WIP update tests for aggregate fetching

pkg/transformers/integration_tests/bite.go

@@ -45,17 +45,24 @@ var _ = Describe("Bite Transformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		initializer := factories.Transformer{
 			Config:     config,
 			Converter:  &bite.BiteConverter{},
 			Repository: &bite.BiteRepository{},
-			Fetcher:    &shared.Fetcher{},
 		}
-		transformer := initializer.NewTransformer(db, blockChain)
-		err = transformer.Execute()
+		transformer := initializer.NewTransformer(db)
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			[]common.Address{common.HexToAddress(config.ContractAddresses[0])},
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []bite.BiteModel

pkg/transformers/integration_tests/cat_file.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
 	"sort"
@@ -39,6 +40,7 @@ var _ = Describe("Cat File transformer", func() {
 		rpcClient  client.RpcClient
 		err        error
 		ethClient  *ethclient.Client
+		fetcher    shared.Fetcher
 	)
 
 	BeforeEach(func() {
@@ -48,13 +50,15 @@ var _ = Describe("Cat File transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+
+		fetcher = shared.NewFetcher(blockChain)
 	})
 
 	// Cat contract Kovan address: 0x2f34f22a00ee4b7a8f8bbc4eaee1658774c624e0
 	It("persists a chop lump event", func() {
 		// transaction: 0x98574bfba4d05c3875be10d2376e678d005dbebe9a4520363407508fd21f4014
 		chopLumpBlockNumber := int64(8762253)
-		err = persistHeader(db, chopLumpBlockNumber, blockChain)
+		header, err := persistHeader(db, chopLumpBlockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		config := chop_lump.CatFileChopLumpConfig
@@ -65,10 +69,16 @@ var _ = Describe("Cat File transformer", func() {
 			Config:     config,
 			Converter:  &chop_lump.CatFileChopLumpConverter{},
 			Repository: &chop_lump.CatFileChopLumpRepository{},
-			Fetcher:    &shared.Fetcher{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err := transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		logs, err := fetcher.FetchLogs(
+			[]common.Address{common.HexToAddress(config.ContractAddresses[0])},
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []chop_lump.CatFileChopLumpModel
@@ -92,7 +102,7 @@ var _ = Describe("Cat File transformer", func() {
 	It("persists a flip event", func() {
 		// transaction: 0x44bc18fdb1a5a263db114e7879653304db3e19ceb4e4496f21bc0a76c5faccbe
 		flipBlockNumber := int64(8751794)
-		err = persistHeader(db, flipBlockNumber, blockChain)
+		header, err := persistHeader(db, flipBlockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		config := flip.CatFileFlipConfig
@@ -103,10 +113,17 @@ var _ = Describe("Cat File transformer", func() {
 			Config:     config,
 			Converter:  &flip.CatFileFlipConverter{},
 			Repository: &flip.CatFileFlipRepository{},
-			Fetcher:    &shared.Fetcher{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err := transformer.Execute()
+
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		logs, err := fetcher.FetchLogs(
+			[]common.Address{common.HexToAddress(config.ContractAddresses[0])},
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []flip.CatFileFlipModel
@@ -122,7 +139,7 @@ var _ = Describe("Cat File transformer", func() {
 	It("persists a pit vow event", func() {
 		// transaction: 0x44bc18fdb1a5a263db114e7879653304db3e19ceb4e4496f21bc0a76c5faccbe
 		pitVowBlockNumber := int64(8751794)
-		err = persistHeader(db, pitVowBlockNumber, blockChain)
+		header, err := persistHeader(db, pitVowBlockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		config := pit_vow.CatFilePitVowConfig
@@ -133,10 +150,16 @@ var _ = Describe("Cat File transformer", func() {
 			Config:     config,
 			Converter:  &pit_vow.CatFilePitVowConverter{},
 			Repository: &pit_vow.CatFilePitVowRepository{},
-			Fetcher:    &shared.Fetcher{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err := transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		logs, err := fetcher.FetchLogs(
+			[]common.Address{common.HexToAddress(config.ContractAddresses[0])},
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []pit_vow.CatFilePitVowModel

pkg/transformers/integration_tests/deal.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 
@@ -29,8 +30,13 @@ import (
 
 var _ = Describe("Deal transformer", func() {
 	var (
-		db         *postgres.DB
-		blockChain core.BlockChain
+		db          *postgres.DB
+		blockChain  core.BlockChain
+		config      shared.TransformerConfig
+		initializer factories.LogNoteTransformer
+		fetcher     shared.Fetcher
+		addresses   []common.Address
+		topics      []common.Hash
 	)
 
 	BeforeEach(func() {
@@ -40,26 +46,35 @@ var _ = Describe("Deal transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+
+		config = deal.DealConfig
+
+		initializer = factories.LogNoteTransformer{
+			Config:     config,
+			Converter:  &deal.DealConverter{},
+			Repository: &deal.DealRepository{},
+		}
+
+		fetcher = shared.NewFetcher(blockChain)
+		addresses = shared.HexStringsToAddresses(config.ContractAddresses)
+		topics = []common.Hash{common.HexToHash(config.Topic)}
+
 	})
 
 	It("persists a flip deal log event", func() {
 		// transaction: 0x05b5eabac2ace136f0f7e0efc61d7d42abe8e8938cc0f04fbf1a6ba545d59e58
 		flipBlockNumber := int64(8958007)
-		err := persistHeader(db, flipBlockNumber, blockChain)
+		header, err := persistHeader(db, flipBlockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		config := deal.DealConfig
-		config.StartingBlockNumber = flipBlockNumber
-		config.EndingBlockNumber = flipBlockNumber
+		initializer.Config.StartingBlockNumber = flipBlockNumber
+		initializer.Config.EndingBlockNumber = flipBlockNumber
 
-		initializer := factories.LogNoteTransformer{
-			Config:     config,
-			Converter:  &deal.DealConverter{},
-			Repository: &deal.DealRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []deal.DealModel
@@ -77,21 +92,17 @@ var _ = Describe("Deal transformer", func() {
 
 	It("persists a flap deal log event", func() {
 		flapBlockNumber := int64(9004628)
-		err := persistHeader(db, flapBlockNumber, blockChain)
+		header, err := persistHeader(db, flapBlockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		config := deal.DealConfig
-		config.StartingBlockNumber = flapBlockNumber
-		config.EndingBlockNumber = flapBlockNumber
+		initializer.Config.StartingBlockNumber = flapBlockNumber
+		initializer.Config.EndingBlockNumber = flapBlockNumber
 
-		initializer := factories.LogNoteTransformer{
-			Config:     config,
-			Converter:  &deal.DealConverter{},
-			Repository: &deal.DealRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []deal.DealModel

pkg/transformers/integration_tests/dent.go

@@ -1,6 +1,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared/constants"
@@ -15,8 +16,14 @@ import (
 
 var _ = Describe("Dent transformer", func() {
 	var (
-		db         *postgres.DB
-		blockChain core.BlockChain
+		db          *postgres.DB
+		blockChain  core.BlockChain
+		fetcher     shared.Fetcher
+		transformer shared.Transformer
+		config      shared.TransformerConfig
+		addresses   []common.Address
+		topics      []common.Hash
+		initializer factories.LogNoteTransformer
 	)
 
 	BeforeEach(func() {
@@ -26,25 +33,31 @@ var _ = Describe("Dent transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+
+		config = dent.DentConfig
+		addresses = shared.HexStringsToAddresses(config.ContractAddresses)
+		topics = []common.Hash{common.HexToHash(config.Topic)}
+		fetcher = shared.NewFetcher(blockChain)
+
+		initializer = factories.LogNoteTransformer{
+			Config:     config,
+			Converter:  &dent.DentConverter{},
+			Repository: &dent.DentRepository{},
+		}
 	})
 
 	It("persists a flop dent log event", func() {
 		blockNumber := int64(8955613)
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		config := dent.DentConfig
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		initializer := factories.LogNoteTransformer{
-			Config:     config,
-			Converter:  &dent.DentConverter{},
-			Repository: &dent.DentRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []dent.DentModel

pkg/transformers/integration_tests/drip_drip.go

@@ -15,8 +15,11 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
 
@@ -25,32 +28,43 @@ import (
 )
 
 var _ = Describe("DripDrip Transformer", func() {
+	var (
+		db         *postgres.DB
+		blockChain core.BlockChain
+	)
+
+	BeforeEach(func() {
+		rpcClient, ethClient, err := getClients(ipc)
+		Expect(err).NotTo(HaveOccurred())
+		blockChain, err = getBlockChain(rpcClient, ethClient)
+		Expect(err).NotTo(HaveOccurred())
+		db = test_config.NewTestDB(blockChain.Node())
+		test_config.CleanTestDB(db)
+	})
 	It("transforms DripDrip log events", func() {
 		blockNumber := int64(8934775)
 		config := drip_drip.DripDripConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		rpcClient, ethClient, err := getClients(ipc)
-		Expect(err).NotTo(HaveOccurred())
-		blockChain, err := getBlockChain(rpcClient, ethClient)
-		Expect(err).NotTo(HaveOccurred())
-
-		db := test_config.NewTestDB(blockChain.Node())
-		test_config.CleanTestDB(db)
-
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		initializer := factories.LogNoteTransformer{
 			Config:     config,
 			Converter:  &drip_drip.DripDripConverter{},
 			Repository: &drip_drip.DripDripRepository{},
-			Fetcher:    &shared.Fetcher{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
+		transformer := initializer.NewLogNoteTransformer(db)
 
-		err = transformer.Execute()
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResults []drip_drip.DripDripModel

pkg/transformers/integration_tests/drip_file_vow.go

@@ -15,8 +15,11 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
 
@@ -25,31 +28,44 @@ import (
 )
 
 var _ = Describe("Drip File Vow LogNoteTransformer", func() {
+	var (
+		db         *postgres.DB
+		blockChain core.BlockChain
+	)
+
+	BeforeEach(func() {
+		rpcClient, ethClient, err := getClients(ipc)
+		Expect(err).NotTo(HaveOccurred())
+		blockChain, err = getBlockChain(rpcClient, ethClient)
+		Expect(err).NotTo(HaveOccurred())
+		db = test_config.NewTestDB(blockChain.Node())
+		test_config.CleanTestDB(db)
+	})
+
 	It("transforms DripFileVow log events", func() {
 		blockNumber := int64(8762197)
 		config := vow.DripFileVowConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		rpcClient, ethClient, err := getClients(ipc)
-		Expect(err).NotTo(HaveOccurred())
-		blockChain, err := getBlockChain(rpcClient, ethClient)
-		Expect(err).NotTo(HaveOccurred())
-
-		db := test_config.NewTestDB(blockChain.Node())
-		test_config.CleanTestDB(db)
-
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		initializer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vow.DripFileVowConverter{},
 			Repository: &vow.DripFileVowRepository{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []vow.DripFileVowModel

pkg/transformers/integration_tests/flap_kick.go

@@ -15,6 +15,10 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+	"github.com/vulcanize/vulcanizedb/test_config"
 	"time"
 
 	. "github.com/onsi/ginkgo"
@@ -23,35 +27,46 @@ import (
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/flap_kick"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
-	"github.com/vulcanize/vulcanizedb/test_config"
 )
 
 var _ = Describe("FlapKick Transformer", func() {
+	var (
+		db         *postgres.DB
+		blockChain core.BlockChain
+	)
+
+	BeforeEach(func() {
+		rpcClient, ethClient, err := getClients(ipc)
+		Expect(err).NotTo(HaveOccurred())
+		blockChain, err = getBlockChain(rpcClient, ethClient)
+		Expect(err).NotTo(HaveOccurred())
+		db = test_config.NewTestDB(blockChain.Node())
+		test_config.CleanTestDB(db)
+	})
+
 	It("fetches and transforms a FlapKick event from Kovan chain", func() {
 		blockNumber := int64(9002933)
 		config := flap_kick.FlapKickConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		rpcClient, ethClient, err := getClients(ipc)
-		Expect(err).NotTo(HaveOccurred())
-		blockChain, err := getBlockChain(rpcClient, ethClient)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		db := test_config.NewTestDB(blockChain.Node())
-		test_config.CleanTestDB(db)
-
-		err = persistHeader(db, blockNumber, blockChain)
-		Expect(err).NotTo(HaveOccurred())
-
-		initializer := factories.Transformer{
+		transformer := factories.Transformer{
 			Config:     config,
 			Converter:  &flap_kick.FlapKickConverter{},
 			Repository: &flap_kick.FlapKickRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewTransformer(db)
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []flap_kick.FlapKickModel

pkg/transformers/integration_tests/flip_kick.go

@@ -65,21 +65,26 @@ var _ = Describe("FlipKick Transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		blockChain, err := getBlockChain(rpcClient, ethClient)
 		Expect(err).NotTo(HaveOccurred())
-
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.Transformer{
+		transformer := factories.Transformer{
 			Config:     config,
 			Converter:  &flip_kick.FlipKickConverter{},
 			Repository: &flip_kick.FlipKickRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewTransformer(db)
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []flip_kick.FlipKickModel

pkg/transformers/integration_tests/flop_kick.go

@@ -35,8 +35,13 @@ import (
 
 var _ = Describe("FlopKick Transformer", func() {
 	var (
-		db         *postgres.DB
-		blockChain core.BlockChain
+		db          *postgres.DB
+		blockChain  core.BlockChain
+		config      shared.TransformerConfig
+		initializer factories.Transformer
+		fetcher     shared.LogFetcher
+		addresses   []common.Address
+		topics      []common.Hash
 	)
 
 	BeforeEach(func() {
@@ -46,25 +51,33 @@ var _ = Describe("FlopKick Transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+
+		config = flop_kick.Config
+
+		initializer = factories.Transformer{
+			Config:     config,
+			Converter:  &flop_kick.FlopKickConverter{},
+			Repository: &flop_kick.FlopKickRepository{},
+		}
+
+		fetcher = shared.NewFetcher(blockChain)
+		addresses = shared.HexStringsToAddresses(config.ContractAddresses)
+		topics = []common.Hash{common.HexToHash(config.Topic)}
 	})
 
 	It("fetches and transforms a FlopKick event from Kovan chain", func() {
 		blockNumber := int64(8672119)
-		config := flop_kick.Config
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.Transformer{
-			Config:     config,
-			Converter:  &flop_kick.FlopKickConverter{},
-			Repository: &flop_kick.FlopKickRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []flop_kick.Model
@@ -82,21 +95,17 @@ var _ = Describe("FlopKick Transformer", func() {
 
 	It("fetches and transforms another FlopKick event from Kovan chain", func() {
 		blockNumber := int64(8955611)
-		config := flop_kick.Config
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.Transformer{
-			Config:     config,
-			Converter:  &flop_kick.FlopKickConverter{},
-			Repository: &flop_kick.FlopKickRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []flop_kick.Model

pkg/transformers/integration_tests/frob.go

@@ -33,8 +33,11 @@ import (
 
 var _ = Describe("Frob Transformer", func() {
 	var (
-		db         *postgres.DB
-		blockChain core.BlockChain
+		db          *postgres.DB
+		blockChain  core.BlockChain
+		fetcher     shared.Fetcher
+		config      shared.TransformerConfig
+		initializer factories.Transformer
 	)
 
 	BeforeEach(func() {
@@ -44,25 +47,32 @@ var _ = Describe("Frob Transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+
+		fetcher = shared.NewFetcher(blockChain)
+		config = frob.FrobConfig
+		initializer = factories.Transformer{
+			Config:     config,
+			Converter:  &frob.FrobConverter{},
+			Repository: &frob.FrobRepository{},
+		}
 	})
 
 	It("fetches and transforms a Frob event from Kovan chain", func() {
 		blockNumber := int64(8935258)
-		config := frob.FrobConfig
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.Transformer{
-			Config:     config,
-			Converter:  &frob.FrobConverter{},
-			Repository: &frob.FrobRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := initializer.NewTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []frob.FrobModel

pkg/transformers/integration_tests/helpers.go

@@ -42,12 +42,13 @@ func getBlockChain(rpcClient client.RpcClient, ethClient *ethclient.Client) (cor
 	return blockChain, nil
 }
 
-func persistHeader(db *postgres.DB, blockNumber int64, blockChain core.BlockChain) error {
+// Persist the header for a given block to postgres. Returns the header if successful.
+func persistHeader(db *postgres.DB, blockNumber int64, blockChain core.BlockChain) (core.Header, error) {
 	header, err := blockChain.GetHeaderByNumber(blockNumber)
 	if err != nil {
-		return err
+		return core.Header{}, err
 	}
 	headerRepository := repositories.NewHeaderRepository(db)
 	_, err = headerRepository.CreateOrUpdateHeader(header)
-	return err
+	return header, err
 }

pkg/transformers/integration_tests/pit_file_debt_ceiling.go

@@ -15,8 +15,11 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
 
@@ -25,31 +28,44 @@ import (
 )
 
 var _ = Describe("PitFileDebtCeiling LogNoteTransformer", func() {
+	var (
+		db         *postgres.DB
+		blockChain core.BlockChain
+	)
+
+	BeforeEach(func() {
+		rpcClient, ethClient, err := getClients(ipc)
+		Expect(err).NotTo(HaveOccurred())
+		blockChain, err = getBlockChain(rpcClient, ethClient)
+		Expect(err).NotTo(HaveOccurred())
+		db = test_config.NewTestDB(blockChain.Node())
+		test_config.CleanTestDB(db)
+	})
+
 	It("fetches and transforms a PitFileDebtCeiling event from Kovan chain", func() {
 		blockNumber := int64(8535578)
 		config := debt_ceiling.DebtCeilingFileConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		rpcClient, ethClient, err := getClients(ipc)
-		Expect(err).NotTo(HaveOccurred())
-		blockChain, err := getBlockChain(rpcClient, ethClient)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		db := test_config.NewTestDB(blockChain.Node())
-		test_config.CleanTestDB(db)
-
-		err = persistHeader(db, blockNumber, blockChain)
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
 		Expect(err).NotTo(HaveOccurred())
 
 		initializer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &debt_ceiling.PitFileDebtCeilingConverter{},
 			Repository: &debt_ceiling.PitFileDebtCeilingRepository{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []debt_ceiling.PitFileDebtCeilingModel

pkg/transformers/integration_tests/pit_file_ilk.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
@@ -39,17 +40,24 @@ var _ = Describe("PitFileIlk LogNoteTransformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
 		initializer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &ilk.PitFileIlkConverter{},
 			Repository: &ilk.PitFileIlkRepository{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []ilk.PitFileIlkModel

pkg/transformers/integration_tests/price_feeds.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 
@@ -29,8 +30,11 @@ import (
 
 var _ = Describe("Price feeds transformer", func() {
 	var (
-		db         *postgres.DB
-		blockChain core.BlockChain
+		db          *postgres.DB
+		blockChain  core.BlockChain
+		config      shared.TransformerConfig
+		fetcher     shared.Fetcher
+		initializer factories.LogNoteTransformer
 	)
 
 	BeforeEach(func() {
@@ -40,30 +44,36 @@ var _ = Describe("Price feeds transformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+		config = price_feeds.PriceFeedConfig
+		fetcher = shared.NewFetcher(blockChain)
+
+		initializer = factories.LogNoteTransformer{
+			Config:     config,
+			Converter:  &price_feeds.PriceFeedConverter{},
+			Repository: &price_feeds.PriceFeedRepository{},
+		}
 	})
 
 	It("persists a ETH/USD price feed event", func() {
 		blockNumber := int64(8763054)
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
-		config := price_feeds.PriceFeedConfig
-		config.ContractAddresses = []string{constants.PipContractAddress}
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.ContractAddresses = []string{constants.PipContractAddress}
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		transformerInitializer := factories.LogNoteTransformer{
-			Config:     config,
-			Converter:  &price_feeds.PriceFeedConverter{},
-			Repository: &price_feeds.PriceFeedRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := transformerInitializer.NewLogNoteTransformer(db, blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(initializer.Config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
 
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 
 		Expect(err).NotTo(HaveOccurred())
 		var model price_feeds.PriceFeedModel
-		err = db.Get(&model, `SELECT block_number, medianizer_address, usd_value, tx_idx, raw_log FROM maker.price_feeds WHERE block_number = $1`, config.StartingBlockNumber)
+		err = db.Get(&model, `SELECT block_number, medianizer_address, usd_value, tx_idx, raw_log FROM maker.price_feeds WHERE block_number = $1`, initializer.Config.StartingBlockNumber)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(model.UsdValue).To(Equal("207.314891143000011198"))
 		Expect(model.MedianizerAddress).To(Equal(config.ContractAddresses[0]))
@@ -71,26 +81,24 @@ var _ = Describe("Price feeds transformer", func() {
 
 	It("persists a MKR/USD price feed event", func() {
 		blockNumber := int64(8763059)
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
-		config := price_feeds.PriceFeedConfig
-		config.ContractAddresses = []string{constants.PepContractAddress}
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.ContractAddresses = []string{constants.PepContractAddress}
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		transformerInitializer := factories.LogNoteTransformer{
-			Config:     config,
-			Converter:  &price_feeds.PriceFeedConverter{},
-			Repository: &price_feeds.PriceFeedRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := transformerInitializer.NewLogNoteTransformer(db, blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(initializer.Config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
 
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 
 		Expect(err).NotTo(HaveOccurred())
 		var model price_feeds.PriceFeedModel
-		err = db.Get(&model, `SELECT block_number, medianizer_address, usd_value, tx_idx, raw_log FROM maker.price_feeds WHERE block_number = $1`, config.StartingBlockNumber)
+		err = db.Get(&model, `SELECT block_number, medianizer_address, usd_value, tx_idx, raw_log FROM maker.price_feeds WHERE block_number = $1`, initializer.Config.StartingBlockNumber)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(model.UsdValue).To(Equal("391.803979212000001553"))
 		Expect(model.MedianizerAddress).To(Equal(config.ContractAddresses[0]))
@@ -98,26 +106,24 @@ var _ = Describe("Price feeds transformer", func() {
 
 	It("persists a REP/USD price feed event", func() {
 		blockNumber := int64(8763062)
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
-		config := price_feeds.PriceFeedConfig
-		config.ContractAddresses = []string{constants.RepContractAddress}
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.ContractAddresses = []string{constants.RepContractAddress}
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		transformerInitializer := factories.LogNoteTransformer{
-			Config:     config,
-			Converter:  &price_feeds.PriceFeedConverter{},
-			Repository: &price_feeds.PriceFeedRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}
-		transformer := transformerInitializer.NewLogNoteTransformer(db, blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
 
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 
 		Expect(err).NotTo(HaveOccurred())
 		var model price_feeds.PriceFeedModel
-		err = db.Get(&model, `SELECT block_number, medianizer_address, usd_value, tx_idx, raw_log FROM maker.price_feeds WHERE block_number = $1`, config.StartingBlockNumber)
+		err = db.Get(&model, `SELECT block_number, medianizer_address, usd_value, tx_idx, raw_log FROM maker.price_feeds WHERE block_number = $1`, initializer.Config.StartingBlockNumber)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(model.UsdValue).To(Equal("12.816928482699999847"))
 		Expect(model.MedianizerAddress).To(Equal(config.ContractAddresses[0]))

pkg/transformers/integration_tests/tend.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/vulcanize/vulcanizedb/pkg/core"
@@ -28,8 +29,13 @@ import (
 
 var _ = Describe("Tend LogNoteTransformer", func() {
 	var (
-		db         *postgres.DB
-		blockChain core.BlockChain
+		db          *postgres.DB
+		blockChain  core.BlockChain
+		config      shared.TransformerConfig
+		fetcher     shared.Fetcher
+		initializer factories.LogNoteTransformer
+		addresses   []common.Address
+		topics      []common.Hash
 	)
 
 	BeforeEach(func() {
@@ -39,25 +45,31 @@ var _ = Describe("Tend LogNoteTransformer", func() {
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+
+		fetcher = shared.NewFetcher(blockChain)
+		addresses = shared.HexStringsToAddresses(config.ContractAddresses)
+		topics = []common.Hash{common.HexToHash(config.Topic)}
+
+		initializer = factories.LogNoteTransformer{
+			Config:     tend.TendConfig,
+			Converter:  &tend.TendConverter{},
+			Repository: &tend.TendRepository{},
+		}
 	})
 
 	It("fetches and transforms a Flip Tend event from Kovan chain", func() {
 		blockNumber := int64(8935601)
-		config := tend.TendConfig
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
-			Config:     config,
-			Fetcher:    &shared.Fetcher{},
-			Converter:  &tend.TendConverter{},
-			Repository: &tend.TendRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []tend.TendModel
@@ -80,21 +92,17 @@ var _ = Describe("Tend LogNoteTransformer", func() {
 
 	It("fetches and transforms a subsequent Flip Tend event from Kovan chain for the same auction", func() {
 		blockNumber := int64(8935731)
-		config := tend.TendConfig
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
-			Config:     config,
-			Fetcher:    &shared.Fetcher{},
-			Converter:  &tend.TendConverter{},
-			Repository: &tend.TendRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []tend.TendModel
@@ -117,21 +125,17 @@ var _ = Describe("Tend LogNoteTransformer", func() {
 
 	It("fetches and transforms a Flap Tend event from the Kovan chain", func() {
 		blockNumber := int64(9003177)
-		config := tend.TendConfig
-		config.StartingBlockNumber = blockNumber
-		config.EndingBlockNumber = blockNumber
+		initializer.Config.StartingBlockNumber = blockNumber
+		initializer.Config.EndingBlockNumber = blockNumber
 
-		err := persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
-			Config:     config,
-			Fetcher:    &shared.Fetcher{},
-			Converter:  &tend.TendConverter{},
-			Repository: &tend.TendRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		logs, err := fetcher.FetchLogs(addresses, topics, header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := initializer.NewLogNoteTransformer(db)
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []tend.TendModel

pkg/transformers/integration_tests/vat_flux.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 
@@ -39,17 +40,24 @@ var _ = Describe("VatFlux LogNoteTransformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
+		Expect(err).NotTo(HaveOccurred())
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
 		Expect(err).NotTo(HaveOccurred())
 
 		initializer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vat_flux.VatFluxConverter{},
 			Repository: &vat_flux.VatFluxRepository{},
 		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		transformer := initializer.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []vat_flux.VatFluxModel

pkg/transformers/integration_tests/vat_fold.go

@@ -18,39 +18,53 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+	"github.com/vulcanize/vulcanizedb/test_config"
 
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/vat_fold"
-	"github.com/vulcanize/vulcanizedb/test_config"
 )
 
 var _ = Describe("VatFold Transformer", func() {
+	var (
+		db         *postgres.DB
+		blockChain core.BlockChain
+	)
+
+	BeforeEach(func() {
+		rpcClient, ethClient, err := getClients(ipc)
+		Expect(err).NotTo(HaveOccurred())
+		blockChain, err = getBlockChain(rpcClient, ethClient)
+		Expect(err).NotTo(HaveOccurred())
+		db = test_config.NewTestDB(blockChain.Node())
+		test_config.CleanTestDB(db)
+	})
+
 	It("transforms VatFold log events", func() {
 		blockNumber := int64(9051149)
 		config := vat_fold.VatFoldConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		rpcClient, ethClient, err := getClients(ipc)
-		Expect(err).NotTo(HaveOccurred())
-		blockChain, err := getBlockChain(rpcClient, ethClient)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		db := test_config.NewTestDB(blockChain.Node())
-		test_config.CleanTestDB(db)
-
-		err = persistHeader(db, blockNumber, blockChain)
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
+		transformer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vat_fold.VatFoldConverter{},
 			Repository: &vat_fold.VatFoldRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResults []vat_fold.VatFoldModel

pkg/transformers/integration_tests/vat_grab.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	"math/big"
 
 	. "github.com/onsi/ginkgo"
@@ -41,17 +42,23 @@ var _ = Describe("Vat Grab Transformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
+		Expect(err).NotTo(HaveOccurred())
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
 		Expect(err).NotTo(HaveOccurred())
 
 		transformer := factories.LogNoteTransformer{
 			Config:     config,
 			Converter:  &vat_grab.VatGrabConverter{},
 			Repository: &vat_grab.VatGrabRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}.NewLogNoteTransformer(db, blockChain)
+		}.NewLogNoteTransformer(db)
 
-		err = transformer.Execute()
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []vat_grab.VatGrabModel

pkg/transformers/integration_tests/vat_heal.go

@@ -40,17 +40,23 @@ var _ = Describe("VatHeal Transformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
+		Expect(err).NotTo(HaveOccurred())
+
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
 		Expect(err).NotTo(HaveOccurred())
 
 		transformer := factories.LogNoteTransformer{
 			Config:     config,
 			Converter:  &vat_heal.VatHealConverter{},
 			Repository: &vat_heal.VatHealRepository{},
-			Fetcher:    &shared.Fetcher{},
-		}.NewLogNoteTransformer(db, blockChain)
+		}.NewLogNoteTransformer(db)
 
-		err = transformer.Execute()
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResults []vat_heal.VatHealModel

pkg/transformers/integration_tests/vat_init.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
@@ -39,17 +40,23 @@ var _ = Describe("VatInit LogNoteTransformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vat_init.VatInitConverter{},
 			Repository: &vat_init.VatInitRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResults []vat_init.VatInitModel

pkg/transformers/integration_tests/vat_move.go

@@ -40,17 +40,23 @@ var _ = Describe("VatMove LogNoteTransformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vat_move.VatMoveConverter{},
 			Repository: &vat_move.VatMoveRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResults []vat_move.VatMoveModel

pkg/transformers/integration_tests/vat_slip.go

@@ -1,6 +1,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 
@@ -18,31 +19,38 @@ var _ = Describe("Vat slip transformer", func() {
 		blockChain core.BlockChain
 	)
 
-	It("persists vat slip event", func() {
+	BeforeEach(func() {
 		rpcClient, ethClient, err := getClients(ipc)
 		Expect(err).NotTo(HaveOccurred())
 		blockChain, err = getBlockChain(rpcClient, ethClient)
 		Expect(err).NotTo(HaveOccurred())
 		db = test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
+	})
 
+	It("persists vat slip event", func() {
 		blockNumber := int64(8953655)
 		config := vat_slip.VatSlipConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vat_slip.VatSlipConverter{},
 			Repository: &vat_slip.VatSlipRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
+		}.NewLogNoteTransformer(db)
 
-		err = transformer.Execute()
+		err = transformer.Execute(logs, header)
 
 		Expect(err).NotTo(HaveOccurred())
 		var headerID int64

pkg/transformers/integration_tests/vat_tune.go

@@ -15,6 +15,7 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	"math/big"
 
 	. "github.com/onsi/ginkgo"
@@ -41,17 +42,23 @@ var _ = Describe("VatTune LogNoteTransformer", func() {
 		db := test_config.NewTestDB(blockChain.Node())
 		test_config.CleanTestDB(db)
 
-		err = persistHeader(db, blockNumber, blockChain)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		initializer := factories.LogNoteTransformer{
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
+		Expect(err).NotTo(HaveOccurred())
+
+		transformer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vat_tune.VatTuneConverter{},
 			Repository: &vat_tune.VatTuneRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []vat_tune.VatTuneModel

pkg/transformers/integration_tests/vow_flog.go

@@ -15,8 +15,11 @@
 package integration_tests
 
 import (
+	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/factories"
 	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
@@ -25,32 +28,43 @@ import (
 )
 
 var _ = Describe("VowFlog LogNoteTransformer", func() {
+	var (
+		db         *postgres.DB
+		blockChain core.BlockChain
+	)
+
+	BeforeEach(func() {
+		rpcClient, ethClient, err := getClients(ipc)
+		Expect(err).NotTo(HaveOccurred())
+		blockChain, err = getBlockChain(rpcClient, ethClient)
+		Expect(err).NotTo(HaveOccurred())
+		db = test_config.NewTestDB(blockChain.Node())
+		test_config.CleanTestDB(db)
+	})
+
 	It("transforms VowFlog log events", func() {
 		blockNumber := int64(8946819)
 		config := vow_flog.VowFlogConfig
 		config.StartingBlockNumber = blockNumber
 		config.EndingBlockNumber = blockNumber
 
-		rpcClient, ethClient, err := getClients(ipc)
-		Expect(err).NotTo(HaveOccurred())
-		blockChain, err := getBlockChain(rpcClient, ethClient)
+		header, err := persistHeader(db, blockNumber, blockChain)
 		Expect(err).NotTo(HaveOccurred())
 
-		db := test_config.NewTestDB(blockChain.Node())
-		test_config.CleanTestDB(db)
-
-		err = persistHeader(db, blockNumber, blockChain)
+		fetcher := shared.NewFetcher(blockChain)
+		logs, err := fetcher.FetchLogs(
+			shared.HexStringsToAddresses(config.ContractAddresses),
+			[]common.Hash{common.HexToHash(config.Topic)},
+			header)
 		Expect(err).NotTo(HaveOccurred())
-		Expect(1).To(Equal(1))
 
-		initializer := factories.LogNoteTransformer{
+		transformer := factories.LogNoteTransformer{
 			Config:     config,
-			Fetcher:    &shared.Fetcher{},
 			Converter:  &vow_flog.VowFlogConverter{},
 			Repository: &vow_flog.VowFlogRepository{},
-		}
-		transformer := initializer.NewLogNoteTransformer(db, blockChain)
-		err = transformer.Execute()
+		}.NewLogNoteTransformer(db)
+
+		err = transformer.Execute(logs, header)
 		Expect(err).NotTo(HaveOccurred())
 
 		var dbResult []vow_flog.VowFlogModel