path: root/integration_test/node.go

// Copyright 2018 The dexon-consensus Authors
// This file is part of the dexon-consensus library.
//
// The dexon-consensus library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus library. If not, see
// <http://www.gnu.org/licenses/>.

package integration

import (
    "fmt"
    "time"

    "github.com/dexon-foundation/dexon-consensus/common"
    "github.com/dexon-foundation/dexon-consensus/core"
    "github.com/dexon-foundation/dexon-consensus/core/blockdb"
    "github.com/dexon-foundation/dexon-consensus/core/crypto"
    "github.com/dexon-foundation/dexon-consensus/core/test"
    "github.com/dexon-foundation/dexon-consensus/core/types"
)

type consensusEventType int

const (
    evtProposeBlock consensusEventType = iota
    evtReceiveBlock
)

type consensusEventPayload struct {
    Type      consensusEventType
    PiggyBack interface{}
}

// newProposeBlockEvent constructs an test.Event that would trigger
// block proposing.
func newProposeBlockEvent(nID types.NodeID,
    roundID uint64, chainID uint32, when time.Time) *test.Event {
    return test.NewEvent(nID, when, &consensusEventPayload{
        Type: evtProposeBlock,
        PiggyBack: &struct {
            round uint64
            chain uint32
        }{roundID, chainID},
    })
}

// newReceiveBlockEvent constructs an test.Event that would trigger
// block received.
func newReceiveBlockEvent(
    nID types.NodeID, when time.Time, block *types.Block) *test.Event {

    return test.NewEvent(nID, when, &consensusEventPayload{
        Type:      evtReceiveBlock,
        PiggyBack: block,
    })
}

// Node is designed to work with test.Scheduler.
type Node struct {
    ID               types.NodeID
    ownChains        []uint32
    roundEndTimes    []time.Time
    roundToNotify    uint64
    lattice          *core.Lattice
    appModule        *test.App
    stateModule      *test.State
    govModule        *test.Governance
    dbModule         blockdb.BlockDatabase
    broadcastTargets map[types.NodeID]struct{}
    networkLatency   test.LatencyModel
    proposingLatency test.LatencyModel
    prevFinalHeight  uint64
    pendings         []*types.Block
    prevHash         common.Hash
    // This variable caches the maximum NumChains seen by this node when
    // it's notified for round switching.
    latticeMaxNumChains uint32
}

// newNode constructs an instance of Node.
func newNode(
    gov *test.Governance,
    privateKey crypto.PrivateKey,
    dMoment time.Time,
    ownChains []uint32,
    networkLatency test.LatencyModel,
    proposingLatency test.LatencyModel) (*Node, error) {
    // Load all configs prepared in core.Governance into core.Lattice.
    copiedGov := gov.Clone()
    configs := loadAllConfigs(copiedGov)
    // Setup blockdb.
    db, err := blockdb.NewMemBackedBlockDB()
    if err != nil {
        return nil, err
    }
    // Setup test.App
    app := test.NewApp(copiedGov.State())
    // Setup lattice instance.
    lattice := core.NewLattice(
        dMoment,
        0,
        configs[0],
        core.NewAuthenticator(privateKey),
        app,
        app,
        db,
        &common.NullLogger{})
    n := &Node{
        ID:                  types.NewNodeID(privateKey.PublicKey()),
        ownChains:           ownChains,
        roundEndTimes:       genRoundEndTimes(configs, dMoment),
        roundToNotify:       2,
        networkLatency:      networkLatency,
        proposingLatency:    proposingLatency,
        appModule:           app,
        stateModule:         copiedGov.State(),
        dbModule:            db,
        govModule:           copiedGov,
        lattice:             lattice,
        latticeMaxNumChains: configs[0].NumChains,
    }
    for idx, config := range configs[1:] {
        if err := lattice.AppendConfig(uint64(idx+1), config); err != nil {
            return nil, err
        }
        if config.NumChains > n.latticeMaxNumChains {
            n.latticeMaxNumChains = config.NumChains
        }
    }
    return n, nil
}

// Handle implements test.EventHandler interface.
func (n *Node) Handle(e *test.Event) (events []*test.Event) {
    payload := e.Payload.(*consensusEventPayload)
    switch payload.Type {
    case evtProposeBlock:
        events, e.ExecError = n.handleProposeBlock(e.Time, payload.PiggyBack)
    case evtReceiveBlock:
        events, e.ExecError = n.handleReceiveBlock(payload.PiggyBack)
    default:
        panic(fmt.Errorf("unknown consensus event type: %v", payload.Type))
    }
    return
}

func (n *Node) handleProposeBlock(when time.Time, payload interface{}) (
    events []*test.Event, err error) {
    pos := payload.(*struct {
        round uint64
        chain uint32
    })
    b, err := n.prepareBlock(pos.round, pos.chain, when)
    if err != nil {
        if err == core.ErrInvalidChainID {
            // This chain is not included in this round, retry in next round.
            events = append(events, newProposeBlockEvent(
                n.ID, b.Position.Round+1, b.Position.ChainID,
                n.roundEndTimes[b.Position.Round]))
        }
        return
    }
    if events, err = n.processBlock(b); err != nil {
        // It's shouldn't be error when prepared.
        panic(err)
    }
    // Create 'block received' event for each other nodes.
    for nID := range n.broadcastTargets {
        events = append(events, newReceiveBlockEvent(
            nID, when.Add(n.networkLatency.Delay()), b.Clone()))
    }
    // Create next 'block proposing' event for this nodes.
    events = append(events, newProposeBlockEvent(n.ID,
        b.Position.Round,
        b.Position.ChainID,
        when.Add(n.proposingLatency.Delay())))
    return
}

func (n *Node) handleReceiveBlock(piggyback interface{}) (
    events []*test.Event, err error) {
    events, err = n.processBlock(piggyback.(*types.Block))
    if err != nil {
        panic(err)
    }
    return
}

func (n *Node) prepareBlock(
    round uint64, chainID uint32, when time.Time) (b *types.Block, err error) {
    b = &types.Block{
        Position: types.Position{
            Round:   round,
            ChainID: chainID,
        }}
    if err = n.lattice.PrepareBlock(b, when); err != nil {
        if err == core.ErrRoundNotSwitch {
            b.Position.Round++
            err = n.lattice.PrepareBlock(b, when)
        }
    }
    return
}

func (n *Node) processBlock(b *types.Block) (events []*test.Event, err error) {
    // TODO(mission): this segment of code is identical to testLatticeMgr in
    //                core/lattice_test.go, except the compaction-chain part.
    var (
        delivered []*types.Block
    )
    n.pendings = append([]*types.Block{b}, n.pendings...)
    for {
        var (
            newPendings  []*types.Block
            tmpDelivered []*types.Block
            tmpErr       error
        )
        updated := false
        for _, p := range n.pendings {
            if tmpErr = n.lattice.SanityCheck(p); tmpErr != nil {
                if tmpErr == core.ErrRetrySanityCheckLater {
                    newPendings = append(newPendings, p)
                } else {
                    // Those blocks are prepared by lattice module, they should
                    // not be wrong.
                    panic(tmpErr)
                }
                continue
            }
            if tmpDelivered, tmpErr =
                n.lattice.ProcessBlock(p); tmpErr != nil {
                // It's not allowed that sanity checked block failed to
                // be added to lattice.
                panic(tmpErr)
            }
            delivered = append(delivered, tmpDelivered...)
            updated = true
        }
        n.pendings = newPendings
        if !updated {
            break
        }
    }
    // Deliver blocks.
    for _, b = range delivered {
        if err = n.dbModule.Put(*b); err != nil {
            panic(err)
        }
        b.Finalization.Height = n.prevFinalHeight + 1
        b.Finalization.ParentHash = n.prevHash
        n.appModule.BlockDelivered(b.Hash, b.Position, b.Finalization)
        n.prevFinalHeight++
        n.prevHash = b.Hash
        events = append(events, n.checkRoundSwitch(b)...)
    }
    if err = n.lattice.PurgeBlocks(delivered); err != nil {
        panic(err)
    }
    return
}

func (n *Node) checkRoundSwitch(b *types.Block) (evts []*test.Event) {
    if !b.Timestamp.After(n.roundEndTimes[b.Position.Round]) {
        return
    }
    if b.Position.Round+2 != n.roundToNotify {
        return
    }
    // Handle round switching logic.
    n.govModule.NotifyRoundHeight(n.roundToNotify, b.Finalization.Height)
    if n.roundToNotify == uint64(len(n.roundEndTimes)) {
        config := n.govModule.Configuration(n.roundToNotify)
        if config == nil {
            panic(fmt.Errorf(
                "config is not ready for round: %v", n.roundToNotify-1))
        }
        // Cache round ended time for each round.
        n.roundEndTimes = append(n.roundEndTimes,
            n.roundEndTimes[len(n.roundEndTimes)-1].Add(
                config.RoundInterval))
        // Add new config to lattice module.
        if err := n.lattice.AppendConfig(n.roundToNotify, config); err != nil {
            panic(err)
        }
        if config.NumChains > n.latticeMaxNumChains {
            // We can be sure that lattice module can support this number of
            // chains.
            for _, chainID := range n.ownChains {
                if chainID < n.latticeMaxNumChains {
                    continue
                }
                if chainID >= config.NumChains {
                    continue
                }
                // For newly added chains, add block proposing seed event.
                evts = append(evts, newProposeBlockEvent(n.ID, n.roundToNotify,
                    chainID, n.roundEndTimes[n.roundToNotify-1]))
            }
            n.latticeMaxNumChains = config.NumChains
        }
    } else if n.roundToNotify > uint64(len(n.roundEndTimes)) {
        panic(fmt.Errorf(
            "config notification not incremental: %v, cached configs: %v",
            n.roundToNotify, len(n.roundEndTimes)))
    }
    n.roundToNotify++
    return
}

// Bootstrap this node with block proposing event.
func (n *Node) Bootstrap(sch *test.Scheduler, now time.Time) (err error) {
    sch.RegisterEventHandler(n.ID, n)
    for _, chainID := range n.ownChains {
        if chainID >= n.latticeMaxNumChains {
            continue
        }
        err = sch.Seed(newProposeBlockEvent(n.ID, 0, chainID, now))
        if err != nil {
            return
        }
    }
    return
}

func (n *Node) setBroadcastTargets(targets map[types.NodeID]struct{}) {
    // Clone targets, except self.
    targetsCopy := make(map[types.NodeID]struct{})
    for nID := range targets {
        if nID == n.ID {
            continue
        }
        targetsCopy[nID] = struct{}{}
    }
    n.broadcastTargets = targetsCopy
}

func (n *Node) app() *test.App {
    return n.appModule
}

func (n *Node) db() blockdb.BlockDatabase {
    return n.dbModule
}

func (n *Node) gov() *test.Governance {
    return n.govModule
}