start adapting other pkgs to new pubsub

consensus/byzantine_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 	cmn "github.com/tendermint/tendermint/libs/common"
+	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/types"
 )
@@ -49,7 +50,7 @@ func TestByzantine(t *testing.T) {
 		switches[i].SetLogger(p2pLogger.With("validator", i))
 	}
 
-	eventChans := make([]chan interface{}, N)
+	eventSubs := make([]*tmpubsub.Subscription, N)
 	reactors := make([]p2p.Reactor, N)
 	for i := 0; i < N; i++ {
 		// make first val byzantine
@@ -68,8 +69,8 @@ func TestByzantine(t *testing.T) {
 		eventBus := css[i].eventBus
 		eventBus.SetLogger(logger.With("module", "events", "validator", i))
 
-		eventChans[i] = make(chan interface{}, 1)
+		var err error
-		err := eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock, eventChans[i])
+		eventSubs[i], err = eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock)
 		require.NoError(t, err)
 
 		conR := NewConsensusReactor(css[i], true) // so we dont start the consensus states
@@ -134,7 +135,7 @@ func TestByzantine(t *testing.T) {
 	p2p.Connect2Switches(switches, ind1, ind2)
 
 	// wait for someone in the big partition (B) to make a block
-	<-eventChans[ind2]
+	<-eventSubs[ind2].Out()
 
 	t.Log("A block has been committed. Healing partition")
 	p2p.Connect2Switches(switches, ind0, ind1)
@@ -146,7 +147,7 @@ func TestByzantine(t *testing.T) {
 	wg.Add(2)
 	for i := 1; i < N-1; i++ {
 		go func(j int) {
-			<-eventChans[j]
+			<-eventSubs[j].Out()
 			wg.Done()
 		}(i)
 	}

consensus/common_test.go

@@ -25,6 +25,7 @@ import (
 	cmn "github.com/tendermint/tendermint/libs/common"
 	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
+	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
@@ -220,18 +221,17 @@ func validatePrevoteAndPrecommit(t *testing.T, cs *ConsensusState, thisRound, lo
 
 // genesis
 func subscribeToVoter(cs *ConsensusState, addr []byte) chan interface{} {
-	voteCh0 := make(chan interface{})
+	voteCh0Sub, err := cs.eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryVote)
-	err := cs.eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryVote, voteCh0)
 	if err != nil {
 		panic(fmt.Sprintf("failed to subscribe %s to %v", testSubscriber, types.EventQueryVote))
 	}
 	voteCh := make(chan interface{})
 	go func() {
-		for v := range voteCh0 {
+		for msgAndTags := range voteCh0Sub.Out() {
-			vote := v.(types.EventDataVote)
+			vote := msgAndTags.Msg.(types.EventDataVote)
 			// we only fire for our own votes
 			if bytes.Equal(addr, vote.Vote.ValidatorAddress) {
-				voteCh <- v
+				voteCh <- msgAndTags.Msg
 			}
 		}
 	}()
@@ -311,7 +311,7 @@ func randConsensusState(nValidators int) (*ConsensusState, []*validatorStub) {
 
 //-------------------------------------------------------------------------------
 
-func ensureNoNewEvent(ch <-chan interface{}, timeout time.Duration,
+func ensureNoNewEvent(ch <-chan tmpubsub.MsgAndTags, timeout time.Duration,
 	errorMessage string) {
 	select {
 	case <-time.After(timeout):
@@ -321,28 +321,28 @@ func ensureNoNewEvent(ch <-chan interface{}, timeout time.Duration,
 	}
 }
 
-func ensureNoNewEventOnChannel(ch <-chan interface{}) {
+func ensureNoNewEventOnChannel(ch <-chan tmpubsub.MsgAndTags) {
 	ensureNoNewEvent(
 		ch,
 		ensureTimeout,
 		"We should be stuck waiting, not receiving new event on the channel")
 }
 
-func ensureNoNewRoundStep(stepCh <-chan interface{}) {
+func ensureNoNewRoundStep(stepCh <-chan tmpubsub.MsgAndTags) {
 	ensureNoNewEvent(
 		stepCh,
 		ensureTimeout,
 		"We should be stuck waiting, not receiving NewRoundStep event")
 }
 
-func ensureNoNewUnlock(unlockCh <-chan interface{}) {
+func ensureNoNewUnlock(unlockCh <-chan tmpubsub.MsgAndTags) {
 	ensureNoNewEvent(
 		unlockCh,
 		ensureTimeout,
 		"We should be stuck waiting, not receiving Unlock event")
 }
 
-func ensureNoNewTimeout(stepCh <-chan interface{}, timeout int64) {
+func ensureNoNewTimeout(stepCh <-chan tmpubsub.MsgAndTags, timeout int64) {
 	timeoutDuration := time.Duration(timeout*5) * time.Nanosecond
 	ensureNoNewEvent(
 		stepCh,
@@ -351,7 +351,7 @@ func ensureNoNewTimeout(stepCh <-chan interface{}, timeout int64) {
 }
 
 func ensureNewEvent(
-	ch <-chan interface{},
+	ch <-chan tmpubsub.MsgAndTags,
 	height int64,
 	round int,
 	timeout time.Duration,
@@ -361,7 +361,7 @@ func ensureNewEvent(
 	case <-time.After(timeout):
 		panic(errorMessage)
 	case ev := <-ch:
-		rs, ok := ev.(types.EventDataRoundState)
+		rs, ok := ev.Msg.(types.EventDataRoundState)
 		if !ok {
 			panic(
 				fmt.Sprintf(
@@ -378,12 +378,12 @@ func ensureNewEvent(
 	}
 }
 
-func ensureNewRound(roundCh <-chan interface{}, height int64, round int) {
+func ensureNewRound(roundCh <-chan tmpubsub.MsgAndTags, height int64, round int) {
 	select {
 	case <-time.After(ensureTimeout):
 		panic("Timeout expired while waiting for NewRound event")
 	case ev := <-roundCh:
-		rs, ok := ev.(types.EventDataNewRound)
+		rs, ok := ev.Msg.(types.EventDataNewRound)
 		if !ok {
 			panic(
 				fmt.Sprintf(
@@ -399,18 +399,18 @@ func ensureNewRound(roundCh <-chan interface{}, height int64, round int) {
 	}
 }
 
-func ensureNewTimeout(timeoutCh <-chan interface{}, height int64, round int, timeout int64) {
+func ensureNewTimeout(timeoutCh <-chan tmpubsub.MsgAndTags, height int64, round int, timeout int64) {
 	timeoutDuration := time.Duration(timeout*3) * time.Nanosecond
 	ensureNewEvent(timeoutCh, height, round, timeoutDuration,
 		"Timeout expired while waiting for NewTimeout event")
 }
 
-func ensureNewProposal(proposalCh <-chan interface{}, height int64, round int) {
+func ensureNewProposal(proposalCh <-chan tmpubsub.MsgAndTags, height int64, round int) {
 	select {
 	case <-time.After(ensureTimeout):
 		panic("Timeout expired while waiting for NewProposal event")
 	case ev := <-proposalCh:
-		rs, ok := ev.(types.EventDataCompleteProposal)
+		rs, ok := ev.Msg.(types.EventDataCompleteProposal)
 		if !ok {
 			panic(
 				fmt.Sprintf(
@@ -426,17 +426,17 @@ func ensureNewProposal(proposalCh <-chan interface{}, height int64, round int) {
 	}
 }
 
-func ensureNewValidBlock(validBlockCh <-chan interface{}, height int64, round int) {
+func ensureNewValidBlock(validBlockCh <-chan tmpubsub.MsgAndTags, height int64, round int) {
 	ensureNewEvent(validBlockCh, height, round, ensureTimeout,
 		"Timeout expired while waiting for NewValidBlock event")
 }
 
-func ensureNewBlock(blockCh <-chan interface{}, height int64) {
+func ensureNewBlock(blockCh <-chan tmpubsub.MsgAndTags, height int64) {
 	select {
 	case <-time.After(ensureTimeout):
 		panic("Timeout expired while waiting for NewBlock event")
 	case ev := <-blockCh:
-		block, ok := ev.(types.EventDataNewBlock)
+		block, ok := ev.Msg.(types.EventDataNewBlock)
 		if !ok {
 			panic(fmt.Sprintf("expected a *types.EventDataNewBlock, "+
 				"got %v. wrong subscription channel?",
@@ -448,12 +448,12 @@ func ensureNewBlock(blockCh <-chan interface{}, height int64) {
 	}
 }
 
-func ensureNewBlockHeader(blockCh <-chan interface{}, height int64, blockHash cmn.HexBytes) {
+func ensureNewBlockHeader(blockCh <-chan tmpubsub.MsgAndTags, height int64, blockHash cmn.HexBytes) {
 	select {
 	case <-time.After(ensureTimeout):
 		panic("Timeout expired while waiting for NewBlockHeader event")
 	case ev := <-blockCh:
-		blockHeader, ok := ev.(types.EventDataNewBlockHeader)
+		blockHeader, ok := ev.Msg.(types.EventDataNewBlockHeader)
 		if !ok {
 			panic(fmt.Sprintf("expected a *types.EventDataNewBlockHeader, "+
 				"got %v. wrong subscription channel?",
@@ -468,11 +468,43 @@ func ensureNewBlockHeader(blockCh <-chan interface{}, height int64, blockHash cm
 	}
 }
 
-func ensureNewUnlock(unlockCh <-chan interface{}, height int64, round int) {
+func ensureNewUnlock(unlockCh <-chan tmpubsub.MsgAndTags, height int64, round int) {
 	ensureNewEvent(unlockCh, height, round, ensureTimeout,
 		"Timeout expired while waiting for NewUnlock event")
 }
 
+func ensureProposal(proposalCh <-chan tmpubsub.MsgAndTags, height int64, round int, propId types.BlockID) {
+	select {
+	case <-time.After(ensureTimeout):
+		panic("Timeout expired while waiting for NewProposal event")
+	case ev := <-proposalCh:
+		rs, ok := ev.Msg.(types.EventDataCompleteProposal)
+		if !ok {
+			panic(
+				fmt.Sprintf(
+					"expected a EventDataCompleteProposal, got %v.Wrong subscription channel?",
+					reflect.TypeOf(rs)))
+		}
+		if rs.Height != height {
+			panic(fmt.Sprintf("expected height %v, got %v", height, rs.Height))
+		}
+		if rs.Round != round {
+			panic(fmt.Sprintf("expected round %v, got %v", round, rs.Round))
+		}
+		if !rs.BlockID.Equals(propId) {
+			panic("Proposed block does not match expected block")
+		}
+	}
+}
+
+func ensurePrecommit(voteCh <-chan interface{}, height int64, round int) {
+	ensureVote(voteCh, height, round, types.PrecommitType)
+}
+
+func ensurePrevote(voteCh <-chan interface{}, height int64, round int) {
+	ensureVote(voteCh, height, round, types.PrevoteType)
+}
+
 func ensureVote(voteCh <-chan interface{}, height int64, round int,
 	voteType types.SignedMsgType) {
 	select {
@@ -498,39 +530,7 @@ func ensureVote(voteCh <-chan interface{}, height int64, round int,
 	}
 }
 
-func ensureProposal(proposalCh <-chan interface{}, height int64, round int, propId types.BlockID) {
+func ensureNewEventOnChannel(ch <-chan tmpubsub.MsgAndTags) {
-	select {
-	case <-time.After(ensureTimeout):
-		panic("Timeout expired while waiting for NewProposal event")
-	case ev := <-proposalCh:
-		rs, ok := ev.(types.EventDataCompleteProposal)
-		if !ok {
-			panic(
-				fmt.Sprintf(
-					"expected a EventDataCompleteProposal, got %v.Wrong subscription channel?",
-					reflect.TypeOf(rs)))
-		}
-		if rs.Height != height {
-			panic(fmt.Sprintf("expected height %v, got %v", height, rs.Height))
-		}
-		if rs.Round != round {
-			panic(fmt.Sprintf("expected round %v, got %v", round, rs.Round))
-		}
-		if !rs.BlockID.Equals(propId) {
-			panic("Proposed block does not match expected block")
-		}
-	}
-}
-
-func ensurePrecommit(voteCh <-chan interface{}, height int64, round int) {
-	ensureVote(voteCh, height, round, types.PrecommitType)
-}
-
-func ensurePrevote(voteCh <-chan interface{}, height int64, round int) {
-	ensureVote(voteCh, height, round, types.PrevoteType)
-}
-
-func ensureNewEventOnChannel(ch <-chan interface{}) {
 	select {
 	case <-time.After(ensureTimeout):
 		panic("Timeout expired while waiting for new activity on the channel")

consensus/mempool_test.go

@@ -118,7 +118,7 @@ func TestMempoolTxConcurrentWithCommit(t *testing.T) {
 		ticker := time.NewTicker(time.Second * 30)
 		select {
 		case b := <-newBlockCh:
-			evt := b.(types.EventDataNewBlock)
+			evt := b.Msg.(types.EventDataNewBlock)
 			nTxs += int(evt.Block.Header.NumTxs)
 		case <-ticker.C:
 			panic("Timed out waiting to commit blocks with transactions")

consensus/reactor_test.go

@@ -21,6 +21,7 @@ import (
 	cfg "github.com/tendermint/tendermint/config"
 	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
+	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
 	sm "github.com/tendermint/tendermint/state"
@@ -34,9 +35,14 @@ func init() {
 //----------------------------------------------
 // in-process testnets
 
-func startConsensusNet(t *testing.T, css []*ConsensusState, N int) ([]*ConsensusReactor, []chan interface{}, []*types.EventBus) {
+func startConsensusNet(t *testing.T, css []*ConsensusState, N int) (
+	[]*ConsensusReactor,
+	[]*tmpubsub.Subscription,
+	[]*types.EventBus,
+) {
+	var err error
 	reactors := make([]*ConsensusReactor, N)
-	eventChans := make([]chan interface{}, N)
+	eventSubs := make([]*tmpubsub.Subscription, N)
 	eventBuses := make([]*types.EventBus, N)
 	for i := 0; i < N; i++ {
 		/*logger, err := tmflags.ParseLogLevel("consensus:info,*:error", logger, "info")
@@ -48,8 +54,7 @@ func startConsensusNet(t *testing.T, css []*ConsensusState, N int) ([]*Consensus
 		eventBuses[i] = css[i].eventBus
 		reactors[i].SetEventBus(eventBuses[i])
 
-		eventChans[i] = make(chan interface{}, 1)
+		eventSubs[i], err = eventBuses[i].Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock)
-		err := eventBuses[i].Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock, eventChans[i])
 		require.NoError(t, err)
 	}
 	// make connected switches and start all reactors
@@ -67,7 +72,7 @@ func startConsensusNet(t *testing.T, css []*ConsensusState, N int) ([]*Consensus
 		s := reactors[i].conS.GetState()
 		reactors[i].SwitchToConsensus(s, 0)
 	}
-	return reactors, eventChans, eventBuses
+	return reactors, eventSubs, eventBuses
 }
 
 func stopConsensusNet(logger log.Logger, reactors []*ConsensusReactor, eventBuses []*types.EventBus) {
@@ -87,11 +92,11 @@ func stopConsensusNet(logger log.Logger, reactors []*ConsensusReactor, eventBuse
 func TestReactorBasic(t *testing.T) {
 	N := 4
 	css := randConsensusNet(N, "consensus_reactor_test", newMockTickerFunc(true), newCounter)
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, N)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, N)
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
 	// wait till everyone makes the first new block
 	timeoutWaitGroup(t, N, func(j int) {
-		<-eventChans[j]
+		<-eventSubs[j].Out()
 	}, css)
 }
 
@@ -163,20 +168,20 @@ func TestReactorWithEvidence(t *testing.T) {
 		css[i] = cs
 	}
 
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, nValidators)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, nValidators)
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
 
 	// wait till everyone makes the first new block with no evidence
 	timeoutWaitGroup(t, nValidators, func(j int) {
-		blockI := <-eventChans[j]
+		blockI := <-eventSubs[j].Out()
-		block := blockI.(types.EventDataNewBlock).Block
+		block := blockI.Msg.(types.EventDataNewBlock).Block
 		assert.True(t, len(block.Evidence.Evidence) == 0)
 	}, css)
 
 	// second block should have evidence
 	timeoutWaitGroup(t, nValidators, func(j int) {
-		blockI := <-eventChans[j]
+		blockI := <-eventSubs[j].Out()
-		block := blockI.(types.EventDataNewBlock).Block
+		block := blockI.Msg.(types.EventDataNewBlock).Block
 		assert.True(t, len(block.Evidence.Evidence) > 0)
 	}, css)
 }
@@ -221,7 +226,7 @@ func TestReactorCreatesBlockWhenEmptyBlocksFalse(t *testing.T) {
 		func(c *cfg.Config) {
 			c.Consensus.CreateEmptyBlocks = false
 		})
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, N)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, N)
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
 
 	// send a tx
@@ -231,7 +236,7 @@ func TestReactorCreatesBlockWhenEmptyBlocksFalse(t *testing.T) {
 
 	// wait till everyone makes the first new block
 	timeoutWaitGroup(t, N, func(j int) {
-		<-eventChans[j]
+		<-eventSubs[j].Out()
 	}, css)
 }
 
@@ -239,12 +244,12 @@ func TestReactorCreatesBlockWhenEmptyBlocksFalse(t *testing.T) {
 func TestReactorRecordsVotesAndBlockParts(t *testing.T) {
 	N := 4
 	css := randConsensusNet(N, "consensus_reactor_test", newMockTickerFunc(true), newCounter)
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, N)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, N)
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
 
 	// wait till everyone makes the first new block
 	timeoutWaitGroup(t, N, func(j int) {
-		<-eventChans[j]
+		<-eventSubs[j].Out()
 	}, css)
 
 	// Get peer
@@ -263,7 +268,7 @@ func TestReactorVotingPowerChange(t *testing.T) {
 	nVals := 4
 	logger := log.TestingLogger()
 	css := randConsensusNet(nVals, "consensus_voting_power_changes_test", newMockTickerFunc(true), newPersistentKVStore)
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, nVals)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, nVals)
 	defer stopConsensusNet(logger, reactors, eventBuses)
 
 	// map of active validators
@@ -275,7 +280,7 @@ func TestReactorVotingPowerChange(t *testing.T) {
 
 	// wait till everyone makes block 1
 	timeoutWaitGroup(t, nVals, func(j int) {
-		<-eventChans[j]
+		<-eventSubs[j].Out()
 	}, css)
 
 	//---------------------------------------------------------------------------
@@ -286,10 +291,10 @@ func TestReactorVotingPowerChange(t *testing.T) {
 	updateValidatorTx := kvstore.MakeValSetChangeTx(val1PubKeyABCI, 25)
 	previousTotalVotingPower := css[0].GetRoundState().LastValidators.TotalVotingPower()
 
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css, updateValidatorTx)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css, updateValidatorTx)
-	waitForAndValidateBlockWithTx(t, nVals, activeVals, eventChans, css, updateValidatorTx)
+	waitForAndValidateBlockWithTx(t, nVals, activeVals, eventSubs, css, updateValidatorTx)
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css)
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css)
 
 	if css[0].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
 		t.Fatalf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[0].GetRoundState().LastValidators.TotalVotingPower())
@@ -298,10 +303,10 @@ func TestReactorVotingPowerChange(t *testing.T) {
 	updateValidatorTx = kvstore.MakeValSetChangeTx(val1PubKeyABCI, 2)
 	previousTotalVotingPower = css[0].GetRoundState().LastValidators.TotalVotingPower()
 
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css, updateValidatorTx)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css, updateValidatorTx)
-	waitForAndValidateBlockWithTx(t, nVals, activeVals, eventChans, css, updateValidatorTx)
+	waitForAndValidateBlockWithTx(t, nVals, activeVals, eventSubs, css, updateValidatorTx)
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css)
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css)
 
 	if css[0].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
 		t.Fatalf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[0].GetRoundState().LastValidators.TotalVotingPower())
@@ -310,10 +315,10 @@ func TestReactorVotingPowerChange(t *testing.T) {
 	updateValidatorTx = kvstore.MakeValSetChangeTx(val1PubKeyABCI, 26)
 	previousTotalVotingPower = css[0].GetRoundState().LastValidators.TotalVotingPower()
 
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css, updateValidatorTx)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css, updateValidatorTx)
-	waitForAndValidateBlockWithTx(t, nVals, activeVals, eventChans, css, updateValidatorTx)
+	waitForAndValidateBlockWithTx(t, nVals, activeVals, eventSubs, css, updateValidatorTx)
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css)
-	waitForAndValidateBlock(t, nVals, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nVals, activeVals, eventSubs, css)
 
 	if css[0].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
 		t.Fatalf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[0].GetRoundState().LastValidators.TotalVotingPower())
@@ -327,7 +332,7 @@ func TestReactorValidatorSetChanges(t *testing.T) {
 
 	logger := log.TestingLogger()
 
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, nPeers)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, nPeers)
 	defer stopConsensusNet(logger, reactors, eventBuses)
 
 	// map of active validators
@@ -339,7 +344,7 @@ func TestReactorValidatorSetChanges(t *testing.T) {
 
 	// wait till everyone makes block 1
 	timeoutWaitGroup(t, nPeers, func(j int) {
-		<-eventChans[j]
+		<-eventSubs[j].Out()
 	}, css)
 
 	//---------------------------------------------------------------------------
@@ -352,22 +357,22 @@ func TestReactorValidatorSetChanges(t *testing.T) {
 	// wait till everyone makes block 2
 	// ensure the commit includes all validators
 	// send newValTx to change vals in block 3
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, newValidatorTx1)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css, newValidatorTx1)
 
 	// wait till everyone makes block 3.
 	// it includes the commit for block 2, which is by the original validator set
-	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventChans, css, newValidatorTx1)
+	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventSubs, css, newValidatorTx1)
 
 	// wait till everyone makes block 4.
 	// it includes the commit for block 3, which is by the original validator set
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css)
 
 	// the commits for block 4 should be with the updated validator set
 	activeVals[string(newValidatorPubKey1.Address())] = struct{}{}
 
 	// wait till everyone makes block 5
 	// it includes the commit for block 4, which should have the updated validator set
-	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)
+	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventSubs, css)
 
 	//---------------------------------------------------------------------------
 	logger.Info("---------------------------- Testing changing the voting power of one validator")
@@ -377,10 +382,10 @@ func TestReactorValidatorSetChanges(t *testing.T) {
 	updateValidatorTx1 := kvstore.MakeValSetChangeTx(updatePubKey1ABCI, 25)
 	previousTotalVotingPower := css[nVals].GetRoundState().LastValidators.TotalVotingPower()
 
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, updateValidatorTx1)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css, updateValidatorTx1)
-	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventChans, css, updateValidatorTx1)
+	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventSubs, css, updateValidatorTx1)
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css)
-	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)
+	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventSubs, css)
 
 	if css[nVals].GetRoundState().LastValidators.TotalVotingPower() == previousTotalVotingPower {
 		t.Errorf("expected voting power to change (before: %d, after: %d)", previousTotalVotingPower, css[nVals].GetRoundState().LastValidators.TotalVotingPower())
@@ -397,12 +402,12 @@ func TestReactorValidatorSetChanges(t *testing.T) {
 	newVal3ABCI := types.TM2PB.PubKey(newValidatorPubKey3)
 	newValidatorTx3 := kvstore.MakeValSetChangeTx(newVal3ABCI, testMinPower)
 
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, newValidatorTx2, newValidatorTx3)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css, newValidatorTx2, newValidatorTx3)
-	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventChans, css, newValidatorTx2, newValidatorTx3)
+	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventSubs, css, newValidatorTx2, newValidatorTx3)
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css)
 	activeVals[string(newValidatorPubKey2.Address())] = struct{}{}
 	activeVals[string(newValidatorPubKey3.Address())] = struct{}{}
-	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)
+	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventSubs, css)
 
 	//---------------------------------------------------------------------------
 	logger.Info("---------------------------- Testing removing two validators at once")
@@ -410,12 +415,12 @@ func TestReactorValidatorSetChanges(t *testing.T) {
 	removeValidatorTx2 := kvstore.MakeValSetChangeTx(newVal2ABCI, 0)
 	removeValidatorTx3 := kvstore.MakeValSetChangeTx(newVal3ABCI, 0)
 
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css, removeValidatorTx2, removeValidatorTx3)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css, removeValidatorTx2, removeValidatorTx3)
-	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventChans, css, removeValidatorTx2, removeValidatorTx3)
+	waitForAndValidateBlockWithTx(t, nPeers, activeVals, eventSubs, css, removeValidatorTx2, removeValidatorTx3)
-	waitForAndValidateBlock(t, nPeers, activeVals, eventChans, css)
+	waitForAndValidateBlock(t, nPeers, activeVals, eventSubs, css)
 	delete(activeVals, string(newValidatorPubKey2.Address()))
 	delete(activeVals, string(newValidatorPubKey3.Address()))
-	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventChans, css)
+	waitForBlockWithUpdatedValsAndValidateIt(t, nPeers, activeVals, eventSubs, css)
 }
 
 // Check we can make blocks with skip_timeout_commit=false
@@ -427,23 +432,30 @@ func TestReactorWithTimeoutCommit(t *testing.T) {
 		css[i].config.SkipTimeoutCommit = false
 	}
 
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, N-1)
+	reactors, eventSubs, eventBuses := startConsensusNet(t, css, N-1)
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
 
 	// wait till everyone makes the first new block
 	timeoutWaitGroup(t, N-1, func(j int) {
-		<-eventChans[j]
+		<-eventSubs[j].Out()
 	}, css)
 }
 
-func waitForAndValidateBlock(t *testing.T, n int, activeVals map[string]struct{}, eventChans []chan interface{}, css []*ConsensusState, txs ...[]byte) {
+func waitForAndValidateBlock(
+	t *testing.T,
+	n int,
+	activeVals map[string]struct{},
+	eventSubs []*tmpubsub.Subscription,
+	css []*ConsensusState,
+	txs ...[]byte,
+) {
 	timeoutWaitGroup(t, n, func(j int) {
 		css[j].Logger.Debug("waitForAndValidateBlock")
-		newBlockI, ok := <-eventChans[j]
+		newBlockI, ok := <-eventSubs[j].Out()
 		if !ok {
 			return
 		}
-		newBlock := newBlockI.(types.EventDataNewBlock).Block
+		newBlock := newBlockI.Msg.(types.EventDataNewBlock).Block
 		css[j].Logger.Debug("waitForAndValidateBlock: Got block", "height", newBlock.Height)
 		err := validateBlock(newBlock, activeVals)
 		assert.Nil(t, err)
@@ -454,17 +466,24 @@ func waitForAndValidateBlock(t *testing.T, n int, activeVals map[string]struct{}
 	}, css)
 }
 
-func waitForAndValidateBlockWithTx(t *testing.T, n int, activeVals map[string]struct{}, eventChans []chan interface{}, css []*ConsensusState, txs ...[]byte) {
+func waitForAndValidateBlockWithTx(
+	t *testing.T,
+	n int,
+	activeVals map[string]struct{},
+	eventSubs []*tmpubsub.Subscription,
+	css []*ConsensusState,
+	txs ...[]byte,
+) {
 	timeoutWaitGroup(t, n, func(j int) {
 		ntxs := 0
 	BLOCK_TX_LOOP:
 		for {
 			css[j].Logger.Debug("waitForAndValidateBlockWithTx", "ntxs", ntxs)
-			newBlockI, ok := <-eventChans[j]
+			newBlockI, ok := <-eventSubs[j].Out()
 			if !ok {
 				return
 			}
-			newBlock := newBlockI.(types.EventDataNewBlock).Block
+			newBlock := newBlockI.Msg.(types.EventDataNewBlock).Block
 			css[j].Logger.Debug("waitForAndValidateBlockWithTx: Got block", "height", newBlock.Height)
 			err := validateBlock(newBlock, activeVals)
 			assert.Nil(t, err)
@@ -485,18 +504,24 @@ func waitForAndValidateBlockWithTx(t *testing.T, n int, activeVals map[string]st
 	}, css)
 }
 
-func waitForBlockWithUpdatedValsAndValidateIt(t *testing.T, n int, updatedVals map[string]struct{}, eventChans []chan interface{}, css []*ConsensusState) {
+func waitForBlockWithUpdatedValsAndValidateIt(
+	t *testing.T,
+	n int,
+	updatedVals map[string]struct{},
+	eventSubs []*tmpubsub.Subscription,
+	css []*ConsensusState,
+) {
 	timeoutWaitGroup(t, n, func(j int) {
 
 		var newBlock *types.Block
 	LOOP:
 		for {
 			css[j].Logger.Debug("waitForBlockWithUpdatedValsAndValidateIt")
-			newBlockI, ok := <-eventChans[j]
+			newBlockI, ok := <-eventSubs[j].Out()
 			if !ok {
 				return
 			}
-			newBlock = newBlockI.(types.EventDataNewBlock).Block
+			newBlock = newBlockI.Msg.(types.EventDataNewBlock).Block
 			if newBlock.LastCommit.Size() == len(updatedVals) {
 				css[j].Logger.Debug("waitForBlockWithUpdatedValsAndValidateIt: Got block", "height", newBlock.Height)
 				break LOOP

consensus/replay.go

@@ -17,6 +17,7 @@ import (
 	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
 
+	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
@@ -42,7 +43,7 @@ var crc32c = crc32.MakeTable(crc32.Castagnoli)
 // Unmarshal and apply a single message to the consensus state as if it were
 // received in receiveRoutine.  Lines that start with "#" are ignored.
 // NOTE: receiveRoutine should not be running.
-func (cs *ConsensusState) readReplayMessage(msg *TimedWALMessage, newStepCh chan interface{}) error {
+func (cs *ConsensusState) readReplayMessage(msg *TimedWALMessage, newStepSub *tmpubsub.Subscription) error {
 	// Skip meta messages which exist for demarcating boundaries.
 	if _, ok := msg.Msg.(EndHeightMessage); ok {
 		return nil
@@ -54,15 +55,17 @@ func (cs *ConsensusState) readReplayMessage(msg *TimedWALMessage, newStepCh chan
 		cs.Logger.Info("Replay: New Step", "height", m.Height, "round", m.Round, "step", m.Step)
 		// these are playback checks
 		ticker := time.After(time.Second * 2)
-		if newStepCh != nil {
+		if newStepSub != nil {
 			select {
-			case mi := <-newStepCh:
+			case mi := <-newStepSub.Out():
-				m2 := mi.(types.EventDataRoundState)
+				m2 := mi.Msg.(types.EventDataRoundState)
 				if m.Height != m2.Height || m.Round != m2.Round || m.Step != m2.Step {
 					return fmt.Errorf("RoundState mismatch. Got %v; Expected %v", m2, m)
 				}
+			case <-newStepSub.Cancelled():
+				return fmt.Errorf("Failed to read off newStepSub.Out(). newStepSub was cancelled")
 			case <-ticker:
-				return fmt.Errorf("Failed to read off newStepCh")
+				return fmt.Errorf("Failed to read off newStepSub.Out()")
 			}
 		}
 	case msgInfo:

consensus/replay_file.go

@@ -16,6 +16,7 @@ import (
 	cmn "github.com/tendermint/tendermint/libs/common"
 	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
+	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
@@ -51,25 +52,13 @@ func (cs *ConsensusState) ReplayFile(file string, console bool) error {
 	cs.startForReplay()
 
 	// ensure all new step events are regenerated as expected
-	newStepCh := make(chan interface{}, 1)
 
 	ctx := context.Background()
-	err := cs.eventBus.Subscribe(ctx, subscriber, types.EventQueryNewRoundStep, newStepCh)
+	newStepSub, err := cs.eventBus.Subscribe(ctx, subscriber, types.EventQueryNewRoundStep)
 	if err != nil {
 		return errors.Errorf("failed to subscribe %s to %v", subscriber, types.EventQueryNewRoundStep)
 	}
-	defer func() {
+	defer cs.eventBus.Unsubscribe(ctx, subscriber, types.EventQueryNewRoundStep)
-		// drain newStepCh to make sure we don't block
-	LOOP:
-		for {
-			select {
-			case <-newStepCh:
-			default:
-				break LOOP
-			}
-		}
-		cs.eventBus.Unsubscribe(ctx, subscriber, types.EventQueryNewRoundStep)
-	}()
 
 	// just open the file for reading, no need to use wal
 	fp, err := os.OpenFile(file, os.O_RDONLY, 0600)
@@ -94,7 +83,8 @@ func (cs *ConsensusState) ReplayFile(file string, console bool) error {
 			return err
 		}
 
-		if err := pb.cs.readReplayMessage(msg, newStepCh); err != nil {
+		// TODO: pass a subscription
+		if err := pb.cs.readReplayMessage(msg, newStepSub); err != nil {
 			return err
 		}
 
@@ -132,7 +122,7 @@ func newPlayback(fileName string, fp *os.File, cs *ConsensusState, genState sm.S
 }
 
 // go back count steps by resetting the state and running (pb.count - count) steps
-func (pb *playback) replayReset(count int, newStepCh chan interface{}) error {
+func (pb *playback) replayReset(count int, newStepSub *tmpubsub.Subscription) error {
 	pb.cs.Stop()
 	pb.cs.Wait()
 
@@ -162,7 +152,7 @@ func (pb *playback) replayReset(count int, newStepCh chan interface{}) error {
 		} else if err != nil {
 			return err
 		}
-		if err := pb.cs.readReplayMessage(msg, newStepCh); err != nil {
+		if err := pb.cs.readReplayMessage(msg, newStepSub); err != nil {
 			return err
 		}
 		pb.count++
@@ -226,27 +216,16 @@ func (pb *playback) replayConsoleLoop() int {
 
 			ctx := context.Background()
 			// ensure all new step events are regenerated as expected
-			newStepCh := make(chan interface{}, 1)
 
-			err := pb.cs.eventBus.Subscribe(ctx, subscriber, types.EventQueryNewRoundStep, newStepCh)
+			newStepSub, err := pb.cs.eventBus.Subscribe(ctx, subscriber, types.EventQueryNewRoundStep)
 			if err != nil {
 				cmn.Exit(fmt.Sprintf("failed to subscribe %s to %v", subscriber, types.EventQueryNewRoundStep))
 			}
-			defer func() {
+			defer pb.cs.eventBus.Unsubscribe(ctx, subscriber, types.EventQueryNewRoundStep)
-				// drain newStepCh to make sure we don't block
-			LOOP:
-				for {
-					select {
-					case <-newStepCh:
-					default:
-						break LOOP
-					}
-				}
-				pb.cs.eventBus.Unsubscribe(ctx, subscriber, types.EventQueryNewRoundStep)
-			}()
 
 			if len(tokens) == 1 {
-				if err := pb.replayReset(1, newStepCh); err != nil {
+				// TODO: pass a subscription
+				if err := pb.replayReset(1, newStepSub); err != nil {
 					pb.cs.Logger.Error("Replay reset error", "err", err)
 				}
 			} else {
@@ -256,7 +235,8 @@ func (pb *playback) replayConsoleLoop() int {
 				} else if i > pb.count {
 					fmt.Printf("argument to back must not be larger than the current count (%d)\n", pb.count)
 				} else {
-					if err := pb.replayReset(i, newStepCh); err != nil {
+					// TODO: pass a subscription
+					if err := pb.replayReset(i, newStepSub); err != nil {
 						pb.cs.Logger.Error("Replay reset error", "err", err)
 					}
 				}

consensus/replay_test.go

@@ -70,13 +70,14 @@ func startNewConsensusStateAndWaitForBlock(t *testing.T, lastBlockHeight int64,
 	// in the WAL itself. Assuming the consensus state is running, replay of any
 	// WAL, including the empty one, should eventually be followed by a new
 	// block, or else something is wrong.
-	newBlockCh := make(chan interface{}, 1)
+	newBlockSub, err := cs.eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock)
-	err = cs.eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock, newBlockCh)
 	require.NoError(t, err)
 	select {
-	case <-newBlockCh:
+	case <-newBlockSub.Out():
+	case <-newBlockSub.Cancelled():
+		t.Fatal("newBlockSub was cancelled")
 	case <-time.After(60 * time.Second):
-		t.Fatalf("Timed out waiting for new block (see trace above)")
+		t.Fatal("Timed out waiting for new block (see trace above)")
 	}
 }
 

consensus/state_test.go

@@ -1565,11 +1565,11 @@ func TestStateOutputVoteStats(t *testing.T) {
 }
 
 // subscribe subscribes test client to the given query and returns a channel with cap = 1.
-func subscribe(eventBus *types.EventBus, q tmpubsub.Query) <-chan interface{} {
+func subscribe(eventBus *types.EventBus, q tmpubsub.Query) <-chan tmpubsub.MsgAndTags {
-	out := make(chan interface{}, 1)
+	sub, err := eventBus.Subscribe(context.Background(), testSubscriber, q)
-	err := eventBus.Subscribe(context.Background(), testSubscriber, q, out)
 	if err != nil {
 		panic(fmt.Sprintf("failed to subscribe %s to %v", testSubscriber, q))
 	}
-	return out
+	// XXX: return a subscription?
+	return sub.Out()
 }

rpc/core/events.go

@@ -101,16 +101,30 @@ func Subscribe(wsCtx rpctypes.WSRPCContext, query string) (*ctypes.ResultSubscri
 
 	ctx, cancel := context.WithTimeout(context.Background(), subscribeTimeout)
 	defer cancel()
-	ch := make(chan interface{})
+	sub, err := eventBusFor(wsCtx).Subscribe(ctx, addr, q)
-	err = eventBusFor(wsCtx).Subscribe(ctx, addr, q, ch)
 	if err != nil {
 		return nil, err
 	}
 
 	go func() {
-		for event := range ch {
+		for {
-			tmResult := &ctypes.ResultEvent{query, event.(tmtypes.TMEventData)}
+			select {
-			wsCtx.TryWriteRPCResponse(rpctypes.NewRPCSuccessResponse(wsCtx.Codec(), rpctypes.JSONRPCStringID(fmt.Sprintf("%v#event", wsCtx.Request.ID)), tmResult))
+			case event := <-sub.Out():
+				tmResult := &ctypes.ResultEvent{query, event.Msg.(tmtypes.TMEventData)}
+				wsCtx.TryWriteRPCResponse(
+					rpctypes.NewRPCSuccessResponse(
+						wsCtx.Codec(),
+						rpctypes.JSONRPCStringID(fmt.Sprintf("%v#event", wsCtx.Request.ID)),
+						tmResult,
+					))
+			case <-sub.Cancelled():
+				wsCtx.TryWriteRPCResponse(
+					rpctypes.RPCServerError(rpctypes.JSONRPCStringID(
+						fmt.Sprintf("%v#event", wsCtx.Request.ID)),
+						fmt.Errorf("subscription was cancelled (reason: %v)", sub.Err()),
+					))
+				return
+			}
 		}
 	}()
 

rpc/core/mempool.go

@@ -169,26 +169,14 @@ func BroadcastTxCommit(tx types.Tx) (*ctypes.ResultBroadcastTxCommit, error) {
 	// Subscribe to tx being committed in block.
 	ctx, cancel := context.WithTimeout(context.Background(), subscribeTimeout)
 	defer cancel()
-	deliverTxResCh := make(chan interface{}, 1)
 	q := types.EventQueryTxFor(tx)
-	err := eventBus.Subscribe(ctx, "mempool", q, deliverTxResCh)
+	deliverTxSub, err := eventBus.Subscribe(ctx, "mempool", q)
 	if err != nil {
 		err = errors.Wrap(err, "failed to subscribe to tx")
 		logger.Error("Error on broadcast_tx_commit", "err", err)
 		return nil, err
 	}
-	defer func() {
+	defer eventBus.Unsubscribe(context.Background(), "mempool", q)
-		// drain deliverTxResCh to make sure we don't block
-	LOOP:
-		for {
-			select {
-			case <-deliverTxResCh:
-			default:
-				break LOOP
-			}
-		}
-		eventBus.Unsubscribe(context.Background(), "mempool", q)
-	}()
 
 	// Broadcast tx and wait for CheckTx result
 	checkTxResCh := make(chan *abci.Response, 1)
@@ -213,17 +201,22 @@ func BroadcastTxCommit(tx types.Tx) (*ctypes.ResultBroadcastTxCommit, error) {
 	// TODO: configurable?
 	var deliverTxTimeout = rpcserver.WriteTimeout / 2
 	select {
-	case deliverTxResMsg, ok := <-deliverTxResCh: // The tx was included in a block.
+	case deliverTxResMsg := <-deliverTxSub.Out(): // The tx was included in a block.
-		if !ok {
+		deliverTxRes := deliverTxResMsg.Msg.(types.EventDataTx)
-			return nil, errors.New("Error on broadcastTxCommit: expected DeliverTxResult, got nil. Did the Tendermint stop?")
-		}
-		deliverTxRes := deliverTxResMsg.(types.EventDataTx)
 		return &ctypes.ResultBroadcastTxCommit{
 			CheckTx:   *checkTxRes,
 			DeliverTx: deliverTxRes.Result,
 			Hash:      tx.Hash(),
 			Height:    deliverTxRes.Height,
 		}, nil
+	case <-deliverTxSub.Cancelled():
+		err = errors.New("deliverTxSub was cancelled. Did the Tendermint stop?")
+		logger.Error("Error on broadcastTxCommit", "err", err)
+		return &ctypes.ResultBroadcastTxCommit{
+			CheckTx:   *checkTxRes,
+			DeliverTx: abci.ResponseDeliverTx{},
+			Hash:      tx.Hash(),
+		}, err
 	case <-time.After(deliverTxTimeout):
 		err = errors.New("Timed out waiting for tx to be included in a block")
 		logger.Error("Error on broadcastTxCommit", "err", err)

state/execution_test.go

@@ -317,8 +317,7 @@ func TestEndBlockValidatorUpdates(t *testing.T) {
 	defer eventBus.Stop()
 	blockExec.SetEventBus(eventBus)
 
-	updatesCh := make(chan interface{}, 1)
+	updatesSub, err := eventBus.Subscribe(context.Background(), "TestEndBlockValidatorUpdates", types.EventQueryValidatorSetUpdates)
-	err = eventBus.Subscribe(context.Background(), "TestEndBlockValidatorUpdates", types.EventQueryValidatorSetUpdates, updatesCh)
 	require.NoError(t, err)
 
 	block := makeBlock(state, 1)
@@ -342,13 +341,15 @@ func TestEndBlockValidatorUpdates(t *testing.T) {
 
 	// test we threw an event
 	select {
-	case e := <-updatesCh:
+	case e := <-updatesSub.Out():
-		event, ok := e.(types.EventDataValidatorSetUpdates)
+		event, ok := e.Msg.(types.EventDataValidatorSetUpdates)
 		require.True(t, ok, "Expected event of type EventDataValidatorSetUpdates, got %T", e)
 		if assert.NotEmpty(t, event.ValidatorUpdates) {
 			assert.Equal(t, pubkey, event.ValidatorUpdates[0].PubKey)
 			assert.EqualValues(t, 10, event.ValidatorUpdates[0].VotingPower)
 		}
+	case <-updatesSub.Cancelled():
+		t.Fatal("updatesSub was cancelled.")
 	case <-time.After(1 * time.Second):
 		t.Fatal("Did not receive EventValidatorSetUpdates within 1 sec.")
 	}

state/txindex/indexer_service.go

@@ -31,35 +31,44 @@ func NewIndexerService(idr TxIndexer, eventBus *types.EventBus) *IndexerService
 // OnStart implements cmn.Service by subscribing for all transactions
 // and indexing them by tags.
 func (is *IndexerService) OnStart() error {
-	blockHeadersCh := make(chan interface{})
+	blockHeadersSub, err := is.eventBus.Subscribe(context.Background(), subscriber, types.EventQueryNewBlockHeader)
-	if err := is.eventBus.Subscribe(context.Background(), subscriber, types.EventQueryNewBlockHeader, blockHeadersCh); err != nil {
+	if err != nil {
 		return err
 	}
 
-	txsCh := make(chan interface{})
+	txsSub, err := is.eventBus.Subscribe(context.Background(), subscriber, types.EventQueryTx)
-	if err := is.eventBus.Subscribe(context.Background(), subscriber, types.EventQueryTx, txsCh); err != nil {
+	if err != nil {
 		return err
 	}
 
 	go func() {
 		for {
-			e, ok := <-blockHeadersCh
+			select {
-			if !ok {
+			case msgAndTags := <-blockHeadersSub.Out():
-				return
+				header := msgAndTags.Msg.(types.EventDataNewBlockHeader).Header
-			}
-			header := e.(types.EventDataNewBlockHeader).Header
 				batch := NewBatch(header.NumTxs)
 				for i := int64(0); i < header.NumTxs; i++ {
-				e, ok := <-txsCh
+					select {
-				if !ok {
+					case msgAndTags := <-txsSub.Out():
-					is.Logger.Error("Failed to index all transactions due to closed transactions channel", "height", header.Height, "numTxs", header.NumTxs, "numProcessed", i)
+						txResult := msgAndTags.Msg.(types.EventDataTx).TxResult
+						batch.Add(&txResult)
+					case <-txsSub.Cancelled():
+						is.Logger.Error("Failed to index a block. txsSub was cancelled. Did the Tendermint stop?",
+							"err", txsSub.Err(),
+							"height", header.Height,
+							"numTxs", header.NumTxs,
+							"numProcessed", i,
+						)
 						return
 					}
-				txResult := e.(types.EventDataTx).TxResult
-				batch.Add(&txResult)
 				}
 				is.idr.AddBatch(batch)
 				is.Logger.Info("Indexed block", "height", header.Height)
+			case <-blockHeadersSub.Cancelled():
+				is.Logger.Error("Failed to index a block. blockHeadersSub was cancelled. Did the Tendermint stop?",
+					"reason", blockHeadersSub.Err())
+				return
+			}
 		}
 	}()
 	return nil

types/event_bus.go

@@ -12,7 +12,7 @@ import (
 const defaultCapacity = 0
 
 type EventBusSubscriber interface {
-	Subscribe(ctx context.Context, subscriber string, query tmpubsub.Query, out chan<- interface{}) error
+	Subscribe(ctx context.Context, subscriber string, query tmpubsub.Query, outCapacity ...int) (*tmpubsub.Subscription, error)
 	Unsubscribe(ctx context.Context, subscriber string, query tmpubsub.Query) error
 	UnsubscribeAll(ctx context.Context, subscriber string) error
 }
@@ -52,8 +52,8 @@ func (b *EventBus) OnStop() {
 	b.pubsub.Stop()
 }
 
-func (b *EventBus) Subscribe(ctx context.Context, subscriber string, query tmpubsub.Query, out chan<- interface{}) error {
+func (b *EventBus) Subscribe(ctx context.Context, subscriber string, query tmpubsub.Query, outCapacity ...int) (*tmpubsub.Subscription, error) {
-	return b.pubsub.Subscribe(ctx, subscriber, query, out)
+	return b.pubsub.Subscribe(ctx, subscriber, query, outCapacity...)
 }
 
 func (b *EventBus) Unsubscribe(ctx context.Context, subscriber string, query tmpubsub.Query) error {

types/event_bus_test.go

@@ -24,23 +24,20 @@ func TestEventBusPublishEventTx(t *testing.T) {
 	tx := Tx("foo")
 	result := abci.ResponseDeliverTx{Data: []byte("bar"), Tags: []cmn.KVPair{{Key: []byte("baz"), Value: []byte("1")}}}
 
-	txEventsCh := make(chan interface{})
-
 	// PublishEventTx adds all these 3 tags, so the query below should work
 	query := fmt.Sprintf("tm.event='Tx' AND tx.height=1 AND tx.hash='%X' AND baz=1", tx.Hash())
-	err = eventBus.Subscribe(context.Background(), "test", tmquery.MustParse(query), txEventsCh)
+	txEventsSub, err := eventBus.Subscribe(context.Background(), "test", tmquery.MustParse(query))
 	require.NoError(t, err)
 
 	done := make(chan struct{})
 	go func() {
-		for e := range txEventsCh {
+		e := <-txEventsSub.Out()
-			edt := e.(EventDataTx)
+		edt := e.Msg.(EventDataTx)
 		assert.Equal(t, int64(1), edt.Height)
 		assert.Equal(t, uint32(0), edt.Index)
 		assert.Equal(t, tx, edt.Tx)
 		assert.Equal(t, result, edt.Result)
 		close(done)
-		}
 	}()
 
 	err = eventBus.PublishEventTx(EventDataTx{TxResult{
@@ -68,22 +65,19 @@ func TestEventBusPublishEventNewBlock(t *testing.T) {
 	resultBeginBlock := abci.ResponseBeginBlock{Tags: []cmn.KVPair{{Key: []byte("baz"), Value: []byte("1")}}}
 	resultEndBlock := abci.ResponseEndBlock{Tags: []cmn.KVPair{{Key: []byte("foz"), Value: []byte("2")}}}
 
-	txEventsCh := make(chan interface{})
-
 	// PublishEventNewBlock adds the tm.event tag, so the query below should work
 	query := "tm.event='NewBlock' AND baz=1 AND foz=2"
-	err = eventBus.Subscribe(context.Background(), "test", tmquery.MustParse(query), txEventsCh)
+	txEventsSub, err := eventBus.Subscribe(context.Background(), "test", tmquery.MustParse(query))
 	require.NoError(t, err)
 
 	done := make(chan struct{})
 	go func() {
-		for e := range txEventsCh {
+		e := <-txEventsSub.Out()
-			edt := e.(EventDataNewBlock)
+		edt := e.Msg.(EventDataNewBlock)
 		assert.Equal(t, block, edt.Block)
 		assert.Equal(t, resultBeginBlock, edt.ResultBeginBlock)
 		assert.Equal(t, resultEndBlock, edt.ResultEndBlock)
 		close(done)
-		}
 	}()
 
 	err = eventBus.PublishEventNewBlock(EventDataNewBlock{
@@ -110,22 +104,19 @@ func TestEventBusPublishEventNewBlockHeader(t *testing.T) {
 	resultBeginBlock := abci.ResponseBeginBlock{Tags: []cmn.KVPair{{Key: []byte("baz"), Value: []byte("1")}}}
 	resultEndBlock := abci.ResponseEndBlock{Tags: []cmn.KVPair{{Key: []byte("foz"), Value: []byte("2")}}}
 
-	txEventsCh := make(chan interface{})
-
 	// PublishEventNewBlockHeader adds the tm.event tag, so the query below should work
 	query := "tm.event='NewBlockHeader' AND baz=1 AND foz=2"
-	err = eventBus.Subscribe(context.Background(), "test", tmquery.MustParse(query), txEventsCh)
+	txEventsSub, err := eventBus.Subscribe(context.Background(), "test", tmquery.MustParse(query))
 	require.NoError(t, err)
 
 	done := make(chan struct{})
 	go func() {
-		for e := range txEventsCh {
+		e := <-txEventsSub.Out()
-			edt := e.(EventDataNewBlockHeader)
+		edt := e.Msg.(EventDataNewBlockHeader)
 		assert.Equal(t, block.Header, edt.Header)
 		assert.Equal(t, resultBeginBlock, edt.ResultBeginBlock)
 		assert.Equal(t, resultEndBlock, edt.ResultEndBlock)
 		close(done)
-		}
 	}()
 
 	err = eventBus.PublishEventNewBlockHeader(EventDataNewBlockHeader{
@@ -148,18 +139,18 @@ func TestEventBusPublish(t *testing.T) {
 	require.NoError(t, err)
 	defer eventBus.Stop()
 
-	eventsCh := make(chan interface{})
+	eventsSub, err := eventBus.Subscribe(context.Background(), "test", tmquery.Empty{})
-	err = eventBus.Subscribe(context.Background(), "test", tmquery.Empty{}, eventsCh)
 	require.NoError(t, err)
 
 	const numEventsExpected = 14
 	done := make(chan struct{})
 	go func() {
 		numEvents := 0
-		for range eventsCh {
+		for range eventsSub.Out() {
 			numEvents++
 			if numEvents >= numEventsExpected {
 				close(done)
+				return
 			}
 		}
 	}()
@@ -243,15 +234,22 @@ func benchmarkEventBus(numClients int, randQueries bool, randEvents bool, b *tes
 	q := EventQueryNewBlock
 
 	for i := 0; i < numClients; i++ {
-		ch := make(chan interface{})
-		go func() {
-			for range ch {
-			}
-		}()
 		if randQueries {
 			q = randQuery()
 		}
-		eventBus.Subscribe(ctx, fmt.Sprintf("client-%d", i), q, ch)
+		sub, err := eventBus.Subscribe(ctx, fmt.Sprintf("client-%d", i), q)
+		if err != nil {
+			b.Fatal(err)
+		}
+		go func() {
+			for {
+				select {
+				case <-sub.Out():
+				case <-sub.Cancelled():
+					return
+				}
+			}
+		}()
 	}
 
 	eventType := EventNewBlock