[#1465] node: Prevent process from killing by systemd when shutting down

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

CHANGELOG.md

@@ -25,6 +25,7 @@ Changelog for FrostFS Node
 - Correct status error for expired session token (#2207)
 - Set flag `mode` required for `frostfs-cli control shards set-mode` (#8)
 - Fix `dirty` suffix in debian package version (#53)
+- Prevent node process from killing by systemd when shutting down (#1465)
 
 ### Removed
 ### Updated

cmd/frostfs-node/config.go

@@ -911,19 +911,44 @@ type dCfg struct {
 	}
 }
 
-func (c *cfg) configWatcher(ctx context.Context) {
+func (c *cfg) signalWatcher() {
 	ch := make(chan os.Signal, 1)
-	signal.Notify(ch, syscall.SIGHUP)
+	signal.Notify(ch, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
 
 	for {
 		select {
-		case <-ch:
+		case sig := <-ch:
+			switch sig {
+			case syscall.SIGHUP:
+				c.reloadConfig()
+			case syscall.SIGTERM, syscall.SIGINT:
+				c.log.Info("termination signal has been received, stopping...")
+				// TODO (@acid-ant): #49 need to cover case when stuck at the middle(node health UNDEFINED or STARTING)
+
+				c.shutdown()
+
+				c.log.Info("termination signal processing is complete")
+				return
+			}
+		case err := <-c.internalErr: // internal application error
+			c.log.Warn("internal application error",
+				zap.String("message", err.Error()))
+
+			c.shutdown()
+
+			c.log.Info("internal error processing is complete")
+			return
+		}
+	}
+}
+
+func (c *cfg) reloadConfig() {
 	c.log.Info("SIGHUP has been received, rereading configuration...")
 
 	err := c.readConfig(c.appCfg)
 	if err != nil {
 		c.log.Error("configuration reading", zap.Error(err))
-				continue
+		return
 	}
 
 	// all the components are expected to support
@@ -935,7 +960,7 @@ func (c *cfg) configWatcher(ctx context.Context) {
 	logPrm, err := c.loggerPrm()
 	if err != nil {
 		c.log.Error("logger configuration preparation", zap.Error(err))
-				continue
+		return
 	}
 
 	components = append(components, dCfg{name: "logger", cfg: logPrm})
@@ -950,7 +975,7 @@ func (c *cfg) configWatcher(ctx context.Context) {
 	err = c.cfgObject.cfgLocalStorage.localStorage.Reload(rcfg)
 	if err != nil {
 		c.log.Error("storage engine configuration update", zap.Error(err))
-				continue
+		return
 	}
 
 	for _, component := range components {
@@ -963,8 +988,14 @@ func (c *cfg) configWatcher(ctx context.Context) {
 	}
 
 	c.log.Info("configuration has been reloaded successfully")
-		case <-ctx.Done():
-			return
 }
+
+func (c *cfg) shutdown() {
+	c.setHealthStatus(control.HealthStatus_SHUTTING_DOWN)
+
+	c.ctxCancel()
+	for i := range c.closers {
+		c.closers[len(c.closers)-1-i]()
 	}
+	close(c.internalErr)
 }

cmd/frostfs-node/main.go

@@ -6,8 +6,6 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"os/signal"
-	"syscall"
 
 	"github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config"
 	"github.com/TrueCloudLab/frostfs-node/misc"
@@ -66,10 +64,6 @@ func main() {
 	c.setHealthStatus(control.HealthStatus_READY)
 
 	wait(c)
-
-	c.setHealthStatus(control.HealthStatus_SHUTTING_DOWN)
-
-	shutdown(c)
 }
 
 func initAndLog(c *cfg, name string, initializer func(*cfg)) {
@@ -79,9 +73,18 @@ func initAndLog(c *cfg, name string, initializer func(*cfg)) {
 }
 
 func initApp(c *cfg) {
-	initLocalStorage(c)
+	c.ctx, c.ctxCancel = context.WithCancel(context.Background())
 
-	c.ctx, c.ctxCancel = signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	c.wg.Add(1)
+	go func() {
+		c.signalWatcher()
+		c.wg.Done()
+	}()
+
+	initAndLog(c, "pprof", initProfiler)
+	initAndLog(c, "prometheus", initMetrics)
+
+	initLocalStorage(c)
 
 	initAndLog(c, "storage engine", func(c *cfg) {
 		fatalOnErr(c.cfgObject.cfgLocalStorage.localStorage.Open())
@@ -96,14 +99,10 @@ func initApp(c *cfg) {
 	initAndLog(c, "reputation", initReputationService)
 	initAndLog(c, "notification", initNotifications)
 	initAndLog(c, "object", initObjectService)
-	initAndLog(c, "pprof", initProfiler)
-	initAndLog(c, "prometheus", initMetrics)
 	initAndLog(c, "tree", initTreeService)
 	initAndLog(c, "control", initControlService)
 
 	initAndLog(c, "morph notifications", listenMorphNotifications)
-
-	c.workers = append(c.workers, newWorkerFromFunc(c.configWatcher))
 }
 
 func runAndLog(c *cfg, name string, logSuccess bool, starter func(*cfg)) {
@@ -128,21 +127,7 @@ func wait(c *cfg) {
 	c.log.Info("application started",
 		zap.String("version", misc.Version))
 
-	select {
-	case <-c.ctx.Done(): // graceful shutdown
-	case err := <-c.internalErr: // internal application error
-		close(c.internalErr)
-		c.ctxCancel()
-
-		c.log.Warn("internal application error",
-			zap.String("message", err.Error()))
-	}
-}
-
-func shutdown(c *cfg) {
-	for _, closer := range c.closers {
-		closer()
-	}
+	<-c.ctx.Done() // graceful shutdown
 
 	c.log.Debug("waiting for all processes to stop")
 

pkg/morph/client/multi.go

@@ -126,7 +126,20 @@ func (c *Client) notificationLoop() {
 				continue
 			}
 
-			c.notifications <- n
+			select {
+			case c.notifications <- n:
+				continue
+			case <-c.cfg.ctx.Done():
+				_ = c.UnsubscribeAll()
+				c.close()
+
+				return
+			case <-c.closeChan:
+				_ = c.UnsubscribeAll()
+				c.close()
+
+				return
+			}
 		}
 	}
 }

pkg/morph/client/notifications.go

@@ -14,7 +14,7 @@ func (c *Client) Close() {
 	// closing should be done via the channel
 	// to prevent switching to another RPC node
 	// in the notification loop
-	c.closeChan <- struct{}{}
+	close(c.closeChan)
 }
 
 // SubscribeForExecutionNotifications adds subscription for notifications