118 lines
2.4 KiB
Go
118 lines
2.4 KiB
Go
package notifications
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import (
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"context"
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"fmt"
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"sync"
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"time"
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"github.com/nats-io/nats.go"
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"github.com/nspcc-dev/neofs-s3-gw/api/layer"
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)
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const (
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DefaultTimeout = 30 * time.Second
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)
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type Options struct {
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URL string
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TLSCertFilepath string
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TLSAuthPrivateKeyFilePath string
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Timeout time.Duration
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RootCAFiles []string
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}
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type Controller struct {
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taskQueueConnection *nats.Conn
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jsClient nats.JetStreamContext
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handlers map[string]Stream
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mu sync.RWMutex
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}
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type Stream struct {
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h layer.MsgHandler
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ch chan *nats.Msg
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}
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func NewController(p *Options) (*Controller, error) {
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if p == nil {
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return nil, nil
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}
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ncopts := []nats.Option{
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nats.Timeout(p.Timeout),
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}
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if len(p.TLSCertFilepath) != 0 && len(p.TLSAuthPrivateKeyFilePath) != 0 {
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ncopts = append(ncopts, nats.ClientCert(p.TLSCertFilepath, p.TLSAuthPrivateKeyFilePath))
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}
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if len(p.RootCAFiles) != 0 {
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ncopts = append(ncopts, nats.RootCAs(p.RootCAFiles...))
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}
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nc, err := nats.Connect(p.URL, ncopts...)
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if err != nil {
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return nil, err
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}
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js, err := nc.JetStream()
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if err != nil {
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return nil, err
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}
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return &Controller{
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taskQueueConnection: nc,
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jsClient: js,
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handlers: make(map[string]Stream),
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}, nil
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}
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func (c *Controller) Subscribe(ctx context.Context, topic string, handler layer.MsgHandler) error {
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ch := make(chan *nats.Msg, 1)
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c.mu.RLock()
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if _, ok := c.handlers[topic]; ok {
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return fmt.Errorf("already subscribed to topic '%s'", topic)
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}
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c.mu.RUnlock()
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if _, err := c.jsClient.AddStream(&nats.StreamConfig{Name: topic}); err != nil {
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return err
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}
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if _, err := c.jsClient.ChanSubscribe(topic, ch); err != nil {
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return fmt.Errorf("could not subscribe: %w", err)
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}
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c.mu.Lock()
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c.handlers[topic] = Stream{
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h: handler,
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ch: ch,
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}
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c.mu.Unlock()
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return nil
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}
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func (c *Controller) Listen(ctx context.Context) {
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c.mu.RLock()
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defer c.mu.RUnlock()
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for _, stream := range c.handlers {
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go func(stream Stream) {
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for {
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select {
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case msg := <-stream.ch:
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fmt.Printf("got message: %s\n", msg.Data)
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if err := stream.h.HandleMessage(ctx, msg); err != nil {
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fmt.Printf("could not handle message: %s", err)
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} else if err = msg.Ack(); err != nil {
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fmt.Printf("could not ACK message: %s", err)
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}
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case <-ctx.Done():
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return
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}
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}
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}(stream)
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}
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}
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