From a5558a23049c04b58e526f8e6574267e803a4527 Mon Sep 17 00:00:00 2001
From: Rick Payne <rickp@OtoloNetworks.com>
Date: Sat, 4 Nov 2017 16:08:22 +1300
Subject: [PATCH] Work around OTP applications which do not respond

---
 apps/epl_st/src/epl_st.erl | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/apps/epl_st/src/epl_st.erl b/apps/epl_st/src/epl_st.erl
index 53fa81b..55730c8 100644
--- a/apps/epl_st/src/epl_st.erl
+++ b/apps/epl_st/src/epl_st.erl
@@ -9,6 +9,8 @@
 
 -behaviour(gen_server).
 
+-define(LIVENESS_TIMEOUT, 1000).
+
 %% API
 -export([start_link/0,
          subscribe/0,
@@ -101,8 +103,13 @@ generate_sup_tree(undefined) ->
     #{};
 generate_sup_tree(MasterPid) ->
     {SupPid, _SupName} = command(fun application_master:get_child/1, [MasterPid]),
-    Children = command(fun supervisor:which_children/1, [SupPid]),
-    sup_node(SupPid, generate_children(Children)).
+    case catch sys:get_status(SupPid, ?LIVENESS_TIMEOUT) of
+        {'EXIT', {timeout, _}} ->
+            #{};
+        _ ->
+            Children = command(fun supervisor:which_children/1, [SupPid]),
+            sup_node(SupPid, generate_children(Children))
+    end.
 
 generate_children(Children) ->
     lists:filtermap(