or undefined
-%%
-target_type(AbsName) ->
-    case rebar_app_utils:is_app_dir(AbsName) of
-        {true, AppFile} ->
-            {app, AppFile};
-        false ->
-            case rebar_rel_utils:is_rel_dir(AbsName) of
-                true ->
-                    {rel, ""};
-                false ->
-                    undefined
-            end
-    end.
-
-
-%%
-%% Given a command and target type, determine if the command is applicable
-%%
-valid_command(compile, app) -> true;
-valid_command(clean, _Any)  -> true;
-valid_command(_, _)         -> false.
-
-
-%%
-%% Add all application targets to the front of the code path
-%%
-update_code_path([]) ->     
-    ok;
-update_code_path([{app, Dir, _} | Rest]) ->
-    EbinDir = filename:join([Dir, "ebin"]),
-    true = code:add_patha(EbinDir),
-    update_code_path(Rest);
-update_code_path([_ | Rest]) ->
-    update_code_path(Rest).
-
-
-apply_commands(_Targets, []) ->
-    ok;
-apply_commands(Targets, [CommandStr | Rest]) ->
-    %% Convert the command into an atom for convenience
-    Command = list_to_atom(CommandStr),
-
-    %% Filter out all the targets, based on the specified command.
-    FilteredTargets = [{Type, Dir, Filename} || {Type, Dir, Filename} <- Targets,
-                                                valid_command(Command, Type) == true],
-    case apply_command(FilteredTargets, Command) of
-        ok ->
-            apply_commands(Targets, Rest);
-        Other ->
-            Other
-    end.
-
-apply_command([], _Command) ->
-    ok;
-apply_command([{Type, Dir, File} | Rest], Command) ->
-    ok = file:set_cwd(Dir),
-    Config = rebar_config:new(Dir),
-
-    %% Provide some info on where we are
-    ?CONSOLE("==> ~s (~s)\n", [filename:basename(Dir), Command]),
-
-    %% Pull the list of modules that are associated with Type operations. Each module
-    %% will be inspected for a function matching Command and if found, will execute that. 
-    Modules = rebar_config:get_modules(Config, Type),
-    case catch(run_modules(Modules, Command, Config, File)) of
-        ok ->
-            apply_command(Rest, Command);
-        Other ->
-            ?CONSOLE("~p failed while processing ~s: ~p", [Command, Dir, Other])
-    end.
-
-
-run_modules([], _Command, _Config, _File) ->
-    ok;
-run_modules([Module | Rest], Command, Config, File) ->
-    case Module:Command(Config, File) of
-        ok ->
-            run_modules(Rest, Command, Config, File);
-        {error, Reason} ->
-            {error, Reason}
-    end.
+main(Args) ->
+    rebar_core:run(Args).
diff --git a/src/rebar_app_installer.erl b/src/rebar_app_installer.erl
new file mode 100644
index 0000000..ae723c5
--- /dev/null
+++ b/src/rebar_app_installer.erl
@@ -0,0 +1,68 @@
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2009 Dave Smith (dizzyd@dizzyd.com)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+-module(rebar_app_installer).
+
+-export([install/2]).
+
+-include("rebar.hrl").
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+install(Config, File) ->
+    %% Load the app name and version from the .app file and construct
+    %% the app identifier
+    {ok, AppName, AppData} = rebar_app_utils:load_app_file(File),
+    Vsn = proplists:get_value(vsn, AppData),
+    AppId = ?FMT("~s-~s", [AppName, Vsn]),
+    ?CONSOLE("Installing: ~s\n", [AppId]),
+
+    %% Check the erlang lib directory to see if this app identifier
+    %% is already present.
+    AppDir = filename:join([code:lib_dir(), AppId]),
+    case filelib:is_dir(AppDir) of
+        true ->
+            %% Already exists -- check for force=1 global flag and only
+            %% continue if it's set
+            case rebar_config:get_global(force, "0") of
+                "0" ->
+                    ?ERROR("~s already exists. Installation failed."),
+                    ?FAIL;
+                "1" ->
+                    ?WARN("~s already exists, but forcibly overwriting."),                    
+            end;
+        false ->
+            ok
+    end,
+
+    %% Wipe out any previous versions
+    ok = rebar_file_utils:rm_rf(Appdir),
+
+    %% Re-create target
+    ok = rebar_file_utils:mkdir_p(AppDir),
+
+    %% By default we copy the ebin, include, src and priv directories
+    
diff --git a/src/rebar_app_utils.erl b/src/rebar_app_utils.erl
index 24c8e1b..900fff0 100644
--- a/src/rebar_app_utils.erl
+++ b/src/rebar_app_utils.erl
@@ -24,7 +24,14 @@
 %% -------------------------------------------------------------------
 -module(rebar_app_utils).
 
--export([is_app_dir/0, is_app_dir/1]).
+-export([is_app_dir/0, is_app_dir/1,
+         load_app_file/1]).
+
+-include("rebar.hrl").
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
 
 is_app_dir() ->
     is_app_dir(rebar_util:get_cwd()).
@@ -37,3 +44,15 @@ is_app_dir(Dir) ->
         _ ->
             false
     end.
+
+load_app_file(Filename) ->
+    case file:consult(Filename) of
+        {ok, [{application, AppName, AppData}]} ->
+            {ok, AppName, AppData};
+        {error, Reason} ->
+            ?ERROR("Failed to load app file from ~s: ~p\n", [Filename, Reason]),
+            error;
+        Other ->
+            ?ERROR("Unexpected terms from app file ~s: ~p\n", [Filename, Other]),
+            error
+    end.
diff --git a/src/rebar_config.erl b/src/rebar_config.erl
index 0b3ffee..3e2087c 100644
--- a/src/rebar_config.erl
+++ b/src/rebar_config.erl
@@ -26,7 +26,8 @@
 
 -export([new/1,
          get_modules/2,
-         get_list/3]).
+         get_list/3,
+         set_global/2, get_global/2]).
 
 -include("rebar.hrl").
 
@@ -72,7 +73,17 @@ get_list(Config, Key, Default) ->
         {ok, List} ->
             List
     end.
-    
+
+set_global(Key, Value) ->
+    application:set_env(rebar_global, Key, Value).
+
+get_global(Key, Default) ->
+    case application:get_env(rebar_global, Key) of
+        undefined ->
+            Default;
+        {ok, Value} ->
+            Value
+    end.
 
 
 %% ===================================================================
@@ -82,6 +93,6 @@ get_list(Config, Key, Default) ->
 merge_terms([], Dict) ->
     Dict;
 merge_terms([{Key, Value} | Rest], Dict) ->
-    merge_terms(Rest, orddict:append(Key, Value, Dict));
+    merge_terms(Rest, orddict:store(Key, Value, Dict));
 merge_terms([_ | Rest], Dict) ->
     merge_terms(Rest, Dict).
diff --git a/src/rebar_core.erl b/src/rebar_core.erl
new file mode 100644
index 0000000..a18370e
--- /dev/null
+++ b/src/rebar_core.erl
@@ -0,0 +1,208 @@
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2009 Dave Smith (dizzyd@dizzyd.com)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+-module(rebar_core).
+
+-export([run/1]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+run(Args) ->
+    %% Filter all the flags (i.e. string of form key=value) from the
+    %% command line arguments. What's left will be the commands to run.
+    Commands = filter_flags(Args, []),
+    
+    %% Pre-load the rebar app so that we get default configuration
+    application:load(rebar),
+
+    %% Initialize logging system
+    rebar_log:init(),
+    
+    %% From the current working directory, search recursively and find
+    %% all the application and release directories. We always terminate the
+    %% recursion at an application or release directory.
+    Cwd = rebar_utils:get_cwd(),
+    case target_type(Cwd) of
+        undefined ->
+            Targets = find_targets(Cwd);
+        {Type, Filename} ->
+            Targets = [{Type, Cwd, Filename}]
+    end,
+
+    %% Prefix all the app targets to the code path so that inter-app compilation
+    %% works properly
+    update_code_path(Targets),
+
+    %% Finally, apply the specified command to each target
+    apply_commands(Targets, Commands)
+
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
+
+%%
+%% Seperate all commands (single-words) from flags (key=value) and store
+%% values into the rebar_config global storage.
+%%
+filter_flags([], Commands) ->
+    lists:reverse(Commands);
+filter_flags([Item | Rest], Commands) ->
+    case string:tokens(Item, "=") of
+        [Command] ->
+            filter_flags(Rest, [Command | Commands]);
+        [KeyStr, Value] ->
+            Key = list_to_atom(KeyStr),
+            rebar_config:set_global(Key, Value),
+            filter_flags(Rest, Commands);
+        Other ->
+            ?CONSOLE("Ignoring command line argument: ~p\n", [Other]),
+            filter_flags(Rest, Commands)
+    end.
+            
+
+
+%%
+%% Recursively find all the targets starting at a root directory
+%%
+find_targets(Root) ->
+    {ok, Files} = file:list_dir(Root),
+    find_targets(Files, Root, [], 1).
+
+find_targets([], _Root, Acc, _Depth) ->
+    Acc;
+find_targets(_Files, _Root, Acc, 10) ->
+    Acc;
+find_targets([F | Rest], Root, Acc, Depth) ->
+    AbsName = filename:join([Root, F]),
+    case target_type(AbsName) of
+        undefined ->
+            case filelib:is_dir(AbsName) of
+                true ->
+                    {ok, SubFiles} = file:list_dir(AbsName),
+                    Acc2 = find_targets(SubFiles, AbsName, Acc, Depth+1);
+                false ->
+                    Acc2 = Acc
+            end;
+        {Type, Filename} ->
+            Acc2 = [{Type, AbsName, Filename} | Acc]
+    end,
+    find_targets(Rest, Root, Acc2, Depth).
+
+%%
+%% Determine the target type of a given file: app, rel or undefined
+%%
+target_type(AbsName) ->
+    case rebar_app_utils:is_app_dir(AbsName) of
+        {true, AppFile} ->
+            {app, AppFile};
+        false ->
+            case rebar_rel_utils:is_rel_dir(AbsName) of
+                true ->
+                    {rel, ""};
+                false ->
+                    undefined
+            end
+    end.
+
+
+%%
+%% Given a command and target type, determine if the command is applicable
+%%
+valid_command(compile, app) -> true;
+valid_command(install, app) -> true;
+valid_command(clean, _Any)  -> true;
+valid_command(_, _)         -> false.
+
+
+%%
+%% Add all application targets to the front of the code path
+%%
+update_code_path([]) ->     
+    ok;
+update_code_path([{app, Dir, _} | Rest]) ->
+    EbinDir = filename:join([Dir, "ebin"]),
+    true = code:add_patha(EbinDir),
+    update_code_path(Rest);
+update_code_path([_ | Rest]) ->
+    update_code_path(Rest).
+
+
+apply_commands(_Targets, []) ->
+    ok;
+apply_commands(Targets, [CommandStr | Rest]) ->
+    %% Convert the command into an atom for convenience
+    Command = list_to_atom(CommandStr),
+
+    %% Filter out all the targets, based on the specified command.
+    FilteredTargets = [{Type, Dir, Filename} || {Type, Dir, Filename} <- Targets,
+                                                valid_command(Command, Type) == true],
+    case apply_command(FilteredTargets, Command) of
+        ok ->
+            apply_commands(Targets, Rest);
+        Other ->
+            Other
+    end.
+
+apply_command([], _Command) ->
+    ok;
+apply_command([{Type, Dir, File} | Rest], Command) ->
+    ok = file:set_cwd(Dir),
+    Config = rebar_config:new(Dir),
+
+    %% Provide some info on where we are
+    ?CONSOLE("==> ~s (~s)\n", [filename:basename(Dir), Command]),
+
+    %% Pull the list of modules that are associated with Type operations. Each module
+    %% will be inspected for a function matching Command and if found, will execute that. 
+    Modules = rebar_config:get_modules(Config, Type),
+    case catch(run_modules(Modules, Command, Config, File)) of
+        ok ->
+            apply_command(Rest, Command);
+        Other ->
+            ?ERROR("~p failed while processing ~s: ~p", [Command, Dir, Other])
+    end.
+
+
+run_modules([], _Command, _Config, _File) ->
+    ok;
+run_modules([Module | Rest], Command, Config, File) ->
+    case invoke_command(Module, Command, Config, File) of
+        ok ->
+            run_modules(Rest, Command, Config, File);
+        {error, Reason} ->
+            {error, Reason}
+    end.
+
+invoke_command(Module, Command, Config, File) ->
+    Exports = Module:module_info(exports),
+    case lists:member({Command, 2}, Exports) of
+        true ->
+            Module:Command(Config, File);
+        false ->
+            ?DEBUG("Skipping ~s:~s/2 (not exported)\n", [Module, Command]),
+            ok
+    end.
diff --git a/src/rebar_erlc_compiler.erl b/src/rebar_erlc_compiler.erl
index 0218f77..ac1e733 100644
--- a/src/rebar_erlc_compiler.erl
+++ b/src/rebar_erlc_compiler.erl
@@ -66,7 +66,7 @@ do_compile(Config, SrcWildcard, OutDir, InExt, OutExt, CompileFn, FirstFiles) ->
             %% Build list of output files
             Targets = [target_file(S, OutDir, InExt, OutExt) || S <- Srcs],
             Files = lists:zip(Srcs, Targets),
-            
+
             %% Make sure target directory exists
             ok = filelib:ensure_dir(hd(Targets)),
             
@@ -87,6 +87,7 @@ compile_each([{Src, Target} | Rest], Config, CompileFn) ->
             ?CONSOLE("Compiling ~s\n", [Src]),
             CompileFn(Src, Config);
         false ->
+            ?INFO("Skipping ~s\n", [Src]),
             ok
     end,
     compile_each(Rest, Config, CompileFn).
@@ -98,10 +99,12 @@ needs_compile(Src, Target) ->
 target_file(F, TargetDir, InExt, OutExt) ->
     filename:join([TargetDir, filename:basename(F, InExt) ++ OutExt]).
 
+compile_opts(Config, Key) ->
+    rebar_config:get_list(Config, Key, []).
 
 compile_erl(Source, Config) ->
-    Opts = rebar_config:get_list(Config, erl_opts, []),
-    case compile:file(Source, [{i, "include"}, {outdir, "ebin"}, report] ++ Opts) of
+    Opts = [{i, "include"}, {outdir, "ebin"}, report] ++ compile_opts(Config, erl_opts),
+    case compile:file(Source, Opts) of
         {ok, _} ->
             ok;
         error ->
@@ -109,8 +112,8 @@ compile_erl(Source, Config) ->
     end.
 
 compile_mib(Source, Config) ->
-    Opts = rebar_config:get_list(Config, mib_opts, []),
-    case snmpc:compile(Source, [{outdir, "priv/mibs"}, {i, ["priv/mibs"]}] ++ Opts) of
+    Opts = [{outdir, "priv/mibs"}, {i, ["priv/mibs"]}] ++ compile_opts(Config, mib_opts),
+    case snmpc:compile(Source, Opts) of
         {ok, _} ->
             ok;
         {error, compilation_failed} ->
diff --git a/src/rebar_log.erl b/src/rebar_log.erl
new file mode 100644
index 0000000..58f7992
--- /dev/null
+++ b/src/rebar_log.erl
@@ -0,0 +1,84 @@
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2009 Dave Smith (dizzyd@dizzyd.com)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+-module(rebar_log).
+
+-export([init/0,
+         set_level/1, get_level/0,
+         log/3]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+init() ->
+    case rebar_config:get_global(verbose, "0") of
+        "1" ->
+            set_level(debug);
+        _ ->
+            set_level(error)
+    end.
+            
+
+set_level(Level) ->
+    ok = application:set_env(rebar, log_level, Level).
+
+get_level() ->
+    case application:get_env(rebar, log_level) of
+        undefined ->
+            error;
+        {ok, Value} ->
+            Value
+    end.
+
+log(Level, Str, Args) ->
+    {ok, LogLevel} = application:get_env(rebar, log_level),
+    case should_log(LogLevel, Level) of
+        true ->
+            io:format(log_prefix(Level) ++ Str, Args);
+        false ->
+            ok
+    end.
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
+
+should_log(debug, _)     -> true;
+should_log(info, debug)  -> false;
+should_log(info, _)      -> true;
+should_log(warn, debug)  -> false;
+should_log(warn, info)   -> false;
+should_log(warn, _)      -> true;
+should_log(error, error) -> true;
+should_log(error, _)     -> false;
+should_log(_, _)         -> false.
+    
+log_prefix(debug) -> "DEBUG:" ;
+log_prefix(info)  -> "INFO: ";
+log_prefix(warn)  -> "WARN: ";
+log_prefix(error) -> "ERROR: ".
+
+     
+