forked from TrueCloudLab/neoneo-go
5811687836
Execution events are followed by block events, not vise versa, thus, we can wait until VUB block to be accepted to be sure that transaction wasn't accepted to chain.
307 lines
9.6 KiB
Go
307 lines
9.6 KiB
Go
package actor
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import (
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"context"
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"errors"
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"fmt"
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"time"
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"github.com/nspcc-dev/neo-go/pkg/core/block"
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"github.com/nspcc-dev/neo-go/pkg/core/state"
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"github.com/nspcc-dev/neo-go/pkg/neorpc"
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"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
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"github.com/nspcc-dev/neo-go/pkg/util"
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)
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// PollingWaiterRetryCount is a threshold for a number of subsequent failed
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// attempts to get block count from the RPC server for PollingWaiter. If it fails
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// to retrieve block count PollingWaiterRetryCount times in a raw then transaction
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// awaiting attempt considered to be failed and an error is returned.
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const PollingWaiterRetryCount = 3
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var (
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// ErrTxNotAccepted is returned when transaction wasn't accepted to the chain
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// even after ValidUntilBlock block persist.
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ErrTxNotAccepted = errors.New("transaction was not accepted to chain")
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// ErrContextDone is returned when Waiter context has been done in the middle
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// of transaction awaiting process and no result was received yet.
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ErrContextDone = errors.New("waiter context done")
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// ErrAwaitingNotSupported is returned from Wait method if Waiter instance
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// doesn't support transaction awaiting.
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ErrAwaitingNotSupported = errors.New("awaiting not supported")
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// ErrMissedEvent is returned when RPCEventWaiter closes receiver channel
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// which happens if missed event was received from the RPC server.
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ErrMissedEvent = errors.New("some event was missed")
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)
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type (
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// Waiter is an interface providing transaction awaiting functionality to Actor.
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Waiter interface {
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// Wait allows to wait until transaction will be accepted to the chain. It can be
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// used as a wrapper for Send or SignAndSend and accepts transaction hash,
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// ValidUntilBlock value and an error. It returns transaction execution result
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// or an error if transaction wasn't accepted to the chain.
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Wait(h util.Uint256, vub uint32, err error) (*state.AppExecResult, error)
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// WaitAny waits until at least one of the specified transactions will be accepted
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// to the chain until vub (including). It returns execution result of this
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// transaction or an error if none of the transactions was accepted to the chain.
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// It uses underlying RPCPollingWaiter or RPCEventWaiter context to interrupt
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// awaiting process, but additional ctx can be passed as an argument for the same
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// purpose.
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WaitAny(ctx context.Context, vub uint32, hashes ...util.Uint256) (*state.AppExecResult, error)
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}
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// RPCPollingWaiter is an interface that enables transaction awaiting functionality
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// for Actor instance based on periodical BlockCount and ApplicationLog polls.
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RPCPollingWaiter interface {
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// Context should return the RPC client context to be able to gracefully
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// shut down all running processes (if so).
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Context() context.Context
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GetVersion() (*result.Version, error)
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GetBlockCount() (uint32, error)
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GetApplicationLog(hash util.Uint256, trig *trigger.Type) (*result.ApplicationLog, error)
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}
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// RPCEventWaiter is an interface that enables improved transaction awaiting functionality
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// for Actor instance based on web-socket Block and ApplicationLog notifications. RPCEventWaiter
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// contains RPCPollingWaiter under the hood and falls back to polling when subscription-based
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// awaiting fails.
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RPCEventWaiter interface {
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RPCPollingWaiter
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ReceiveBlocks(flt *neorpc.BlockFilter, rcvr chan<- *block.Block) (string, error)
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ReceiveExecutions(flt *neorpc.ExecutionFilter, rcvr chan<- *state.AppExecResult) (string, error)
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Unsubscribe(id string) error
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}
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)
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// NullWaiter is a Waiter stub that doesn't support transaction awaiting functionality.
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type NullWaiter struct{}
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// PollingWaiter is a polling-based Waiter.
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type PollingWaiter struct {
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polling RPCPollingWaiter
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version *result.Version
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}
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// EventWaiter is a websocket-based Waiter.
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type EventWaiter struct {
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ws RPCEventWaiter
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polling Waiter
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}
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// newWaiter creates Waiter instance. It can be either websocket-based or
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// polling-base, otherwise Waiter stub is returned.
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func newWaiter(ra RPCActor, v *result.Version) Waiter {
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if eventW, ok := ra.(RPCEventWaiter); ok {
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return &EventWaiter{
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ws: eventW,
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polling: &PollingWaiter{
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polling: eventW,
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version: v,
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},
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}
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}
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if pollW, ok := ra.(RPCPollingWaiter); ok {
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return &PollingWaiter{
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polling: pollW,
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version: v,
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}
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}
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return NewNullWaiter()
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}
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// NewNullWaiter creates an instance of Waiter stub.
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func NewNullWaiter() NullWaiter {
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return NullWaiter{}
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}
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// Wait implements Waiter interface.
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func (NullWaiter) Wait(h util.Uint256, vub uint32, err error) (*state.AppExecResult, error) {
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return nil, ErrAwaitingNotSupported
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}
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// WaitAny implements Waiter interface.
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func (NullWaiter) WaitAny(ctx context.Context, vub uint32, hashes ...util.Uint256) (*state.AppExecResult, error) {
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return nil, ErrAwaitingNotSupported
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}
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// NewPollingWaiter creates an instance of Waiter supporting poll-based transaction awaiting.
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func NewPollingWaiter(waiter RPCPollingWaiter) (*PollingWaiter, error) {
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v, err := waiter.GetVersion()
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if err != nil {
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return nil, err
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}
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return &PollingWaiter{
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polling: waiter,
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version: v,
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}, nil
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}
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// Wait implements Waiter interface.
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func (w *PollingWaiter) Wait(h util.Uint256, vub uint32, err error) (*state.AppExecResult, error) {
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if err != nil {
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return nil, err
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}
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return w.WaitAny(context.TODO(), vub, h)
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}
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// WaitAny implements Waiter interface.
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func (w *PollingWaiter) WaitAny(ctx context.Context, vub uint32, hashes ...util.Uint256) (*state.AppExecResult, error) {
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var (
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currentHeight uint32
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failedAttempt int
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pollTime = time.Millisecond * time.Duration(w.version.Protocol.MillisecondsPerBlock) / 2
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)
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if pollTime == 0 {
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pollTime = time.Second
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}
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timer := time.NewTicker(pollTime)
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defer timer.Stop()
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for {
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select {
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case <-timer.C:
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blockCount, err := w.polling.GetBlockCount()
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if err != nil {
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failedAttempt++
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if failedAttempt > PollingWaiterRetryCount {
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return nil, fmt.Errorf("failed to retrieve block count: %w", err)
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}
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continue
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}
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failedAttempt = 0
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if blockCount-1 > currentHeight {
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currentHeight = blockCount - 1
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}
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t := trigger.Application
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for _, h := range hashes {
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res, err := w.polling.GetApplicationLog(h, &t)
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if err == nil {
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return &state.AppExecResult{
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Container: res.Container,
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Execution: res.Executions[0],
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}, nil
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}
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}
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if currentHeight >= vub {
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return nil, ErrTxNotAccepted
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}
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case <-w.polling.Context().Done():
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return nil, fmt.Errorf("%w: %v", ErrContextDone, w.polling.Context().Err())
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case <-ctx.Done():
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return nil, fmt.Errorf("%w: %v", ErrContextDone, ctx.Err())
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}
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}
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}
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// NewEventWaiter creates an instance of Waiter supporting websocket event-based transaction awaiting.
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// EventWaiter contains PollingWaiter under the hood and falls back to polling when subscription-based
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// awaiting fails.
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func NewEventWaiter(waiter RPCEventWaiter) (*EventWaiter, error) {
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polling, err := NewPollingWaiter(waiter)
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if err != nil {
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return nil, err
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}
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return &EventWaiter{
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ws: waiter,
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polling: polling,
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}, nil
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}
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// Wait implements Waiter interface.
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func (w *EventWaiter) Wait(h util.Uint256, vub uint32, err error) (res *state.AppExecResult, waitErr error) {
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if err != nil {
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return nil, err
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}
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return w.WaitAny(context.TODO(), vub, h)
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}
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// WaitAny implements Waiter interface.
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func (w *EventWaiter) WaitAny(ctx context.Context, vub uint32, hashes ...util.Uint256) (res *state.AppExecResult, waitErr error) {
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var wsWaitErr error
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defer func() {
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if wsWaitErr != nil {
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res, waitErr = w.polling.WaitAny(ctx, vub, hashes...)
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if waitErr != nil {
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waitErr = fmt.Errorf("WS waiter error: %w, simple waiter error: %v", wsWaitErr, waitErr)
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}
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}
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}()
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bRcvr := make(chan *block.Block)
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aerRcvr := make(chan *state.AppExecResult)
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defer func() {
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drainLoop:
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// Drain receivers to avoid other notification receivers blocking.
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for {
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select {
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case <-bRcvr:
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case <-aerRcvr:
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default:
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break drainLoop
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}
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}
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if wsWaitErr == nil || !errors.Is(wsWaitErr, ErrMissedEvent) {
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close(bRcvr)
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close(aerRcvr)
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}
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}()
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// Execution event precedes the block event, thus wait until the VUB-th block to be sure.
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since := vub
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blocksID, err := w.ws.ReceiveBlocks(&neorpc.BlockFilter{Since: &since}, bRcvr)
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if err != nil {
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wsWaitErr = fmt.Errorf("failed to subscribe for new blocks: %w", err)
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return
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}
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defer func() {
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err = w.ws.Unsubscribe(blocksID)
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if err != nil {
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errFmt := "failed to unsubscribe from blocks (id: %s): %v"
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errArgs := []interface{}{blocksID, err}
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if waitErr != nil {
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errFmt += "; wait error: %w"
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errArgs = append(errArgs, waitErr)
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}
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waitErr = fmt.Errorf(errFmt, errArgs...)
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}
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}()
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for _, h := range hashes {
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txsID, err := w.ws.ReceiveExecutions(&neorpc.ExecutionFilter{Container: &h}, aerRcvr)
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if err != nil {
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wsWaitErr = fmt.Errorf("failed to subscribe for execution results: %w", err)
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return
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}
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defer func() {
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err = w.ws.Unsubscribe(txsID)
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if err != nil {
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errFmt := "failed to unsubscribe from transactions (id: %s): %v"
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errArgs := []interface{}{txsID, err}
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if waitErr != nil {
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errFmt += "; wait error: %w"
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errArgs = append(errArgs, waitErr)
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}
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waitErr = fmt.Errorf(errFmt, errArgs...)
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}
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}()
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}
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select {
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case _, ok := <-bRcvr:
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if !ok {
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// We're toast, retry with non-ws client.
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wsWaitErr = ErrMissedEvent
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return
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}
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waitErr = ErrTxNotAccepted
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case aer, ok := <-aerRcvr:
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if !ok {
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// We're toast, retry with non-ws client.
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wsWaitErr = ErrMissedEvent
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return
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}
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res = aer
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case <-w.ws.Context().Done():
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waitErr = fmt.Errorf("%w: %v", ErrContextDone, w.ws.Context().Err())
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case <-ctx.Done():
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waitErr = fmt.Errorf("%w: %v", ErrContextDone, ctx.Err())
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}
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return
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}
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