fix: allow run without consul

cmd/librarian/main.go

@@ -13,7 +13,6 @@ import (
 	searcher "github.com/tuihub/protos/pkg/librarian/searcher/v1"
 
 	"github.com/go-kratos/kratos/v2"
-	"github.com/go-kratos/kratos/v2/registry"
 	"github.com/go-kratos/kratos/v2/transport/grpc"
 	"github.com/go-kratos/kratos/v2/transport/http"
 	"github.com/google/wire"
@@ -42,15 +41,28 @@ var ProviderSet = wire.NewSet(
 	minerClientSelector,
 )
 
-func newApp(gs *grpc.Server, hs *http.Server, mq *libmq.MQ, cron *libcron.Cron, r registry.Registrar) *kratos.App {
-	return kratos.New(
-		kratos.ID(id+name),
+func newApp(
+	gs *grpc.Server,
+	hs *http.Server,
+	mq *libmq.MQ,
+	cron *libcron.Cron,
+	consul *conf.Consul,
+) (*kratos.App, error) {
+	options := []kratos.Option{
+		kratos.ID(id + name),
 		kratos.Name(name),
 		kratos.Version(version),
 		kratos.Metadata(map[string]string{}),
 		kratos.Server(gs, hs, mq, cron),
-		kratos.Registrar(r),
-	)
+	}
+	if consul != nil {
+		r, err := libapp.NewRegistrar(consul)
+		if err != nil {
+			return nil, err
+		}
+		options = append(options, kratos.Registrar(r))
+	}
+	return kratos.New(options...), nil
 }
 
 func main() {

cmd/librarian/wire.go

@@ -48,7 +48,6 @@ func wireApp(
 			libmq.ProviderSet,
 			libcron.ProviderSet,
 			libcache.ProviderSet,
-			libapp.ProviderSet,
 			ProviderSet,
 		),
 	)

internal/lib/libapp/service_discovery.go

@@ -23,6 +23,14 @@ func NewDiscovery(c *conf.Consul) (registry.Discovery, error) {
 	if err != nil {
 		return nil, err
 	}
+	// check if the consul agent is available
+	_, err = client.Status().Leader()
+	if err != nil {
+		if c == nil { // if consul is not configured, return an empty discovery
+			return emptyDiscovery{}, nil
+		}
+		return nil, err
+	}
 	return consul.New(client), nil
 }
 
@@ -59,3 +67,23 @@ func NewNodeFilter() selector.NodeFilter {
 		return newNodes
 	}
 }
+
+type emptyDiscovery struct{}
+
+func (e emptyDiscovery) GetService(ctx context.Context, serviceName string) ([]*registry.ServiceInstance, error) {
+	return []*registry.ServiceInstance{}, nil
+}
+
+func (e emptyDiscovery) Watch(ctx context.Context, serviceName string) (registry.Watcher, error) {
+	return &emptyWatcher{}, nil
+}
+
+type emptyWatcher struct{}
+
+func (e emptyWatcher) Next() ([]*registry.ServiceInstance, error) {
+	return []*registry.ServiceInstance{}, nil
+}
+
+func (e emptyWatcher) Stop() error {
+	return nil
+}

internal/lib/libapp/service_watcher.go

@@ -21,6 +21,17 @@ func NewHealthChecker(serviceName string, c *conf.Consul) (*HealthChecker, error
 	if err != nil {
 		return nil, err
 	}
+	// check if the consul agent is available
+	_, err = client.Status().Leader()
+	if err != nil {
+		if c == nil {
+			return &HealthChecker{
+				healthClient: nil,
+				serviceName:  serviceName,
+			}, nil
+		}
+		return nil, err
+	}
 
 	return &HealthChecker{
 		healthClient: client.Health(),
@@ -29,6 +40,9 @@ func NewHealthChecker(serviceName string, c *conf.Consul) (*HealthChecker, error
 }
 
 func (hc *HealthChecker) GetAliveInstances() ([]*api.ServiceEntry, error) {
+	if hc.healthClient == nil {
+		return []*api.ServiceEntry{}, nil
+	}
 	instances, _, err := hc.healthClient.Service(hc.serviceName, "", true, nil)
 	return instances, err
 }