From: Peter Lemenkov <lemenkov@gmail.com>
Date: Thu, 19 May 2016 16:04:56 +0300
Subject: [PATCH] Remove excessive sd_notify code

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>

diff --git a/src/rabbit.erl b/src/rabbit.erl
index d328a78d4..9a21d22b5 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -293,121 +293,8 @@ broker_start() ->
     Plugins = rabbit_plugins:setup(),
     ToBeLoaded = Plugins ++ ?APPS,
     start_apps(ToBeLoaded),
-    maybe_sd_notify(),
     ok = log_broker_started(rabbit_plugins:active()).
 
-%% Try to send systemd ready notification if it makes sense in the
-%% current environment. standard_error is used intentionally in all
-%% logging statements, so all this messages will end in systemd
-%% journal.
-maybe_sd_notify() ->
-    case sd_notify_ready() of
-        false ->
-            io:format(standard_error, "systemd READY notification failed, beware of timeouts~n", []);
-        _ ->
-            ok
-    end.
-
-sd_notify_ready() ->
-    case {os:type(), os:getenv("NOTIFY_SOCKET")} of
-        {{win32, _}, _} ->
-            true;
-        {_, [_|_]} -> %% Non-empty NOTIFY_SOCKET, give it a try
-            sd_notify_legacy() orelse sd_notify_socat();
-        _ ->
-            true
-    end.
-
-sd_notify_data() ->
-    "READY=1\nSTATUS=Initialized\nMAINPID=" ++ os:getpid() ++ "\n".
-
-sd_notify_legacy() ->
-    case code:load_file(sd_notify) of
-        {module, sd_notify} ->
-            SDNotify = sd_notify,
-            SDNotify:sd_notify(0, sd_notify_data()),
-            true;
-        {error, _} ->
-            false
-    end.
-
-%% socat(1) is the most portable way the sd_notify could be
-%% implemented in erlang, without introducing some NIF. Currently the
-%% following issues prevent us from implementing it in a more
-%% reasonable way:
-%% - systemd-notify(1) is unstable for non-root users
-%% - erlang doesn't support unix domain sockets.
-%%
-%% Some details on how we ended with such a solution:
-%%   https://github.com/rabbitmq/rabbitmq-server/issues/664
-sd_notify_socat() ->
-    case sd_current_unit() of
-        {ok, Unit} ->
-            io:format(standard_error, "systemd unit for activation check: \"~s\"~n", [Unit]),
-            sd_notify_socat(Unit);
-        _ ->
-            false
-    end.
-
-socat_socket_arg("@" ++ AbstractUnixSocket) ->
-    "abstract-sendto:" ++ AbstractUnixSocket;
-socat_socket_arg(UnixSocket) ->
-    "unix-sendto:" ++ UnixSocket.
-
-sd_open_port() ->
-    open_port(
-      {spawn_executable, os:find_executable("socat")},
-      [{args, [socat_socket_arg(os:getenv("NOTIFY_SOCKET")), "STDIO"]},
-       use_stdio, out]).
-
-sd_notify_socat(Unit) ->
-    try sd_open_port() of
-        Port ->
-            Port ! {self(), {command, sd_notify_data()}},
-            Result = sd_wait_activation(Port, Unit),
-            port_close(Port),
-            Result
-    catch
-        Class:Reason ->
-            io:format(standard_error, "Failed to start socat ~p:~p~n", [Class, Reason]),
-            false
-    end.
-
-sd_current_unit() ->
-    case catch re:run(os:cmd("systemctl status " ++ os:getpid()), "([-.@0-9a-zA-Z]+)", [unicode, {capture, all_but_first, list}]) of
-        {'EXIT', _} ->
-            error;
-        {match, [Unit]} ->
-            {ok, Unit};
-        _ ->
-            error
-    end.
-
-sd_wait_activation(Port, Unit) ->
-    case os:find_executable("systemctl") of
-        false ->
-            io:format(standard_error, "'systemctl' unavailable, falling back to sleep~n", []),
-            timer:sleep(5000),
-            true;
-        _ ->
-            sd_wait_activation(Port, Unit, 10)
-    end.
-
-sd_wait_activation(_, _, 0) ->
-    io:format(standard_error, "Service still in 'activating' state, bailing out~n", []),
-    false;
-sd_wait_activation(Port, Unit, AttemptsLeft) ->
-    case os:cmd("systemctl show --property=ActiveState " ++ Unit) of
-        "ActiveState=activating\n" ->
-            timer:sleep(1000),
-            sd_wait_activation(Port, Unit, AttemptsLeft - 1);
-        "ActiveState=" ++ _ ->
-            true;
-        _ = Err->
-            io:format(standard_error, "Unexpected status from systemd ~p~n", [Err]),
-            false
-    end.
-
 start_it(StartFun) ->
     Marker = spawn_link(fun() -> receive stop -> ok end end),
     case catch register(rabbit_boot, Marker) of