fix(relup): inject relup instructions to the end of relup file

rebar.config.erl

@@ -129,7 +129,8 @@ prod_overrides() ->
     [{add, [ {erl_opts, [deterministic]}]}].
 
 relup_deps(Profile) ->
-    {post_hooks, [{"(linux|darwin|solaris|freebsd|netbsd|openbsd)", compile, "scripts/inject-deps.escript " ++ atom_to_list(Profile)}]}.
+    {post_hooks, [{"(linux|darwin|solaris|freebsd|netbsd|openbsd)", release,
+                        "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx"])}]}.
 
 profiles() ->
     Vsn = get_vsn(),

scripts/inject-relup.escript

@@ -0,0 +1,58 @@
+#!/usr/bin/env escript
+
+%% This script injects implicit relup instructions for emqx applications.
+
+-mode(compile).
+
+-define(ERROR(FORMAT, ARGS), io:format(standard_error, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
+-define(INFO(FORMAT, ARGS), io:format(user, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
+
+usage() ->
+  "Usage: " ++ escript:script_name() ++ " <path-to-release-dir>".
+
+main([Dir]) ->
+  case filelib:is_dir(Dir) of
+    true ->
+      ok = inject(Dir);
+    false ->
+      ?ERROR("not a valid dir: ~p", [Dir]),
+      erlang:halt(1)
+  end;
+main(_Args) ->
+  ?ERROR("~s", [usage()]),
+  erlang:halt(1).
+
+inject(Dir) ->
+  RelupFiles = filelib:wildcard(filename:join([Dir, "releases", "*", "relup"])),
+  lists:foreach(fun(File) ->
+      case file:consult(File) of
+        {ok, [{CurrRelVsn, UpVsnRUs, DnVsnRUs}]} ->
+          ?INFO("injecting instructions to: ~p", [File]),
+          UpdatedContent = [{CurrRelVsn, inject_relup_instrs(CurrRelVsn, UpVsnRUs),
+                              inject_relup_instrs(CurrRelVsn, DnVsnRUs)}],
+          file:write_file("/tmp/" ++ filename:basename(File), term_to_text(UpdatedContent));
+        {ok, _BadFormat} ->
+          ?ERROR("bad formatted relup file: ~p", [File]);
+        {error, Reason} ->
+          ?ERROR("read relup file ~p failed: ~p", [File, Reason])
+      end
+    end, RelupFiles).
+
+inject_relup_instrs(CurrRelVsn, RUs) ->
+  [{Vsn, Desc, append_emqx_relup_instrs(CurrRelVsn, Vsn, Instrs)} || {Vsn, Desc, Instrs} <- RUs].
+
+%% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
+%% the instruction lists.
+append_emqx_relup_instrs(CurrRelVsn, Vsn, Instrs) ->
+  case lists:reverse(Instrs) of
+    [{apply, {emqx_relup, post_release_upgrade, _}} | _] ->
+      Instrs;
+    RInstrs ->
+      lists:reverse([instr_post_release_upgrade(CurrRelVsn, Vsn) | RInstrs])
+  end.
+
+instr_post_release_upgrade(CurrRelVsn, Vsn) ->
+  {apply, {emqx_relup, post_release_upgrade, [CurrRelVsn, Vsn]}}.
+
+term_to_text(Term) ->
+  io_lib:format("~p.", [Term]).