Merge #2414

2414: Merge Signer-indices to master r=zhangchiqing a=zhangchiqing

This PR merges signer indices to master.

## What does signer indices do?

Each block header contains a list of signer's identifier in `Header.ParentVoteIDs` field to indicate who have signed (voted) for this block. 

For instance, for a group of 8 nodes: `[A,B,C,D,E,F,G,H]`, if a block is signed by 6 of them, `[A,C,D,E,G,H]`, then `Header.ParentVoteIDs` could be:
```
Header.ParentVoteIDs = [
    "0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
    "0xCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC",
    "0xDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD",
    "0xEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE",
    "0xGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG",
    "0xHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH",
]
```

Although it's straightforward, the problem is it could take lots of space. On mainnet, ParentVoteIDs field takes about half size of a block head. 

How to optimize?

The idea is that instead of indicating who signed by "name" (their identifier), we indicate by "position" (their index). 
Since the full group identities is known, and there is a canonical order for the full identities, we can simply indicate by saying the block is signed by the "first" node, and the "third" node, and ...

Therefore, in our example, we could use 8 bits `[1,0,1,1,1,0,1]` to indicate a block is signed by `A,C,D,E,G,H`. Each bit indicates whether a node at that index in the canonical order signed the block. We call these bits - "signer indices".[ It replaced the `Header.ParentVoteIDs` field](https://github.com/onflow/flow-go/pull/2414/files#diff-399868065526597108c7691678684ed898cf1a394918fd73f18c67324e374897L67-R65), which is `32 bytes * 6` big, with `Header.ParentVoterIndices` field, which is only `1 byte` big.



Co-authored-by: Leo Zhang <zhangchiqing@gmail.com>
Co-authored-by: Leo Zhang (zhangchiqing) <zhangchiqing@gmail.com>

cmd/bootstrap/cmd/clusters.go

@@ -5,6 +5,8 @@ import (
 	model "github.com/onflow/flow-go/model/bootstrap"
 	"github.com/onflow/flow-go/model/cluster"
 	"github.com/onflow/flow-go/model/flow"
+	"github.com/onflow/flow-go/model/flow/assignment"
+	"github.com/onflow/flow-go/model/flow/factory"
 	"github.com/onflow/flow-go/model/flow/filter"
 )
 
@@ -23,20 +25,22 @@ func constructClusterAssignment(partnerNodes, internalNodes []model.NodeInfo, se
 	internals = internals.DeterministicShuffle(seed)
 
 	nClusters := flagCollectionClusters
-	assignments := make(flow.AssignmentList, nClusters)
+	identifierLists := make([]flow.IdentifierList, nClusters)
 
 	// first, round-robin internal nodes into each cluster
 	for i, node := range internals {
-		assignments[i%len(assignments)] = append(assignments[i%len(assignments)], node.NodeID)
+		identifierLists[i%len(identifierLists)] = append(identifierLists[i%len(identifierLists)], node.NodeID)
 	}
 
 	// next, round-robin partner nodes into each cluster
 	for i, node := range partners {
-		assignments[i%len(assignments)] = append(assignments[i%len(assignments)], node.NodeID)
+		identifierLists[i%len(identifierLists)] = append(identifierLists[i%len(identifierLists)], node.NodeID)
 	}
 
+	assignments := assignment.FromIdentifierLists(identifierLists)
+
 	collectors := append(partners, internals...)
-	clusters, err := flow.NewClusterList(assignments, collectors)
+	clusters, err := factory.NewClusterList(assignments, collectors)
 	if err != nil {
 		log.Fatal().Err(err).Msg("could not create cluster list")
 	}

cmd/bootstrap/cmd/seal.go

@@ -7,6 +7,7 @@ import (
 	"github.com/onflow/flow-go/model/dkg"
 	"github.com/onflow/flow-go/model/flow"
 	"github.com/onflow/flow-go/model/flow/order"
+	"github.com/onflow/flow-go/module/signature"
 )
 
 func constructRootResultAndSeal(
@@ -43,9 +44,24 @@ func constructRootResultAndSeal(
 		RandomSource:       flagBootstrapRandomSeed,
 	}
 
+	qcsWithSignerIDs := make([]*flow.QuorumCertificateWithSignerIDs, 0, len(clusterQCs))
+	for i, clusterQC := range clusterQCs {
+		members := assignments[i]
+		signerIDs, err := signature.DecodeSignerIndicesToIdentifiers(members, clusterQC.SignerIndices)
+		if err != nil {
+			log.Fatal().Err(err).Msgf("could not decode signer IDs from clusterQC at index %v", i)
+		}
+		qcsWithSignerIDs = append(qcsWithSignerIDs, &flow.QuorumCertificateWithSignerIDs{
+			View:      clusterQC.View,
+			BlockID:   clusterQC.BlockID,
+			SignerIDs: signerIDs,
+			SigData:   clusterQC.SigData,
+		})
+	}
+
 	epochCommit := &flow.EpochCommit{
 		Counter:            flagEpochCounter,
-		ClusterQCs:         flow.ClusterQCVoteDatasFromQCs(clusterQCs),
+		ClusterQCs:         flow.ClusterQCVoteDatasFromQCs(qcsWithSignerIDs),
 		DKGGroupKey:        dkgData.PubGroupKey,
 		DKGParticipantKeys: dkgData.PubKeyShares,
 	}

cmd/bootstrap/run/block.go

@@ -19,7 +19,7 @@ func GenerateRootBlock(chainID flow.ChainID, parentID flow.Identifier, height ui
 		PayloadHash:        payload.Hash(),
 		Timestamp:          timestamp,
 		View:               0,
-		ParentVoterIDs:     nil,
+		ParentVoterIndices: nil,
 		ParentVoterSigData: nil,
 		ProposerID:         flow.ZeroID,
 		ProposerSigData:    nil,

cmd/bootstrap/run/cluster_qc.go

@@ -15,6 +15,7 @@ import (
 	"github.com/onflow/flow-go/model/bootstrap"
 	"github.com/onflow/flow-go/model/cluster"
 	"github.com/onflow/flow-go/model/flow"
+	"github.com/onflow/flow-go/model/flow/order"
 	"github.com/onflow/flow-go/module/local"
 )
 
@@ -29,7 +30,8 @@ func GenerateClusterRootQC(signers []bootstrap.NodeInfo, allCommitteeMembers flo
 	}
 
 	// STEP 2: create VoteProcessor
-	committee, err := committees.NewStaticCommittee(allCommitteeMembers, flow.Identifier{}, nil, nil)
+	ordered := allCommitteeMembers.Sort(order.Canonical)
+	committee, err := committees.NewStaticCommittee(ordered, flow.Identifier{}, nil, nil)
 	if err != nil {
 		return nil, err
 	}

cmd/bootstrap/run/qc_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/onflow/flow-go/crypto"
 	"github.com/onflow/flow-go/model/bootstrap"
 	"github.com/onflow/flow-go/model/flow"
+	"github.com/onflow/flow-go/model/flow/order"
 	"github.com/onflow/flow-go/module/signature"
 	"github.com/onflow/flow-go/utils/unittest"
 )
@@ -32,7 +33,7 @@ func TestGenerateRootQC(t *testing.T) {
 }
 
 func createSignerData(t *testing.T, n int) *ParticipantData {
-	identities := unittest.IdentityListFixture(n)
+	identities := unittest.IdentityListFixture(n).Sort(order.Canonical)
 
 	networkingKeys := unittest.NetworkingKeys(n)
 	stakingKeys := unittest.StakingKeys(n)

cmd/util/cmd/epochs/cmd/reset_test.go

@@ -30,7 +30,7 @@ func TestReset_LocalSnapshot(t *testing.T) {
 		unittest.RunWithTempDir(t, func(bootDir string) {
 
 			// create a root snapshot
-			rootSnapshot := unittest.RootSnapshotFixture(unittest.IdentityListFixture(10))
+			rootSnapshot := unittest.RootSnapshotFixture(unittest.IdentityListFixture(10, unittest.WithAllRoles()))
 
 			// write snapshot to correct path in bootDir
 			err := writeRootSnapshot(bootDir, rootSnapshot)
@@ -62,7 +62,7 @@ func TestReset_LocalSnapshot(t *testing.T) {
 		unittest.RunWithTempDir(t, func(bootDir string) {
 
 			// create a root snapshot
-			rootSnapshot := unittest.RootSnapshotFixture(unittest.IdentityListFixture(10))
+			rootSnapshot := unittest.RootSnapshotFixture(unittest.IdentityListFixture(10, unittest.WithAllRoles()))
 
 			// write snapshot to correct path in bootDir
 			err := writeRootSnapshot(bootDir, rootSnapshot)

cmd/util/cmd/exec-data-json-export/block_exporter.go

@@ -16,12 +16,12 @@ import (
 )
 
 type blockSummary struct {
-	BlockHeight    uint64   `json:"block_height"`
-	BlockID        string   `json:"block_id"`
-	ParentBlockID  string   `json:"parent_block_id"`
-	ParentVoterIDs []string `json:"parent_voter_ids"`
-	// ParentVoterSigData []string  `json:"parent_voter_sig"`
-	ProposerID string `json:"proposer_id"`
+	BlockHeight        uint64 `json:"block_height"`
+	BlockID            string `json:"block_id"`
+	ParentBlockID      string `json:"parent_block_id"`
+	ParentVoterIndices string `json:"parent_voter_indices"`
+	ParentVoterSigData string `json:"parent_voter_sig"`
+	ProposerID         string `json:"proposer_id"`
 	// ProposerSigData    string  `json:"proposer_sig"`
 	Timestamp         time.Time `json:"timestamp"`
 	CollectionIDs     []string  `json:"collection_ids"`
@@ -87,22 +87,18 @@ func ExportBlocks(blockID flow.Identifier, dbPath string, outputPath string) (fl
 			sealsStates = append(sealsStates, hex.EncodeToString(s.FinalState[:]))
 		}
 
-		pvIDs := make([]string, 0)
-		for _, i := range header.ParentVoterIDs {
-			pvIDs = append(pvIDs, hex.EncodeToString(i[:]))
-		}
-
 		b := blockSummary{
-			BlockID:           hex.EncodeToString(activeBlockID[:]),
-			BlockHeight:       header.Height,
-			ParentBlockID:     hex.EncodeToString(header.ParentID[:]),
-			ParentVoterIDs:    pvIDs,
-			ProposerID:        hex.EncodeToString(header.ProposerID[:]),
-			Timestamp:         header.Timestamp,
-			CollectionIDs:     cols,
-			SealedBlocks:      seals,
-			SealedResults:     sealsResults,
-			SealedFinalStates: sealsStates,
+			BlockID:            hex.EncodeToString(activeBlockID[:]),
+			BlockHeight:        header.Height,
+			ParentBlockID:      hex.EncodeToString(header.ParentID[:]),
+			ParentVoterIndices: hex.EncodeToString(header.ParentVoterIndices),
+			ParentVoterSigData: hex.EncodeToString(header.ParentVoterSigData),
+			ProposerID:         hex.EncodeToString(header.ProposerID[:]),
+			Timestamp:          header.Timestamp,
+			CollectionIDs:      cols,
+			SealedBlocks:       seals,
+			SealedResults:      sealsResults,
+			SealedFinalStates:  sealsStates,
 		}
 
 		jsonData, err := json.Marshal(b)

consensus/follower_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/onflow/flow-go/module/signature"
+
 	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
@@ -68,9 +70,9 @@ func (s *HotStuffFollowerSuite) SetupTest() {
 
 	// mock consensus committee
 	s.committee = &mockhotstuff.Committee{}
-	s.committee.On("Identities", mock.Anything, mock.Anything).Return(
-		func(blockID flow.Identifier, selector flow.IdentityFilter) flow.IdentityList {
-			return identities.Filter(selector)
+	s.committee.On("Identities", mock.Anything).Return(
+		func(blockID flow.Identifier) flow.IdentityList {
+			return identities
 		},
 		nil,
 	)
@@ -105,10 +107,13 @@ func (s *HotStuffFollowerSuite) SetupTest() {
 		Height:    21053,
 		View:      52078,
 	}
+
+	signerIndices, err := signature.EncodeSignersToIndices(identities.NodeIDs(), identities.NodeIDs()[:3])
+	require.NoError(s.T(), err)
 	s.rootQC = &flow.QuorumCertificate{
-		View:      s.rootHeader.View,
-		BlockID:   s.rootHeader.ID(),
-		SignerIDs: identities.NodeIDs()[:3],
+		View:          s.rootHeader.View,
+		BlockID:       s.rootHeader.ID(),
+		SignerIndices: signerIndices,
 	}
 
 	// we start with the latest finalized block being the root block
@@ -335,6 +340,7 @@ func (mc *MockConsensus) extendBlock(blockView uint64, parent *flow.Header) *flo
 	nextBlock := unittest.BlockHeaderWithParentFixture(parent)
 	nextBlock.View = blockView
 	nextBlock.ProposerID = mc.identities[int(blockView)%len(mc.identities)].NodeID
-	nextBlock.ParentVoterIDs = mc.identities.NodeIDs()
+	signerIndices, _ := signature.EncodeSignersToIndices(mc.identities.NodeIDs(), mc.identities.NodeIDs())
+	nextBlock.ParentVoterIndices = signerIndices
 	return &nextBlock
 }

consensus/hotstuff/blockproducer/block_producer.go

@@ -33,7 +33,7 @@ func (bp *BlockProducer) MakeBlockProposal(qc *flow.QuorumCertificate, view uint
 	// in hotstuff, we use this for view number and signature-related fields
 	setHotstuffFields := func(header *flow.Header) error {
 		header.View = view
-		header.ParentVoterIDs = qc.SignerIDs
+		header.ParentVoterIndices = qc.SignerIndices
 		header.ParentVoterSigData = qc.SigData
 		header.ProposerID = bp.committee.Self()
 

consensus/hotstuff/committee.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Committee accounts for the fact that we might have multiple HotStuff instances
-// (collector committees and main consensus committee). Each hostuff instance is supposed to
+// (collector committees and main consensus committee). Each HotStuff instance is supposed to
 // have a dedicated Committee state.
 // A Committee provides subset of the protocol.State, which is restricted to exactly those
 // nodes that participate in the current HotStuff instance: the state of all legitimate HotStuff
@@ -17,14 +17,12 @@ import (
 // Given a collector block, some logic is required to find the main consensus block
 // for determining the valid collector-HotStuff participants.
 type Committee interface {
-
 	// Identities returns a IdentityList with legitimate HotStuff participants for the specified block.
-	// The list of participants is filtered by the provided selector. The returned list of HotStuff participants
+	// The returned list of HotStuff participants
 	//   * contains nodes that are allowed to sign the specified block (legitimate participants with NON-ZERO WEIGHT)
 	//   * is ordered in the canonical order
 	//   * contains no duplicates.
-	// The list of all legitimate HotStuff participants for the specified block can be obtained by using `filter.Any`
-	Identities(blockID flow.Identifier, selector flow.IdentityFilter) (flow.IdentityList, error)
+	Identities(blockID flow.Identifier) (flow.IdentityList, error)
 
 	// Identity returns the full Identity for specified HotStuff participant.
 	// The node must be a legitimate HotStuff participant with NON-ZERO WEIGHT at the specified block.

consensus/hotstuff/committees/cluster_committee.go

@@ -61,8 +61,12 @@ func NewClusterCommittee(
 	return com, nil
 }
 
-func (c *Cluster) Identities(blockID flow.Identifier, selector flow.IdentityFilter) (flow.IdentityList, error) {
-
+// Identities returns the identities of all cluster members that are authorized to
+// participate at the given block. The order of the identities is the canonical order.
+func (c *Cluster) Identities(blockID flow.Identifier) (flow.IdentityList, error) {
+	// blockID is a collection block not a block produced by consensus,
+	// to query the identities from protocol state, we need to use the reference block id from the payload
+	//
 	// first retrieve the cluster block payload
 	payload, err := c.payloads.ByBlockID(blockID)
 	if err != nil {
@@ -74,14 +78,12 @@ func (c *Cluster) Identities(blockID flow.Identifier, selector flow.IdentityFilt
 
 	// use the initial cluster members for root block
 	if isRootBlock {
-		return c.initialClusterMembers.Filter(selector), nil
+		return c.initialClusterMembers, nil
 	}
 
 	// otherwise use the snapshot given by the reference block
-	identities, err := c.state.AtBlockID(payload.ReferenceBlockID).Identities(filter.And(
-		selector,
-		c.clusterMemberFilter,
-	))
+	identities, err := c.state.AtBlockID(payload.ReferenceBlockID).Identities(c.clusterMemberFilter) // remove ejected nodes
+
 	return identities, err
 }
 

consensus/hotstuff/committees/consensus_committee.go

@@ -68,11 +68,10 @@ func NewConsensusCommittee(state protocol.State, me flow.Identifier) (*Consensus
 	return com, nil
 }
 
-func (c *Consensus) Identities(blockID flow.Identifier, selector flow.IdentityFilter) (flow.IdentityList, error) {
-	il, err := c.state.AtBlockID(blockID).Identities(filter.And(
-		filter.IsVotingConsensusCommitteeMember,
-		selector,
-	))
+// Identities returns the identities of all authorized consensus participants at the given block.
+// The order of the identities is the canonical order.
+func (c *Consensus) Identities(blockID flow.Identifier) (flow.IdentityList, error) {
+	il, err := c.state.AtBlockID(blockID).Identities(filter.IsVotingConsensusCommitteeMember)
 	return il, err
 }