Fix plugin expansion during runtime configuration changes

Blowing away the plugin expand directory when we make runtime changes
is wrong and we don't need to strip away expanded plugins when they're
disabled, since the directory is cleaned on each restart and leaving
the files in place isn't an issue.

1 files changed, 17 insertions, 14 deletions

diff --git a/src/rabbit_plugins.erl b/src/rabbit_plugins.erl
index 6fe4c12788..1799570d15 100644
--- a/src/rabbit_plugins.erl
+++ b/src/rabbit_plugins.erl
@@ -38,20 +38,27 @@
 
 %%----------------------------------------------------------------------------
 
-enable(Plugins) ->
-    setup(),
-    rabbit_boot:start(Plugins).
+enable(Enabled) ->
+    prepare_plugins(Enabled),
+    rabbit_boot:start(Enabled).
 
 disable(Plugins) ->
-    setup(),
     rabbit_boot:stop(Plugins).
 
 %% @doc Prepares the file system and installs all enabled plugins.
 setup() ->
-    {ok, PluginDir}   = application:get_env(rabbit, plugins_dir),
     {ok, ExpandDir}   = application:get_env(rabbit, plugins_expand_dir),
+
+    %% Eliminate the contents of the destination directory
+    case delete_recursively(ExpandDir) of
+        ok          -> ok;
+        {error, E1} -> throw({error, {cannot_delete_plugins_expand_dir,
+                                      [ExpandDir, E1]}})
+    end,
+
     {ok, EnabledFile} = application:get_env(rabbit, enabled_plugins_file),
-    prepare_plugins(EnabledFile, PluginDir, ExpandDir).
+    Enabled = read_enabled(EnabledFile),
+    prepare_plugins(Enabled).
 
 %% @doc Lists the plugins which are currently running.
 active() ->
@@ -114,9 +121,11 @@ dependencies(Reverse, Sources, AllPlugins) ->
 
 %%----------------------------------------------------------------------------
 
-prepare_plugins(EnabledFile, PluginsDistDir, ExpandDir) ->
+prepare_plugins(Enabled) ->
+    {ok, PluginsDistDir} = application:get_env(rabbit, plugins_dir),
+    {ok, ExpandDir} = application:get_env(rabbit, plugins_expand_dir),
+
     AllPlugins = list(PluginsDistDir),
-    Enabled = read_enabled(EnabledFile),
     ToUnpack = dependencies(false, Enabled, AllPlugins),
     ToUnpackPlugins = lookup_plugins(ToUnpack, AllPlugins),
 
@@ -127,12 +136,6 @@ prepare_plugins(EnabledFile, PluginsDistDir, ExpandDir) ->
                      [Missing])
     end,
 
-    %% Eliminate the contents of the destination directory
-    case delete_recursively(ExpandDir) of
-        ok          -> ok;
-        {error, E1} -> throw({error, {cannot_delete_plugins_expand_dir,
-                                      [ExpandDir, E1]}})
-    end,
     case filelib:ensure_dir(ExpandDir ++ "/") of
         ok          -> ok;
         {error, E2} -> throw({error, {cannot_create_plugins_expand_dir,