setup embedded NATS cluster nats

2 files changed, 93 insertions, 0 deletions

diff --git a/internal/nats/log.go b/internal/nats/log.go
new file mode 100644
index 0000000..cc9d1c2
--- /dev/null
+++ b/internal/nats/log.go
@@ -0,0 +1,27 @@
+package nats
+
+import (
+	"go.alanpearce.eu/x/log"
+	"go.uber.org/zap"
+)
+
+type Logger struct {
+	*zap.SugaredLogger
+}
+
+func adaptLogger(log *log.Logger) *Logger {
+	if log == nil {
+		panic("zl cannot be nil")
+	}
+	return &Logger{
+		log.GetLogger().Sugar(),
+	}
+}
+
+func (l *Logger) Tracef(format string, v ...any) {
+	l.Debugf(format, v...)
+}
+
+func (l *Logger) Noticef(format string, v ...any) {
+	l.Infof(format, v...)
+}
diff --git a/internal/nats/nats.go b/internal/nats/nats.go
new file mode 100644
index 0000000..9662868
--- /dev/null
+++ b/internal/nats/nats.go
@@ -0,0 +1,66 @@
+package nats
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/nats-io/nats-server/v2/server"
+	"gitlab.com/tozd/go/errors"
+	"go.alanpearce.eu/x/log"
+)
+
+const flyPrivateHostname = "fly-local-6pn"
+
+var srv *server.Server
+
+func Start(log *log.Logger) error {
+	var err error
+
+	appName := os.Getenv("FLY_APP_NAME")
+	if appName == "" {
+		log.Warn("no FLY_APP_NAME")
+
+		return nil
+	}
+	privateIP := os.Getenv("FLY_PRIVATE_IP")
+	if privateIP == "" {
+		log.Warn("no FLY_PRIVATE_IP")
+
+		return nil
+	}
+
+	hostname := fmt.Sprintf("%s.internal", appName)
+
+	opts := &server.Options{
+		ServerName: os.Getenv("FLY_MACHINE_ID"),
+		Host:       flyPrivateHostname,
+		Port:       4222,
+		Cluster: server.ClusterOpts{
+			Name:           appName,
+			Host:           flyPrivateHostname,
+			Port:           7221,
+			ConnectRetries: 60,
+		},
+		RoutesStr: "nats-route://" + hostname + ":7221",
+	}
+
+	srv, err = server.NewServer(opts)
+	if err != nil {
+		return errors.WithMessage(err, "could not start NATS server")
+	}
+
+	srv.SetLoggerV2(adaptLogger(log), false, false, false)
+	srv.Start()
+
+	if !srv.ReadyForConnections(4 * time.Second) {
+		log.Warn("server not ready")
+	}
+
+	return nil
+}
+
+func Stop() {
+	go srv.Shutdown()
+	srv.WaitForShutdown()
+}