go/staking: add ConensusParameters query method

go/consensus/tendermint/apps/staking/query.go

@@ -23,6 +23,7 @@ type Query interface {
 	Delegations(context.Context, signature.PublicKey) (map[signature.PublicKey]*staking.Delegation, error)
 	DebondingDelegations(context.Context, signature.PublicKey) (map[signature.PublicKey][]*staking.DebondingDelegation, error)
 	Genesis(context.Context) (*staking.Genesis, error)
+	ConsensusParameters(context.Context) (*staking.ConsensusParameters, error)
 }
 
 // QueryFactory is the staking query factory.
@@ -105,6 +106,10 @@ func (sq *stakingQuerier) DebondingDelegations(ctx context.Context, id signature
 	return sq.state.DebondingDelegationsFor(id)
 }
 
+func (sq *stakingQuerier) ConsensusParameters(ctx context.Context) (*staking.ConsensusParameters, error) {
+	return sq.state.ConsensusParameters()
+}
+
 func (app *stakingApplication) QueryFactory() interface{} {
 	return &QueryFactory{app}
 }

go/consensus/tendermint/staking/staking.go

@@ -140,6 +140,14 @@ func (tb *tendermintBackend) StateToGenesis(ctx context.Context, height int64) (
 	return q.Genesis(ctx)
 }
 
+func (tb *tendermintBackend) ConsensusParameters(ctx context.Context, height int64) (*api.ConsensusParameters, error) {
+	q, err := tb.querier.QueryAt(ctx, height)
+	if err != nil {
+		return nil, err
+	}
+
+	return q.ConsensusParameters(ctx)
+}
 func (tb *tendermintBackend) Cleanup() {
 	<-tb.closedCh
 }

go/staking/api/api.go

@@ -98,6 +98,9 @@ type Backend interface {
 	// StateToGenesis returns the genesis state at specified block height.
 	StateToGenesis(ctx context.Context, height int64) (*Genesis, error)
 
+	// Paremeters returns the staking consensus parameters.
+	ConsensusParameters(ctx context.Context, height int64) (*ConsensusParameters, error)
+
 	// WatchTransfers returns a channel that produces a stream of TranserEvent
 	// on all balance transfers.
 	WatchTransfers(ctx context.Context) (<-chan *TransferEvent, pubsub.ClosableSubscription, error)

go/staking/api/grpc.go

@@ -33,6 +33,8 @@ var (
 	methodDebondingDelegations = serviceName.NewMethod("DebondingDelegations", OwnerQuery{})
 	// methodStateToGenesis is the StateToGenesis method.
 	methodStateToGenesis = serviceName.NewMethod("StateToGenesis", int64(0))
+	// methodConsensusParameters is the ConsensusParameters method.
+	methodConsensusParameters = serviceName.NewMethod("ConsensusParameters", int64(0))
 
 	// methodWatchTransfers is the WatchTransfers method.
 	methodWatchTransfers = serviceName.NewMethod("WatchTransfers", nil)
@@ -82,6 +84,10 @@ var (
 				MethodName: methodStateToGenesis.ShortName(),
 				Handler:    handlerStateToGenesis,
 			},
+			{
+				MethodName: methodConsensusParameters.ShortName(),
+				Handler:    handlerConsensusParameters,
+			},
 		},
 		Streams: []grpc.StreamDesc{
 			{
@@ -310,6 +316,29 @@ func handlerStateToGenesis( // nolint: golint
 	return interceptor(ctx, height, info, handler)
 }
 
+func handlerConsensusParameters( // nolint: golint
+	srv interface{},
+	ctx context.Context,
+	dec func(interface{}) error,
+	interceptor grpc.UnaryServerInterceptor,
+) (interface{}, error) {
+	var height int64
+	if err := dec(&height); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(Backend).ConsensusParameters(ctx, height)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: methodConsensusParameters.FullName(),
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(Backend).ConsensusParameters(ctx, req.(int64))
+	}
+	return interceptor(ctx, height, info, handler)
+}
+
 func handlerWatchTransfers(srv interface{}, stream grpc.ServerStream) error {
 	if err := stream.RecvMsg(nil); err != nil {
 		return err
@@ -475,6 +504,14 @@ func (c *stakingClient) StateToGenesis(ctx context.Context, height int64) (*Gene
 	return &rsp, nil
 }
 
+func (c *stakingClient) ConsensusParameters(ctx context.Context, height int64) (*ConsensusParameters, error) {
+	var rsp ConsensusParameters
+	if err := c.conn.Invoke(ctx, methodConsensusParameters.FullName(), height, &rsp); err != nil {
+		return nil, err
+	}
+	return &rsp, nil
+}
+
 func (c *stakingClient) WatchTransfers(ctx context.Context) (<-chan *TransferEvent, pubsub.ClosableSubscription, error) {
 	ctx, sub := pubsub.NewContextSubscription(ctx)