remove pkg/transformers; extract shared files needed to

libraries/shared; work on automated db migration management

libraries/shared/fetcher/log_fetcher.go

@@ -0,0 +1,58 @@
+// VulcanizeDB
+// Copyright © 2018 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package fetcher
+
+import (
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+)
+
+type LogFetcher interface {
+	FetchLogs(contractAddresses []common.Address, topics []common.Hash, missingHeader core.Header) ([]types.Log, error)
+}
+
+type Fetcher struct {
+	blockChain core.BlockChain
+}
+
+func NewFetcher(blockchain core.BlockChain) *Fetcher {
+	return &Fetcher{
+		blockChain: blockchain,
+	}
+}
+
+// Checks all topic0s, on all addresses, fetching matching logs for the given header
+func (fetcher Fetcher) FetchLogs(addresses []common.Address, topic0s []common.Hash, header core.Header) ([]types.Log, error) {
+	blockHash := common.HexToHash(header.Hash)
+	query := ethereum.FilterQuery{
+		BlockHash: &blockHash,
+		Addresses: addresses,
+		// Search for _any_ of the topics in topic0 position; see docs on `FilterQuery`
+		Topics: [][]common.Hash{topic0s},
+	}
+
+	logs, err := fetcher.blockChain.GetEthLogsWithCustomQuery(query)
+	if err != nil {
+		// TODO review aggregate fetching error handling
+		return []types.Log{}, err
+	}
+
+	return logs, nil
+}

libraries/shared/fetcher/log_fetcher_test.go

@@ -0,0 +1,70 @@
+// VulcanizeDB
+// Copyright © 2018 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package fetcher_test
+
+import (
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/common"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	fetch "github.com/vulcanize/vulcanizedb/libraries/shared/fetcher"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/fakes"
+)
+
+var _ = Describe("Fetcher", func() {
+	Describe("FetchLogs", func() {
+		It("fetches logs based on the given query", func() {
+			blockChain := fakes.NewMockBlockChain()
+			fetcher := fetch.NewFetcher(blockChain)
+			header := fakes.FakeHeader
+
+			addresses := []common.Address{
+				common.HexToAddress("0xfakeAddress"),
+				common.HexToAddress("0xanotherFakeAddress"),
+			}
+
+			topicZeros := []common.Hash{common.BytesToHash([]byte{1, 2, 3, 4, 5})}
+
+			_, err := fetcher.FetchLogs(addresses, topicZeros, header)
+
+			address1 := common.HexToAddress("0xfakeAddress")
+			address2 := common.HexToAddress("0xanotherFakeAddress")
+			Expect(err).NotTo(HaveOccurred())
+
+			blockHash := common.HexToHash(header.Hash)
+			expectedQuery := ethereum.FilterQuery{
+				BlockHash: &blockHash,
+				Addresses: []common.Address{address1, address2},
+				Topics:    [][]common.Hash{topicZeros},
+			}
+			blockChain.AssertGetEthLogsWithCustomQueryCalledWith(expectedQuery)
+		})
+
+		It("returns an error if fetching the logs fails", func() {
+			blockChain := fakes.NewMockBlockChain()
+			blockChain.SetGetEthLogsWithCustomQueryErr(fakes.FakeError)
+			fetcher := fetch.NewFetcher(blockChain)
+
+			_, err := fetcher.FetchLogs([]common.Address{}, []common.Hash{}, core.Header{})
+
+			Expect(err).To(HaveOccurred())
+			Expect(err).To(MatchError(fakes.FakeError))
+		})
+	})
+})