Handle the move of the enabled_plugins file

We look for the enabled_plugins file at the deprecated location, and at the new location. If it exists only at the deprecated location, we attempt to use that file. If the deprecated location is read-only, we allow the cli command to fail (or not) as it always used to.

Part of the changes intended to address rabbitmq/rabbitmq-server#2234

Author: HoloRin

lib/rabbitmq/cli/plugins/commands/directories_command.ex

@@ -71,8 +71,14 @@ defmodule RabbitMQ.CLI.Plugins.Commands.DirectoriesCommand do
   end
 
   def run([], %{offline: true} = opts) do
-    do_run(fn key ->
-      Config.get_option(key, opts)
+    do_run(fn
+      :enabled_plugins_file ->
+        case PluginHelpers.enabled_plugins_file(opts) do
+          {:ok, plugins_file} -> plugins_file
+          _ -> nil
+        end
+      key ->
+        Config.get_option(key, opts)
     end)
   end
 

lib/rabbitmq/cli/plugins/plugins_helpers.ex

@@ -70,17 +70,44 @@ defmodule RabbitMQ.CLI.Plugins.Helpers do
     end
   end
 
+  @spec enabled_plugins_file(map()) :: {:ok, charlist()} | {:error, any()}
   def enabled_plugins_file(opts) do
     case Config.get_option(:enabled_plugins_file, opts) do
-      nil -> {:error, :no_plugins_file}
-      file -> {:ok, file}
+      nil ->
+        case :os.type do
+          {:unix, _} ->
+            sys_prefix = System.get_env("SYS_PREFIX", "/")
+            config_base_dir = Path.join([sys_prefix, "etc", "rabbitmq"])
+            data_dir = Path.join([sys_prefix, "var", "lib", "rabbitmq"])
+            legacy_location = Path.absname(Path.join([config_base_dir, "enabled_plugins"]))
+            modern_location = Path.absname(Path.join([data_dir, "enabled_plugins"]))
+            case {File.exists?(modern_location), File.exists?(legacy_location)} do
+              {false, true} ->
+                {:ok, legacy_location}
+              _ ->
+                {:ok, modern_location}
+            end
+          {:win32, _} ->
+            rabbitmq_base = case System.fetch_env("RABBITMQ_BASE") do
+                              {:ok, Value} ->
+                                Value
+                              _ ->
+                                app_data = System.get_env("APPDATA")
+                                Path.join([app_data, "RabbitMQ"])
+                            end
+            {:ok, Path.join([rabbitmq_base, "enabled_plugins"])}
+        end
+      file ->
+        {:ok, file}
     end
   end
 
+  @spec enabled_plugins_file(any(), map()) :: {:ok, charlist()} | {:error, any()}
   def enabled_plugins_file(_, opts) do
     enabled_plugins_file(opts)
   end
 
+  @spec set_enabled_plugins([atom()], map()) :: {:ok, Enumerable.t()} | {:error, any()}
   def set_enabled_plugins(plugins, opts) do
     plugin_atoms = :lists.usort(for plugin <- plugins, do: to_atom(plugin))
     require_rabbit_and_plugins(opts)
@@ -89,11 +116,11 @@ defmodule RabbitMQ.CLI.Plugins.Helpers do
   end
 
   @spec update_enabled_plugins(
-          [atom()],
-          :online | :offline | :best_effort,
-          node(),
-          map()
-        ) :: map() | {:error, any()}
+    [atom()],
+    :online | :offline | :best_effort,
+    node(),
+    map()
+  ) :: map() | {:error, any()}
   def update_enabled_plugins(enabled_plugins, mode, node_name, opts) do
     {:ok, plugins_file} = enabled_plugins_file(opts)
 

test/plugins/directories_command_test.exs

@@ -23,9 +23,6 @@ defmodule DirectoriesCommandTest do
     RabbitMQ.CLI.Core.Distribution.start()
     node = get_rabbit_hostname()
 
-    {:ok, plugins_file} = :rabbit_misc.rpc_call(node,
-                                                :application, :get_env,
-                                                [:rabbit, :enabled_plugins_file])
     {:ok, plugins_dir} = :rabbit_misc.rpc_call(node,
                                                :application, :get_env,
                                                [:rabbit, :plugins_dir])
@@ -36,7 +33,7 @@ defmodule DirectoriesCommandTest do
     rabbitmq_home = :rabbit_misc.rpc_call(node, :code, :lib_dir, [:rabbit])
 
     {:ok, opts: %{
-        plugins_file: plugins_file,
+        plugins_file: nil,
         plugins_dir: plugins_dir,
         plugins_expand_dir: plugins_expand_dir,
         rabbitmq_home: rabbitmq_home,
@@ -100,12 +97,49 @@ defmodule DirectoriesCommandTest do
     assert @command.validate_execution_environment([], opts) == :ok
   end
 
-
   test "run: when --online is used, lists plugin directories", context do
     opts = Map.merge(context[:opts], %{online: true})
+
+    {:ok, plugins_file} = :rabbit_misc.rpc_call(Map.get(opts, :node),
+                                                :application, :get_env,
+                                                [:rabbit, :enabled_plugins_file])
+
+    dirs = %{plugins_dir: to_string(Map.get(opts, :plugins_dir)),
+             plugins_expand_dir: to_string(Map.get(opts, :plugins_expand_dir)),
+             enabled_plugins_file: to_string(plugins_file)}
+
+    assert @command.run([], opts) == {:ok, dirs}
+  end
+
+  test "run: when --offline is used, checks for enabled_plugins in the data dir, falling back to the config dir", context do
+    sys_prefix = Path.join([System.tmp_dir(), "DirectoriesCommandTest"])
+
+    System.put_env("SYS_PREFIX", sys_prefix)
+
+    config_dir = Path.join([sys_prefix, "etc", "rabbitmq"])
+    legacy_file = Path.join([config_dir, "enabled_plugins"])
+
+    data_dir = Path.join([sys_prefix, "var", "lib", "rabbitmq"])
+    modern_file = Path.join([data_dir, "enabled_plugins"])
+
+    File.rm(legacy_file)
+    File.rm(modern_file)
+
+    opts = Map.merge(context[:opts], %{offline: true})
+
     dirs = %{plugins_dir: to_string(Map.get(opts, :plugins_dir)),
              plugins_expand_dir: to_string(Map.get(opts, :plugins_expand_dir)),
-             enabled_plugins_file: to_string(Map.get(opts, :plugins_file))}
+             enabled_plugins_file: modern_file}
+
+    assert @command.run([], opts) == {:ok, dirs}
+
+    :ok = File.mkdir_p(config_dir)
+    :ok = File.touch(legacy_file)
+
+    assert @command.run([], opts) == {:ok, Map.merge(dirs, %{enabled_plugins_file: legacy_file})}
+
+    :ok = File.mkdir_p(data_dir)
+    :ok = File.touch(modern_file)
 
     assert @command.run([], opts) == {:ok, dirs}
   end