MINOR: mworker/cli: implement hard-reload over the master CLI

The mworker mode never had a proper 'hard-stop' (-st) for the reload,
this is a mode which was commonly used with the daemon mode, but it was
never implemented in mworker mode.

This patch fixes the problem by implementing a "hard-reload" command
over the master CLI. It does the same as the "reload" command, but
instead of waiting for the connections to stop in the previous process,
it immediately quits the previous process after binding.

doc/management.txt

@@ -4059,6 +4059,14 @@ experimental-mode [on|off]
 
   See also "experimental-mode" in Section 9.3 and "mcli-debug-mode" in 9.4.1.
 
+hard-reload
+  This command does the same as the "reload" command over the master CLI with
+  the expection that it does a hard-stop (-st) instead of a stop-stop (-sf) of
+  the previous process. This means the previous process does not wait to
+  achieve anything before exiting, so all connections will be closed.
+
+  See also the "reload" command.
+
 mcli-debug-mode [on|off]
   This keyword allows a special mode in the master CLI which enables every
   keywords that were meant for a worker CLI on the master CLI, allowing to debug
@@ -4128,6 +4136,7 @@ reload
   will close the connection to the CLI.
 
   Note that a reload will close all connections to the master CLI.
+  See also the "hard-reload" command.
 
 show proc
   The master CLI introduces a 'show proc' command to surpervise the

include/haproxy/global.h

@@ -66,7 +66,7 @@ int compare_current_version(const char *version);
 void display_version();
 
 void mworker_accept_wrapper(int fd);
-void mworker_reload(void);
+void mworker_reload(int hardreload);
 
 /* to be used with warned and WARN_* */
 static inline int already_warned(unsigned int warning)

src/haproxy.c

@@ -686,7 +686,7 @@ int delete_oldpid(int pid)
  * When called, this function reexec haproxy with -sf followed by current
  * children PIDs and possibly old children PIDs if they didn't leave yet.
  */
-static void mworker_reexec()
+static void mworker_reexec(int hardreload)
 {
 	char **next_argv = NULL;
 	int old_argc = 0; /* previous number of argument */
@@ -749,7 +749,10 @@ static void mworker_reexec()
 		if (mworker_child_nb() > 0) {
 			struct mworker_proc *child;
 
-			next_argv[next_argc++] = "-sf";
+			if (hardreload)
+				next_argv[next_argc++] = "-st";
+			else
+				next_argv[next_argc++] = "-sf";
 
 			list_for_each_entry(child, &proc_list, list) {
 				if (!(child->options & PROC_O_LEAVING) && (child->options & PROC_O_TYPE_WORKER))
@@ -792,16 +795,16 @@ alloc_error:
 static void mworker_reexec_waitmode()
 {
 	setenv("HAPROXY_MWORKER_WAIT_ONLY", "1", 1);
-	mworker_reexec();
+	mworker_reexec(0);
 }
 
 /* reload haproxy and emit a warning */
-void mworker_reload()
+void mworker_reload(int hardreload)
 {
 	struct mworker_proc *child;
 	struct per_thread_deinit_fct *ptdf;
 
-	ha_notice("Reloading HAProxy\n");
+	ha_notice("Reloading HAProxy%s\n", hardreload?" (hard-reload)":"");
 
 	/* close the poller FD and the thread waker pipe FD */
 	list_for_each_entry(ptdf, &per_thread_deinit_list, list)
@@ -816,7 +819,7 @@ void mworker_reload()
 	if (global.tune.options & GTUNE_USE_SYSTEMD)
 		sd_notify(0, "RELOADING=1\nSTATUS=Reloading Configuration.\n");
 #endif
-	mworker_reexec();
+	mworker_reexec(hardreload);
 }
 
 static void mworker_loop()

src/mworker.c

@@ -316,7 +316,7 @@ void mworker_broadcast_signal(struct sig_handler *sh)
  */
 void mworker_catch_sighup(struct sig_handler *sh)
 {
-	mworker_reload();
+	mworker_reload(0);
 }
 
 void mworker_catch_sigterm(struct sig_handler *sh)
@@ -685,10 +685,15 @@ static int cli_parse_reload(char **args, char *payload, struct appctx *appctx, v
 	struct stream *strm = NULL;
 	struct connection *conn = NULL;
 	int fd = -1;
+	int hardreload = 0;
 
 	if (!cli_has_level(appctx, ACCESS_LVL_OPER))
 		return 1;
 
+	/* hard reload requested */
+	if (*args[0] == 'h')
+		hardreload = 1;
+
 	/* This ask for a synchronous reload, which means we will keep this FD
 	   instead of closing it. */
 
@@ -704,7 +709,7 @@ static int cli_parse_reload(char **args, char *payload, struct appctx *appctx, v
 	if (fd != -1 && send_fd_uxst(proc_self->ipc_fd[0], fd) == 0) {
 		fd_delete(fd); /* avoid the leak of the FD after sending it via the socketpair */
 	}
-	mworker_reload();
+	mworker_reload(hardreload);
 
 	return 1;
 }
@@ -807,7 +812,8 @@ static struct cli_kw_list cli_kws = {{ },{
 	{ { "@!<pid>", NULL },         "@!<pid>                                 : send a command to the <pid> process", cli_parse_default, NULL, NULL, NULL, ACCESS_MASTER_ONLY},
 	{ { "@master", NULL },         "@master                                 : send a command to the master process", cli_parse_default, NULL, NULL, NULL, ACCESS_MASTER_ONLY},
 	{ { "show", "proc", NULL },    "show proc                               : show processes status", cli_parse_default, cli_io_handler_show_proc, NULL, NULL, ACCESS_MASTER_ONLY},
-	{ { "reload", NULL },          "reload                                  : reload haproxy", cli_parse_reload, NULL, NULL, NULL, ACCESS_MASTER_ONLY},
+	{ { "reload", NULL },          "reload                                  : achieve a soft-reload (-sf) of haproxy", cli_parse_reload, NULL, NULL, NULL, ACCESS_MASTER_ONLY},
+	{ { "hard-reload", NULL },     "hard-reload                             : achieve a hard-reload (-st) of haproxy", cli_parse_reload, NULL, NULL, NULL, ACCESS_MASTER_ONLY},
 	{ { "_loadstatus", NULL },     NULL,                                                             cli_parse_default, cli_io_handler_show_loadstatus, NULL, NULL, ACCESS_MASTER_ONLY},
 	{{},}
 }};