package consensus import ( "bytes" "context" "errors" "fmt" "io" "io/ioutil" "os" "path" "runtime" "testing" "time" "github.com/stretchr/testify/require" "github.com/tendermint/abci/example/dummy" abci "github.com/tendermint/abci/types" crypto "github.com/tendermint/go-crypto" wire "github.com/tendermint/go-wire" auto "github.com/tendermint/tmlibs/autofile" cmn "github.com/tendermint/tmlibs/common" dbm "github.com/tendermint/tmlibs/db" cfg "github.com/tendermint/tendermint/config" "github.com/tendermint/tendermint/proxy" sm "github.com/tendermint/tendermint/state" "github.com/tendermint/tendermint/types" "github.com/tendermint/tmlibs/log" ) var consensusReplayConfig *cfg.Config func init() { consensusReplayConfig = ResetConfig("consensus_replay_test") } // These tests ensure we can always recover from failure at any part of the consensus process. // There are two general failure scenarios: failure during consensus, and failure while applying the block. // Only the latter interacts with the app and store, // but the former has to deal with restrictions on re-use of priv_validator keys. // The `WAL Tests` are for failures during the consensus; // the `Handshake Tests` are for failures in applying the block. // With the help of the WAL, we can recover from it all! // NOTE: Files in this dir are generated by running the `build.sh` therein. // It's a simple way to generate wals for a single block, or multiple blocks, with random transactions, // and different part sizes. The output is not deterministic. // It should only have to be re-run if there is some breaking change to the consensus data structures (eg. blocks, votes) // or to the behaviour of the app (eg. computes app hash differently) var data_dir = path.Join(cmn.GoPath(), "src/github.com/tendermint/tendermint/consensus", "test_data") //------------------------------------------------------------------------------------------ // WAL Tests // TODO: It would be better to verify explicitly which states we can recover from without the wal // and which ones we need the wal for - then we'd also be able to only flush the // wal writer when we need to, instead of with every message. func startNewConsensusStateAndWaitForBlock(t *testing.T, lastBlockHeight int, blockDB dbm.DB, stateDB dbm.DB) { logger := log.TestingLogger() state, _ := sm.GetState(stateDB, consensusReplayConfig.GenesisFile()) state.SetLogger(logger.With("module", "state")) privValidator := loadPrivValidator(consensusReplayConfig) cs := newConsensusStateWithConfigAndBlockStore(consensusReplayConfig, state, privValidator, dummy.NewDummyApplication(), blockDB) cs.SetLogger(logger) bytes, _ := ioutil.ReadFile(cs.config.WalFile()) // fmt.Printf("====== WAL: \n\r%s\n", bytes) t.Logf("====== WAL: \n\r%s\n", bytes) _, err := cs.Start() require.NoError(t, err) defer func() { cs.Stop() }() // This is just a signal that we haven't halted; its not something contained // in the WAL itself. Assuming the consensus state is running, replay of any // WAL, including the empty one, should eventually be followed by a new // block, or else something is wrong. newBlockCh := make(chan interface{}, 1) err = cs.eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock, newBlockCh) require.NoError(t, err) select { case <-newBlockCh: case <-time.After(10 * time.Second): t.Fatalf("Timed out waiting for new block (see trace above)") } } func sendTxs(cs *ConsensusState, ctx context.Context) { i := 0 for { select { case <-ctx.Done(): return default: cs.mempool.CheckTx([]byte{byte(i)}, nil) i++ } } } // TestWALCrash uses crashing WAL to test we can recover from any WAL failure. func TestWALCrash(t *testing.T) { testCases := []struct { name string initFn func(*ConsensusState, context.Context) heightToStop uint64 }{ {"empty block", func(cs *ConsensusState, ctx context.Context) {}, 1}, {"block with a smaller part size", func(cs *ConsensusState, ctx context.Context) { // XXX: is there a better way to change BlockPartSizeBytes? params := cs.state.Params params.BlockPartSizeBytes = 512 cs.state.Params = params sendTxs(cs, ctx) }, 1}, {"many non-empty blocks", sendTxs, 3}, } for _, tc := range testCases { t.Run(tc.name, func(t *testing.T) { crashWALandCheckLiveness(t, tc.initFn, tc.heightToStop) }) } } func crashWALandCheckLiveness(t *testing.T, initFn func(*ConsensusState, context.Context), heightToStop uint64) { walPaniced := make(chan error) crashingWal := &crashingWAL{panicCh: walPaniced, heightToStop: heightToStop} i := 1 LOOP: for { // fmt.Printf("====== LOOP %d\n", i) t.Logf("====== LOOP %d\n", i) // create consensus state from a clean slate logger := log.NewNopLogger() stateDB := dbm.NewMemDB() state, _ := sm.MakeGenesisStateFromFile(stateDB, consensusReplayConfig.GenesisFile()) state.SetLogger(logger.With("module", "state")) privValidator := loadPrivValidator(consensusReplayConfig) blockDB := dbm.NewMemDB() cs := newConsensusStateWithConfigAndBlockStore(consensusReplayConfig, state, privValidator, dummy.NewDummyApplication(), blockDB) cs.SetLogger(logger) // start sending transactions ctx, cancel := context.WithCancel(context.Background()) go initFn(cs, ctx) // clean up WAL file from the previous iteration walFile := cs.config.WalFile() os.Remove(walFile) // set crashing WAL csWal, err := cs.OpenWAL(walFile) require.NoError(t, err) crashingWal.next = csWal // reset the message counter crashingWal.msgIndex = 1 cs.wal = crashingWal // start consensus state _, err = cs.Start() require.NoError(t, err) i++ select { case err := <-walPaniced: t.Logf("WAL paniced: %v", err) // make sure we can make blocks after a crash startNewConsensusStateAndWaitForBlock(t, cs.Height, blockDB, stateDB) // stop consensus state and transactions sender (initFn) cs.Stop() cancel() // if we reached the required height, exit if _, ok := err.(ReachedHeightToStopError); ok { break LOOP } case <-time.After(10 * time.Second): t.Fatal("WAL did not panic for 10 seconds (check the log)") } } } // crashingWAL is a WAL which crashes or rather simulates a crash during Save // (before and after). It remembers a message for which we last panicked // (lastPanicedForMsgIndex), so we don't panic for it in subsequent iterations. type crashingWAL struct { next WAL panicCh chan error heightToStop uint64 msgIndex int // current message index lastPanicedForMsgIndex int // last message for which we panicked } // WALWriteError indicates a WAL crash. type WALWriteError struct { msg string } func (e WALWriteError) Error() string { return e.msg } // ReachedHeightToStopError indicates we've reached the required consensus // height and may exit. type ReachedHeightToStopError struct { height uint64 } func (e ReachedHeightToStopError) Error() string { return fmt.Sprintf("reached height to stop %d", e.height) } // Save simulate WAL's crashing by sending an error to the panicCh and then // exiting the cs.receiveRoutine. func (w *crashingWAL) Save(m WALMessage) { if endMsg, ok := m.(EndHeightMessage); ok { if endMsg.Height == w.heightToStop { w.panicCh <- ReachedHeightToStopError{endMsg.Height} runtime.Goexit() } else { w.next.Save(m) } return } if w.msgIndex > w.lastPanicedForMsgIndex { w.lastPanicedForMsgIndex = w.msgIndex _, file, line, _ := runtime.Caller(1) w.panicCh <- WALWriteError{fmt.Sprintf("failed to write %T to WAL (fileline: %s:%d)", m, file, line)} runtime.Goexit() } else { w.msgIndex++ w.next.Save(m) } } func (w *crashingWAL) Group() *auto.Group { return w.next.Group() } func (w *crashingWAL) SearchForEndHeight(height uint64) (gr *auto.GroupReader, found bool, err error) { return w.next.SearchForEndHeight(height) } func (w *crashingWAL) Start() (bool, error) { return w.next.Start() } func (w *crashingWAL) Stop() bool { return w.next.Stop() } func (w *crashingWAL) Wait() { w.next.Wait() } //------------------------------------------------------------------------------------------ // Handshake Tests var ( NUM_BLOCKS = 6 // number of blocks in the test_data/many_blocks.cswal mempool = types.MockMempool{} ) //--------------------------------------- // Test handshake/replay // 0 - all synced up // 1 - saved block but app and state are behind // 2 - save block and committed but state is behind var modes = []uint{0, 1, 2} // Sync from scratch func TestHandshakeReplayAll(t *testing.T) { for _, m := range modes { testHandshakeReplay(t, 0, m) } } // Sync many, not from scratch func TestHandshakeReplaySome(t *testing.T) { for _, m := range modes { testHandshakeReplay(t, 1, m) } } // Sync from lagging by one func TestHandshakeReplayOne(t *testing.T) { for _, m := range modes { testHandshakeReplay(t, NUM_BLOCKS-1, m) } } // Sync from caught up func TestHandshakeReplayNone(t *testing.T) { for _, m := range modes { testHandshakeReplay(t, NUM_BLOCKS, m) } } func writeWAL(walMsgs []byte) string { walFile, err := ioutil.TempFile("", "wal") if err != nil { panic(fmt.Errorf("failed to create temp WAL file: %v", err)) } _, err = walFile.Write(walMsgs) if err != nil { panic(fmt.Errorf("failed to write to temp WAL file: %v", err)) } if err := walFile.Close(); err != nil { panic(fmt.Errorf("failed to close temp WAL file: %v", err)) } return walFile.Name() } // Make some blocks. Start a fresh app and apply nBlocks blocks. Then restart the app and sync it up with the remaining blocks func testHandshakeReplay(t *testing.T, nBlocks int, mode uint) { config := ResetConfig("proxy_test_") // copy the many_blocks file walBody, err := cmn.ReadFile(path.Join(data_dir, "many_blocks.cswal")) if err != nil { t.Fatal(err) } walFile := writeWAL(walBody) config.Consensus.SetWalFile(walFile) privVal := types.LoadPrivValidatorFS(config.PrivValidatorFile()) wal, err := NewWAL(walFile, false) if err != nil { t.Fatal(err) } wal.SetLogger(log.TestingLogger()) if _, err := wal.Start(); err != nil { t.Fatal(err) } chain, commits, err := makeBlockchainFromWAL(wal) if err != nil { t.Fatalf(err.Error()) } state, store := stateAndStore(config, privVal.GetPubKey()) store.chain = chain store.commits = commits // run the chain through state.ApplyBlock to build up the tendermint state latestAppHash := buildTMStateFromChain(config, state, chain, mode) // make a new client creator dummyApp := dummy.NewPersistentDummyApplication(path.Join(config.DBDir(), "2")) clientCreator2 := proxy.NewLocalClientCreator(dummyApp) if nBlocks > 0 { // run nBlocks against a new client to build up the app state. // use a throwaway tendermint state proxyApp := proxy.NewAppConns(clientCreator2, nil) state, _ := stateAndStore(config, privVal.GetPubKey()) buildAppStateFromChain(proxyApp, state, chain, nBlocks, mode) } // now start the app using the handshake - it should sync handshaker := NewHandshaker(state, store) proxyApp := proxy.NewAppConns(clientCreator2, handshaker) if _, err := proxyApp.Start(); err != nil { t.Fatalf("Error starting proxy app connections: %v", err) } // get the latest app hash from the app res, err := proxyApp.Query().InfoSync(abci.RequestInfo{""}) if err != nil { t.Fatal(err) } // the app hash should be synced up if !bytes.Equal(latestAppHash, res.LastBlockAppHash) { t.Fatalf("Expected app hashes to match after handshake/replay. got %X, expected %X", res.LastBlockAppHash, latestAppHash) } expectedBlocksToSync := NUM_BLOCKS - nBlocks if nBlocks == NUM_BLOCKS && mode > 0 { expectedBlocksToSync += 1 } else if nBlocks > 0 && mode == 1 { expectedBlocksToSync += 1 } if handshaker.NBlocks() != expectedBlocksToSync { t.Fatalf("Expected handshake to sync %d blocks, got %d", expectedBlocksToSync, handshaker.NBlocks()) } } func applyBlock(st *sm.State, blk *types.Block, proxyApp proxy.AppConns) { testPartSize := st.Params.BlockPartSizeBytes err := st.ApplyBlock(types.NopEventBus{}, proxyApp.Consensus(), blk, blk.MakePartSet(testPartSize).Header(), mempool) if err != nil { panic(err) } } func buildAppStateFromChain(proxyApp proxy.AppConns, state *sm.State, chain []*types.Block, nBlocks int, mode uint) { // start a new app without handshake, play nBlocks blocks if _, err := proxyApp.Start(); err != nil { panic(err) } validators := types.TM2PB.Validators(state.Validators) proxyApp.Consensus().InitChainSync(abci.RequestInitChain{validators}) defer proxyApp.Stop() switch mode { case 0: for i := 0; i < nBlocks; i++ { block := chain[i] applyBlock(state, block, proxyApp) } case 1, 2: for i := 0; i < nBlocks-1; i++ { block := chain[i] applyBlock(state, block, proxyApp) } if mode == 2 { // update the dummy height and apphash // as if we ran commit but not applyBlock(state, chain[nBlocks-1], proxyApp) } } } func buildTMStateFromChain(config *cfg.Config, state *sm.State, chain []*types.Block, mode uint) []byte { // run the whole chain against this client to build up the tendermint state clientCreator := proxy.NewLocalClientCreator(dummy.NewPersistentDummyApplication(path.Join(config.DBDir(), "1"))) proxyApp := proxy.NewAppConns(clientCreator, nil) // sm.NewHandshaker(config, state, store, ReplayLastBlock)) if _, err := proxyApp.Start(); err != nil { panic(err) } defer proxyApp.Stop() validators := types.TM2PB.Validators(state.Validators) proxyApp.Consensus().InitChainSync(abci.RequestInitChain{validators}) var latestAppHash []byte switch mode { case 0: // sync right up for _, block := range chain { applyBlock(state, block, proxyApp) } latestAppHash = state.AppHash case 1, 2: // sync up to the penultimate as if we stored the block. // whether we commit or not depends on the appHash for _, block := range chain[:len(chain)-1] { applyBlock(state, block, proxyApp) } // apply the final block to a state copy so we can // get the right next appHash but keep the state back stateCopy := state.Copy() applyBlock(stateCopy, chain[len(chain)-1], proxyApp) latestAppHash = stateCopy.AppHash } return latestAppHash } //-------------------------- // utils for making blocks func makeBlockchainFromWAL(wal WAL) ([]*types.Block, []*types.Commit, error) { // Search for height marker gr, found, err := wal.SearchForEndHeight(0) if err != nil { return nil, nil, err } if !found { return nil, nil, errors.New(cmn.Fmt("WAL does not contain height %d.", 1)) } defer gr.Close() // log.Notice("Build a blockchain by reading from the WAL") var blockParts *types.PartSet var blocks []*types.Block var commits []*types.Commit dec := NewWALDecoder(gr) for { msg, err := dec.Decode() if err == io.EOF { break } else if err != nil { return nil, nil, err } piece := readPieceFromWAL(msg) if piece == nil { continue } switch p := piece.(type) { case *types.PartSetHeader: // if its not the first one, we have a full block if blockParts != nil { var n int block := wire.ReadBinary(&types.Block{}, blockParts.GetReader(), 0, &n, &err).(*types.Block) blocks = append(blocks, block) } blockParts = types.NewPartSetFromHeader(*p) case *types.Part: _, err := blockParts.AddPart(p, false) if err != nil { return nil, nil, err } case *types.Vote: if p.Type == types.VoteTypePrecommit { commit := &types.Commit{ BlockID: p.BlockID, Precommits: []*types.Vote{p}, } commits = append(commits, commit) } } } // grab the last block too var n int block := wire.ReadBinary(&types.Block{}, blockParts.GetReader(), 0, &n, &err).(*types.Block) blocks = append(blocks, block) return blocks, commits, nil } func readPieceFromWAL(msg *TimedWALMessage) interface{} { // skip meta messages if _, ok := msg.Msg.(EndHeightMessage); ok { return nil } // for logging switch m := msg.Msg.(type) { case msgInfo: switch msg := m.Msg.(type) { case *ProposalMessage: return &msg.Proposal.BlockPartsHeader case *BlockPartMessage: return msg.Part case *VoteMessage: return msg.Vote } } return nil } // fresh state and mock store func stateAndStore(config *cfg.Config, pubKey crypto.PubKey) (*sm.State, *mockBlockStore) { stateDB := dbm.NewMemDB() state, _ := sm.MakeGenesisStateFromFile(stateDB, config.GenesisFile()) state.SetLogger(log.TestingLogger().With("module", "state")) store := NewMockBlockStore(config, state.Params) return state, store } //---------------------------------- // mock block store type mockBlockStore struct { config *cfg.Config params types.ConsensusParams chain []*types.Block commits []*types.Commit } // TODO: NewBlockStore(db.NewMemDB) ... func NewMockBlockStore(config *cfg.Config, params types.ConsensusParams) *mockBlockStore { return &mockBlockStore{config, params, nil, nil} } func (bs *mockBlockStore) Height() int { return len(bs.chain) } func (bs *mockBlockStore) LoadBlock(height int) *types.Block { return bs.chain[height-1] } func (bs *mockBlockStore) LoadBlockMeta(height int) *types.BlockMeta { block := bs.chain[height-1] return &types.BlockMeta{ BlockID: types.BlockID{block.Hash(), block.MakePartSet(bs.params.BlockPartSizeBytes).Header()}, Header: block.Header, } } func (bs *mockBlockStore) LoadBlockPart(height int, index int) *types.Part { return nil } func (bs *mockBlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.Commit) { } func (bs *mockBlockStore) LoadBlockCommit(height int) *types.Commit { return bs.commits[height-1] } func (bs *mockBlockStore) LoadSeenCommit(height int) *types.Commit { return bs.commits[height-1] }