Add aggregator backfill, pulling fine+coarse buckets from collectors

cmd/collector/server.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"time"
 
+	st "git.ipng.ch/ipng/nginx-logtail/internal/store"
 	pb "git.ipng.ch/ipng/nginx-logtail/proto/logtailpb"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -70,6 +71,33 @@ func peerAddr(ctx context.Context) string {
 	return "unknown"
 }
 
+func (srv *Server) DumpSnapshots(_ *pb.DumpSnapshotsRequest, stream grpc.ServerStreamingServer[pb.Snapshot]) error {
+	fine, coarse := srv.store.DumpRings()
+	for _, snap := range fine {
+		if err := stream.Send(storeSnapshotToProto(snap, srv.source, false)); err != nil {
+			return err
+		}
+	}
+	for _, snap := range coarse {
+		if err := stream.Send(storeSnapshotToProto(snap, srv.source, true)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func storeSnapshotToProto(snap st.Snapshot, source string, isCoarse bool) *pb.Snapshot {
+	msg := &pb.Snapshot{
+		Source:    source,
+		Timestamp: snap.Timestamp.Unix(),
+		IsCoarse:  isCoarse,
+	}
+	for _, e := range snap.Entries {
+		msg.Entries = append(msg.Entries, &pb.TopNEntry{Label: e.Label, Count: e.Count})
+	}
+	return msg
+}
+
 func (srv *Server) StreamSnapshots(req *pb.SnapshotRequest, stream grpc.ServerStreamingServer[pb.Snapshot]) error {
 	ch := srv.store.Subscribe()
 	defer srv.store.Unsubscribe(ch)