feat: add logic

go.mod

@@ -0,0 +1,12 @@
+module github.com/jar3b/nacl
+
+go 1.13
+
+require (
+	github.com/jar3b/grawt v0.1.5
+	github.com/nats-io/nats-server/v2 v2.1.2 // indirect
+	github.com/nats-io/nats-streaming-server v0.16.2 // indirect
+	github.com/nats-io/nats.go v1.9.1
+	github.com/nats-io/stan.go v0.6.0
+	github.com/sirupsen/logrus v1.4.2
+)

nacl.go

@@ -0,0 +1,76 @@
+package nacl
+
+import (
+	"fmt"
+	"github.com/jar3b/grawt"
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/stan.go"
+	"time"
+)
+
+var (
+	NatsClient *nats.Conn
+	StanClient stan.Conn
+)
+
+type (
+	Msg          = stan.Msg
+	NatsMsg      = nats.Msg
+	Subscription = stan.Subscription
+)
+
+func SetupNats(host string, port int, user string, pass string, closeHandler *grawt.CloseHandler) error {
+	var err error
+
+	// init connection string
+	connectionString := fmt.Sprintf("%s:%d", host, port)
+	if user != "" && pass != "" {
+		connectionString = fmt.Sprintf("%s:%s@%s", user, pass, connectionString)
+	}
+	connectionString = fmt.Sprintf("nats://%s", connectionString)
+
+	// connect
+	NatsClient, err = nats.Connect(
+		connectionString,
+		nats.ClosedHandler(func(conn *nats.Conn) {
+			closeHandler.Halt(nil)
+		}),
+		nats.MaxReconnects(5),
+		nats.ReconnectWait(time.Second*2),
+	)
+	if err != nil {
+		return fmt.Errorf("cannot connect to NATS: %v", err)
+	}
+
+	return nil
+}
+
+func SetupStan(clusterName string, clientId string, host string, port int, user string, pass string, closeHandler *grawt.CloseHandler) (err error) {
+	if err = SetupNats(host, port, user, pass, closeHandler); err != nil {
+		return err
+	}
+
+	// stan connection
+	StanClient, err = stan.Connect(
+		clusterName,
+		clientId,
+		stan.NatsConn(NatsClient),
+	)
+	if err != nil {
+		return fmt.Errorf("cannot connect to STAN: %v", err)
+	}
+
+	return nil
+}
+
+func FinalizeStan(subscriptions *[]Subscription) error {
+	for _, subscription := range *subscriptions {
+		_ = subscription.Unsubscribe()
+	}
+
+	if err := StanClient.Close(); err != nil {
+		return fmt.Errorf("cannot disconnect from STAN")
+	}
+
+	return nil
+}