From 4456a1a46b36b472cc29641cee5fe7e15da5393a Mon Sep 17 00:00:00 2001
From: Matthias Radestock <matthias@rabbitmq.com>
Date: Thu, 25 Aug 2011 22:31:00 +0100
Subject: one way to check whether rabbit is running and avoid timeouts in
 application:which_applications() in doing so

---
 src/rabbit.erl         | 15 +++++++++++++--
 src/rabbit_control.erl |  8 +-------
 src/rabbit_direct.erl  |  2 +-
 src/rabbit_upgrade.erl |  8 +-------
 4 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/src/rabbit.erl b/src/rabbit.erl
index 8cae7fde..b8dbccc7 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -18,7 +18,8 @@
 
 -behaviour(application).
 
--export([prepare/0, start/0, stop/0, stop_and_halt/0, status/0, environment/0,
+-export([prepare/0, start/0, stop/0, stop_and_halt/0, status/0,
+         is_running/0 , is_running/1, environment/0,
          rotate_logs/1, force_event_refresh/0]).
 
 -export([start/2, stop/1]).
@@ -196,6 +197,8 @@
                {os, {atom(), atom()}} |
                {erlang_version, string()} |
                {memory, any()}]).
+-spec(is_running/0 :: () -> boolean()).
+-spec(is_running/1 :: (node()) -> boolean()).
 -spec(environment/0 :: () -> [{atom() | term()}]).
 -spec(log_location/1 :: ('sasl' | 'kernel') -> log_location()).
 
@@ -233,11 +236,19 @@ stop_and_halt() ->
 
 status() ->
     [{pid, list_to_integer(os:getpid())},
-     {running_applications, application:which_applications()},
+     {running_applications, application:which_applications(infinity)},
      {os, os:type()},
      {erlang_version, erlang:system_info(system_version)},
      {memory, erlang:memory()}].
 
+is_running() -> is_running(node()).
+
+is_running(Node) ->
+    case rpc:call(Node, application, which_applications, [infinity]) of
+        {badrpc, _} -> false;
+        Apps        -> proplists:is_defined(rabbit, Apps)
+    end.
+
 environment() ->
     lists:keysort(
       1, [P || P = {K, _} <- application:get_all_env(rabbit),
diff --git a/src/rabbit_control.erl b/src/rabbit_control.erl
index b9e550c9..d920ca31 100644
--- a/src/rabbit_control.erl
+++ b/src/rabbit_control.erl
@@ -362,7 +362,7 @@ wait_for_application(Node, PidFile, Inform) ->
 
 wait_for_application(Node, Pid) ->
     case process_up(Pid) of
-        true  -> case node_up(Node) of
+        true  -> case rabbit:is_running(Node) of
                      true  -> ok;
                      false -> timer:sleep(1000),
                               wait_for_application(Node, Pid)
@@ -378,12 +378,6 @@ wait_and_read_pid_file(PidFile) ->
         {error, _} = E  -> exit({error, {could_not_read_pid, E}})
     end.
 
-node_up(Node) ->
-    case rpc_call(Node, application, which_applications, [infinity]) of
-        {badrpc, _} -> false;
-        Apps        -> proplists:is_defined(rabbit, Apps)
-    end.
-
 % Test using some OS clunkiness since we shouldn't trust
 % rpc:call(os, getpid, []) at this point
 process_up(Pid) ->
diff --git a/src/rabbit_direct.erl b/src/rabbit_direct.erl
index 68afaf5d..6f9a4650 100644
--- a/src/rabbit_direct.erl
+++ b/src/rabbit_direct.erl
@@ -72,7 +72,7 @@ list() ->
 %%----------------------------------------------------------------------------
 
 connect(Username, VHost, Protocol, Pid, Infos) ->
-    case lists:keymember(rabbit, 1, application:which_applications()) of
+    case rabbit:is_running() of
         true  ->
             case rabbit_access_control:check_user_login(Username, []) of
                 {ok, User} ->
diff --git a/src/rabbit_upgrade.erl b/src/rabbit_upgrade.erl
index 9739f6b7..e7a302f8 100644
--- a/src/rabbit_upgrade.erl
+++ b/src/rabbit_upgrade.erl
@@ -228,13 +228,7 @@ secondary_upgrade(AllNodes) ->
     ok.
 
 nodes_running(Nodes) ->
-    [N || N <- Nodes, node_running(N)].
-
-node_running(Node) ->
-    case rpc:call(Node, application, which_applications, []) of
-        {badrpc, _} -> false;
-        Apps        -> lists:keysearch(rabbit, 1, Apps) =/= false
-    end.
+    [N || N <- Nodes, rabbit:is_running(N)].
 
 %% -------------------------------------------------------------------
 
-- 
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