fix: issue with calling SIGTERM from lambda gateway

Made 'start()' blocking again and made the 'stop()' execute in a go routine, which will unblock start when the servers shutdown.

membrane/membrane.go

@@ -242,9 +242,8 @@ func (s *Membrane) Start() error {
 		hndlr = handler.NewHttpHandler(s.childAddress)
 		break
 	}
-
-	err = s.gatewayPlugin.Start(hndlr)
-	return err
+
+	return s.gatewayPlugin.Start(hndlr)
 }
 
 func (s *Membrane) Stop() {

plugins/gateway/app_platform/http.go

@@ -60,18 +60,14 @@ func (s *HttpGateway) Start(handler handler.TriggerHandler) error {
 		Handler: httpHandler(handler),
 	}
 
-	go (func() {
-		err := s.server.ListenAndServe(s.address)
-		if err != nil {
-			panic(err)
-		}
-	})()
-
-	return nil
+	return s.server.ListenAndServe(s.address)
 }
 
 func (s *HttpGateway) Stop() error {
-	return s.server.Shutdown()
+	if s.server != nil {
+		return s.server.Shutdown()
+	}
+	return nil
 }
 
 // Create new HTTP gateway

plugins/gateway/appservice/http.go

@@ -138,17 +138,14 @@ func (s *HttpService) Start(handler handler.TriggerHandler) error {
 		Handler: httpHandler(handler),
 	}
 
-	go (func() {
-		err := s.server.ListenAndServe(s.address)
-		if err != nil {
-			panic(err)
-		}
-	})()
-	return nil
+	return s.server.ListenAndServe(s.address)
 }
 
 func (s *HttpService) Stop() error {
-	return s.server.Shutdown()
+	if s.server != nil {
+		return s.server.Shutdown()
+	}
+	return nil
 }
 
 // Create a new HTTP Gateway plugin

plugins/gateway/cloudrun/http.go

@@ -95,17 +95,14 @@ func (s *HttpProxyGateway) Start(handler handler.TriggerHandler) error {
 		Handler: httpHandler(handler),
 	}
 
-	go (func() {
-		err := s.server.ListenAndServe(s.address)
-		if err != nil {
-			panic(err)
-		}
-	})()
-	return nil
+	return s.server.ListenAndServe(s.address)
 }
 
 func (s *HttpProxyGateway) Stop() error {
-	return s.server.Shutdown()
+	if s.server != nil {
+		return s.server.Shutdown()
+	}
+	return nil
 }
 
 // Create new DynamoDB documents server

plugins/gateway/dev/gateway.go

@@ -86,17 +86,14 @@ func (s *HttpGateway) Start(handler handler.TriggerHandler) error {
 		Handler: httpHandler(handler),
 	}
 
-	go (func() {
-		err := s.server.ListenAndServe(s.address)
-		if err != nil {
-			panic(err)
-		}
-	})()
-	return nil
+	return s.server.ListenAndServe(s.address)
 }
 
 func (s *HttpGateway) Stop() error {
-	return s.server.Shutdown()
+	if s.server != nil {
+		return s.server.Shutdown()
+	}
+	return nil
 }
 
 // Create new HTTP gateway

plugins/gateway/lambda/lambda.go

@@ -25,7 +25,6 @@ import (
 	"github.com/nitric-dev/membrane/sdk"
 	"github.com/nitric-dev/membrane/triggers"
 	"strings"
-	"syscall"
 )
 
 type eventType int
@@ -162,6 +161,7 @@ type LambdaGateway struct {
 	handler handler.TriggerHandler
 	runtime LambdaRuntimeHandler
 	sdk.UnimplementedGatewayPlugin
+	finished chan int
 }
 
 func (s *LambdaGateway) handle(ctx context.Context, event Event) (interface{}, error) {
@@ -222,30 +222,34 @@ func (s *LambdaGateway) handle(ctx context.Context, event Event) (interface{}, e
 
 // Start the lambda gateway handler
 func (s *LambdaGateway) Start(handler handler.TriggerHandler) error {
+	//s.finished = make(chan int)
 	s.handler = handler
 	// Here we want to begin polling lambda for incoming requests...
-	// Assuming that this is blocking
 	s.runtime(s.handle)
-	// Signal process to terminate if no more lambda requests to handle
-	return syscall.Kill(syscall.Getpid(), syscall.SIGTERM)
+	// Unblock the 'Stop' function if it's waiting.
+	go func(){s.finished <- 1}()
+	return nil
 }
 
 func (s *LambdaGateway) Stop() error {
 	// XXX: This is a NO_OP Process, as this is a pull based system
 	// We don't need to stop listening to anything
-	fmt.Println("Shutting down lambda gateway")
-
+	fmt.Println("gateway 'Stop' called, waiting for lambda runtime to finish")
+	// Lambda can't be stopped, need to wait for it to finish
+	<- s.finished
 	return nil
 }
 
 func New() (sdk.GatewayService, error) {
 	return &LambdaGateway{
 		runtime: lambda.Start,
+		finished: make(chan int),
 	}, nil
 }
 
 func NewWithRuntime(runtime LambdaRuntimeHandler) (sdk.GatewayService, error) {
 	return &LambdaGateway{
 		runtime: runtime,
+		finished: make(chan int),
 	}, nil
 }

providers/aws/membrane.go

@@ -68,8 +68,10 @@ func main() {
 		log.Fatalf("There was an error initialising the membrane server: %v", err)
 	}
 
-	go (m.Start)()
-	// Wait for a terminate interrupt
-	<-term
-	m.Stop()
+	go(func(){
+		<-term
+		m.Stop()
+	})()
+
+	m.Start()
 }

providers/azure/membrane.go

@@ -51,8 +51,10 @@ func main() {
 		log.Fatalf("There was an error initialising the membrane server: %v", err)
 	}
 
-	go (m.Start)()
-	// Wait for a terminate interrupt
-	<-term
-	m.Stop()
+	go(func(){
+		<-term
+		m.Stop()
+	})()
+
+	m.Start()
 }