Safe and organized exit when receiving sigterm while loading (#10003)

on the signal handler we are enabling server.shutdown_asap flag instead of just doing `exit()`,
and then catch it on the whileBlockedCron() where we prepare for shutdown correctly.

this is a more ore organized and safe termination, the old approach was missing these for example:
1. removal of the pidfile
2. shutdown event to modules

1 files changed, 9 insertions, 2 deletions

diff --git a/src/server.c b/src/server.c
index 046f9ac74..6d531449e 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1373,6 +1373,14 @@ void whileBlockedCron() {
 
     latencyEndMonitor(latency);
     latencyAddSampleIfNeeded("while-blocked-cron",latency);
+
+    /* We received a SIGTERM during loading, shutting down here in a safe way,
+     * as it isn't ok doing so inside the signal handler. */
+    if (server.shutdown_asap && server.loading) {
+        if (prepareForShutdown(SHUTDOWN_NOSAVE) == C_OK) exit(0);
+        serverLog(LL_WARNING,"SIGTERM received but errors trying to shut down the server, check the logs for more information");
+        server.shutdown_asap = 0;
+    }
 }
 
 extern int ProcessingEventsWhileBlocked;
@@ -5587,8 +5595,7 @@ static void sigShutdownHandler(int sig) {
         rdbRemoveTempFile(getpid(), 1);
         exit(1); /* Exit with an error since this was not a clean shutdown. */
     } else if (server.loading) {
-        serverLogFromHandler(LL_WARNING, "Received shutdown signal during loading, exiting now.");
-        exit(0);
+        msg = "Received shutdown signal during loading, scheduling shutdown.";
     }
 
     serverLogFromHandler(LL_WARNING, msg);