fixes from review

rpc/client/httpclient.go

@@ -126,6 +126,15 @@ func (c *HTTP) DumpConsensusState() (*ctypes.ResultDumpConsensusState, error) {
 	return result, nil
 }
 
+func (c *HTTP) ConsensusState() (*ctypes.ResultConsensusState, error) {
+	result := new(ctypes.ResultConsensusState)
+	_, err := c.rpc.Call("consensus_state", map[string]interface{}{}, result)
+	if err != nil {
+		return nil, errors.Wrap(err, "ConsensusState")
+	}
+	return result, nil
+}
+
 func (c *HTTP) Health() (*ctypes.ResultHealth, error) {
 	result := new(ctypes.ResultHealth)
 	_, err := c.rpc.Call("health", map[string]interface{}{}, result)

rpc/client/interface.go

@@ -84,6 +84,7 @@ type Client interface {
 type NetworkClient interface {
 	NetInfo() (*ctypes.ResultNetInfo, error)
 	DumpConsensusState() (*ctypes.ResultDumpConsensusState, error)
+	ConsensusState() (*ctypes.ResultConsensusState, error)
 	Health() (*ctypes.ResultHealth, error)
 }
 

rpc/client/localclient.go

@@ -84,6 +84,10 @@ func (Local) DumpConsensusState() (*ctypes.ResultDumpConsensusState, error) {
 	return core.DumpConsensusState()
 }
 
+func (Local) ConsensusState() (*ctypes.ResultConsensusState, error) {
+	return core.ConsensusState()
+}
+
 func (Local) Health() (*ctypes.ResultHealth, error) {
 	return core.Health()
 }

rpc/client/rpc_test.go

@@ -78,6 +78,17 @@ func TestDumpConsensusState(t *testing.T) {
 	}
 }
 
+func TestConsensusState(t *testing.T) {
+	for i, c := range GetClients() {
+		// FIXME: fix server so it doesn't panic on invalid input
+		nc, ok := c.(client.NetworkClient)
+		require.True(t, ok, "%d", i)
+		cons, err := nc.ConsensusState()
+		require.Nil(t, err, "%d: %+v", i, err)
+		assert.NotEmpty(t, cons.RoundState)
+	}
+}
+
 func TestHealth(t *testing.T) {
 	for i, c := range GetClients() {
 		nc, ok := c.(client.NetworkClient)

rpc/core/consensus.go

@@ -212,7 +212,48 @@ func DumpConsensusState() (*ctypes.ResultDumpConsensusState, error) {
 	return &ctypes.ResultDumpConsensusState{roundState, peerStates}, nil
 }
 
+// ConsensusState returns a concise summary of the consensus state.
 // UNSTABLE
+//
+// ```shell
+// curl 'localhost:46657/consensus_state'
+// ```
+//
+// ```go
+// client := client.NewHTTP("tcp://0.0.0.0:46657", "/websocket")
+// state, err := client.ConsensusState()
+// ```
+//
+// The above command returns JSON structured like this:
+//
+// ```json
+//{
+//  "jsonrpc": "2.0",
+//  "id": "",
+//  "result": {
+//    "round_state": {
+//      "height/round/step": "9336/0/1",
+//      "start_time": "2018-05-14T10:25:45.72595357-04:00",
+//      "proposal_block_hash": "",
+//      "locked_block_hash": "",
+//      "valid_block_hash": "",
+//      "height_vote_set": [
+//        {
+//          "round": 0,
+//          "prevotes": [
+//            "nil-Vote"
+//          ],
+//          "prevotes_bit_array": "BA{1:_} 0/10 = 0.00",
+//          "precommits": [
+//            "nil-Vote"
+//          ],
+//          "precommits_bit_array": "BA{1:_} 0/10 = 0.00"
+//        }
+//      ]
+//    }
+//  }
+//}
+//```
 func ConsensusState() (*ctypes.ResultConsensusState, error) {
 	// Get self round state.
 	bz, err := consensusState.GetRoundStateSimpleJSON()