split rabbit_plugins into client and server side modules

4 files changed, 334 insertions, 285 deletions

diff --git a/scripts/rabbitmq-plugins b/scripts/rabbitmq-plugins
index 14a18d57..97c74791 100755
--- a/scripts/rabbitmq-plugins
+++ b/scripts/rabbitmq-plugins
@@ -31,7 +31,7 @@ exec erl \
     -noinput \
     -hidden \
     -sname rabbitmq-plugins$$ \
-    -s rabbit_plugins \
+    -s rabbit_plugins_main \
     -enabled_plugins_file "$RABBITMQ_ENABLED_PLUGINS_FILE" \
     -plugins_dist_dir "$RABBITMQ_PLUGINS_DIR" \
     -extra "$@"
diff --git a/scripts/rabbitmq-plugins.bat b/scripts/rabbitmq-plugins.bat
index 66a900a1..bc198393 100755
--- a/scripts/rabbitmq-plugins.bat
+++ b/scripts/rabbitmq-plugins.bat
@@ -45,7 +45,7 @@ if "!RABBITMQ_ENABLED_PLUGINS_FILE!"=="" (
 

 set RABBITMQ_PLUGINS_DIR=!TDP0!..\plugins

 

-"!ERLANG_HOME!\bin\erl.exe" -pa "!TDP0!..\ebin" -noinput -hidden -sname rabbitmq-plugins!RANDOM! -s rabbit_plugins -enabled_plugins_file "!RABBITMQ_ENABLED_PLUGINS_FILE!" -plugins_dist_dir "!RABBITMQ_PLUGINS_DIR:\=/!" -extra !STAR!

+"!ERLANG_HOME!\bin\erl.exe" -pa "!TDP0!..\ebin" -noinput -hidden -sname rabbitmq-plugins!RANDOM! -s rabbit_plugins_main -enabled_plugins_file "!RABBITMQ_ENABLED_PLUGINS_FILE!" -plugins_dist_dir "!RABBITMQ_PLUGINS_DIR:\=/!" -extra !STAR!

 

 endlocal

 endlocal

diff --git a/src/rabbit_plugins.erl b/src/rabbit_plugins.erl
index 8a8e7052..06773cdb 100644
--- a/src/rabbit_plugins.erl
+++ b/src/rabbit_plugins.erl
@@ -17,69 +17,27 @@
 -module(rabbit_plugins).
 -include("rabbit.hrl").
 
--export([start/0, stop/0, prepare_plugins/0, active_plugins/0]).
-
--define(VERBOSE_OPT, "-v").
--define(MINIMAL_OPT, "-m").
--define(ENABLED_OPT, "-E").
--define(ENABLED_ALL_OPT, "-e").
+-export([prepare_plugins/0, active_plugins/0, read_enabled_plugins/1,
+         find_plugins/1, calculate_plugin_dependencies/3]).
 
 %%----------------------------------------------------------------------------
 
 -ifdef(use_specs).
 
--spec(start/0 :: () -> no_return()).
--spec(stop/0 :: () -> 'ok').
 -spec(prepare_plugins/0 :: () -> [atom()]).
 -spec(active_plugins/0 :: () -> [atom()]).
+-spec(find_plugins/1 :: (string()) -> [#plugin{}]).
+-spec(read_enabled_plugins/1 :: (file:filename()) -> [atom()]).
+-spec(calculate_plugin_dependencies/3 ::
+            (boolean(), [atom()], [#plugin{}]) -> [atom()]).
 
 -endif.
 
 %%----------------------------------------------------------------------------
 
-start() ->
-    {ok, [[PluginsFile|_]|_]} =
-        init:get_argument(enabled_plugins_file),
-    {ok, [[PluginsDir|_]|_]} = init:get_argument(plugins_dist_dir),
-    {[Command0 | Args], Opts} =
-        case rabbit_misc:get_options([{flag, ?VERBOSE_OPT},
-                                      {flag, ?MINIMAL_OPT},
-                                      {flag, ?ENABLED_OPT},
-                                      {flag, ?ENABLED_ALL_OPT}],
-                                     init:get_plain_arguments()) of
-            {[], _Opts}    -> usage();
-            CmdArgsAndOpts -> CmdArgsAndOpts
-        end,
-    Command = list_to_atom(Command0),
-    PrintInvalidCommandError =
-        fun () ->
-                print_error("invalid command '~s'",
-                            [string:join([atom_to_list(Command) | Args], " ")])
-        end,
-
-    case catch action(Command, Args, Opts, PluginsFile, PluginsDir) of
-        ok ->
-            rabbit_misc:quit(0);
-        {'EXIT', {function_clause, [{?MODULE, action, _} | _]}} ->
-            PrintInvalidCommandError(),
-            usage();
-        {'EXIT', {function_clause, [{?MODULE, action, _, _} | _]}} ->
-            PrintInvalidCommandError(),
-            usage();
-        {error, Reason} ->
-            print_error("~p", [Reason]),
-            rabbit_misc:quit(2);
-        {error_string, Reason} ->
-            print_error("~s", [Reason]),
-            rabbit_misc:quit(2);
-        Other ->
-            print_error("~p", [Other]),
-            rabbit_misc:quit(2)
-    end.
-
-stop() ->
-    ok.
-
+%%
+%% @doc Prepares the file system and installs all enabled plugins.
+%%
 prepare_plugins() ->
     {ok, PluginDir} = application:get_env(rabbit, plugins_dir),
     {ok, ExpandDir} = application:get_env(rabbit, plugins_expand_dir),
@@ -89,18 +47,69 @@ prepare_plugins() ->
     [prepare_dir_plugin(PluginName) ||
             PluginName <- filelib:wildcard(ExpandDir ++ "/*/ebin/*.app")].
 
+%% @doc Lists the plugins which are currently running.
 active_plugins() ->
     {ok, ExpandDir} = application:get_env(rabbit, plugins_expand_dir),
     InstalledPlugins = [ P#plugin.name || P <- find_plugins(ExpandDir) ],
     [App || {App, _, _} <- application:which_applications(),
             lists:member(App, InstalledPlugins)].
 
+%% @doc Get the list of plugins which are ready to be enabled.
+find_plugins(PluginsDir) ->
+    EZs = [{ez, EZ} || EZ <- filelib:wildcard("*.ez", PluginsDir)],
+    FreeApps = [{app, App} ||
+                   App <- filelib:wildcard("*/ebin/*.app", PluginsDir)],
+    {Plugins, Problems} =
+        lists:foldl(fun ({error, EZ, Reason}, {Plugins1, Problems1}) ->
+                            {Plugins1, [{EZ, Reason} | Problems1]};
+                        (Plugin = #plugin{}, {Plugins1, Problems1}) ->
+                            {[Plugin|Plugins1], Problems1}
+                    end, {[], []},
+                    [get_plugin_info(PluginsDir, Plug) ||
+                        Plug <- EZs ++ FreeApps]),
+    case Problems of
+        [] -> ok;
+        _  -> io:format("Warning: Problem reading some plugins: ~p~n",
+                        [Problems])
+    end,
+    Plugins.
+
+%% @doc Read the list of enabled plugins from the supplied term file.
+read_enabled_plugins(PluginsFile) ->
+    case rabbit_file:read_term_file(PluginsFile) of
+        {ok, [Plugins]} -> Plugins;
+        {ok, []}        -> [];
+        {ok, [_|_]}      -> throw({error, {malformed_enabled_plugins_file,
+                                           PluginsFile}});
+        {error, enoent} -> [];
+        {error, Reason} -> throw({error, {cannot_read_enabled_plugins_file,
+                                          PluginsFile, Reason}})
+    end.
+
+%%
+%% @doc Calculate the dependency graph from <i>Sources</i>.
+%% When Reverse =:= true the bottom/leaf level applications are returned in
+%% the resulting list, otherwise they're skipped.
+%%
+calculate_plugin_dependencies(Reverse, Sources, AllPlugins) ->
+    {ok, G} = rabbit_misc:build_acyclic_graph(
+                fun (App, _Deps) -> [{App, App}] end,
+                fun (App,  Deps) -> [{App, Dep} || Dep <- Deps] end,
+                [{Name, Deps}
+                 || #plugin{name = Name, dependencies = Deps} <- AllPlugins]),
+    Dests = case Reverse of
+                false -> digraph_utils:reachable(Sources, G);
+                true  -> digraph_utils:reaching(Sources, G)
+            end,
+    true = digraph:delete(G),
+    Dests.
+
 %%----------------------------------------------------------------------------
 
 prepare_plugins(EnabledPluginsFile, PluginsDistDir, DestDir) ->
     AllPlugins = find_plugins(PluginsDistDir),
     Enabled = read_enabled_plugins(EnabledPluginsFile),
-    ToUnpack = calculate_required_plugins(Enabled, AllPlugins),
+    ToUnpack = calculate_plugin_dependencies(false, Enabled, AllPlugins),
     ToUnpackPlugins = lookup_plugins(ToUnpack, AllPlugins),
 
     Missing = Enabled -- plugin_names(ToUnpackPlugins),
@@ -136,75 +145,6 @@ prepare_dir_plugin(PluginAppDescFn) ->
 
 %%----------------------------------------------------------------------------
 
-action(list, [], Opts, PluginsFile, PluginsDir) ->
-    action(list, [".*"], Opts, PluginsFile, PluginsDir);
-action(list, [Pat], Opts, PluginsFile, PluginsDir) ->
-    format_plugins(Pat, Opts, PluginsFile, PluginsDir);
-
-action(enable, ToEnable0, _Opts, PluginsFile, PluginsDir) ->
-    case ToEnable0 of
-        [] -> throw({error_string, "Not enough arguments for 'enable'"});
-        _  -> ok
-    end,
-    AllPlugins = find_plugins(PluginsDir),
-    Enabled = read_enabled_plugins(PluginsFile),
-    ImplicitlyEnabled = calculate_required_plugins(Enabled, AllPlugins),
-    ToEnable = [list_to_atom(Name) || Name <- ToEnable0],
-    Missing = ToEnable -- plugin_names(AllPlugins),
-    case Missing of
-        [] -> ok;
-        _  -> throw({error_string,
-                     fmt_list("The following plugins could not be found:",
-                              Missing)})
-    end,
-    NewEnabled = lists:usort(Enabled ++ ToEnable),
-    write_enabled_plugins(PluginsFile, NewEnabled),
-    NewImplicitlyEnabled = calculate_required_plugins(NewEnabled, AllPlugins),
-    maybe_warn_mochiweb(NewImplicitlyEnabled),
-    case NewEnabled -- ImplicitlyEnabled of
-        [] -> io:format("Plugin configuration unchanged.~n");
-        _  -> print_list("The following plugins have been enabled:",
-                         NewImplicitlyEnabled -- ImplicitlyEnabled),
-              report_change()
-    end;
-
-action(disable, ToDisable0, _Opts, PluginsFile, PluginsDir) ->
-    case ToDisable0 of
-        [] -> throw({error_string, "Not enough arguments for 'disable'"});
-        _  -> ok
-    end,
-    ToDisable = [list_to_atom(Name) || Name <- ToDisable0],
-    Enabled = read_enabled_plugins(PluginsFile),
-    AllPlugins = find_plugins(PluginsDir),
-    Missing = ToDisable -- plugin_names(AllPlugins),
-    case Missing of
-        [] -> ok;
-        _  -> print_list("Warning: the following plugins could not be found:",
-                         Missing)
-    end,
-    ToDisableDeps = calculate_dependencies(true, ToDisable, AllPlugins),
-    NewEnabled = Enabled -- ToDisableDeps,
-    case length(Enabled) =:= length(NewEnabled) of
-        true  -> io:format("Plugin configuration unchanged.~n");
-        false -> ImplicitlyEnabled =
-                     calculate_required_plugins(Enabled, AllPlugins),
-                 NewImplicitlyEnabled =
-                     calculate_required_plugins(NewEnabled, AllPlugins),
-                 print_list("The following plugins have been disabled:",
-                            ImplicitlyEnabled -- NewImplicitlyEnabled),
-                 write_enabled_plugins(PluginsFile, NewEnabled),
-                 report_change()
-    end.
-
-%%----------------------------------------------------------------------------
-
-print_error(Format, Args) ->
-    rabbit_misc:format_stderr("Error: " ++ Format ++ "~n", Args).
-
-usage() ->
-    io:format("~s", [rabbit_plugins_usage:usage()]),
-    rabbit_misc:quit(1).
-
 delete_recursively(Fn) ->
     case rabbit_file:recursive_delete([Fn]) of
         ok                 -> ok;
@@ -219,26 +159,6 @@ prepare_plugin(#plugin{type = dir, name = Name, location = Location},
     rabbit_file:recursive_copy(Location,
                               filename:join([PluginsDestDir, Name])).
 
-%% Get the #plugin{}s ready to be enabled.
-find_plugins(PluginsDir) ->
-    EZs = [{ez, EZ} || EZ <- filelib:wildcard("*.ez", PluginsDir)],
-    FreeApps = [{app, App} ||
-                   App <- filelib:wildcard("*/ebin/*.app", PluginsDir)],
-    {Plugins, Problems} =
-        lists:foldl(fun ({error, EZ, Reason}, {Plugins1, Problems1}) ->
-                            {Plugins1, [{EZ, Reason} | Problems1]};
-                        (Plugin = #plugin{}, {Plugins1, Problems1}) ->
-                            {[Plugin|Plugins1], Problems1}
-                    end, {[], []},
-                    [get_plugin_info(PluginsDir, Plug) ||
-                        Plug <- EZs ++ FreeApps]),
-    case Problems of
-        [] -> ok;
-        _  -> io:format("Warning: Problem reading some plugins: ~p~n",
-                        [Problems])
-    end,
-    Plugins.
-
 %% Get the #plugin{} from an .ez.
 get_plugin_info(Base, {ez, EZ0}) ->
     EZ = filename:join([Base, EZ0]),
@@ -298,82 +218,6 @@ parse_binary(Bin) ->
         Err -> {error, {invalid_app, Err}}
     end.
 
-%% Pretty print a list of plugins.
-format_plugins(Pattern, Opts, PluginsFile, PluginsDir) ->
-    Verbose = proplists:get_bool(?VERBOSE_OPT, Opts),
-    Minimal = proplists:get_bool(?MINIMAL_OPT, Opts),
-    Format = case {Verbose, Minimal} of
-                 {false, false} -> normal;
-                 {true,  false} -> verbose;
-                 {false, true}  -> minimal;
-                 {true,  true}  -> throw({error_string,
-                                          "Cannot specify -m and -v together"})
-             end,
-    OnlyEnabled = proplists:get_bool(?ENABLED_OPT, Opts),
-    OnlyEnabledAll = proplists:get_bool(?ENABLED_ALL_OPT, Opts),
-
-    AvailablePlugins = find_plugins(PluginsDir),
-    EnabledExplicitly = read_enabled_plugins(PluginsFile),
-    EnabledImplicitly =
-        calculate_required_plugins(EnabledExplicitly, AvailablePlugins) --
-        EnabledExplicitly,
-    {ok, RE} = re:compile(Pattern),
-    Plugins = [ Plugin ||
-                  Plugin = #plugin{name = Name} <- AvailablePlugins,
-                  re:run(atom_to_list(Name), RE, [{capture, none}]) =:= match,
-                  if OnlyEnabled -> lists:member(Name, EnabledExplicitly);
-                     true        -> true
-                  end,
-                  if OnlyEnabledAll ->
-                          lists:member(Name, EnabledImplicitly) or
-                              lists:member(Name, EnabledExplicitly);
-                     true ->
-                          true
-                  end],
-    Plugins1 = usort_plugins(Plugins),
-    MaxWidth = lists:max([length(atom_to_list(Name)) ||
-                             #plugin{name = Name} <- Plugins1] ++ [0]),
-    [format_plugin(P, EnabledExplicitly, EnabledImplicitly, Format,
-                   MaxWidth) || P <- Plugins1],
-    ok.
-
-format_plugin(#plugin{name = Name, version = Version,
-                      description = Description, dependencies = Deps},
-              EnabledExplicitly, EnabledImplicitly, Format, MaxWidth) ->
-    Glyph = case {lists:member(Name, EnabledExplicitly),
-                  lists:member(Name, EnabledImplicitly)} of
-                {true, false} -> "[E]";
-                {false, true} -> "[e]";
-                _             -> "[ ]"
-            end,
-    case Format of
-        minimal -> io:format("~s~n", [Name]);
-        normal  -> io:format("~s ~-" ++ integer_to_list(MaxWidth) ++
-                                 "w ~s~n", [Glyph, Name, Version]);
-        verbose -> io:format("~s ~w~n", [Glyph, Name]),
-                   io:format("    Version:    \t~s~n", [Version]),
-                   case Deps of
-                       [] -> ok;
-                       _  -> io:format("    Dependencies:\t~p~n", [Deps])
-                   end,
-                   io:format("    Description:\t~s~n", [Description]),
-                   io:format("~n")
-    end.
-
-print_list(Header, Plugins) ->
-    io:format(fmt_list(Header, Plugins)).
-
-fmt_list(Header, Plugins) ->
-    lists:flatten(
-      [Header, $\n, [io_lib:format("  ~s~n", [P]) || P <- Plugins]]).
-
-usort_plugins(Plugins) ->
-    lists:usort(fun plugins_cmp/2, Plugins).
-
-plugins_cmp(#plugin{name = N1, version = V1},
-            #plugin{name = N2, version = V2}) ->
-    {N1, V1} =< {N2, V2}.
-
 %% Filter out applications that can be loaded *right now*.
 filter_applications(Applications) ->
     [Application || Application <- Applications,
@@ -397,71 +241,5 @@ plugin_names(Plugins) ->
 lookup_plugins(Names, AllPlugins) ->
     [P || P = #plugin{name = Name} <- AllPlugins, lists:member(Name, Names)].
 
-%% Read the enabled plugin names from disk.
-read_enabled_plugins(PluginsFile) ->
-    case rabbit_file:read_term_file(PluginsFile) of
-        {ok, [Plugins]} -> Plugins;
-        {ok, []}        -> [];
-        {ok, [_|_]}      -> throw({error, {malformed_enabled_plugins_file,
-                                           PluginsFile}});
-        {error, enoent} -> [];
-        {error, Reason} -> throw({error, {cannot_read_enabled_plugins_file,
-                                          PluginsFile, Reason}})
-    end.
-
-%% Write the enabled plugin names on disk.
-write_enabled_plugins(PluginsFile, Plugins) ->
-    case rabbit_file:write_term_file(PluginsFile, [Plugins]) of
-        ok              -> ok;
-        {error, Reason} -> throw({error, {cannot_write_enabled_plugins_file,
-                                          PluginsFile, Reason}})
-    end.
-
-calculate_required_plugins(Sources, AllPlugins) ->
-    calculate_dependencies(false, Sources, AllPlugins).
 
-calculate_dependencies(Reverse, Sources, AllPlugins) ->
-    {ok, G} = rabbit_misc:build_acyclic_graph(
-                fun (App, _Deps) -> [{App, App}] end,
-                fun (App,  Deps) -> [{App, Dep} || Dep <- Deps] end,
-                [{Name, Deps}
-                 || #plugin{name = Name, dependencies = Deps} <- AllPlugins]),
-    Dests = case Reverse of
-                false -> digraph_utils:reachable(Sources, G);
-                true  -> digraph_utils:reaching(Sources, G)
-            end,
-    true = digraph:delete(G),
-    Dests.
-
-maybe_warn_mochiweb(Enabled) ->
-    V = erlang:system_info(otp_release),
-    case lists:member(mochiweb, Enabled) andalso V < "R13B01" of
-        true ->
-            Stars = string:copies("*", 80),
-            io:format("~n~n~s~n"
-                      "  Warning: Mochiweb enabled and Erlang version ~s "
-                      "detected.~n"
-                      "  Enabling plugins that depend on Mochiweb is not "
-                      "supported on this Erlang~n"
-                      "  version. At least R13B01 is required.~n~n"
-                      "  RabbitMQ will not start successfully in this "
-                      "configuration. You *must*~n"
-                      "  disable the Mochiweb plugin, or upgrade Erlang.~n"
-                      "~s~n~n~n", [Stars, V, Stars]);
-        false ->
-            ok
-    end.
-
-report_change() ->
-    io:format("Plugin configuration has changed. "
-              "Restart RabbitMQ for changes to take effect.~n"),
-    case os:type() of
-        {win32, _OsName} ->
-             io:format("If you have RabbitMQ running as a service then you must"
-                       " reinstall by running~n  rabbitmq-service.bat stop~n"
-                       "  rabbitmq-service.bat install~n"
-                       "  rabbitmq-service.bat start~n~n");
-        _ ->
-             ok
-    end.
 
diff --git a/src/rabbit_plugins_main.erl b/src/rabbit_plugins_main.erl
new file mode 100644
index 00000000..a27ad986
--- /dev/null
+++ b/src/rabbit_plugins_main.erl
@@ -0,0 +1,271 @@
+%% The contents of this file are subject to the Mozilla Public License
+%% Version 1.1 (the "License"); you may not use this file except in
+%% compliance with the License. You may obtain a copy of the License
+%% at http://www.mozilla.org/MPL/
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and
+%% limitations under the License.
+%%
+%% The Original Code is RabbitMQ.
+%%
+%% The Initial Developer of the Original Code is VMware, Inc.
+%% Copyright (c) 2011-2012 VMware, Inc.  All rights reserved.
+%%
+
+-module(rabbit_plugins_main).
+-include("rabbit.hrl").
+
+-export([start/0, stop/0]).
+
+-define(VERBOSE_OPT, "-v").
+-define(MINIMAL_OPT, "-m").
+-define(ENABLED_OPT, "-E").
+-define(ENABLED_ALL_OPT, "-e").
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-spec(start/0 :: () -> no_return()).
+-spec(stop/0 :: () -> 'ok').
+
+-endif.
+
+%%----------------------------------------------------------------------------
+
+start() ->
+    {ok, [[PluginsFile|_]|_]} =
+        init:get_argument(enabled_plugins_file),
+    {ok, [[PluginsDir|_]|_]} = init:get_argument(plugins_dist_dir),
+    {[Command0 | Args], Opts} =
+        case rabbit_misc:get_options([{flag, ?VERBOSE_OPT},
+                                      {flag, ?MINIMAL_OPT},
+                                      {flag, ?ENABLED_OPT},
+                                      {flag, ?ENABLED_ALL_OPT}],
+                                     init:get_plain_arguments()) of
+            {[], _Opts}    -> usage();
+            CmdArgsAndOpts -> CmdArgsAndOpts
+        end,
+    Command = list_to_atom(Command0),
+    PrintInvalidCommandError =
+        fun () ->
+                print_error("invalid command '~s'",
+                            [string:join([atom_to_list(Command) | Args], " ")])
+        end,
+
+    case catch action(Command, Args, Opts, PluginsFile, PluginsDir) of
+        ok ->
+            rabbit_misc:quit(0);
+        {'EXIT', {function_clause, [{?MODULE, action, _} | _]}} ->
+            PrintInvalidCommandError(),
+            usage();
+        {'EXIT', {function_clause, [{?MODULE, action, _, _} | _]}} ->
+            PrintInvalidCommandError(),
+            usage();
+        {error, Reason} ->
+            print_error("~p", [Reason]),
+            rabbit_misc:quit(2);
+        {error_string, Reason} ->
+            print_error("~s", [Reason]),
+            rabbit_misc:quit(2);
+        Other ->
+            print_error("~p", [Other]),
+            rabbit_misc:quit(2)
+    end.
+
+stop() ->
+    ok.
+
+%%----------------------------------------------------------------------------
+
+action(list, [], Opts, PluginsFile, PluginsDir) ->
+    action(list, [".*"], Opts, PluginsFile, PluginsDir);
+action(list, [Pat], Opts, PluginsFile, PluginsDir) ->
+    format_plugins(Pat, Opts, PluginsFile, PluginsDir);
+
+action(enable, ToEnable0, _Opts, PluginsFile, PluginsDir) ->
+    case ToEnable0 of
+        [] -> throw({error_string, "Not enough arguments for 'enable'"});
+        _  -> ok
+    end,
+    AllPlugins = rabbit_plugins:find_plugins(PluginsDir),
+    Enabled = rabbit_plugins:read_enabled_plugins(PluginsFile),
+    ImplicitlyEnabled = rabbit_plugins:calculate_plugin_dependencies(false, Enabled, AllPlugins),
+    ToEnable = [list_to_atom(Name) || Name <- ToEnable0],
+    Missing = ToEnable -- plugin_names(AllPlugins),
+    case Missing of
+        [] -> ok;
+        _  -> throw({error_string,
+                     fmt_list("The following plugins could not be found:",
+                              Missing)})
+    end,
+    NewEnabled = lists:usort(Enabled ++ ToEnable),
+    write_enabled_plugins(PluginsFile, NewEnabled),
+    NewImplicitlyEnabled = rabbit_plugins:calculate_plugin_dependencies(false, NewEnabled, AllPlugins),
+    maybe_warn_mochiweb(NewImplicitlyEnabled),
+    case NewEnabled -- ImplicitlyEnabled of
+        [] -> io:format("Plugin configuration unchanged.~n");
+        _  -> print_list("The following plugins have been enabled:",
+                         NewImplicitlyEnabled -- ImplicitlyEnabled),
+              report_change()
+    end;
+
+action(disable, ToDisable0, _Opts, PluginsFile, PluginsDir) ->
+    case ToDisable0 of
+        [] -> throw({error_string, "Not enough arguments for 'disable'"});
+        _  -> ok
+    end,
+    ToDisable = [list_to_atom(Name) || Name <- ToDisable0],
+    Enabled = rabbit_plugins:read_enabled_plugins(PluginsFile),
+    AllPlugins = rabbit_plugins:find_plugins(PluginsDir),
+    Missing = ToDisable -- plugin_names(AllPlugins),
+    case Missing of
+        [] -> ok;
+        _  -> print_list("Warning: the following plugins could not be found:",
+                         Missing)
+    end,
+    ToDisableDeps = rabbit_plugins:calculate_plugin_dependencies(true, ToDisable, AllPlugins),
+    NewEnabled = Enabled -- ToDisableDeps,
+    case length(Enabled) =:= length(NewEnabled) of
+        true  -> io:format("Plugin configuration unchanged.~n");
+        false -> ImplicitlyEnabled =
+                     rabbit_plugins:calculate_plugin_dependencies(false, Enabled, AllPlugins),
+                 NewImplicitlyEnabled =
+                     rabbit_plugins:calculate_plugin_dependencies(false, NewEnabled, AllPlugins),
+                 print_list("The following plugins have been disabled:",
+                            ImplicitlyEnabled -- NewImplicitlyEnabled),
+                 write_enabled_plugins(PluginsFile, NewEnabled),
+                 report_change()
+    end.
+
+%%----------------------------------------------------------------------------
+
+print_error(Format, Args) ->
+    rabbit_misc:format_stderr("Error: " ++ Format ++ "~n", Args).
+
+usage() ->
+    io:format("~s", [rabbit_plugins_usage:usage()]),
+    rabbit_misc:quit(1).
+
+%% Pretty print a list of plugins.
+format_plugins(Pattern, Opts, PluginsFile, PluginsDir) ->
+    Verbose = proplists:get_bool(?VERBOSE_OPT, Opts),
+    Minimal = proplists:get_bool(?MINIMAL_OPT, Opts),
+    Format = case {Verbose, Minimal} of
+                 {false, false} -> normal;
+                 {true,  false} -> verbose;
+                 {false, true}  -> minimal;
+                 {true,  true}  -> throw({error_string,
+                                          "Cannot specify -m and -v together"})
+             end,
+    OnlyEnabled = proplists:get_bool(?ENABLED_OPT, Opts),
+    OnlyEnabledAll = proplists:get_bool(?ENABLED_ALL_OPT, Opts),
+
+    AvailablePlugins = rabbit_plugins:find_plugins(PluginsDir),
+    EnabledExplicitly = rabbit_plugins:read_enabled_plugins(PluginsFile),
+    EnabledImplicitly =
+        rabbit_plugins:calculate_plugin_dependencies(false, EnabledExplicitly, AvailablePlugins) --
+        EnabledExplicitly,
+    {ok, RE} = re:compile(Pattern),
+    Plugins = [ Plugin ||
+                  Plugin = #plugin{name = Name} <- AvailablePlugins,
+                  re:run(atom_to_list(Name), RE, [{capture, none}]) =:= match,
+                  if OnlyEnabled -> lists:member(Name, EnabledExplicitly);
+                     true        -> true
+                  end,
+                  if OnlyEnabledAll ->
+                          lists:member(Name, EnabledImplicitly) or
+                              lists:member(Name, EnabledExplicitly);
+                     true ->
+                          true
+                  end],
+    Plugins1 = usort_plugins(Plugins),
+    MaxWidth = lists:max([length(atom_to_list(Name)) ||
+                             #plugin{name = Name} <- Plugins1] ++ [0]),
+    [format_plugin(P, EnabledExplicitly, EnabledImplicitly, Format,
+                   MaxWidth) || P <- Plugins1],
+    ok.
+
+format_plugin(#plugin{name = Name, version = Version,
+                      description = Description, dependencies = Deps},
+              EnabledExplicitly, EnabledImplicitly, Format, MaxWidth) ->
+    Glyph = case {lists:member(Name, EnabledExplicitly),
+                  lists:member(Name, EnabledImplicitly)} of
+                {true, false} -> "[E]";
+                {false, true} -> "[e]";
+                _             -> "[ ]"
+            end,
+    case Format of
+        minimal -> io:format("~s~n", [Name]);
+        normal  -> io:format("~s ~-" ++ integer_to_list(MaxWidth) ++
+                                 "w ~s~n", [Glyph, Name, Version]);
+        verbose -> io:format("~s ~w~n", [Glyph, Name]),
+                   io:format("    Version:    \t~s~n", [Version]),
+                   case Deps of
+                       [] -> ok;
+                       _  -> io:format("    Dependencies:\t~p~n", [Deps])
+                   end,
+                   io:format("    Description:\t~s~n", [Description]),
+                   io:format("~n")
+    end.
+
+print_list(Header, Plugins) ->
+    io:format(fmt_list(Header, Plugins)).
+
+fmt_list(Header, Plugins) ->
+    lists:flatten(
+      [Header, $\n, [io_lib:format("  ~s~n", [P]) || P <- Plugins]]).
+
+usort_plugins(Plugins) ->
+    lists:usort(fun plugins_cmp/2, Plugins).
+
+plugins_cmp(#plugin{name = N1, version = V1},
+            #plugin{name = N2, version = V2}) ->
+    {N1, V1} =< {N2, V2}.
+
+%% Return the names of the given plugins.
+plugin_names(Plugins) ->
+    [Name || #plugin{name = Name} <- Plugins].
+
+%% Write the enabled plugin names on disk.
+write_enabled_plugins(PluginsFile, Plugins) ->
+    case rabbit_file:write_term_file(PluginsFile, [Plugins]) of
+        ok              -> ok;
+        {error, Reason} -> throw({error, {cannot_write_enabled_plugins_file,
+                                          PluginsFile, Reason}})
+    end.
+
+maybe_warn_mochiweb(Enabled) ->
+    V = erlang:system_info(otp_release),
+    case lists:member(mochiweb, Enabled) andalso V < "R13B01" of
+        true ->
+            Stars = string:copies("*", 80),
+            io:format("~n~n~s~n"
+                      "  Warning: Mochiweb enabled and Erlang version ~s "
+                      "detected.~n"
+                      "  Enabling plugins that depend on Mochiweb is not "
+                      "supported on this Erlang~n"
+                      "  version. At least R13B01 is required.~n~n"
+                      "  RabbitMQ will not start successfully in this "
+                      "configuration. You *must*~n"
+                      "  disable the Mochiweb plugin, or upgrade Erlang.~n"
+                      "~s~n~n~n", [Stars, V, Stars]);
+        false ->
+            ok
+    end.
+
+report_change() ->
+    io:format("Plugin configuration has changed. "
+              "Restart RabbitMQ for changes to take effect.~n"),
+    case os:type() of
+        {win32, _OsName} ->
+             io:format("If you have RabbitMQ running as a service then you must"
+                       " reinstall by running~n  rabbitmq-service.bat stop~n"
+                       "  rabbitmq-service.bat install~n"
+                       "  rabbitmq-service.bat start~n~n");
+        _ ->
+             ok
+    end.
+