/
watcher.go
201 lines (173 loc) · 6.38 KB
/
watcher.go
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package accountant
import (
"context"
"encoding/hex"
"encoding/json"
"fmt"
"reflect"
"time"
"github.com/deltaswapio/deltaswap/node/pkg/common"
"github.com/deltaswapio/deltaswap/sdk/vaa"
ethCommon "github.com/ethereum/go-ethereum/common"
tmAbci "github.com/tendermint/tendermint/abci/types"
tmHttp "github.com/tendermint/tendermint/rpc/client/http"
tmCoreTypes "github.com/tendermint/tendermint/rpc/core/types"
tmTypes "github.com/tendermint/tendermint/types"
"go.uber.org/zap"
)
// watcher reads transaction events from the smart contract and publishes them.
func (acct *Accountant) watcher(ctx context.Context) error {
errC := make(chan error)
acct.logger.Info("acctwatch: creating watcher", zap.String("url", acct.wsUrl), zap.String("contract", acct.contract))
tmConn, err := tmHttp.New(acct.wsUrl, "/websocket")
if err != nil {
connectionErrors.Inc()
return fmt.Errorf("failed to establish tendermint connection: %w", err)
}
if err := tmConn.Start(); err != nil {
connectionErrors.Inc()
return fmt.Errorf("failed to start tendermint connection: %w", err)
}
defer func() {
if err := tmConn.Stop(); err != nil {
connectionErrors.Inc()
acct.logger.Error("acctwatch: failed to stop tendermint connection", zap.Error(err))
}
}()
query := fmt.Sprintf("execute._contract_address='%s'", acct.contract)
events, err := tmConn.Subscribe(
ctx,
"phylaxd",
query,
64, // channel capacity
)
if err != nil {
return fmt.Errorf("failed to subscribe to accountant events: %w", err)
}
defer func() {
if err := tmConn.UnsubscribeAll(ctx, "phylaxd"); err != nil {
acct.logger.Error("acctwatch: failed to unsubscribe from events", zap.Error(err))
}
}()
go acct.handleEvents(ctx, events, errC)
select {
case <-ctx.Done():
return ctx.Err()
case err := <-errC:
return err
}
}
// handleEvents handles events from the tendermint client library.
func (acct *Accountant) handleEvents(ctx context.Context, evts <-chan tmCoreTypes.ResultEvent, errC chan error) {
defer close(errC)
for {
select {
case <-ctx.Done():
return
case e := <-evts:
tx, ok := e.Data.(tmTypes.EventDataTx)
if !ok {
acct.logger.Error("unknown data from event subscription", zap.Stringer("e.Data", reflect.TypeOf(e.Data)), zap.Any("event", e))
continue
}
for _, event := range tx.Result.Events {
if event.Type == "wasm-Observation" {
evt, err := parseEvent[WasmObservation](acct.logger, event, "wasm-Observation", acct.contract)
if err != nil {
acct.logger.Error("failed to parse wasm transfer event", zap.Error(err), zap.Stringer("e.Data", reflect.TypeOf(e.Data)), zap.Any("event", event))
continue
}
eventsReceived.Inc()
acct.processPendingTransfer(evt)
} else if event.Type == "wasm-ObservationError" {
evt, err := parseEvent[WasmObservationError](acct.logger, event, "wasm-ObservationError", acct.contract)
if err != nil {
acct.logger.Error("failed to parse wasm observation error event", zap.Error(err), zap.Stringer("e.Data", reflect.TypeOf(e.Data)), zap.Any("event", event))
continue
}
errorEventsReceived.Inc()
acct.handleTransferError(evt.Key.String(), evt.Error, "transfer error event received")
} else {
acct.logger.Debug("ignoring uninteresting event", zap.String("eventType", event.Type))
}
}
}
}
}
type (
// WasmObservation represents a transfer event from the smart contract.
WasmObservation Observation
// WasmObservationError represents an error event from the smart contract.
WasmObservationError struct {
Key TransferKey `json:"key"`
Error string `json:"error"`
}
)
func parseEvent[T any](logger *zap.Logger, event tmAbci.Event, name string, contractAddress string) (*T, error) {
attrs := make(map[string]json.RawMessage)
for _, attr := range event.Attributes {
if string(attr.Key) == "_contract_address" {
if string(attr.Value) != contractAddress {
return nil, fmt.Errorf("%s event from unexpected contract: %s", name, string(attr.Value))
}
} else {
logger.Debug("event attribute", zap.String("event", name), zap.String("key", string(attr.Key)), zap.String("value", string(attr.Value)))
attrs[string(attr.Key)] = attr.Value
}
}
attrBytes, err := json.Marshal(attrs)
if err != nil {
return nil, fmt.Errorf("failed to marshal %s event attributes: %w", name, err)
}
evt := new(T)
if err := json.Unmarshal(attrBytes, evt); err != nil {
return nil, fmt.Errorf("failed to unmarshal %s event: %w", name, err)
}
return evt, nil
}
// processPendingTransfer takes a WasmObservation event, determines if we are expecting it, and if so, publishes it.
func (acct *Accountant) processPendingTransfer(xfer *WasmObservation) {
acct.pendingTransfersLock.Lock()
defer acct.pendingTransfersLock.Unlock()
acct.logger.Info("acctwatch: transfer event detected",
zap.String("tx_hash", hex.EncodeToString(xfer.TxHash)),
zap.Uint32("timestamp", xfer.Timestamp),
zap.Uint32("nonce", xfer.Nonce),
zap.Stringer("emitter_chain", vaa.ChainID(xfer.EmitterChain)),
zap.Stringer("emitter_address", xfer.EmitterAddress),
zap.Uint64("sequence", xfer.Sequence),
zap.Uint8("consistency_level", xfer.ConsistencyLevel),
zap.String("payload", hex.EncodeToString(xfer.Payload)),
)
msg := &common.MessagePublication{
TxHash: ethCommon.BytesToHash(xfer.TxHash),
Timestamp: time.Unix(int64(xfer.Timestamp), 0),
Nonce: xfer.Nonce,
Sequence: xfer.Sequence,
EmitterChain: vaa.ChainID(xfer.EmitterChain),
EmitterAddress: xfer.EmitterAddress,
Payload: xfer.Payload,
ConsistencyLevel: xfer.ConsistencyLevel,
}
msgId := msg.MessageIDString()
pe, exists := acct.pendingTransfers[msgId]
if exists {
digest := msg.CreateDigest()
if pe.digest != digest {
digestMismatches.Inc()
acct.logger.Error("acctwatch: digest mismatch, dropping transfer",
zap.String("msgID", msgId),
zap.String("oldDigest", pe.digest),
zap.String("newDigest", digest),
)
acct.deletePendingTransferAlreadyLocked(msgId)
return
}
acct.logger.Info("acctwatch: pending transfer has been approved", zap.String("msgId", msgId))
acct.publishTransferAlreadyLocked(pe)
transfersApproved.Inc()
} else {
// TODO: We could issue a reobservation request here since it looks like other phylaxs have seen this transfer but we haven't.
acct.logger.Info("acctwatch: unknown transfer has been approved, ignoring it", zap.String("msgId", msgId))
}
}