jestream: allow caller to optionally waitForDid

This is handy because the knotserver only subscribes to specific dids,
and we don't want jestream to run without (which defaults to all dids).
The oppsite is true for the appview which wants to see all dids.

Also adds some nil checks to ensure it doesn't break when event is not a
Commit.

appview/state/state.go

···
 
 	resolver := appview.NewResolver()
 
-	jc, err := jetstream.NewJetstreamClient("appview", []string{tangled.GraphFollowNSID}, nil, db)
+	jc, err := jetstream.NewJetstreamClient("appview", []string{tangled.GraphFollowNSID}, nil, db, false)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create jetstream client: %w", err)
 	}
 	err = jc.StartJetstream(context.Background(), func(ctx context.Context, e *models.Event) error {
+		if e.Kind != models.EventKindCommit {
+			return nil
+		}
+
 		did := e.Did
-		raw := e.Commit.Record
+		fmt.Println("got event", e.Commit.Collection, e.Commit.RKey, e.Commit.Record)
+		raw := json.RawMessage(e.Commit.Record)
 
 		switch e.Commit.Collection {
 		case tangled.GraphFollowNSID:

cmd/knotserver/main.go

···
 	jc, err := jetstream.NewJetstreamClient("knotserver", []string{
 		tangled.PublicKeyNSID,
 		tangled.KnotMemberNSID,
-	}, nil, db)
+	}, nil, db, true)
 	if err != nil {
 		l.Error("failed to setup jetstream", "error", err)
 	}

jetstream/jetstream.go

···
 
 	db          DB
 	reconnectCh chan struct{}
+	waitForDid  bool
 	mu          sync.RWMutex
 }
 
···
 	j.reconnectCh <- struct{}{}
 }
 
-func NewJetstreamClient(ident string, collections []string, cfg *client.ClientConfig, db DB) (*JetstreamClient, error) {
+func NewJetstreamClient(ident string, collections []string, cfg *client.ClientConfig, db DB, waitForDid bool) (*JetstreamClient, error) {
 	if cfg == nil {
 		cfg = client.DefaultClientConfig()
 		cfg.WebsocketURL = "wss://jetstream1.us-west.bsky.network/subscribe"
···
 	}
 
 	return &JetstreamClient{
-		cfg:         cfg,
-		ident:       ident,
-		db:          db,
+		cfg:   cfg,
+		ident: ident,
+		db:    db,
+
+		// This will make the goroutine in StartJetstream wait until
+		// cfg.WantedDids has been populated, typically using UpdateDids.
+		waitForDid:  waitForDid,
 		reconnectCh: make(chan struct{}, 1),
 	}, nil
 }
···
 
 	go func() {
 		lastTimeUs := j.getLastTimeUs(ctx)
-		for len(j.cfg.WantedDids) == 0 {
-			time.Sleep(time.Second)
+		if j.waitForDid {
+			for len(j.cfg.WantedDids) == 0 {
+				time.Sleep(time.Second)
+			}
 		}
+		logger.Info("done waiting for did")
 		j.connectAndRead(ctx, &lastTimeUs)
 	}()
 

knotserver/jetstream.go

···
 
 func (h *Handle) processMessages(ctx context.Context, event *models.Event) error {
 	did := event.Did
+	if event.Kind != models.EventKindCommit {
+		return nil
+	}
 
 	raw := json.RawMessage(event.Commit.Record)