abci: Refactor tagging events using list of lists (#3643)

## PR

This PR introduces a fundamental breaking change to the structure of ABCI response and tx tags and the way they're processed. Namely, the SDK can support more complex and aggregated events for distribution and slashing. In addition, block responses can include duplicate keys in events.

    Implement new Event type. An event has a type and a list of KV pairs (ie. list-of-lists). Typical events may look like:

"rewards": [{"amount": "5000uatom", "validator": "...", "recipient": "..."}]
"sender": [{"address": "...", "balance": "100uatom"}]

The events are indexed by {even.type}.{even.attribute[i].key}/.... In this case a client would subscribe or query for rewards.recipient='...'

    ABCI response types and related types now include Events []Event instead of Tags []cmn.KVPair.
    PubSub logic now publishes/matches against map[string][]string instead of map[string]string to support duplicate keys in response events (from #1385). A match is successful if the value is found in the slice of strings.

closes: #1859
closes: #2905

## Commits:

* Implement Event ABCI type and updates responses to use events

* Update messages_test.go

* Update kvstore.go

* Update event_bus.go

* Update subscription.go

* Update pubsub.go

* Update kvstore.go

* Update query logic to handle slice of strings in events

* Update Empty#Matches and unit tests

* Update pubsub logic

* Update EventBus#Publish

* Update kv tx indexer

* Update godocs

* Update ResultEvent to use slice of strings; update RPC

* Update more tests

* Update abci.md

* Check for key in validateAndStringifyEvents

* Fix KV indexer to skip empty keys

* Fix linting errors

* Update CHANGELOG_PENDING.md

* Update docs/spec/abci/abci.md

Co-Authored-By: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

* Update abci/types/types.proto

Co-Authored-By: Ethan Buchman <ethan@coinculture.info>

* Update docs/spec/abci/abci.md

Co-Authored-By: Ethan Buchman <ethan@coinculture.info>

* Update libs/pubsub/query/query.go

Co-Authored-By: Ethan Buchman <ethan@coinculture.info>

* Update match function to match if ANY value matches

* Implement TestSubscribeDuplicateKeys

* Update TestMatches to include multi-key test cases

* Update events.go

* Update Query interface godoc

* Update match godoc

* Add godoc for matchValue

* DRY-up tx indexing

* Return error from PublishWithEvents in EventBus#Publish

* Update PublishEventNewBlockHeader to return an error

* Fix build

* Update events doc in ABCI

* Update ABCI events godoc

* Implement TestEventBusPublishEventTxDuplicateKeys

* Update TestSubscribeDuplicateKeys to be table-driven

* Remove mod file

* Remove markdown from events godoc

* Implement TestTxSearchDeprecatedIndexing test

types/event_bus.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/tendermint/tendermint/abci/types"
 	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
 	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
@@ -90,20 +91,32 @@ func (b *EventBus) UnsubscribeAll(ctx context.Context, subscriber string) error
 func (b *EventBus) Publish(eventType string, eventData TMEventData) error {
 	// no explicit deadline for publishing events
 	ctx := context.Background()
-	b.pubsub.PublishWithTags(ctx, eventData, map[string]string{EventTypeKey: eventType})
-	return nil
+	return b.pubsub.PublishWithEvents(ctx, eventData, map[string][]string{EventTypeKey: {eventType}})
 }
 
-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)
+// validateAndStringifyEvents takes a slice of event objects and creates a
+// map of stringified events where each key is composed of the event
+// type and each of the event's attributes keys in the form of
+// "{event.Type}.{attribute.Key}" and the value is each attribute's value.
+func (b *EventBus) validateAndStringifyEvents(events []types.Event, logger log.Logger) map[string][]string {
+	result := make(map[string][]string)
+	for _, event := range events {
+		if len(event.Type) == 0 {
+			logger.Debug("Got an event with an empty type (skipping)", "event", event)
 			continue
 		}
-		result[string(tag.Key)] = string(tag.Value)
+
+		for _, attr := range event.Attributes {
+			if len(attr.Key) == 0 {
+				logger.Debug("Got an event attribute with an empty key(skipping)", "event", event)
+				continue
+			}
+
+			compositeTag := fmt.Sprintf("%s.%s", event.Type, string(attr.Key))
+			result[compositeTag] = append(result[compositeTag], string(attr.Value))
+		}
 	}
+
 	return result
 }
 
@@ -111,14 +124,13 @@ func (b *EventBus) PublishEventNewBlock(data EventDataNewBlock) error {
 	// 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()))
+	resultEvents := append(data.ResultBeginBlock.Events, data.ResultEndBlock.Events...)
+	events := b.validateAndStringifyEvents(resultEvents, b.Logger.With("block", data.Block.StringShort()))
 
-	// add predefined tags
-	logIfTagExists(EventTypeKey, tags, b.Logger)
-	tags[EventTypeKey] = EventNewBlock
+	// add predefined new block event
+	events[EventTypeKey] = append(events[EventTypeKey], EventNewBlock)
 
-	b.pubsub.PublishWithTags(ctx, data, tags)
+	_ = b.pubsub.PublishWithEvents(ctx, data, events)
 	return nil
 }
 
@@ -126,16 +138,14 @@ func (b *EventBus) PublishEventNewBlockHeader(data EventDataNewBlockHeader) erro
 	// no explicit deadline for publishing events
 	ctx := context.Background()
 
-	resultTags := append(data.ResultBeginBlock.Tags, data.ResultEndBlock.Tags...)
+	resultTags := append(data.ResultBeginBlock.Events, data.ResultEndBlock.Events...)
 	// TODO: Create StringShort method for Header and use it in logger.
-	tags := b.validateAndStringifyTags(resultTags, b.Logger.With("header", data.Header))
+	events := b.validateAndStringifyEvents(resultTags, b.Logger.With("header", data.Header))
 
-	// add predefined tags
-	logIfTagExists(EventTypeKey, tags, b.Logger)
-	tags[EventTypeKey] = EventNewBlockHeader
+	// add predefined new block header event
+	events[EventTypeKey] = append(events[EventTypeKey], EventNewBlockHeader)
 
-	b.pubsub.PublishWithTags(ctx, data, tags)
-	return nil
+	return b.pubsub.PublishWithEvents(ctx, data, events)
 }
 
 func (b *EventBus) PublishEventVote(data EventDataVote) error {
@@ -153,19 +163,14 @@ func (b *EventBus) PublishEventTx(data EventDataTx) error {
 	// no explicit deadline for publishing events
 	ctx := context.Background()
 
-	tags := b.validateAndStringifyTags(data.Result.Tags, b.Logger.With("tx", data.Tx))
+	events := b.validateAndStringifyEvents(data.Result.Events, b.Logger.With("tx", data.Tx))
 
 	// add predefined tags
-	logIfTagExists(EventTypeKey, tags, b.Logger)
-	tags[EventTypeKey] = EventTx
+	events[EventTypeKey] = append(events[EventTypeKey], EventTx)
+	events[TxHashKey] = append(events[TxHashKey], fmt.Sprintf("%X", data.Tx.Hash()))
+	events[TxHeightKey] = append(events[TxHeightKey], fmt.Sprintf("%d", data.Height))
 
-	logIfTagExists(TxHashKey, tags, b.Logger)
-	tags[TxHashKey] = fmt.Sprintf("%X", data.Tx.Hash())
-
-	logIfTagExists(TxHeightKey, tags, b.Logger)
-	tags[TxHeightKey] = fmt.Sprintf("%d", data.Height)
-
-	b.pubsub.PublishWithTags(ctx, data, tags)
+	_ = b.pubsub.PublishWithEvents(ctx, data, events)
 	return nil
 }
 
@@ -209,12 +214,6 @@ func (b *EventBus) PublishEventValidatorSetUpdates(data EventDataValidatorSetUpd
 	return b.Publish(EventValidatorSetUpdates, data)
 }
 
-func logIfTagExists(tag string, tags map[string]string, logger log.Logger) {
-	if value, ok := tags[tag]; ok {
-		logger.Error("Found predefined tag (value will be overwritten)", "tag", tag, "value", value)
-	}
-}
-
 //-----------------------------------------------------------------------------
 type NopEventBus struct{}