chore(nodetool): ensure correct lib dirs

Prioro to this change, ekka lib dir was added by inspecting
the ekka lib version in persisted RELEASES file.
However, this file may not be the true version if a hot
upgrade failed in the middle.
In this fix, it reads the per-version emqx.rel file
content to load lib paths.

bin/emqx

@@ -174,9 +174,10 @@ relx_gen_id() {
 # Control a node
 relx_nodetool() {
     command="$1"; shift
+    export RUNNER_ROOT_DIR
+    export REL_VSN
 
     ERL_FLAGS="$ERL_FLAGS $EPMD_ARG" \
-    ERL_LIBS="${LIB_EKKA_DIR}:${ERL_LIBS:-}" \
     "$ERTS_DIR/bin/escript" "$ROOTDIR/bin/nodetool" "$NAME_TYPE" "$NAME" \
                                 -setcookie "$COOKIE" "$command" "$@"
 }

bin/nodetool

@@ -19,6 +19,7 @@ main(Args) ->
                     ok
             end
     end,
+    ok = add_libs_dir(),
     ok = do_with_halt(Args, "mnesia_dir", fun create_mnesia_dir/2),
     ok = do_with_halt(Args, "chkconfig", fun("-config", X) -> chkconfig(X) end),
     ok = do_with_halt(Args, "chkconfig", fun chkconfig/1),
@@ -288,3 +289,22 @@ join([], Sep) when is_list(Sep) ->
     [];
 join([H|T], Sep) ->
     H ++ lists:append([Sep ++ X || X <- T]).
+
+add_libs_dir() ->
+    [_ | _] = RootDir = os:getenv("RUNNER_ROOT_DIR"),
+    RelFile = filename:join([RootDir, "releases",
+                             os:getenv("REL_VSN"),
+                             "emqx.rel"
+                            ]),
+    {ok, [{release, {_, _RelVsn}, {erts, _ErtsVsn}, Libs}]} = file:consult(RelFile),
+    lists:foreach(
+      fun({Name, Vsn}) -> add_lib_dir(RootDir, Name, Vsn);
+         ({Name, Vsn, _}) -> add_lib_dir(RootDir, Name, Vsn)
+      end, Libs).
+
+add_lib_dir(RootDir, Name, Vsn) ->
+    LibDir = filename:join([RootDir, lib, atom_to_list(Name) ++ "-" ++ Vsn, ebin]),
+    case code:add_pathz(LibDir) of
+        true -> ok;
+        {error, _} -> error(LibDir)
+    end.

data/emqx_vars

@@ -13,7 +13,6 @@ RUNNER_LIB_DIR="{{ runner_lib_dir }}"
 RUNNER_ETC_DIR="{{ runner_etc_dir }}"
 RUNNER_DATA_DIR="{{ runner_data_dir }}"
 RUNNER_USER="{{ runner_user }}"
-LIB_EKKA_DIR="${RUNNER_LIB_DIR}/ekka-$(grep ekka "${RUNNER_ROOT_DIR}/releases/RELEASES" | awk -F '\"' '{print $2}')"
 
 EMQX_LICENSE_CONF=''
 export EMQX_DESCRIPTION='{{ emqx_description }}'