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package kvstore
import (
"bytes"
"encoding/base64"
"encoding/binary"
"encoding/json"
"fmt"
"strconv"
"strings"
"sync"
dbm "github.com/tendermint/tm-db"
"github.com/tendermint/tendermint/abci/example/code"
"github.com/tendermint/tendermint/abci/types"
"github.com/tendermint/tendermint/crypto/encoding"
"github.com/tendermint/tendermint/libs/log"
cryptoproto "github.com/tendermint/tendermint/proto/tendermint/crypto"
"github.com/tendermint/tendermint/version"
)
var (
stateKey = []byte("stateKey")
kvPairPrefixKey = []byte("kvPairKey:")
ProtocolVersion uint64 = 0x1
)
type State struct {
db dbm.DB
Size int64 `json:"size"`
Height int64 `json:"height"`
AppHash []byte `json:"app_hash"`
}
func loadState(db dbm.DB) State {
var state State
state.db = db
stateBytes, err := db.Get(stateKey)
if err != nil {
panic(err)
}
if len(stateBytes) == 0 {
return state
}
err = json.Unmarshal(stateBytes, &state)
if err != nil {
panic(err)
}
return state
}
func saveState(state State) {
stateBytes, err := json.Marshal(state)
if err != nil {
panic(err)
}
err = state.db.Set(stateKey, stateBytes)
if err != nil {
panic(err)
}
}
func prefixKey(key []byte) []byte {
return append(kvPairPrefixKey, key...)
}
//---------------------------------------------------
var _ types.Application = (*Application)(nil)
type Application struct {
types.BaseApplication
mu sync.Mutex
state State
RetainBlocks int64 // blocks to retain after commit (via ResponseCommit.RetainHeight)
logger log.Logger
// validator set
ValUpdates []types.ValidatorUpdate
valAddrToPubKeyMap map[string]cryptoproto.PublicKey
}
func NewApplication() *Application {
return &Application{
logger: log.NewNopLogger(),
state: loadState(dbm.NewMemDB()),
valAddrToPubKeyMap: make(map[string]cryptoproto.PublicKey),
}
}
func (app *Application) InitChain(req types.RequestInitChain) types.ResponseInitChain {
app.mu.Lock()
defer app.mu.Unlock()
for _, v := range req.Validators {
r := app.updateValidator(v)
if r.IsErr() {
app.logger.Error("error updating validators", "r", r)
panic("problem updating validators")
}
}
return types.ResponseInitChain{}
}
func (app *Application) Info(req types.RequestInfo) types.ResponseInfo {
app.mu.Lock()
defer app.mu.Unlock()
return types.ResponseInfo{
Data: fmt.Sprintf("{\"size\":%v}", app.state.Size),
Version: version.ABCIVersion,
AppVersion: ProtocolVersion,
LastBlockHeight: app.state.Height,
LastBlockAppHash: app.state.AppHash,
}
}
// tx is either "val:pubkey!power" or "key=value" or just arbitrary bytes
func (app *Application) handleTx(tx []byte) *types.ExecTxResult {
// if it starts with "val:", update the validator set
// format is "val:pubkey!power"
if isValidatorTx(tx) {
// update validators in the merkle tree
// and in app.ValUpdates
return app.execValidatorTx(tx)
}
if isPrepareTx(tx) {
return app.execPrepareTx(tx)
}
var key, value string
parts := bytes.Split(tx, []byte("="))
if len(parts) == 2 {
key, value = string(parts[0]), string(parts[1])
} else {
key, value = string(tx), string(tx)
}
err := app.state.db.Set(prefixKey([]byte(key)), []byte(value))
if err != nil {
panic(err)
}
app.state.Size++
events := []types.Event{
{
Type: "app",
Attributes: []types.EventAttribute{
{Key: "creator", Value: "Cosmoshi Netowoko", Index: true},
{Key: "key", Value: key, Index: true},
{Key: "index_key", Value: "index is working", Index: true},
{Key: "noindex_key", Value: "index is working", Index: false},
},
},
}
return &types.ExecTxResult{Code: code.CodeTypeOK, Events: events}
}
func (app *Application) Close() error {
app.mu.Lock()
defer app.mu.Unlock()
return app.state.db.Close()
}
func (app *Application) FinalizeBlock(req types.RequestFinalizeBlock) types.ResponseFinalizeBlock {
app.mu.Lock()
defer app.mu.Unlock()
// reset valset changes
app.ValUpdates = make([]types.ValidatorUpdate, 0)
// Punish validators who committed equivocation.
for _, ev := range req.ByzantineValidators {
if ev.Type == types.EvidenceType_DUPLICATE_VOTE {
addr := string(ev.Validator.Address)
if pubKey, ok := app.valAddrToPubKeyMap[addr]; ok {
app.updateValidator(types.ValidatorUpdate{
PubKey: pubKey,
Power: ev.Validator.Power - 1,
})
app.logger.Info("Decreased val power by 1 because of the equivocation",
"val", addr)
} else {
panic(fmt.Errorf("wanted to punish val %q but can't find it", addr))
}
}
}
respTxs := make([]*types.ExecTxResult, len(req.Txs))
for i, tx := range req.Txs {
respTxs[i] = app.handleTx(tx)
}
return types.ResponseFinalizeBlock{TxResults: respTxs, ValidatorUpdates: app.ValUpdates}
}
func (*Application) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx {
return types.ResponseCheckTx{Code: code.CodeTypeOK, GasWanted: 1}
}
func (app *Application) Commit() types.ResponseCommit {
app.mu.Lock()
defer app.mu.Unlock()
// Using a memdb - just return the big endian size of the db
appHash := make([]byte, 8)
binary.PutVarint(appHash, app.state.Size)
app.state.AppHash = appHash
app.state.Height++
saveState(app.state)
resp := types.ResponseCommit{Data: appHash}
if app.RetainBlocks > 0 && app.state.Height >= app.RetainBlocks {
resp.RetainHeight = app.state.Height - app.RetainBlocks + 1
}
return resp
}
// Returns an associated value or nil if missing.
func (app *Application) Query(reqQuery types.RequestQuery) types.ResponseQuery {
app.mu.Lock()
defer app.mu.Unlock()
if reqQuery.Path == "/val" {
key := []byte("val:" + string(reqQuery.Data))
value, err := app.state.db.Get(key)
if err != nil {
panic(err)
}
return types.ResponseQuery{
Key: reqQuery.Data,
Value: value,
}
}
if reqQuery.Prove {
value, err := app.state.db.Get(prefixKey(reqQuery.Data))
if err != nil {
panic(err)
}
resQuery := types.ResponseQuery{
Index: -1,
Key: reqQuery.Data,
Value: value,
Height: app.state.Height,
}
if value == nil {
resQuery.Log = "does not exist"
} else {
resQuery.Log = "exists"
}
return resQuery
}
value, err := app.state.db.Get(prefixKey(reqQuery.Data))
if err != nil {
panic(err)
}
resQuery := types.ResponseQuery{
Key: reqQuery.Data,
Value: value,
Height: app.state.Height,
}
if value == nil {
resQuery.Log = "does not exist"
} else {
resQuery.Log = "exists"
}
return resQuery
}
func (app *Application) PrepareProposal(req types.RequestPrepareProposal) types.ResponsePrepareProposal {
app.mu.Lock()
defer app.mu.Unlock()
return types.ResponsePrepareProposal{
ModifiedTxStatus: types.ResponsePrepareProposal_MODIFIED,
TxRecords: app.substPrepareTx(req.Txs),
}
}
func (*Application) ProcessProposal(req types.RequestProcessProposal) types.ResponseProcessProposal {
for _, tx := range req.Txs {
if len(tx) == 0 {
return types.ResponseProcessProposal{Status: types.ResponseProcessProposal_REJECT}
}
}
return types.ResponseProcessProposal{Status: types.ResponseProcessProposal_ACCEPT}
}
//---------------------------------------------
// update validators
func (app *Application) Validators() (validators []types.ValidatorUpdate) {
app.mu.Lock()
defer app.mu.Unlock()
itr, err := app.state.db.Iterator(nil, nil)
if err != nil {
panic(err)
}
for ; itr.Valid(); itr.Next() {
if isValidatorTx(itr.Key()) {
validator := new(types.ValidatorUpdate)
err := types.ReadMessage(bytes.NewBuffer(itr.Value()), validator)
if err != nil {
panic(err)
}
validators = append(validators, *validator)
}
}
if err = itr.Error(); err != nil {
panic(err)
}
return
}
func MakeValSetChangeTx(pubkey cryptoproto.PublicKey, power int64) []byte {
pk, err := encoding.PubKeyFromProto(pubkey)
if err != nil {
panic(err)
}
pubStr := base64.StdEncoding.EncodeToString(pk.Bytes())
return []byte(fmt.Sprintf("val:%s!%d", pubStr, power))
}
func isValidatorTx(tx []byte) bool {
return strings.HasPrefix(string(tx), ValidatorSetChangePrefix)
}
// format is "val:pubkey!power"
// pubkey is a base64-encoded 32-byte ed25519 key
func (app *Application) execValidatorTx(tx []byte) *types.ExecTxResult {
tx = tx[len(ValidatorSetChangePrefix):]
// get the pubkey and power
pubKeyAndPower := strings.Split(string(tx), "!")
if len(pubKeyAndPower) != 2 {
return &types.ExecTxResult{
Code: code.CodeTypeEncodingError,
Log: fmt.Sprintf("Expected 'pubkey!power'. Got %v", pubKeyAndPower)}
}
pubkeyS, powerS := pubKeyAndPower[0], pubKeyAndPower[1]
// decode the pubkey
pubkey, err := base64.StdEncoding.DecodeString(pubkeyS)
if err != nil {
return &types.ExecTxResult{
Code: code.CodeTypeEncodingError,
Log: fmt.Sprintf("Pubkey (%s) is invalid base64", pubkeyS)}
}
// decode the power
power, err := strconv.ParseInt(powerS, 10, 64)
if err != nil {
return &types.ExecTxResult{
Code: code.CodeTypeEncodingError,
Log: fmt.Sprintf("Power (%s) is not an int", powerS)}
}
// update
return app.updateValidator(types.UpdateValidator(pubkey, power, ""))
}
// add, update, or remove a validator
func (app *Application) updateValidator(v types.ValidatorUpdate) *types.ExecTxResult {
pubkey, err := encoding.PubKeyFromProto(v.PubKey)
if err != nil {
panic(fmt.Errorf("can't decode public key: %w", err))
}
key := []byte("val:" + string(pubkey.Bytes()))
if v.Power == 0 {
// remove validator
hasKey, err := app.state.db.Has(key)
if err != nil {
panic(err)
}
if !hasKey {
pubStr := base64.StdEncoding.EncodeToString(pubkey.Bytes())
return &types.ExecTxResult{
Code: code.CodeTypeUnauthorized,
Log: fmt.Sprintf("Cannot remove non-existent validator %s", pubStr)}
}
if err = app.state.db.Delete(key); err != nil {
panic(err)
}
delete(app.valAddrToPubKeyMap, string(pubkey.Address()))
} else {
// add or update validator
value := bytes.NewBuffer(make([]byte, 0))
if err := types.WriteMessage(&v, value); err != nil {
return &types.ExecTxResult{
Code: code.CodeTypeEncodingError,
Log: fmt.Sprintf("error encoding validator: %v", err)}
}
if err = app.state.db.Set(key, value.Bytes()); err != nil {
panic(err)
}
app.valAddrToPubKeyMap[string(pubkey.Address())] = v.PubKey
}
// we only update the changes array if we successfully updated the tree
app.ValUpdates = append(app.ValUpdates, v)
return &types.ExecTxResult{Code: code.CodeTypeOK}
}
// -----------------------------
// prepare proposal machinery
const PreparePrefix = "prepare"
func isPrepareTx(tx []byte) bool {
return bytes.HasPrefix(tx, []byte(PreparePrefix))
}
// execPrepareTx is noop. tx data is considered as placeholder
// and is substitute at the PrepareProposal.
func (app *Application) execPrepareTx(tx []byte) *types.ExecTxResult {
// noop
return &types.ExecTxResult{}
}
// substPrepareTx substitutes all the transactions prefixed with 'prepare' in the
// proposal for transactions with the prefix strips.
// It marks all of the original transactions as 'REMOVED' so that
// Tendermint will remove them from its mempool.
func (app *Application) substPrepareTx(blockData [][]byte) []*types.TxRecord {
trs := make([]*types.TxRecord, len(blockData))
var removed []*types.TxRecord
for i, tx := range blockData {
if isPrepareTx(tx) {
removed = append(removed, &types.TxRecord{
Tx: tx,
Action: types.TxRecord_REMOVED,
})
trs[i] = &types.TxRecord{
Tx: bytes.TrimPrefix(tx, []byte(PreparePrefix)),
Action: types.TxRecord_ADDED,
}
continue
}
trs[i] = &types.TxRecord{
Tx: tx,
Action: types.TxRecord_UNMODIFIED,
}
}
return append(trs, removed...)
}