Add transformer factory

pkg/transformers/factories/transformer.go

@@ -0,0 +1,101 @@
+// Copyright 2018 Vulcanize
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package factories
+
+import (
+	"github.com/ethereum/go-ethereum/core/types"
+	"log"
+
+	"github.com/ethereum/go-ethereum/common"
+
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+	"github.com/vulcanize/vulcanizedb/pkg/transformers/shared"
+)
+
+type TransformerInitializer struct {
+	Config 		shared.TransformerConfig
+	Converter	Converter
+	Repository	Repository
+}
+
+type Model struct {
+	TransactionIndex uint   `db:"tx_idx"`
+	Raw              []byte `db:"raw_log"`
+}
+
+type Converter interface {
+	ToModel(ethLog types.Log) (Model, error)
+}
+
+type Repository interface {
+	Create(headerID int64, models []Model) error
+	MarkHeaderChecked(headerID int64) error
+	MissingHeaders(startingBlockNumber, endingBlockNumber int64) ([]core.Header, error)
+}
+
+
+func (initializer TransformerInitializer) NewTransformer(db *postgres.DB, blockChain core.BlockChain) shared.Transformer {
+	fetcher := shared.NewFetcher(blockChain)
+	return Transformer{
+		Config:     initializer.Config,
+		Converter:  initializer.Converter,
+		Fetcher:    fetcher,
+		Repository: initializer.Repository,
+	}
+}
+
+type Transformer struct {
+	Config     shared.TransformerConfig
+	Converter  Converter
+	Fetcher    shared.LogFetcher
+	Repository Repository
+}
+
+func (transformer Transformer) Execute() error {
+	missingHeaders, err := transformer.Repository.MissingHeaders(transformer.Config.StartingBlockNumber, transformer.Config.EndingBlockNumber)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("Fetching vat move event logs for %d headers \n", len(missingHeaders))
+	for _, header := range missingHeaders {
+		topics := [][]common.Hash{{common.HexToHash(shared.VatMoveSignature)}}
+		matchingLogs, err := transformer.Fetcher.FetchLogs(transformer.Config.ContractAddresses, topics, header.BlockNumber)
+		if err != nil {
+			return err
+		}
+
+		if len(matchingLogs) < 1 {
+			err := transformer.Repository.MarkHeaderChecked(header.Id)
+			if err != nil {
+				return err
+			}
+		}
+
+		for _, log := range matchingLogs {
+			model, err := transformer.Converter.ToModel(log)
+			if err != nil {
+				return err
+			}
+
+			err = transformer.Repository.Create(header.Id, []Model{model})
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}