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107 lines
3.1 KiB
107 lines
3.1 KiB
package core
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import (
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"context"
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"fmt"
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"github.com/pkg/errors"
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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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ctypes "github.com/tendermint/tendermint/rpc/core/types"
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rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
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)
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const (
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// Buffer on the Tendermint (server) side to allow some slowness in clients.
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subBufferSize = 100
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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 Subscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultSubscribe, error) {
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addr := ctx.RemoteAddr()
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if eventBus.NumClients() >= config.MaxSubscriptionClients {
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return nil, fmt.Errorf("max_subscription_clients %d reached", config.MaxSubscriptionClients)
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} else if eventBus.NumClientSubscriptions(addr) >= config.MaxSubscriptionsPerClient {
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return nil, fmt.Errorf("max_subscriptions_per_client %d reached", config.MaxSubscriptionsPerClient)
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}
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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, errors.Wrap(err, "failed to parse query")
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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 := eventBus.Subscribe(subCtx, addr, q, subBufferSize)
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if err != nil {
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return nil, err
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}
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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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resultEvent := &ctypes.ResultEvent{Query: query, Data: msg.Data(), Events: msg.Events()}
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ctx.WSConn.TryWriteRPCResponse(
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rpctypes.NewRPCSuccessResponse(
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ctx.WSConn.Codec(),
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subscriptionID,
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resultEvent,
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))
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case <-sub.Cancelled():
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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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ctx.WSConn.TryWriteRPCResponse(
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rpctypes.RPCServerError(
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subscriptionID,
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fmt.Errorf("subscription was cancelled (reason: %s)", reason),
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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 &ctypes.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 Unsubscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultUnsubscribe, error) {
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addr := ctx.RemoteAddr()
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logger.Info("Unsubscribe from 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, errors.Wrap(err, "failed to parse query")
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}
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err = eventBus.Unsubscribe(context.Background(), addr, q)
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if err != nil {
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return nil, err
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}
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return &ctypes.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 UnsubscribeAll(ctx *rpctypes.Context) (*ctypes.ResultUnsubscribe, error) {
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addr := ctx.RemoteAddr()
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logger.Info("Unsubscribe from all", "remote", addr)
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err := eventBus.UnsubscribeAll(context.Background(), addr)
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if err != nil {
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return nil, err
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}
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return &ctypes.ResultUnsubscribe{}, nil
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}
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