feat(lib/grandpa) add round state rpc call (ChainSafe#1664)

* chore: add interface for grandpa in rpc pkg

* chore: create roundState rpc call

* chore: coment unused branch

* chore: fix lint

* chore: add test case

* chore: fix lint

* chore: address comments

* chore: fix the diff implementation

* chore: address comment

* chore: change PreVotes and PreCommits interface signature

* chore: remove check

* chore: improve code defs

Makefile

@@ -137,7 +137,7 @@ endif
 	@echo "> Generating mocks at $(path)"
 
 ifeq ($(INMOCKS),1)
-	cd $(path); $(GOPATH)/bin/mockery --name $(interface) --inpackage --keeptree --case underscore
+	cd $(path); $(GOPATH)/bin/mockery --name $(interface) --structname Mock$(interface) --case underscore --keeptree
 else
 	$(GOPATH)/bin/mockery --srcpkg $(path) --name $(interface) --case underscore --inpackage
 endif

dot/node.go

@@ -309,7 +309,7 @@ func NewNode(cfg *Config, ks *keystore.GlobalKeystore, stopFunc func()) (*Node,
 
 	// check if rpc service is enabled
 	if enabled := cfg.RPC.Enabled || cfg.RPC.WS; enabled {
-		rpcSrvc := createRPCService(cfg, stateSrvc, coreSrvc, networkSrvc, bp, rt, sysSrvc)
+		rpcSrvc := createRPCService(cfg, stateSrvc, coreSrvc, networkSrvc, bp, rt, sysSrvc, fg)
 		nodeSrvcs = append(nodeSrvcs, rpcSrvc)
 	} else {
 		logger.Debug("rpc service disabled by default", "rpc", enabled)

dot/rpc/http.go

@@ -49,6 +49,7 @@ type HTTPServerConfig struct {
 	NetworkAPI          modules.NetworkAPI
 	CoreAPI             modules.CoreAPI
 	BlockProducerAPI    modules.BlockProducerAPI
+	BlockFinalityAPI    modules.BlockFinalityAPI
 	RuntimeAPI          modules.RuntimeAPI
 	TransactionQueueAPI modules.TransactionStateAPI
 	RPCAPI              modules.RPCAPI
@@ -100,7 +101,7 @@ func (h *HTTPServer) RegisterModules(mods []string) {
 		case "chain":
 			srvc = modules.NewChainModule(h.serverConfig.BlockAPI)
 		case "grandpa":
-			srvc = modules.NewGrandpaModule(h.serverConfig.BlockAPI)
+			srvc = modules.NewGrandpaModule(h.serverConfig.BlockAPI, h.serverConfig.BlockFinalityAPI)
 		case "state":
 			srvc = modules.NewStateModule(h.serverConfig.NetworkAPI, h.serverConfig.StorageAPI, h.serverConfig.CoreAPI)
 		case "rpc":

dot/rpc/modules/api.go

@@ -7,6 +7,8 @@ import (
 	"github.com/ChainSafe/gossamer/dot/types"
 	"github.com/ChainSafe/gossamer/lib/common"
 	"github.com/ChainSafe/gossamer/lib/crypto"
+	"github.com/ChainSafe/gossamer/lib/crypto/ed25519"
+	"github.com/ChainSafe/gossamer/lib/grandpa"
 	"github.com/ChainSafe/gossamer/lib/runtime"
 	"github.com/ChainSafe/gossamer/lib/transaction"
 )
@@ -93,3 +95,12 @@ type SystemAPI interface {
 	ChainType() string
 	ChainName() string
 }
+
+// BlockFinalityAPI is the interface for handling block finalisation methods
+type BlockFinalityAPI interface {
+	GetSetID() uint64
+	GetRound() uint64
+	GetVoters() grandpa.Voters
+	PreVotes() []ed25519.PublicKeyBytes
+	PreCommits() []ed25519.PublicKeyBytes
+}

dot/rpc/modules/grandpa.go

@@ -20,20 +20,45 @@ import (
 	"net/http"
 
 	"github.com/ChainSafe/gossamer/lib/common"
+	"github.com/ChainSafe/gossamer/lib/crypto/ed25519"
 )
 
 // GrandpaModule init parameters
 type GrandpaModule struct {
-	blockAPI BlockAPI
+	blockAPI         BlockAPI
+	blockFinalityAPI BlockFinalityAPI
 }
 
 // NewGrandpaModule creates a new Grandpa rpc module.
-func NewGrandpaModule(api BlockAPI) *GrandpaModule {
+func NewGrandpaModule(api BlockAPI, finalityAPI BlockFinalityAPI) *GrandpaModule {
 	return &GrandpaModule{
-		blockAPI: api,
+		blockAPI:         api,
+		blockFinalityAPI: finalityAPI,
 	}
 }
 
+// Votes struct formats rpc call
+type Votes struct {
+	CurrentWeight uint32   `json:"currentWeight"`
+	Missing       []string `json:"missing"`
+}
+
+// RoundState json format for roundState RPC call
+type RoundState struct {
+	Round           uint32 `json:"round"`
+	TotalWeight     uint32 `json:"totalWeight"`
+	ThresholdWeight uint32 `json:"thresholdWeight"`
+	Prevotes        Votes  `json:"prevotes"`
+	Precommits      Votes  `json:"precommits"`
+}
+
+// RoundStateResponse response to roundState RPC call
+type RoundStateResponse struct {
+	SetID      uint32       `json:"setId"`
+	Best       RoundState   `json:"best"`
+	Background []RoundState `json:"background"`
+}
+
 // ProveFinalityRequest request struct
 type ProveFinalityRequest struct {
 	blockHashStart common.Hash
@@ -71,3 +96,84 @@ func (gm *GrandpaModule) ProveFinality(r *http.Request, req *ProveFinalityReques
 
 	return nil
 }
+
+// RoundState returns the state of the current best round state as well as the ongoing background rounds.
+func (gm *GrandpaModule) RoundState(r *http.Request, req *EmptyRequest, res *RoundStateResponse) error {
+	voters := gm.blockFinalityAPI.GetVoters()
+	votersPkBytes := make([]ed25519.PublicKeyBytes, len(voters))
+	for i, v := range voters {
+		votersPkBytes[i] = v.PublicKeyBytes()
+	}
+
+	votes := gm.blockFinalityAPI.PreVotes()
+	commits := gm.blockFinalityAPI.PreCommits()
+
+	missingPrevotes, err := toAddress(difference(votersPkBytes, votes))
+	if err != nil {
+		return err
+	}
+
+	missingPrecommits, err := toAddress(difference(votersPkBytes, commits))
+	if err != nil {
+		return err
+	}
+
+	totalWeight := uint32(len(voters))
+	roundstate := RoundStateResponse{
+		SetID: uint32(gm.blockFinalityAPI.GetSetID()),
+		Best: RoundState{
+			Round:           uint32(gm.blockFinalityAPI.GetRound()),
+			ThresholdWeight: thresholdWeight(totalWeight),
+			TotalWeight:     totalWeight,
+			Prevotes: Votes{
+				CurrentWeight: uint32(len(votes)),
+				Missing:       missingPrevotes,
+			},
+			Precommits: Votes{
+				CurrentWeight: uint32(len(commits)),
+				Missing:       missingPrecommits,
+			},
+		},
+		Background: []RoundState{},
+	}
+
+	*res = roundstate
+	return nil
+}
+
+func thresholdWeight(totalWeight uint32) uint32 {
+	return totalWeight * 2 / 3
+}
+
+// difference get the values representing the difference, i.e., the values that are in voters but not in pre.
+// this function returns the authorities that haven't voted yet
+func difference(voters, equivocations []ed25519.PublicKeyBytes) []ed25519.PublicKeyBytes {
+	diff := make([]ed25519.PublicKeyBytes, 0)
+	diffmap := make(map[ed25519.PublicKeyBytes]bool, len(voters))
+
+	for _, eq := range equivocations {
+		diffmap[eq] = true
+	}
+
+	for _, v := range voters {
+		if _, ok := diffmap[v]; !ok {
+			diff = append(diff, v)
+		}
+	}
+
+	return diff
+}
+
+func toAddress(pkb []ed25519.PublicKeyBytes) ([]string, error) {
+	addrs := make([]string, len(pkb))
+	for i, b := range pkb {
+		pk, err := ed25519.NewPublicKey(b[:])
+		if err != nil {
+			return nil, err
+		}
+
+		addrs[i] = string(pk.Address())
+	}
+
+	return addrs, nil
+}

dot/rpc/modules/grandpa_test.go

@@ -21,8 +21,17 @@ import (
 	"testing"
 
 	"github.com/ChainSafe/gossamer/dot/state"
+	"github.com/ChainSafe/gossamer/dot/types"
+	"github.com/ChainSafe/gossamer/lib/crypto/ed25519"
+	"github.com/ChainSafe/gossamer/lib/grandpa"
+	"github.com/ChainSafe/gossamer/lib/keystore"
+	"github.com/stretchr/testify/require"
+
+	rpcmocks "github.com/ChainSafe/gossamer/dot/rpc/modules/mocks"
 )
 
+var kr, _ = keystore.NewEd25519Keyring()
+
 func TestGrandpaProveFinality(t *testing.T) {
 	testStateService := newTestStateService(t)
 
@@ -33,7 +42,7 @@ func TestGrandpaProveFinality(t *testing.T) {
 		t.Errorf("Fail: bestblock failed")
 	}
 
-	gmSvc := NewGrandpaModule(testStateService.Block)
+	gmSvc := NewGrandpaModule(testStateService.Block, nil)
 
 	testStateService.Block.SetJustification(bestBlock.Header.ParentHash, make([]byte, 10))
 	testStateService.Block.SetJustification(bestBlock.Header.Hash(), make([]byte, 11))
@@ -55,3 +64,61 @@ func TestGrandpaProveFinality(t *testing.T) {
 		t.Errorf("Fail: expected: %+v got: %+v\n", res, &expectedResponse)
 	}
 }
+
+func TestRoundState(t *testing.T) {
+	var voters grandpa.Voters
+
+	for _, k := range kr.Keys {
+		voters = append(voters, &types.GrandpaVoter{
+			Key: k.Public().(*ed25519.PublicKey),
+			ID:  1,
+		})
+	}
+
+	grandpamock := new(rpcmocks.MockBlockFinalityAPI)
+	grandpamock.On("GetVoters").Return(voters)
+	grandpamock.On("GetSetID").Return(uint64(0))
+	grandpamock.On("GetRound").Return(uint64(2))
+
+	grandpamock.On("PreVotes").Return([]ed25519.PublicKeyBytes{
+		kr.Alice().Public().(*ed25519.PublicKey).AsBytes(),
+		kr.Bob().Public().(*ed25519.PublicKey).AsBytes(),
+		kr.Charlie().Public().(*ed25519.PublicKey).AsBytes(),
+		kr.Dave().Public().(*ed25519.PublicKey).AsBytes(),
+	})
+
+	grandpamock.On("PreCommits").Return([]ed25519.PublicKeyBytes{
+		kr.Alice().Public().(*ed25519.PublicKey).AsBytes(),
+		kr.Bob().Public().(*ed25519.PublicKey).AsBytes(),
+	})
+
+	mod := NewGrandpaModule(nil, grandpamock)
+
+	res := new(RoundStateResponse)
+	err := mod.RoundState(nil, nil, res)
+
+	require.NoError(t, err)
+
+	// newTestVoters has actually 9 keys with weight of 1
+	require.Equal(t, uint32(9), res.Best.TotalWeight)
+	require.Equal(t, uint32(6), res.Best.ThresholdWeight)
+
+	expectedMissingPrevotes := []string{
+		string(kr.Eve().Public().Address()),
+		string(kr.Ferdie().Public().Address()),
+		string(kr.George().Public().Address()),
+		string(kr.Heather().Public().Address()),
+		string(kr.Ian().Public().Address()),
+	}
+
+	expectedMissingPrecommits := append([]string{
+		string(kr.Charlie().Public().Address()),
+		string(kr.Dave().Public().Address()),
+	}, expectedMissingPrevotes...)
+
+	require.Equal(t, expectedMissingPrevotes, res.Best.Prevotes.Missing)
+	require.Equal(t, expectedMissingPrecommits, res.Best.Precommits.Missing)
+
+	require.Equal(t, uint32(4), res.Best.Prevotes.CurrentWeight)
+	require.Equal(t, uint32(2), res.Best.Precommits.CurrentWeight)
+}

dot/services.go

@@ -317,7 +317,7 @@ func createNetworkService(cfg *Config, stateSrvc *state.Service) (*network.Servi
 // RPC Service
 
 // createRPCService creates the RPC service from the provided core configuration
-func createRPCService(cfg *Config, stateSrvc *state.Service, coreSrvc *core.Service, networkSrvc *network.Service, bp modules.BlockProducerAPI, rt runtime.Instance, sysSrvc *system.Service) *rpc.HTTPServer {
+func createRPCService(cfg *Config, stateSrvc *state.Service, coreSrvc *core.Service, networkSrvc *network.Service, bp modules.BlockProducerAPI, rt runtime.Instance, sysSrvc *system.Service, finSrvc *grandpa.Service) *rpc.HTTPServer {
 	logger.Info(
 		"creating rpc service...",
 		"host", cfg.RPC.Host,
@@ -337,6 +337,7 @@ func createRPCService(cfg *Config, stateSrvc *state.Service, coreSrvc *core.Serv
 		NetworkAPI:          networkSrvc,
 		CoreAPI:             coreSrvc,
 		BlockProducerAPI:    bp,
+		BlockFinalityAPI:    finSrvc,
 		RuntimeAPI:          rt,
 		TransactionQueueAPI: stateSrvc.Transaction,
 		RPCAPI:              rpcService,