Make the signal handler work properly

main.go

@@ -8,6 +8,7 @@ import (
 	"syscall"
 
 	"gitlab.hamburg.ccc.de/ccchh/spaceapid/handlers"
+	"gitlab.hamburg.ccc.de/ccchh/spaceapid/types"
 	"gitlab.hamburg.ccc.de/ccchh/spaceapid/util"
 )
 
@@ -21,20 +22,21 @@ func main() {
 	// Merge old state if present
 	util.MergeOldState(&spaceApiResponse)
 
+	// Register signal handler
+	sc := make(chan os.Signal, 1)
+	signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM)
+	go func(ch chan os.Signal, resp *types.SpaceAPIResponseV14) {
+		<-ch
+		log.Println("Saving state and shutting down...")
+		util.SaveCurrentState(*resp)
+		os.Exit(0)
+	}(sc, &spaceApiResponse)
+
 	// Register HTTP handlers
 	http.HandleFunc("/", handlers.Root(&spaceApiResponse))
 	http.HandleFunc("/state/open", handlers.StateOpen(config.BAUsername, config.BAPassword, &spaceApiResponse))
 
 	// Start webserver
 	log.Println("Starting HTTP server...")
-	go log.Fatalln(http.ListenAndServe(":8080", nil))
-
-	// Wait for exit signal
-	sc := make(chan os.Signal, 1)
-	signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM)
-	<-sc
-
-	// Save state for next run
-	log.Println("Saving state and shutting down...")
-	util.SaveCurrentState(spaceApiResponse)
+	log.Fatalln(http.ListenAndServe(":8080", nil))
 }

util/util.go

@@ -47,12 +47,6 @@ func MergeOldState(response *types.SpaceAPIResponseV14) {
 		oldState []byte
 	)
 
-	// Create state directory if not present
-	err = os.MkdirAll(path.Dir(savedStateJSONPath), 0750)
-	if err != nil {
-		log.Fatalln("Failed creating", savedStateJSONPath, ", aborting... error:", err)
-	}
-
 	// Check if state.json is present
 	_, err = os.Stat(savedStateJSONPath)
 	if err != nil {
@@ -84,6 +78,13 @@ removeOld:
 }
 
 func SaveCurrentState(response types.SpaceAPIResponseV14) {
+	// Create state directory if not present
+	err := os.MkdirAll(path.Dir(savedStateJSONPath), 0750)
+	if err != nil {
+		log.Fatalln("Failed creating", savedStateJSONPath, ", aborting... error:", err)
+	}
+
+	// Open persistent state file for reading
 	file, err := os.OpenFile(savedStateJSONPath, os.O_RDWR|os.O_CREATE, 0644)
 	if err != nil {
 		log.Fatalln("Failed opening", savedStateJSONPath, "while trying to save current state... error:", err)