indexer: support data exporting/forwarding (#103)

To support more effective and flexible blockchain info exploring, we add
`indexer` package, defines the flow of indexer dameon, and integrate
into dex.Dexon fullnode.

For more export options, we use Golang built-in `plugin` package to
support mulitple implementations.

2 files changed, 19 insertions, 0 deletions

diff --git a/dex/backend.go b/dex/backend.go
index 48e05698f..894906a64 100644
--- a/dex/backend.go
+++ b/dex/backend.go
@@ -33,6 +33,7 @@ import (
 	"github.com/dexon-foundation/dexon/eth/gasprice"
 	"github.com/dexon-foundation/dexon/ethdb"
 	"github.com/dexon-foundation/dexon/event"
+	"github.com/dexon-foundation/dexon/indexer"
 	"github.com/dexon-foundation/dexon/internal/ethapi"
 	"github.com/dexon-foundation/dexon/log"
 	"github.com/dexon-foundation/dexon/node"
@@ -75,6 +76,8 @@ type Dexon struct {
 
 	networkID     uint64
 	netRPCService *ethapi.PublicNetAPI
+
+	indexer indexer.Indexer
 }
 
 func New(ctx *node.ServiceContext, config *Config) (*Dexon, error) {
@@ -132,6 +135,14 @@ func New(ctx *node.ServiceContext, config *Config) (*Dexon, error) {
 	}
 	dex.bloomIndexer.Start(dex.blockchain)
 
+	if config.Indexer.Enable {
+		dex.indexer = indexer.NewIndexerFromConfig(
+			indexer.NewROBlockChain(dex.blockchain),
+			config.Indexer,
+		)
+		dex.indexer.Start()
+	}
+
 	if config.TxPool.Journal != "" {
 		config.TxPool.Journal = ctx.ResolvePath(config.TxPool.Journal)
 	}
@@ -241,6 +252,9 @@ func (s *Dexon) Start(srvr *p2p.Server) error {
 func (s *Dexon) Stop() error {
 	s.bp.Stop()
 	s.app.Stop()
+	if s.indexer != nil {
+		s.indexer.Stop()
+	}
 	return nil
 }
 
diff --git a/dex/config.go b/dex/config.go
index 404be2fb0..8aa002222 100644
--- a/dex/config.go
+++ b/dex/config.go
@@ -28,6 +28,7 @@ import (
 	"github.com/dexon-foundation/dexon/core"
 	"github.com/dexon-foundation/dexon/dex/downloader"
 	"github.com/dexon-foundation/dexon/eth/gasprice"
+	"github.com/dexon-foundation/dexon/indexer"
 	"github.com/dexon-foundation/dexon/params"
 )
 
@@ -48,6 +49,7 @@ var DefaultConfig = Config{
 	},
 	BlockProposerEnabled: false,
 	DefaultGasPrice:      big.NewInt(params.GWei),
+	Indexer:              indexer.Config{},
 }
 
 func init() {
@@ -117,4 +119,7 @@ type Config struct {
 
 	// Dexon options
 	DMoment int64
+
+	// Indexer config
+	Indexer indexer.Config
 }