added nats + worker modules

worker/options.go

@@ -0,0 +1,67 @@
+package worker
+
+import (
+	"context"
+	"log/slog"
+	"time"
+
+	"github.com/nats-io/nats.go"
+)
+
+type Handler func(context.Context, *nats.Msg) error
+
+type Option func(*config)
+
+type config struct {
+	streamName    string
+	consumerName  string
+	durableName   string
+	handler       Handler
+	concurrency   int
+	ackWait       time.Duration
+	maxDeliver    int
+	filterSubject string
+	deliverPolicy nats.DeliverPolicy
+	replayPolicy  nats.ReplayPolicy
+	log           *slog.Logger
+	storage       nats.StorageType
+}
+
+func WithStream(name string) Option {
+	return func(c *config) { c.streamName = name }
+}
+
+func WithConsumer(consumer, subject string) Option {
+	return func(c *config) {
+		c.consumerName = consumer
+		c.filterSubject = subject
+	}
+}
+
+func WithDurable(name string) Option {
+	return func(c *config) { c.durableName = name }
+}
+
+func WithHandler(h Handler) Option {
+	return func(c *config) { c.handler = h }
+}
+
+func WithConcurrency(n int) Option {
+	return func(c *config) { c.concurrency = n }
+}
+
+func WithAckWait(d time.Duration) Option {
+	return func(c *config) { c.ackWait = d }
+}
+
+func WithMaxDeliver(n int) Option {
+	return func(c *config) { c.maxDeliver = n }
+}
+
+func WithLogger(l *slog.Logger) Option {
+	return func(c *config) { c.log = l }
+}
+
+func WithStorage(storage nats.StorageType) Option {
+	return func(c *config) { c.storage = storage }
+}