xapp-frame to catch SIGINT and SIGTERM signals for proper shutdown handling.

[ric-plt/xapp-frame.git] / pkg / xapp / xapp.go

diff --git a/pkg/xapp/xapp.go b/pkg/xapp/xapp.go
index 0ae9b02..6c7c567 100755 (executable)
--- a/pkg/xapp/xapp.go
+++ b/pkg/xapp/xapp.go
@@ -23,9 +23,15 @@ import (
        "fmt"
        "github.com/spf13/viper"
        "net/http"
+       "os"
+       "os/signal"
+       "sync/atomic"
+       "syscall"
+       "time"
 )
 
 type ReadyCB func(interface{})
+type ShutdownCB func()
 
 var (
        // XApp is an application instance
@@ -40,6 +46,9 @@ var (
        Alarm         *AlarmClient
        readyCb       ReadyCB
        readyCbParams interface{}
+       shutdownCb    ShutdownCB
+       shutdownFlag  int32
+       shutdownCnt   int32
 )
 
 func IsReady() bool {
@@ -53,12 +62,15 @@ func SetReadyCB(cb ReadyCB, params interface{}) {
 
 func xappReadyCb(params interface{}) {
        Alarm = NewAlarmClient(viper.GetString("alarm.MOId"), viper.GetString("alarm.APPId"))
-
        if readyCb != nil {
                readyCb(readyCbParams)
        }
 }
 
+func SetShutdownCB(cb ShutdownCB) {
+       shutdownCb = cb
+}
+
 func init() {
        // Load xapp configuration
        Logger = LoadConfig()
@@ -80,6 +92,52 @@ func init() {
        } else {
                Sdl = NewSDLClient(viper.GetString("db.namespace"))
        }
+
+       //
+       // Signal handlers to really exit program.
+       // shutdownCb can hang until application has
+       // made all needed gracefull shutdown actions
+       // hardcoded limit for shutdown is 20 seconds
+       //
+       interrupt := make(chan os.Signal, 1)
+       signal.Notify(interrupt, syscall.SIGINT, syscall.SIGTERM)
+       //signal handler function
+       go func() {
+               for _ = range interrupt {
+                       if atomic.CompareAndSwapInt32(&shutdownFlag, 0, 1) {
+                               // close function
+                               go func() {
+                                       timeout := int(20)
+                                       sentry := make(chan struct{})
+                                       defer close(sentry)
+
+                                       // close callback
+                                       go func() {
+                                               if shutdownCb != nil {
+                                                       shutdownCb()
+                                               }
+                                               sentry <- struct{}{}
+                                       }()
+                                       select {
+                                       case <-time.After(time.Duration(timeout) * time.Second):
+                                               Logger.Info("xapp-frame shutdown callback took more than %d seconds", timeout)
+                                       case <-sentry:
+                                               Logger.Info("xapp-frame shutdown callback handled within %d seconds", timeout)
+                                       }
+                                       os.Exit(0)
+                               }()
+                       } else {
+                               newCnt := atomic.AddInt32(&shutdownCnt, 1)
+                               Logger.Info("xapp-frame shutdown already ongoing. Forced exit counter %d/%d ", newCnt, 5)
+                               if newCnt >= 5 {
+                                       Logger.Info("xapp-frame shutdown forced exit")
+                                       os.Exit(0)
+                               }
+                               continue
+                       }
+
+               }
+       }()
 }
 
 func RunWithParams(c MessageConsumer, sdlcheck bool) {