Merge pull request #6263 from oasisprotocol/peternose/trivial/refactor-notifier

go/runtime/registry/notifier: Refactor notifier

Author: peternose

.changelog/6263.trivial.md

@@ -0,0 +1,45 @@
+package service
+
+import (
+	"context"
+	"fmt"
+
+	"golang.org/x/sync/errgroup"
+)
+
+// Group is responsible for concurrently starting a group of services.
+type Group struct {
+	services []Service
+}
+
+// NewGroup creates a new service group with the given list of services.
+func NewGroup(services ...Service) *Group {
+	return &Group{
+		services: services,
+	}
+}
+
+// Add appends one or more services to the group.
+func (g *Group) Add(services ...Service) {
+	g.services = append(g.services, services...)
+}
+
+// Serve starts all services concurrently and blocks until they all complete,
+// one returns an error, or the context is canceled.
+func (g *Group) Serve(ctx context.Context) error {
+	group, ctx := errgroup.WithContext(ctx)
+
+	for _, s := range g.services {
+		group.Go(func() error {
+			if err := s.Serve(ctx); err != nil {
+				if ns, ok := s.(NamedService); ok {
+					return fmt.Errorf("%s stopped: %w", ns.Name(), err)
+				}
+				return fmt.Errorf("service stopped: %w", err)
+			}
+			return nil
+		})
+	}
+
+	return group.Wait()
+}

go/common/service/group.go

@@ -7,6 +7,21 @@ import (
 	"github.com/oasisprotocol/oasis-core/go/common/logging"
 )
 
+// Service is a blocking service.
+type Service interface {
+	// Serve runs the service and blocks until it completes, an error occurs,
+	// or the context is canceled.
+	Serve(ctx context.Context) error
+}
+
+// NamedService is a blocking service with an associated name.
+type NamedService interface {
+	Service
+
+	// Name returns the name of the service.
+	Name() string
+}
+
 // CleanupAble provides a Cleanup method.
 type CleanupAble interface {
 	// Cleanup performs the service specific post-termination cleanup.

go/common/service/service.go

@@ -37,27 +37,6 @@ type Handler interface {
 	Handle(ctx context.Context, body *Body) (*Body, error)
 }
 
-// Notifier is a protocol runtime notifier interface.
-type Notifier interface {
-	// Start the notifier.
-	Start()
-
-	// Stop the notifier.
-	Stop()
-}
-
-// NoOpNotifier is the default no-op runtime notifier implementation.
-type NoOpNotifier struct{}
-
-// Start the no-op notifier.
-func (n *NoOpNotifier) Start() error {
-	return nil
-}
-
-// Stop the no-op notifier.
-func (n *NoOpNotifier) Stop() {
-}
-
 // Connection is a Runtime Host Protocol connection interface.
 type Connection interface {
 	// Close closes the connection.

go/runtime/host/protocol/connection.go

@@ -40,6 +40,9 @@ type RuntimeHostHandlerEnvironment interface {
 
 	// GetRuntimeRegistry returns the runtime registry.
 	GetRuntimeRegistry() Registry
+
+	// GetROFLNotifier returns the ROFL notifier.
+	GetROFLNotifier() (*ROFLNotifier, error)
 }
 
 // RuntimeHostHandler is a runtime host handler suitable for compute runtimes. It provides the
@@ -124,7 +127,11 @@ func (h *runtimeHostHandler) Handle(ctx context.Context, rq *protocol.Body) (*pr
 func (h *runtimeHostHandler) NewSubHandler(comp *bundle.ExplodedComponent) (host.RuntimeHandler, error) {
 	switch comp.Kind {
 	case component.ROFL:
-		return newSubHandlerROFL(comp, h)
+		roflNotifier, err := h.env.GetROFLNotifier()
+		if err != nil {
+			return nil, err
+		}
+		return newSubHandlerROFL(comp, h, roflNotifier)
 	default:
 		return nil, fmt.Errorf("cannot create sub-handler for component '%s'", comp.Kind)
 	}