oktopus/backend/services/acs/internal/nats/nats.go
2024-07-05 16:29:51 -03:00

152 lines
3.5 KiB
Go

package nats
import (
"context"
"errors"
"log"
"oktopUSP/backend/services/acs/internal/config"
"time"
"github.com/nats-io/nats.go"
"github.com/nats-io/nats.go/jetstream"
)
const (
CWMP_STREAM_NAME = "cwmp"
)
type NatsActions struct {
Publish func(string, []byte) error
Subscribe func(string, func(*nats.Msg)) error
}
func StartNatsClient(c config.Nats) NatsActions {
var (
nc *nats.Conn
err error
)
opts := defineOptions(c)
log.Printf("Connecting to NATS server %s", c.Url)
for {
nc, err = nats.Connect(c.Url, opts...)
if err != nil {
time.Sleep(5 * time.Second)
continue
}
break
}
log.Printf("Successfully connected to NATS server %s", c.Url)
js, err := jetstream.New(nc)
if err != nil {
log.Fatalf("Failed to create JetStream client: %v", err)
}
streams := defineStreams()
err = createStreams(c.Ctx, js, streams)
if err != nil {
log.Fatalf("Failed to create Consumer: %v", err)
}
consumers := defineConsumers()
err = createConsumers(c.Ctx, js, consumers)
if err != nil {
log.Fatalf("Failed to create Consumer: %v", err)
}
return NatsActions{
Publish: publisher(js),
Subscribe: subscriber(nc),
}
}
func subscriber(nc *nats.Conn) func(string, func(*nats.Msg)) error {
return func(subject string, handler func(*nats.Msg)) error {
_, err := nc.Subscribe(subject, handler)
if err != nil {
log.Printf("error to subscribe to subject %s error: %q", subject, err)
}
return err
}
}
func publisher(js jetstream.JetStream) func(string, []byte) error {
return func(subject string, payload []byte) error {
_, err := js.PublishAsync(subject, payload)
if err != nil {
log.Printf("error to send jetstream message: %q", err)
}
return err
}
}
func createStreams(ctx context.Context, js jetstream.JetStream, streams []string) error {
for _, stream := range streams {
_, err := js.CreateOrUpdateStream(ctx, jetstream.StreamConfig{
Name: stream,
Description: "Stream for " + stream + " messages",
Subjects: []string{stream + ".>"},
Retention: jetstream.InterestPolicy,
})
if err != nil {
return errors.New(err.Error() + " | consumer:" + stream)
}
}
return nil
}
func createConsumers(ctx context.Context, js jetstream.JetStream, consumers []string) error {
for _, consumer := range consumers {
_, err := js.CreateOrUpdateConsumer(ctx, consumer, jetstream.ConsumerConfig{
Name: consumer,
Description: "Consumer for " + consumer + " messages",
AckPolicy: jetstream.AckExplicitPolicy,
Durable: consumer,
})
if err != nil {
return err
}
}
return nil
}
func defineStreams() []string {
return []string{
CWMP_STREAM_NAME,
}
}
func defineConsumers() []string {
return []string{
CWMP_STREAM_NAME,
}
}
func defineOptions(c config.Nats) []nats.Option {
var opts []nats.Option
opts = append(opts, nats.Name(c.Name))
opts = append(opts, nats.MaxReconnects(-1))
opts = append(opts, nats.ReconnectWait(5*time.Second))
opts = append(opts, nats.DisconnectErrHandler(func(nc *nats.Conn, err error) {
log.Printf("Got disconnected! Reason: %q\n", err)
}))
opts = append(opts, nats.ReconnectHandler(func(nc *nats.Conn) {
log.Printf("Got reconnected to %v!\n", nc.ConnectedUrl())
}))
opts = append(opts, nats.ClosedHandler(func(nc *nats.Conn) {
log.Printf("Connection closed. Reason: %q\n", nc.LastError())
}))
if c.EnableTls {
log.Printf("Load certificates: %s and %s\n", c.Cert.CertFile, c.Cert.KeyFile)
opts = append(opts, nats.RootCAs(c.Cert.CaFile))
opts = append(opts, nats.ClientCert(c.Cert.CertFile, c.Cert.KeyFile))
}
return opts
}