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134 lines
4.3 KiB
134 lines
4.3 KiB
package core
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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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tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
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tmquery "github.com/tendermint/tendermint/libs/pubsub/query"
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"github.com/tendermint/tendermint/rpc/coretypes"
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rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
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)
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const (
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// maxQueryLength is the maximum length of a query string that will be
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// accepted. This is just a safety check to avoid outlandish queries.
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maxQueryLength = 512
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)
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// Subscribe for events via WebSocket.
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// More: https://docs.tendermint.com/master/rpc/#/Websocket/subscribe
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func (env *Environment) Subscribe(ctx *rpctypes.Context, query string) (*coretypes.ResultSubscribe, error) {
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addr := ctx.RemoteAddr()
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if env.EventBus.NumClients() >= env.Config.MaxSubscriptionClients {
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return nil, fmt.Errorf("max_subscription_clients %d reached", env.Config.MaxSubscriptionClients)
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} else if env.EventBus.NumClientSubscriptions(addr) >= env.Config.MaxSubscriptionsPerClient {
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return nil, fmt.Errorf("max_subscriptions_per_client %d reached", env.Config.MaxSubscriptionsPerClient)
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} else if len(query) > maxQueryLength {
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return nil, errors.New("maximum query length exceeded")
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}
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env.Logger.Info("Subscribe to query", "remote", addr, "query", query)
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q, err := tmquery.New(query)
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if err != nil {
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return nil, fmt.Errorf("failed to parse query: %w", err)
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}
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subCtx, cancel := context.WithTimeout(ctx.Context(), SubscribeTimeout)
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defer cancel()
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sub, err := env.EventBus.Subscribe(subCtx, addr, q, env.Config.SubscriptionBufferSize)
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if err != nil {
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return nil, err
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}
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closeIfSlow := env.Config.CloseOnSlowClient
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// Capture the current ID, since it can change in the future.
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subscriptionID := ctx.JSONReq.ID
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go func() {
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for {
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select {
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case msg := <-sub.Out():
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var (
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resultEvent = &coretypes.ResultEvent{Query: query, Data: msg.Data(), Events: msg.Events()}
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resp = rpctypes.NewRPCSuccessResponse(subscriptionID, resultEvent)
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)
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writeCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
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defer cancel()
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if err := ctx.WSConn.WriteRPCResponse(writeCtx, resp); err != nil {
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env.Logger.Info("Can't write response (slow client)",
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"to", addr, "subscriptionID", subscriptionID, "err", err)
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if closeIfSlow {
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var (
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err = errors.New("subscription was canceled (reason: slow client)")
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resp = rpctypes.RPCServerError(subscriptionID, err)
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)
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if !ctx.WSConn.TryWriteRPCResponse(resp) {
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env.Logger.Info("Can't write response (slow client)",
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"to", addr, "subscriptionID", subscriptionID, "err", err)
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}
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return
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}
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}
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case <-sub.Canceled():
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if sub.Err() != tmpubsub.ErrUnsubscribed {
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var reason string
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if sub.Err() == nil {
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reason = "Tendermint exited"
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} else {
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reason = sub.Err().Error()
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}
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var (
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err = fmt.Errorf("subscription was canceled (reason: %s)", reason)
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resp = rpctypes.RPCServerError(subscriptionID, err)
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)
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if ok := ctx.WSConn.TryWriteRPCResponse(resp); !ok {
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env.Logger.Info("Can't write response (slow client)",
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"to", addr, "subscriptionID", subscriptionID, "err", err)
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}
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}
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return
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}
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}
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}()
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return &coretypes.ResultSubscribe{}, nil
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}
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// Unsubscribe from events via WebSocket.
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// More: https://docs.tendermint.com/master/rpc/#/Websocket/unsubscribe
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func (env *Environment) Unsubscribe(ctx *rpctypes.Context, query string) (*coretypes.ResultUnsubscribe, error) {
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args := tmpubsub.UnsubscribeArgs{Subscriber: ctx.RemoteAddr()}
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env.Logger.Info("Unsubscribe from query", "remote", args.Subscriber, "subscription", query)
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var err error
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args.Query, err = tmquery.New(query)
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if err != nil {
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args.ID = query
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}
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err = env.EventBus.Unsubscribe(ctx.Context(), args)
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if err != nil {
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return nil, err
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}
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return &coretypes.ResultUnsubscribe{}, nil
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}
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// UnsubscribeAll from all events via WebSocket.
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// More: https://docs.tendermint.com/master/rpc/#/Websocket/unsubscribe_all
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func (env *Environment) UnsubscribeAll(ctx *rpctypes.Context) (*coretypes.ResultUnsubscribe, error) {
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addr := ctx.RemoteAddr()
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env.Logger.Info("Unsubscribe from all", "remote", addr)
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err := env.EventBus.UnsubscribeAll(ctx.Context(), addr)
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if err != nil {
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return nil, err
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}
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return &coretypes.ResultUnsubscribe{}, nil
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}
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