refactor: filters, pipeline, minor fixes, remove RPC support (#27)

* devnet: snapshot

* refactor: pass struct through pipeline fllters

* refactor: replace timer with ticker

* refactor: filters, jetstream emitter

* add register filter
* update gas filter

* refactor: remove RPC fetcher support

cmd/filters.go

@@ -4,33 +4,50 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/grassrootseconomics/cic-chain-events/internal/events"
 	"github.com/grassrootseconomics/cic-chain-events/internal/filter"
 )
 
+var (
+	systemAddress = strings.ToLower("0x3D85285e39f05773aC92EAD27CB50a4385A529E4")
+)
+
 func initAddressFilter() filter.Filter {
 	// TODO: Bootstrap addresses from smart contract
 	// TODO: Add route to update cache
 	cache := &sync.Map{}
 
 	// Example bootstrap addresses
-	cache.Store(strings.ToLower("0x617f3112bf5397D0467D315cC709EF968D9ba546"), "USDT")
+	cache.Store(strings.ToLower("0xB92463E2262E700e29c16416270c9Fdfa17934D7"), "TRNVoucher")
-	cache.Store(strings.ToLower("0x765DE816845861e75A25fCA122bb6898B8B1282a"), "cUSD")
+	cache.Store(strings.ToLower("0xf2a1fc19Ad275A0EAe3445798761FeD1Eea725d5"), "GasFaucet")
-	cache.Store(strings.ToLower("0xD8763CBa276a3738E6DE85b4b3bF5FDed6D6cA73"), "cEUR")
+	cache.Store(strings.ToLower("0x1e041282695C66944BfC53cabce947cf35CEaf87"), "AddressIndex")
 
 	return filter.NewAddressFilter(filter.AddressFilterOpts{
-		Cache: cache,
+		Cache:         cache,
-		Logg:  lo,
+		Logg:          lo,
+		SystemAddress: systemAddress,
 	})
 }
 
-func initDecodeFilter() filter.Filter {
+func initTransferFilter(eventEmitter events.EventEmitter) filter.Filter {
-	js, err := initJetStream()
+	return filter.NewTransferFilter(filter.TransferFilterOpts{
-	if err != nil {
+		EventEmitter: eventEmitter,
-		lo.Fatal("filters: critical error loading jetstream", "error", err)
+		Logg:         lo,
-	}
+	})
 
-	return filter.NewDecodeFilter(filter.DecodeFilterOpts{
+}
-		Logg:  lo,
+
-		JSCtx: js,
+func initGasGiftFilter(eventEmitter events.EventEmitter) filter.Filter {
+	return filter.NewGasFilter(filter.GasFilterOpts{
+		EventEmitter:  eventEmitter,
+		Logg:          lo,
+		SystemAddress: systemAddress,
+	})
+}
+
+func initRegisterFilter(eventEmitter events.EventEmitter) filter.Filter {
+	return filter.NewRegisterFilter(filter.RegisterFilterOpts{
+		EventEmitter: eventEmitter,
+		Logg:         lo,
 	})
 }

cmd/init.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/grassrootseconomics/cic-chain-events/internal/events"
 	"github.com/grassrootseconomics/cic-chain-events/internal/store"
 	"github.com/grassrootseconomics/cic-chain-events/pkg/fetch"
 	"github.com/jackc/pgx/v5"
@@ -12,7 +13,6 @@ import (
 	"github.com/knadh/koanf/parsers/toml"
 	"github.com/knadh/koanf/providers/env"
 	"github.com/knadh/koanf/providers/file"
-	"github.com/nats-io/nats.go"
 	"github.com/zerodha/logf"
 )
 
@@ -23,6 +23,7 @@ func initLogger(debug bool) logf.Logger {
 
 	if debug {
 		loggOpts.Level = logf.DebugLevel
+		loggOpts.EnableCaller = true
 	}
 
 	return logf.New(loggOpts)
@@ -77,32 +78,16 @@ func initFetcher() fetch.Fetch {
 	})
 }
 
-func initJetStream() (nats.JetStreamContext, error) {
+func initJetStream() (events.EventEmitter, error) {
-	natsConn, err := nats.Connect(ko.MustString("jetstream.endpoint"))
+	jsEmitter, err := events.NewJetStreamEventEmitter(events.JetStreamOpts{
+		ServerUrl:       ko.MustString("jetstream.endpoint"),
+		PersistDuration: time.Duration(ko.MustInt("jetstream.persist_duration_hours")) * time.Hour,
+		DedupDuration:   time.Duration(ko.MustInt("jetstream.dedup_duration_hours")) * time.Hour,
+	})
+
 	if err != nil {
 		return nil, err
 	}
 
-	js, err := natsConn.JetStream()
+	return jsEmitter, nil
-	if err != nil {
-		return nil, err
-	}
-
-	// Bootstrap stream if it does not exist
-	stream, _ := js.StreamInfo(ko.MustString("jetstream.stream_name"))
-	if stream == nil {
-		lo.Info("jetstream: bootstrapping stream")
-		_, err = js.AddStream(&nats.StreamConfig{
-			Name:       ko.MustString("jetstream.stream_name"),
-			MaxAge:     time.Duration(ko.MustInt("jetstream.persist_duration_hours")) * time.Hour,
-			Storage:    nats.FileStorage,
-			Subjects:   ko.MustStrings("jetstream.stream_subjects"),
-			Duplicates: time.Duration(ko.MustInt("jetstream.dedup_duration_hours")) * time.Hour,
-		})
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	return js, nil
 }

cmd/main.go

@@ -10,10 +10,10 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/grassrootseconomics/cic-chain-events/internal/filter"
 	"github.com/grassrootseconomics/cic-chain-events/internal/pipeline"
 	"github.com/grassrootseconomics/cic-chain-events/internal/pool"
 	"github.com/grassrootseconomics/cic-chain-events/internal/syncer"
-	"github.com/grassrootseconomics/cic-chain-events/internal/filter"
 	"github.com/knadh/goyesql/v2"
 	"github.com/knadh/koanf"
 	"github.com/zerodha/logf"
@@ -58,13 +58,20 @@ func main() {
 		lo.Fatal("main: critical error loading pg store", "error", err)
 	}
 
+	jsCtx, err := initJetStream()
+	if err != nil {
+		lo.Fatal("main: critical error loading jetstream context", "error", err)
+	}
+
 	graphqlFetcher := initFetcher()
 
 	pipeline := pipeline.NewPipeline(pipeline.PipelineOpts{
 		BlockFetcher: graphqlFetcher,
 		Filters: []filter.Filter{
 			initAddressFilter(),
-			initDecodeFilter(),
+			initGasGiftFilter(jsCtx),
+			initTransferFilter(jsCtx),
+			initRegisterFilter(jsCtx),
 		},
 		Logg:  lo,
 		Store: pgStore,

config.toml

@@ -1,43 +1,35 @@
 [metrics]
 # Exposes Prometheus metrics
-# /metrics endpoint
 go_process = true
 
 # API server
 [api]
 # Host and port
-address = ":8080"
+address = ":8085"
 
 # Geth API endpoints
 [chain]
-graphql_endpoint = "https://rpc.celo.grassecon.net/graphql"
+graphql_endpoint = "https://rpc.alfajores.celo.grassecon.net/graphql"
-ws_endpoint      = "wss://socket.celo.grassecon.net"
+ws_endpoint      = "wss://ws.alfajores.celo.grassecon.net"
 
+# Syncer configs
 [syncer]
-# Number of goroutines assigned to the janitor worker pool
+# Maximum number of missing blocks pushed into the worker queue every janitor sweep
+janitor_queue_size     = 500
+# Number of goroutines assigned to the worker pool
 janitor_concurrency    = 5
 # Syncer start block
-initial_lower_bound    = 17269000
+initial_lower_bound    = 16373156
-# Max blocks in worker queue awaiting processing
+# Janitor sweep interval, should take into account concurrency and queue_size
-janitor_queue_size     = 500
-# Janitor sweep interval
 janitor_sweep_interval = 5
 
 [postgres]
-# Default is the Docker container DSN
 dsn   = "postgres://postgres:postgres@localhost:5432/cic_chain_events"
 
 # https://docs.nats.io/
 [jetstream]
 endpoint               = "nats://localhost:4222"
-stream_name            = "CHAIN"
+# Duration JetStream should keep the message before GC
-# Duration JetStream should keep the message before remocing it from the persistent store
 persist_duration_hours = 48
 # Duration to ignore duplicate transactions (e.g. due to restart)
 dedup_duration_hours   = 6
-# Stream subjects
-stream_subjects        = [
-    "CHAIN.transfer",
-    "CHAIN.transferFrom",
-    "CHAIN.mintTo"
-]

go.mod

@@ -7,7 +7,6 @@ require (
 	github.com/alitto/pond v1.8.2
 	github.com/celo-org/celo-blockchain v1.6.1
 	github.com/goccy/go-json v0.10.0
-	github.com/grassrootseconomics/cic-celo-sdk v0.3.1
 	github.com/grassrootseconomics/w3-celo-patch v0.1.0
 	github.com/jackc/pgx/v5 v5.2.0
 	github.com/knadh/goyesql/v2 v2.2.0

go.sum

@@ -248,8 +248,6 @@ github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB7
 github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/graph-gophers/graphql-go v1.3.0/go.mod h1:9CQHMSxwO4MprSdzoIEobiHpoLtHm77vfxsvsIN5Vuc=
-github.com/grassrootseconomics/cic-celo-sdk v0.3.1 h1:SzmMFrqxSIdgePqwbUdoS3PNP82MFnlOecycVk2ZYWg=
-github.com/grassrootseconomics/cic-celo-sdk v0.3.1/go.mod h1:EiR6d03GYu6jlVKNL1MbTAw/bqAW2WP3J/lkrZxPMdU=
 github.com/grassrootseconomics/w3-celo-patch v0.1.0 h1:0fev2hYkGEyFX2D4oUG8yy4jXhtHv7qUtLLboXL5ycw=
 github.com/grassrootseconomics/w3-celo-patch v0.1.0/go.mod h1:JtkXc+yDUiQQJdhYTqddZI/itdYGHY7H8PNZzBo4hCk=
 github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0/go.mod h1:8NvIoxWQoOIhqOTXgfV/d3M/q6VIi02HzZEHgUlZvzk=

internal/events/events.go

@@ -0,0 +1,17 @@
+package events
+
+type EventEmitter interface {
+	Close()
+	Publish(subject string, dedupId string, eventPayload interface{}) error
+}
+
+type MinimalTxInfo struct {
+	Block           uint64 `json:"block"`
+	From            string `json:"from"`
+	To              string `json:"to"`
+	ContractAddress string `json:"contractAddress"`
+	Success         bool   `json:"success"`
+	TxHash          string `json:"transactionHash"`
+	TxIndex         uint   `json:"transactionIndex"`
+	Value           uint64 `json:"value"`
+}

internal/events/jetstream.go

@@ -0,0 +1,78 @@
+package events
+
+import (
+	"time"
+
+	"github.com/goccy/go-json"
+	"github.com/nats-io/nats.go"
+)
+
+const (
+	StreamName     string = "CHAIN"
+	StreamSubjects string = "CHAIN.*"
+)
+
+type JetStreamOpts struct {
+	ServerUrl       string
+	PersistDuration time.Duration
+	DedupDuration   time.Duration
+}
+
+type JetStream struct {
+	jsCtx nats.JetStreamContext
+	nc    *nats.Conn
+}
+
+func NewJetStreamEventEmitter(o JetStreamOpts) (EventEmitter, error) {
+	natsConn, err := nats.Connect(o.ServerUrl)
+	if err != nil {
+		return nil, err
+	}
+
+	js, err := natsConn.JetStream()
+	if err != nil {
+		return nil, err
+	}
+
+	// Bootstrap stream if it doesn't exist.
+	stream, _ := js.StreamInfo(StreamName)
+	if stream == nil {
+		_, err = js.AddStream(&nats.StreamConfig{
+			Name:       StreamName,
+			MaxAge:     o.PersistDuration,
+			Storage:    nats.FileStorage,
+			Subjects:   []string{StreamSubjects},
+			Duplicates: o.DedupDuration,
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &JetStream{
+		jsCtx: js,
+		nc:    natsConn,
+	}, nil
+}
+
+// Close gracefully shutdowns the JetStream connection.
+func (js *JetStream) Close() {
+	if js.nc != nil {
+		js.nc.Close()
+	}
+}
+
+// Publish publishes the JSON data to the NATS stream.
+func (js *JetStream) Publish(subject string, dedupId string, eventPayload interface{}) error {
+	jsonData, err := json.Marshal(eventPayload)
+	if err != nil {
+		return err
+	}
+
+	_, err = js.jsCtx.Publish(subject, jsonData, nats.MsgId(dedupId))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

internal/filter/address_filter.go

@@ -9,23 +9,30 @@ import (
 )
 
 type AddressFilterOpts struct {
-	Cache *sync.Map
+	Cache         *sync.Map
-	Logg  logf.Logger
+	Logg          logf.Logger
+	SystemAddress string
 }
 
 type AddressFilter struct {
-	cache *sync.Map
+	cache         *sync.Map
-	logg  logf.Logger
+	logg          logf.Logger
+	systemAddress string
 }
 
 func NewAddressFilter(o AddressFilterOpts) Filter {
 	return &AddressFilter{
-		cache: o.Cache,
+		cache:         o.Cache,
-		logg:  o.Logg,
+		logg:          o.Logg,
+		systemAddress: o.SystemAddress,
 	}
 }
 
-func (f *AddressFilter) Execute(_ context.Context, transaction *fetch.Transaction) (bool, error) {
+func (f *AddressFilter) Execute(_ context.Context, transaction fetch.Transaction) (bool, error) {
+	if transaction.From.Address == f.systemAddress {
+		return true, nil
+	}
+
 	if _, found := f.cache.Load(transaction.To.Address); found {
 		return true, nil
 	}

internal/filter/address_filter_test.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/grassrootseconomics/cic-chain-events/pkg/fetch"
 	"github.com/stretchr/testify/suite"
-	"github.com/zerodha/logf"
 )
 
 type AddressFilterSuite struct {
@@ -20,15 +19,8 @@ func (s *AddressFilterSuite) SetupSuite() {
 
 	addressCache.Store("0x6914ba1c49d3c3f32a9e65a0661d7656cb292e9f", "")
 
-	logg := logf.New(
-		logf.Opts{
-			Level: logf.DebugLevel,
-		},
-	)
-
 	s.filter = NewAddressFilter(AddressFilterOpts{
 		Cache: addressCache,
-		Logg:  logg,
 	})
 }
 
@@ -66,7 +58,7 @@ func (s *AddressFilterSuite) TestAddresses() {
 	}
 
 	for _, test := range tests {
-		next, err := s.filter.Execute(context.Background(), &test.transactionData)
+		next, err := s.filter.Execute(context.Background(), test.transactionData)
 		s.NoError(err)
 		s.Equal(test.want, next)
 	}

internal/filter/decode_filter.go

@@ -1,161 +0,0 @@
-package filter
-
-import (
-	"context"
-	"encoding/json"
-	"math/big"
-
-	"github.com/celo-org/celo-blockchain/common"
-	"github.com/grassrootseconomics/cic-chain-events/pkg/fetch"
-	"github.com/grassrootseconomics/w3-celo-patch"
-	"github.com/nats-io/nats.go"
-	"github.com/zerodha/logf"
-)
-
-var (
-	transferSig     = w3.MustNewFunc("transfer(address, uint256)", "bool")
-	transferFromSig = w3.MustNewFunc("transferFrom(address, address, uint256)", "bool")
-	mintToSig       = w3.MustNewFunc("mintTo(address, uint256)", "bool")
-)
-
-type DecodeFilterOpts struct {
-	Logg  logf.Logger
-	JSCtx nats.JetStreamContext
-}
-
-type DecodeFilter struct {
-	logg logf.Logger
-	js   nats.JetStreamContext
-}
-
-type minimalTxInfo struct {
-	Block        uint64 `json:"block"`
-	From         string `json:"from"`
-	Success      bool   `json:"success"`
-	To           string `json:"to"`
-	TokenAddress string `json:"tokenAddress"`
-	TxHash       string `json:"transactionHash"`
-	TxIndex      uint   `json:"transactionIndex"`
-	Value        uint64 `json:"value"`
-}
-
-func NewDecodeFilter(o DecodeFilterOpts) Filter {
-	return &DecodeFilter{
-		logg: o.Logg,
-		js:   o.JSCtx,
-	}
-}
-
-func (f *DecodeFilter) Execute(_ context.Context, transaction *fetch.Transaction) (bool, error) {
-	switch transaction.InputData[:10] {
-	case "0xa9059cbb":
-		var (
-			to    common.Address
-			value big.Int
-		)
-
-		if err := transferSig.DecodeArgs(w3.B(transaction.InputData), &to, &value); err != nil {
-			return false, err
-		}
-
-		transferEvent := &minimalTxInfo{
-			Block:        transaction.Block.Number,
-			From:         transaction.From.Address,
-			To:           to.Hex(),
-			TokenAddress: transaction.To.Address,
-			TxHash:       transaction.Hash,
-			TxIndex:      transaction.Index,
-			Value:        value.Uint64(),
-		}
-
-		if transaction.Status == 1 {
-			transferEvent.Success = true
-		}
-
-		json, err := json.Marshal(transferEvent)
-		if err != nil {
-			return false, err
-		}
-
-		_, err = f.js.Publish("CHAIN.transfer", json, nats.MsgId(transaction.Hash))
-		if err != nil {
-			return false, err
-		}
-
-		return true, nil
-	case "0x23b872dd":
-		var (
-			from  common.Address
-			to    common.Address
-			value big.Int
-		)
-
-		if err := transferFromSig.DecodeArgs(w3.B(transaction.InputData), &from, &to, &value); err != nil {
-			return false, err
-		}
-
-		transferFromEvent := &minimalTxInfo{
-			Block:        transaction.Block.Number,
-			From:         from.Hex(),
-			To:           to.Hex(),
-			TokenAddress: transaction.To.Address,
-			TxHash:       transaction.Hash,
-			TxIndex:      transaction.Index,
-			Value:        value.Uint64(),
-		}
-
-		if transaction.Status == 1 {
-			transferFromEvent.Success = true
-		}
-
-		json, err := json.Marshal(transferFromEvent)
-		if err != nil {
-			return false, err
-		}
-
-		_, err = f.js.Publish("CHAIN.transferFrom", json, nats.MsgId(transaction.Hash))
-		if err != nil {
-			return false, err
-		}
-
-		return true, nil
-	case "0x449a52f8":
-		var (
-			to    common.Address
-			value big.Int
-		)
-
-		if err := mintToSig.DecodeArgs(w3.B(transaction.InputData), &to, &value); err != nil {
-			return false, err
-		}
-
-		mintToEvent := &minimalTxInfo{
-			Block:        transaction.Block.Number,
-			From:         transaction.From.Address,
-			To:           to.Hex(),
-			TokenAddress: transaction.To.Address,
-			TxHash:       transaction.Hash,
-			TxIndex:      transaction.Index,
-			Value:        value.Uint64(),
-		}
-
-		if transaction.Status == 1 {
-			mintToEvent.Success = true
-		}
-
-		json, err := json.Marshal(mintToEvent)
-		if err != nil {
-			return false, err
-		}
-
-		_, err = f.js.Publish("CHAIN.mintTo", json, nats.MsgId(transaction.Hash))
-		if err != nil {
-			return false, err
-		}
-
-		return true, nil
-	default:
-		f.logg.Debug("unknownSignature", "inpuData", transaction.InputData)
-		return false, nil
-	}
-}

internal/filter/filter.go

@@ -8,5 +8,5 @@ import (
 
 // Filter defines a read only filter which must return next as true/false or an error
 type Filter interface {
-	Execute(ctx context.Context, inputTransaction *fetch.Transaction) (next bool, err error)
+	Execute(ctx context.Context, inputTransaction fetch.Transaction) (next bool, err error)
 }

internal/filter/gas_filter.go

@@ -0,0 +1,68 @@
+package filter
+
+import (
+	"context"
+
+	"github.com/celo-org/celo-blockchain/common/hexutil"
+	"github.com/grassrootseconomics/cic-chain-events/internal/events"
+	"github.com/grassrootseconomics/cic-chain-events/pkg/fetch"
+	"github.com/zerodha/logf"
+)
+
+const (
+	gasFilterEventSubject = "CHAIN.gas"
+)
+
+type GasFilterOpts struct {
+	EventEmitter  events.EventEmitter
+	Logg          logf.Logger
+	SystemAddress string
+}
+
+type GasFilter struct {
+	eventEmitter  events.EventEmitter
+	logg          logf.Logger
+	systemAddress string
+}
+
+func NewGasFilter(o GasFilterOpts) Filter {
+	return &GasFilter{
+		eventEmitter:  o.EventEmitter,
+		logg:          o.Logg,
+		systemAddress: o.SystemAddress,
+	}
+}
+
+func (f *GasFilter) Execute(_ context.Context, transaction fetch.Transaction) (bool, error) {
+	transferValue, err := hexutil.DecodeUint64(transaction.Value)
+	if err != nil {
+		return false, err
+	}
+
+	// TODO: This is a temporary shortcut to gift gas. Switch to gas faucet contract.
+	if transaction.From.Address == f.systemAddress && transferValue > 0 {
+		transferEvent := &events.MinimalTxInfo{
+			Block:   transaction.Block.Number,
+			To:      transaction.To.Address,
+			TxHash:  transaction.Hash,
+			TxIndex: transaction.Index,
+			Value:   transferValue,
+		}
+
+		if transaction.Status == 1 {
+			transferEvent.Success = true
+		}
+
+		if err := f.eventEmitter.Publish(
+			gasFilterEventSubject,
+			transaction.Hash,
+			transferEvent,
+		); err != nil {
+			return false, err
+		}
+
+		return true, nil
+	}
+
+	return true, nil
+}

internal/filter/register_filter.go

@@ -0,0 +1,74 @@
+package filter
+
+import (
+	"context"
+
+	"github.com/celo-org/celo-blockchain/common"
+	"github.com/grassrootseconomics/cic-chain-events/internal/events"
+	"github.com/grassrootseconomics/cic-chain-events/pkg/fetch"
+	"github.com/grassrootseconomics/w3-celo-patch"
+	"github.com/zerodha/logf"
+)
+
+const (
+	registerEventSubject = "CHAIN.register"
+)
+
+var (
+	addSig = w3.MustNewFunc("add(address)", "bool")
+)
+
+type RegisterFilterOpts struct {
+	EventEmitter events.EventEmitter
+	Logg         logf.Logger
+}
+
+type RegisterFilter struct {
+	eventEmitter events.EventEmitter
+	logg         logf.Logger
+}
+
+func NewRegisterFilter(o RegisterFilterOpts) Filter {
+	return &RegisterFilter{
+		eventEmitter: o.EventEmitter,
+		logg:         o.Logg,
+	}
+}
+
+func (f *RegisterFilter) Execute(_ context.Context, transaction fetch.Transaction) (bool, error) {
+	if len(transaction.InputData) < 10 {
+		return true, nil
+	}
+
+	if transaction.InputData[:10] == "0x0a3b0a4f" {
+		var address common.Address
+
+		if err := addSig.DecodeArgs(w3.B(transaction.InputData), &address); err != nil {
+			return false, err
+		}
+
+		addEvent := &events.MinimalTxInfo{
+			Block:           transaction.Block.Number,
+			ContractAddress: transaction.To.Address,
+			To:              transaction.To.Address,
+			TxHash:          transaction.Hash,
+			TxIndex:         transaction.Index,
+		}
+
+		if transaction.Status == 1 {
+			addEvent.Success = true
+		}
+
+		if err := f.eventEmitter.Publish(
+			registerEventSubject,
+			transaction.Hash,
+			addEvent,
+		); err != nil {
+			return false, err
+		}
+
+		return true, nil
+	}
+	
+	return true, nil
+}

internal/filter/transfer_filter.go

@@ -0,0 +1,156 @@
+package filter
+
+import (
+	"context"
+	"math/big"
+
+	"github.com/celo-org/celo-blockchain/common"
+	"github.com/grassrootseconomics/cic-chain-events/internal/events"
+	"github.com/grassrootseconomics/cic-chain-events/pkg/fetch"
+	"github.com/grassrootseconomics/w3-celo-patch"
+	"github.com/zerodha/logf"
+)
+
+const (
+	transferFilterEventSubject = "CHAIN.transfer"
+)
+
+var (
+	transferSig     = w3.MustNewFunc("transfer(address, uint256)", "bool")
+	transferFromSig = w3.MustNewFunc("transferFrom(address, address, uint256)", "bool")
+	mintToSig       = w3.MustNewFunc("mintTo(address, uint256)", "bool")
+)
+
+type TransferFilterOpts struct {
+	EventEmitter events.EventEmitter
+	Logg         logf.Logger
+}
+
+type TransferFilter struct {
+	eventEmitter events.EventEmitter
+	logg         logf.Logger
+}
+
+func NewTransferFilter(o TransferFilterOpts) Filter {
+	return &TransferFilter{
+		eventEmitter: o.EventEmitter,
+		logg:         o.Logg,
+	}
+}
+
+func (f *TransferFilter) Execute(_ context.Context, transaction fetch.Transaction) (bool, error) {
+	if len(transaction.InputData) < 10 {
+		return true, nil
+	}
+
+	switch transaction.InputData[:10] {
+	case "0xa9059cbb":
+		var (
+			to    common.Address
+			value big.Int
+		)
+
+		if err := transferSig.DecodeArgs(w3.B(transaction.InputData), &to, &value); err != nil {
+			return false, err
+		}
+
+		f.logg.Debug("transfer_filter: new reg", "transfer", to)
+
+		transferEvent := &events.MinimalTxInfo{
+			Block:           transaction.Block.Number,
+			From:            transaction.From.Address,
+			To:              to.Hex(),
+			ContractAddress: transaction.To.Address,
+			TxHash:          transaction.Hash,
+			TxIndex:         transaction.Index,
+			Value:           value.Uint64(),
+		}
+
+		if transaction.Status == 1 {
+			transferEvent.Success = true
+		}
+
+		if err := f.eventEmitter.Publish(
+			transferFilterEventSubject,
+			transaction.Hash,
+			transferEvent,
+		); err != nil {
+			return false, err
+		}
+
+		return true, nil
+	case "0x23b872dd":
+		var (
+			from  common.Address
+			to    common.Address
+			value big.Int
+		)
+
+		if err := transferFromSig.DecodeArgs(w3.B(transaction.InputData), &from, &to, &value); err != nil {
+			return false, err
+		}
+
+		f.logg.Debug("transfer_filter: new reg", "transferFrom", to)
+
+		transferEvent := &events.MinimalTxInfo{
+			Block:           transaction.Block.Number,
+			From:            from.Hex(),
+			To:              to.Hex(),
+			ContractAddress: transaction.To.Address,
+			TxHash:          transaction.Hash,
+			TxIndex:         transaction.Index,
+			Value:           value.Uint64(),
+		}
+
+		if transaction.Status == 1 {
+			transferEvent.Success = true
+		}
+
+		if err := f.eventEmitter.Publish(
+			transferFilterEventSubject,
+			transaction.Hash,
+			transferEvent,
+		); err != nil {
+			return false, err
+		}
+
+		return true, nil
+	case "0x449a52f8":
+		var (
+			to    common.Address
+			value big.Int
+		)
+
+		if err := mintToSig.DecodeArgs(w3.B(transaction.InputData), &to, &value); err != nil {
+			return false, err
+		}
+
+		f.logg.Debug("transfer_filter: new reg", "mintTo", to)
+
+		transferEvent := &events.MinimalTxInfo{
+			Block:           transaction.Block.Number,
+			From:            transaction.From.Address,
+			To:              to.Hex(),
+			ContractAddress: transaction.To.Address,
+			TxHash:          transaction.Hash,
+			TxIndex:         transaction.Index,
+			Value:           value.Uint64(),
+		}
+
+		if transaction.Status == 1 {
+			transferEvent.Success = true
+		}
+
+		if err := f.eventEmitter.Publish(
+			transferFilterEventSubject,
+			transaction.Hash,
+			transferEvent,
+		); err != nil {
+			return false, err
+		}
+
+		return true, nil
+	default:
+		return true, nil
+	}
+}

internal/filter/transfer_filter_test.go

@@ -9,24 +9,24 @@ import (
 	"github.com/zerodha/logf"
 )
 
-type DecodeFilterSuite struct {
+type TransferFilterSuite struct {
 	suite.Suite
 	filter Filter
 }
 
-func (s *DecodeFilterSuite) SetupSuite() {
+func (s *TransferFilterSuite) SetupSuite() {
 	logg := logf.New(
 		logf.Opts{
 			Level: logf.DebugLevel,
 		},
 	)
 
-	s.filter = NewDecodeFilter(DecodeFilterOpts{
+	s.filter = NewTransferFilter(TransferFilterOpts{
 		Logg: logg,
 	})
 }
 
-func (s *DecodeFilterSuite) TestTranfserInputs() {
+func (s *TransferFilterSuite) TestTranfserInputs() {
 	type testCase struct {
 		transactionData fetch.Transaction
 		want            bool
@@ -66,12 +66,12 @@ func (s *DecodeFilterSuite) TestTranfserInputs() {
 	}
 
 	for _, test := range tests {
-		next, err := s.filter.Execute(context.Background(), &test.transactionData)
+		next, err := s.filter.Execute(context.Background(), test.transactionData)
 		s.NoError(err)
 		s.Equal(test.want, next)
 	}
 }
 
-func TestDecodeFilterSuite(t *testing.T) {
+func TestTransferFilterSuite(t *testing.T) {
-	suite.Run(t, new(DecodeFilterSuite))
+	suite.Run(t, new(TransferFilterSuite))
 }

internal/pipeline/pipeline.go

@@ -49,7 +49,7 @@ func (md *Pipeline) Run(ctx context.Context, blockNumber uint64) error {
 
 	for _, tx := range fetchResp.Data.Block.Transactions {
 		for _, filter := range md.filters {
-			next, err := filter.Execute(ctx, &tx)
+			next, err := filter.Execute(ctx, tx)
 			if err != nil {
 				return err
 			}

internal/syncer/janitor.go

@@ -48,20 +48,18 @@ func NewJanitor(o JanitorOpts) *Janitor {
 }
 
 func (j *Janitor) Start(ctx context.Context) error {
-	timer := time.NewTimer(j.sweepInterval)
+	ticker := time.NewTicker(j.sweepInterval)
 
 	for {
 		select {
 		case <-ctx.Done():
 			j.logg.Info("janitor: shutdown signal received")
 			return nil
-		case <-timer.C:
+		case <-ticker.C:
 			j.logg.Debug("janitor: starting sweep")
 			if err := j.QueueMissingBlocks(context.Background()); err != nil {
 				j.logg.Error("janitor: queue missing blocks error", "error", err)
 			}
-
-			timer.Reset(j.sweepInterval)
 		}
 	}
 }

pkg/fetch/benchmark_test.go

@@ -1,50 +0,0 @@
-package fetch
-
-import (
-	"context"
-	"testing"
-
-	celo "github.com/grassrootseconomics/cic-celo-sdk"
-)
-
-func Benchmark_RPC(b *testing.B) {
-	celoProvider, err := celo.NewProvider(celo.ProviderOpts{
-		ChainId:     celo.MainnetChainId,
-		RpcEndpoint: rpcEndpoint,
-	})
-
-	rpc := NewRPCFetcher(RPCOpts{
-		RPCProvider: celoProvider,
-	})
-
-	if err != nil {
-		return
-	}
-
-	b.Run("RPC_Block_Fetcher_Benchmark", func(b *testing.B) {
-		for n := 0; n < b.N; n++ {
-			_, err := rpc.Block(context.Background(), 14974600)
-			if err != nil {
-				b.Fatal(err)
-			}
-		}
-		b.ReportAllocs()
-	})
-}
-
-func Benchmark_GraphQL(b *testing.B) {
-	graphql := NewGraphqlFetcher(GraphqlOpts{
-		GraphqlEndpoint: graphqlEndpoint,
-	})
-
-	b.Run("GraphQL_Block_Fetcher_Benchmark", func(b *testing.B) {
-		for n := 0; n < b.N; n++ {
-			_, err := graphql.Block(context.Background(), 14974600)
-			if err != nil {
-				b.Fatal(err)
-			}
-		}
-		b.ReportAllocs()
-	})
-
-}

pkg/fetch/rpc.go

@@ -1,97 +0,0 @@
-package fetch
-
-import (
-	"context"
-	"math/big"
-	"strings"
-
-	"github.com/celo-org/celo-blockchain/common/hexutil"
-	"github.com/celo-org/celo-blockchain/core/types"
-	celo "github.com/grassrootseconomics/cic-celo-sdk"
-	"github.com/grassrootseconomics/w3-celo-patch/module/eth"
-	"github.com/grassrootseconomics/w3-celo-patch/w3types"
-)
-
-// RPCOpts reprsents the required paramters for an RPC fetcher.
-type RPCOpts struct {
-	RPCProvider *celo.Provider
-}
-
-// RPC is a RPC based block and transaction fetcher.
-type RPC struct {
-	provider *celo.Provider
-}
-
-// NewRPCFetcher returns a new RPC fetcher which implemnts Fetch.
-// Note: No rate limiting feeature.
-func NewRPCFetcher(o RPCOpts) Fetch {
-	return &RPC{
-		provider: o.RPCProvider,
-	}
-}
-
-// Block fetches via RPC and transforms the response to adapt to the GraphQL JSON response struct.
-func (f *RPC) Block(ctx context.Context, blockNumber uint64) (FetchResponse, error) {
-	var (
-		block         types.Block
-		fetchResponse FetchResponse
-	)
-
-	if err := f.provider.Client.CallCtx(
-		ctx,
-		eth.BlockByNumber(big.NewInt(int64(blockNumber))).Returns(&block),
-	); err != nil {
-		return fetchResponse, err
-	}
-
-	txCount := len(block.Transactions())
-	batchCalls := make([]w3types.Caller, txCount*2)
-
-	txs := make([]types.Transaction, txCount)
-	txsReceipt := make([]types.Receipt, txCount)
-
-	// Prepare batch calls.
-	for i, tx := range block.Transactions() {
-		batchCalls[i] = eth.Tx(tx.Hash()).Returns(&txs[i])
-		batchCalls[txCount+i] = eth.TxReceipt(tx.Hash()).Returns(&txsReceipt[i])
-	}
-
-	if err := f.provider.Client.CallCtx(
-		ctx,
-		batchCalls...,
-	); err != nil {
-		return fetchResponse, err
-	}
-
-	// Transform response and adapt to FetchResponse.
-	for i := 0; i < txCount; i++ {
-		var txObject Transaction
-
-		txObject.Block.Number = block.NumberU64()
-		txObject.Block.Timestamp = hexutil.EncodeUint64(block.Time())
-
-		from, err := types.Sender(types.LatestSignerForChainID(txs[i].ChainId()), &txs[i])
-		if err != nil {
-			return fetchResponse, err
-		}
-		txObject.From.Address = strings.ToLower(from.Hex())
-		// This check ignores contract deployment transactions.
-		if txs[i].To() != nil {
-			txObject.To.Address = strings.ToLower(txs[i].To().Hex())
-		}
-		txObject.Value = hexutil.EncodeBig(txs[i].Value())
-		txObject.InputData = hexutil.Encode(txs[i].Data())
-
-		txObject.Hash = txsReceipt[i].TxHash.Hex()
-		txObject.Index = txsReceipt[i].TransactionIndex
-		txObject.Status = txsReceipt[i].Status
-		txObject.GasUsed = txsReceipt[i].GasUsed
-
-		fetchResponse.Data.Block.Transactions = append(
-			fetchResponse.Data.Block.Transactions,
-			txObject,
-		)
-	}
-
-	return fetchResponse, nil
-}

pkg/fetch/rpc_test.go

@@ -1,49 +0,0 @@
-package fetch
-
-import (
-	"context"
-	"os"
-	"testing"
-
-	celo "github.com/grassrootseconomics/cic-celo-sdk"
-	"github.com/stretchr/testify/suite"
-)
-
-var (
-	rpcEndpoint = os.Getenv("TEST_RPC_ENDPOINT")
-)
-
-type RPCTestSuite struct {
-	suite.Suite
-	fetch Fetch
-}
-
-func (s *RPCTestSuite) SetupSuite() {
-	celoProvider, err := celo.NewProvider(celo.ProviderOpts{
-		ChainId:     celo.MainnetChainId,
-		RpcEndpoint: rpcEndpoint,
-	})
-
-	if err != nil {
-		return
-	}
-
-	s.fetch = NewRPCFetcher(RPCOpts{
-		RPCProvider: celoProvider,
-	})
-}
-
-func (s *RPCTestSuite) Test_E2E_Fetch_Existing_Block() {
-	resp, err := s.fetch.Block(context.Background(), 14974600)
-	s.NoError(err)
-	s.Len(resp.Data.Block.Transactions, 3)
-}
-
-func (s *RPCTestSuite) Test_E2E_Fetch_Non_Existing_Block() {
-	_, err := s.fetch.Block(context.Background(), 14974600000)
-	s.Error(err)
-}
-
-func TestRPCSuite(t *testing.T) {
-	suite.Run(t, new(RPCTestSuite))
-}