From 171933301a1f2d8e355074231f9330cceeeb43f1 Mon Sep 17 00:00:00 2001
From: Zaiming Shi <zmstone@gmail.com>
Date: Fri, 30 Apr 2021 11:45:36 +0200
Subject: [PATCH] fix(dashboard): display full Erlang/OTP version

---
 apps/emqx_management/src/emqx_mgmt.erl |  2 +-
 src/emqx_vm.erl                        | 15 ++++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/apps/emqx_management/src/emqx_mgmt.erl b/apps/emqx_management/src/emqx_mgmt.erl
index 0f42027b4..8c196f682 100644
--- a/apps/emqx_management/src/emqx_mgmt.erl
+++ b/apps/emqx_management/src/emqx_mgmt.erl
@@ -553,7 +553,7 @@ rpc_call(Node, Fun, Args) ->
     end.
 
 otp_rel() ->
-    lists:concat(["R", erlang:system_info(otp_release), "/", erlang:system_info(version)]).
+    lists:concat([emqx_vm:get_otp_version(), "/", erlang:system_info(version)]).
 
 check_row_limit(Tables) ->
     check_row_limit(Tables, max_row_limit()).
diff --git a/src/emqx_vm.erl b/src/emqx_vm.erl
index 511028c1d..537330b01 100644
--- a/src/emqx_vm.erl
+++ b/src/emqx_vm.erl
@@ -369,16 +369,17 @@ compat_windows(Fun) ->
     end.
 
 %% @doc Return on which Eralng/OTP the current vm is running.
+%% NOTE: This API reads a file, do not use it in critical code paths.
 get_otp_version() ->
-    string:trim(binary_to_list(read_otp_version())).
+    parse_built_on(read_otp_version()).
 
 read_otp_version() ->
     ReleasesDir = filename:join([code:root_dir(), "releases"]),
     Filename = filename:join([ReleasesDir, emqx_app:get_release(), "BUILT_ON"]),
     case file:read_file(Filename) of
-        {ok, Vsn} ->
+        {ok, BuiltOn} ->
             %% running on EQM X release
-            Vsn;
+            BuiltOn;
         {error, enoent} ->
             %% running tests etc.
             OtpMajor = erlang:system_info(otp_release),
@@ -386,3 +387,11 @@ read_otp_version() ->
             {ok, Vsn} = file:read_file(OtpVsnFile),
             Vsn
     end.
+
+parse_built_on(BuiltOn) ->
+    case binary:split(BuiltOn, <<"-">>, [global]) of
+        [Vsn, <<"emqx">>, N | _] ->
+            binary_to_list(Vsn) ++ "-emqx-" ++ binary_to_list(N);
+        [Vsn | _] ->
+            string:trim(binary_to_list(Vsn))
+    end.