types: Emit tags from BeginBlock/EndBlock

This commit makes both EventNewBlock and EventNewBlockHeader emit tags
on the event bus, so subscribers can use them in queries.

This is a BREAKING change due to adding a field to the ABCIResponses
structure which is persisted to disk.

CHANGELOG_PENDING.md

@@ -11,6 +11,7 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
 ### BREAKING CHANGES:
 
 * CLI/RPC/Config
+  * [state] [\#2747](https://github.com/tendermint/tendermint/pull/2747) Add `BeginBlock` response to `ABCIResponses` (BREAKING).
 
 * Apps
 
@@ -22,6 +23,8 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
 
 ### FEATURES:
 
+- [types] [\#1571](https://github.com/tendermint/tendermint/issues/1571) Enable subscription to tags emitted from `BeginBlock`/`EndBlock` (@kostko)
+
 ### IMPROVEMENTS:
 
 ### BUG FIXES:

docs/spec/abci/abci.md

@@ -45,7 +45,9 @@ include a `Tags` field in their `Response*`. Each tag is key-value pair denoting
 something about what happened during the methods execution.
 
 Tags can be used to index transactions and blocks according to what happened
-during their execution.
+during their execution. Note that the set of tags returned for a block from
+`BeginBlock` and `EndBlock` are merged. In case both methods return the same
+tag, only the value defined in `EndBlock` is used.
 
 Keys and values in tags must be UTF-8 encoded strings (e.g.
 "account.owner": "Bob", "balance": "100.0",

state/execution.go

@@ -231,8 +231,9 @@ func execBlockOnProxyApp(
 
 	commitInfo, byzVals := getBeginBlockValidatorInfo(block, lastValSet, stateDB)
 
-	// Begin block.
-	_, err := proxyAppConn.BeginBlockSync(abci.RequestBeginBlock{
+	// Begin block
+	var err error
+	abciResponses.BeginBlock, err = proxyAppConn.BeginBlockSync(abci.RequestBeginBlock{
 		Hash:                block.Hash(),
 		Header:              types.TM2PB.Header(&block.Header),
 		LastCommitInfo:      commitInfo,
@@ -425,8 +426,16 @@ func updateState(
 // Fire TxEvent for every tx.
 // NOTE: if Tendermint crashes before commit, some or all of these events may be published again.
 func fireEvents(logger log.Logger, eventBus types.BlockEventPublisher, block *types.Block, abciResponses *ABCIResponses) {
-	eventBus.PublishEventNewBlock(types.EventDataNewBlock{block})
-	eventBus.PublishEventNewBlockHeader(types.EventDataNewBlockHeader{block.Header})
+	eventBus.PublishEventNewBlock(types.EventDataNewBlock{
+		Block:            block,
+		ResultBeginBlock: *abciResponses.BeginBlock,
+		ResultEndBlock:   *abciResponses.EndBlock,
+	})
+	eventBus.PublishEventNewBlockHeader(types.EventDataNewBlockHeader{
+		Header:           block.Header,
+		ResultBeginBlock: *abciResponses.BeginBlock,
+		ResultEndBlock:   *abciResponses.EndBlock,
+	})
 
 	for i, tx := range block.Data.Txs {
 		eventBus.PublishEventTx(types.EventDataTx{types.TxResult{

state/store.go

@@ -105,8 +105,9 @@ func saveState(db dbm.DB, state State, key []byte) {
 // of the various ABCI calls during block processing.
 // It is persisted to disk for each height before calling Commit.
 type ABCIResponses struct {
-	DeliverTx []*abci.ResponseDeliverTx
-	EndBlock  *abci.ResponseEndBlock
+	DeliverTx  []*abci.ResponseDeliverTx
+	BeginBlock *abci.ResponseBeginBlock
+	EndBlock   *abci.ResponseEndBlock
 }
 
 // NewABCIResponses returns a new ABCIResponses

tools/tm-monitor/monitor/node_test.go

@@ -34,7 +34,7 @@ func TestNodeNewBlockReceived(t *testing.T) {
 	n.SendBlocksTo(blockCh)
 
 	blockHeader := tmtypes.Header{Height: 5}
-	emMock.Call("eventCallback", &em.EventMetric{}, tmtypes.EventDataNewBlockHeader{blockHeader})
+	emMock.Call("eventCallback", &em.EventMetric{}, tmtypes.EventDataNewBlockHeader{Header: blockHeader})
 
 	assert.Equal(t, int64(5), n.Height)
 	assert.Equal(t, blockHeader, <-blockCh)

types/event_bus.go

@@ -71,12 +71,48 @@ func (b *EventBus) Publish(eventType string, eventData TMEventData) error {
 	return nil
 }
 
+func (b *EventBus) validateAndStringifyTags(tags []cmn.KVPair, logger log.Logger) map[string]string {
+	result := make(map[string]string)
+	for _, tag := range tags {
+		// basic validation
+		if len(tag.Key) == 0 {
+			logger.Debug("Got tag with an empty key (skipping)", "tag", tag)
+			continue
+		}
+		result[string(tag.Key)] = string(tag.Value)
+	}
+	return result
+}
+
 func (b *EventBus) PublishEventNewBlock(data EventDataNewBlock) error {
-	return b.Publish(EventNewBlock, data)
+	// no explicit deadline for publishing events
+	ctx := context.Background()
+
+	resultTags := append(data.ResultBeginBlock.Tags, data.ResultEndBlock.Tags...)
+	tags := b.validateAndStringifyTags(resultTags, b.Logger.With("block", data.Block.StringShort()))
+
+	// add predefined tags
+	logIfTagExists(EventTypeKey, tags, b.Logger)
+	tags[EventTypeKey] = EventNewBlock
+
+	b.pubsub.PublishWithTags(ctx, data, tmpubsub.NewTagMap(tags))
+	return nil
 }
 
 func (b *EventBus) PublishEventNewBlockHeader(data EventDataNewBlockHeader) error {
-	return b.Publish(EventNewBlockHeader, data)
+	// no explicit deadline for publishing events
+	ctx := context.Background()
+
+	resultTags := append(data.ResultBeginBlock.Tags, data.ResultEndBlock.Tags...)
+	// TODO: Create StringShort method for Header and use it in logger.
+	tags := b.validateAndStringifyTags(resultTags, b.Logger.With("header", data.Header))
+
+	// add predefined tags
+	logIfTagExists(EventTypeKey, tags, b.Logger)
+	tags[EventTypeKey] = EventNewBlockHeader
+
+	b.pubsub.PublishWithTags(ctx, data, tmpubsub.NewTagMap(tags))
+	return nil
 }
 
 func (b *EventBus) PublishEventVote(data EventDataVote) error {
@@ -94,17 +130,7 @@ func (b *EventBus) PublishEventTx(data EventDataTx) error {
 	// no explicit deadline for publishing events
 	ctx := context.Background()
 
-	tags := make(map[string]string)
-
-	// validate and fill tags from tx result
-	for _, tag := range data.Result.Tags {
-		// basic validation
-		if len(tag.Key) == 0 {
-			b.Logger.Info("Got tag with an empty key (skipping)", "tag", tag, "tx", data.Tx)
-			continue
-		}
-		tags[string(tag.Key)] = string(tag.Value)
-	}
+	tags := b.validateAndStringifyTags(data.Result.Tags, b.Logger.With("tx", data.Tx))
 
 	// add predefined tags
 	logIfTagExists(EventTypeKey, tags, b.Logger)

types/event_bus_test.go

@@ -58,6 +58,90 @@ func TestEventBusPublishEventTx(t *testing.T) {
 	}
 }
 
+func TestEventBusPublishEventNewBlock(t *testing.T) {
+	eventBus := NewEventBus()
+	err := eventBus.Start()
+	require.NoError(t, err)
+	defer eventBus.Stop()
+
+	block := MakeBlock(0, []Tx{}, nil, []Evidence{})
+	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)
+	require.NoError(t, err)
+
+	done := make(chan struct{})
+	go func() {
+		for e := range txEventsCh {
+			edt := e.(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{
+		Block:            block,
+		ResultBeginBlock: resultBeginBlock,
+		ResultEndBlock:   resultEndBlock,
+	})
+	assert.NoError(t, err)
+
+	select {
+	case <-done:
+	case <-time.After(1 * time.Second):
+		t.Fatal("did not receive a block after 1 sec.")
+	}
+}
+
+func TestEventBusPublishEventNewBlockHeader(t *testing.T) {
+	eventBus := NewEventBus()
+	err := eventBus.Start()
+	require.NoError(t, err)
+	defer eventBus.Stop()
+
+	block := MakeBlock(0, []Tx{}, nil, []Evidence{})
+	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)
+	require.NoError(t, err)
+
+	done := make(chan struct{})
+	go func() {
+		for e := range txEventsCh {
+			edt := e.(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{
+		Header:           block.Header,
+		ResultBeginBlock: resultBeginBlock,
+		ResultEndBlock:   resultEndBlock,
+	})
+	assert.NoError(t, err)
+
+	select {
+	case <-done:
+	case <-time.After(1 * time.Second):
+		t.Fatal("did not receive a block header after 1 sec.")
+	}
+}
+
 func TestEventBusPublish(t *testing.T) {
 	eventBus := NewEventBus()
 	err := eventBus.Start()

types/events.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	amino "github.com/tendermint/go-amino"
+	abci "github.com/tendermint/tendermint/abci/types"
 	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	tmquery "github.com/tendermint/tendermint/libs/pubsub/query"
 )
@@ -54,11 +55,17 @@ func RegisterEventDatas(cdc *amino.Codec) {
 
 type EventDataNewBlock struct {
 	Block *Block `json:"block"`
+
+	ResultBeginBlock abci.ResponseBeginBlock `json:"result_begin_block"`
+	ResultEndBlock   abci.ResponseEndBlock   `json:"result_end_block"`
 }
 
 // light weight event for benchmarking
 type EventDataNewBlockHeader struct {
 	Header Header `json:"header"`
+
+	ResultBeginBlock abci.ResponseBeginBlock `json:"result_begin_block"`
+	ResultEndBlock   abci.ResponseEndBlock   `json:"result_end_block"`
 }
 
 // All txs fire EventDataTx