feat: ADR-038 Part 2: StreamingService interface, file writing implementation, and configuration (#8664)

CHANGELOG.md

@@ -46,6 +46,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 - (cli) [#13089](https://github.com/cosmos/cosmos-sdk/pull/13089) Fix rollback command don't actually delete multistore versions, added method `RollbackToVersion` to interface `CommitMultiStore` and added method `CommitMultiStore` to `Application` interface.
 
+### Improvements
+
+* (store) [\#13326](https://github.com/cosmos/cosmos-sdk/pull/13326) Implementation of ADR-038 file StreamingService, backport #8664
+
 ## v0.45.8 - 2022-08-25
 
 ### Improvements

baseapp/abci.go

@@ -196,6 +196,14 @@ func (app *BaseApp) BeginBlock(req abci.RequestBeginBlock) (res abci.ResponseBeg
 	}
 	// set the signed validators for addition to context in deliverTx
 	app.voteInfos = req.LastCommitInfo.GetVotes()
+
+	// call the hooks with the BeginBlock messages
+	for _, streamingListener := range app.abciListeners {
+		if err := streamingListener.ListenBeginBlock(app.deliverState.ctx, req, res); err != nil {
+			app.logger.Error("BeginBlock listening hook failed", "height", req.Header.Height, "err", err)
+		}
+	}
+
 	return res
 }
 
@@ -216,6 +224,13 @@ func (app *BaseApp) EndBlock(req abci.RequestEndBlock) (res abci.ResponseEndBloc
 		res.ConsensusParamUpdates = cp
 	}
 
+	// call the streaming service hooks with the EndBlock messages
+	for _, streamingListener := range app.abciListeners {
+		if err := streamingListener.ListenEndBlock(app.deliverState.ctx, req, res); err != nil {
+			app.logger.Error("EndBlock listening hook failed", "height", req.Height, "err", err)
+		}
+	}
+
 	return res
 }
 
@@ -260,9 +275,17 @@ func (app *BaseApp) CheckTx(req abci.RequestCheckTx) abci.ResponseCheckTx {
 // Otherwise, the ResponseDeliverTx will contain releveant error information.
 // Regardless of tx execution outcome, the ResponseDeliverTx will contain relevant
 // gas execution context.
-func (app *BaseApp) DeliverTx(req abci.RequestDeliverTx) abci.ResponseDeliverTx {
+func (app *BaseApp) DeliverTx(req abci.RequestDeliverTx) (res abci.ResponseDeliverTx) {
 	defer telemetry.MeasureSince(time.Now(), "abci", "deliver_tx")
 
+	defer func() {
+		for _, streamingListener := range app.abciListeners {
+			if err := streamingListener.ListenDeliverTx(app.deliverState.ctx, req, res); err != nil {
+				app.logger.Error("DeliverTx listening hook failed", "err", err)
+			}
+		}
+	}()
+
 	gInfo := sdk.GasInfo{}
 	resultStr := "successful"
 

baseapp/baseapp.go

@@ -131,6 +131,10 @@ type BaseApp struct { //nolint: maligned
 	// indexEvents defines the set of events in the form {eventType}.{attributeKey},
 	// which informs Tendermint what to index. If empty, all events will be indexed.
 	indexEvents map[string]struct{}
+
+	// abciListeners for hooking into the ABCI message processing of the BaseApp
+	// and exposing the requests and responses to external consumers
+	abciListeners []ABCIListener
 }
 
 // NewBaseApp returns a reference to an initialized BaseApp. It accepts a

baseapp/options.go

@@ -247,3 +247,14 @@ func (app *BaseApp) SetInterfaceRegistry(registry types.InterfaceRegistry) {
 	app.grpcQueryRouter.SetInterfaceRegistry(registry)
 	app.msgServiceRouter.SetInterfaceRegistry(registry)
 }
+
+// SetStreamingService is used to set a streaming service into the BaseApp hooks and load the listeners into the multistore
+func (app *BaseApp) SetStreamingService(s StreamingService) {
+	// add the listeners for each StoreKey
+	for key, lis := range s.Listeners() {
+		app.cms.AddListeners(key, lis)
+	}
+	// register the StreamingService within the BaseApp
+	// BaseApp will pass BeginBlock, DeliverTx, and EndBlock requests and responses to the streaming services to update their ABCI context
+	app.abciListeners = append(app.abciListeners, s)
+}

baseapp/streaming.go

@@ -0,0 +1,33 @@
+package baseapp
+
+import (
+	"io"
+	"sync"
+
+	abci "github.com/tendermint/tendermint/abci/types"
+
+	store "github.com/cosmos/cosmos-sdk/store/types"
+	"github.com/cosmos/cosmos-sdk/types"
+)
+
+// ABCIListener interface used to hook into the ABCI message processing of the BaseApp
+type ABCIListener interface {
+	// ListenBeginBlock updates the streaming service with the latest BeginBlock messages
+	ListenBeginBlock(ctx types.Context, req abci.RequestBeginBlock, res abci.ResponseBeginBlock) error
+	// ListenEndBlock updates the steaming service with the latest EndBlock messages
+	ListenEndBlock(ctx types.Context, req abci.RequestEndBlock, res abci.ResponseEndBlock) error
+	// ListenDeliverTx updates the steaming service with the latest DeliverTx messages
+	ListenDeliverTx(ctx types.Context, req abci.RequestDeliverTx, res abci.ResponseDeliverTx) error
+}
+
+// StreamingService interface for registering WriteListeners with the BaseApp and updating the service with the ABCI messages using the hooks
+type StreamingService interface {
+	// Stream is the streaming service loop, awaits kv pairs and writes them to some destination stream or file
+	Stream(wg *sync.WaitGroup) error
+	// Listeners returns the streaming service's listeners for the BaseApp to register
+	Listeners() map[store.StoreKey][]store.WriteListener
+	// ABCIListener interface for hooking into the ABCI messages from inside the BaseApp
+	ABCIListener
+	// Closer interface
+	io.Closer
+}