added errors to abci query

internal/abci/abci.go

@@ -1594,12 +1594,10 @@ func (a *AbciApp) ProcessProposal(ctx context.Context, req *abciTypes.RequestPro
 
 func (a *AbciApp) Query(ctx context.Context, req *abciTypes.RequestQuery) (*abciTypes.ResponseQuery, error) {
 	a.log.Debug("ABCI Query", zap.String("path", req.Path), zap.String("data", string(req.Data)))
-
 	switch {
-	// TODO: why do we not return errors in case of the snapshotter not being configured?
 	case req.Path == statesync.ABCISnapshotQueryPath:
 		if a.snapshotter == nil {
-			return &abciTypes.ResponseQuery{}, nil
+			return nil, fmt.Errorf("this node is not configured to serve snapshots")
 		}
 
 		var snapshot *statesync.Snapshot
@@ -1616,21 +1614,21 @@ func (a *AbciApp) Query(ctx context.Context, req *abciTypes.RequestQuery) (*abci
 		}
 
 		if !exists {
-			return &abciTypes.ResponseQuery{}, nil
+			return nil, fmt.Errorf("snapshot not found for height %s", height)
 		}
 
-		bts, err := json.Marshal(snapshot)
+		bts, err := snapshot.MarshalBinary()
 		if err != nil {
 			return nil, err
 		}
 		return &abciTypes.ResponseQuery{Value: bts}, nil
 	case req.Path == statesync.ABCILatestSnapshotHeightPath:
 		if a.snapshotter == nil {
-			return &abciTypes.ResponseQuery{}, nil
+			return nil, fmt.Errorf("this node is not configured to serve snapshots")
 		}
 		snaps := a.snapshotter.ListSnapshots()
 		if len(snaps) == 0 {
-			return &abciTypes.ResponseQuery{}, nil
+			return nil, fmt.Errorf("no snapshots available")
 		}
 		latest := snaps[len(snaps)-1]
 		for _, snap := range snaps {
@@ -1656,7 +1654,7 @@ func (a *AbciApp) Query(ctx context.Context, req *abciTypes.RequestQuery) (*abci
 
 		paths := strings.Split(req.Path[ABCIPeerFilterPathLen:], "/")
 		if len(paths) != 2 {
-			return &abciTypes.ResponseQuery{Code: 1}, fmt.Errorf("invalid path: %s", req.Path)
+			return nil, fmt.Errorf("invalid path: %s", req.Path)
 		}
 
 		switch paths[0] {
@@ -1667,15 +1665,15 @@ func (a *AbciApp) Query(ctx context.Context, req *abciTypes.RequestQuery) (*abci
 			}
 			// ID is not in the allowed list of peers, so reject the connection
 			a.log.Warn("Connection attempt rejected, peer is not allowed to connect", zap.String("peerID", paths[1]))
-			return &abciTypes.ResponseQuery{Code: 1}, nil
+			return nil, fmt.Errorf("node rejected connection attempt from peer %s", paths[1])
 		case "addr":
 			return &abciTypes.ResponseQuery{Code: abciTypes.CodeTypeOK}, nil
 		default:
-			return &abciTypes.ResponseQuery{Code: 1}, fmt.Errorf("invalid path: %s", req.Path)
+			return nil, fmt.Errorf("invalid path: %s", req.Path)
 		}
 	default:
 		// If the query path is not recognized, return an error.
-		return &abciTypes.ResponseQuery{Code: 1}, fmt.Errorf("unknown query path: %s", req.Path)
+		return nil, fmt.Errorf("unknown query path: %s", req.Path)
 	}
 }