backport: implement the ADR 075 /events method (#7965) (#9497)

* rpc: implement the ADR 075 /events method (#7965)

This method implements the eventlog extension interface to expose ABCI metadata
to the log for query processing. Only the types that have ABCI events need to
implement this.

- Add an event log to the environment
- Add a sketch of the handler method
- Add an /events RPCFunc to the route map
- Implement query logic
- Subscribe to pubsub if confingured, handle termination

* add MatchesEvents test

* add TODO due to backport sequence

Co-authored-by: M. J. Fromberger <fromberger@interchain.io>

types/events.go

@@ -2,6 +2,7 @@ package types
 
 import (
 	"fmt"
+	"strings"
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	tmjson "github.com/tendermint/tendermint/libs/json"
@@ -68,6 +69,11 @@ type EventDataNewBlock struct {
 	ResultEndBlock   abci.ResponseEndBlock   `json:"result_end_block"`
 }
 
+// ABCIEvents implements the eventlog.ABCIEventer interface.
+func (e EventDataNewBlock) ABCIEvents() []abci.Event {
+	return append(e.ResultBeginBlock.Events, e.ResultEndBlock.Events...)
+}
+
 type EventDataNewBlockHeader struct {
 	Header Header `json:"header"`
 
@@ -76,6 +82,11 @@ type EventDataNewBlockHeader struct {
 	ResultEndBlock   abci.ResponseEndBlock   `json:"result_end_block"`
 }
 
+// ABCIEvents implements the eventlog.ABCIEventer interface.
+func (e EventDataNewBlockHeader) ABCIEvents() []abci.Event {
+	return append(e.ResultBeginBlock.Events, e.ResultEndBlock.Events...)
+}
+
 type EventDataNewEvidence struct {
 	Evidence Evidence `json:"evidence"`
 
@@ -87,6 +98,15 @@ type EventDataTx struct {
 	abci.TxResult
 }
 
+// ABCIEvents implements the eventlog.ABCIEventer interface.
+func (e EventDataTx) ABCIEvents() []abci.Event {
+	base := []abci.Event{
+		eventWithAttr(TxHashKey, fmt.Sprintf("%X", Tx(e.Tx).Hash())),
+		eventWithAttr(TxHeightKey, fmt.Sprintf("%d", e.Height)),
+	}
+	return append(base, e.Result.Events...)
+}
+
 // NOTE: This goes into the replay WAL
 type EventDataRoundState struct {
 	Height int64  `json:"height"`
@@ -181,3 +201,16 @@ type BlockEventPublisher interface {
 type TxEventPublisher interface {
 	PublishEventTx(EventDataTx) error
 }
+
+// eventWithAttr constructs a single abci.Event with a single attribute.
+// The type of the event and the name of the attribute are obtained by
+// splitting the event type on period (e.g., "foo.bar").
+func eventWithAttr(etype, value string) abci.Event {
+	parts := strings.SplitN(etype, ".", 2)
+	return abci.Event{
+		Type: parts[0],
+		Attributes: []abci.EventAttribute{{
+			Key: parts[1], Value: value,
+		}},
+	}
+}

types/events_test.go

@@ -7,6 +7,22 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+// Verify that the event data types satisfy their shared interface.
+// TODO: add EventDataBlockSyncStatus and EventDataStateSyncStatus
+// when backport #6700 and #6755.
+var (
+	_ TMEventData = EventDataCompleteProposal{}
+	_ TMEventData = EventDataNewBlock{}
+	_ TMEventData = EventDataNewBlockHeader{}
+	_ TMEventData = EventDataNewEvidence{}
+	_ TMEventData = EventDataNewRound{}
+	_ TMEventData = EventDataRoundState{}
+	_ TMEventData = EventDataTx{}
+	_ TMEventData = EventDataValidatorSetUpdates{}
+	_ TMEventData = EventDataVote{}
+	_ TMEventData = EventDataString("")
+)
+
 func TestQueryTxFor(t *testing.T) {
 	tx := Tx("foo")
 	assert.Equal(t,