Add ERC20 token watcher example

- starting with the totalSupply function
- sets contract config on transformer by passing it into the transformer
initializer
- handles block records with the same number for different nodes for both creating token_supply records, and finding missing blocks

examples/mocks/mocks.go

@@ -0,0 +1,175 @@
+// 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 mocks
+
+import (
+	"errors"
+	"github.com/vulcanize/vulcanizedb/examples/erc20_watcher/every_block"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"math/big"
+)
+
+var TestError = errors.New("TestError")
+
+type Fetcher struct {
+	ContractAddress string
+	Abi             string
+	FetchedBlocks   []int64
+	Blockchain      core.Blockchain
+	supply          big.Int
+}
+
+func (f *Fetcher) SetSupply(supply string) {
+	f.supply.SetString(supply, 10)
+}
+
+func (f Fetcher) GetBlockchain() core.Blockchain {
+	return f.Blockchain
+}
+
+func (f *Fetcher) FetchSupplyOf(contractAbi string, contractAddress string, blockNumber int64) (big.Int, error) {
+	f.Abi = contractAbi
+	f.ContractAddress = contractAddress
+	f.FetchedBlocks = append(f.FetchedBlocks, blockNumber)
+
+	accumulator := big.NewInt(1)
+	f.supply.Add(&f.supply, accumulator)
+
+	return f.supply, nil
+}
+
+type TotalSupplyRepository struct {
+	TotalSuppliesCreated []every_block.TokenSupply
+	MissingBlockNumbers  []int64
+	StartingBlock        int64
+	EndingBlock          int64
+}
+
+func (fr *TotalSupplyRepository) Create(supply every_block.TokenSupply) error {
+	fr.TotalSuppliesCreated = append(fr.TotalSuppliesCreated, supply)
+	return nil
+}
+
+func (fr *TotalSupplyRepository) MissingBlocks(startingBlock int64, highestBlock int64) ([]int64, error) {
+	fr.StartingBlock = startingBlock
+	fr.EndingBlock = highestBlock
+	return fr.MissingBlockNumbers, nil
+}
+
+func (fr *TotalSupplyRepository) SetMissingBlocks(missingBlocks []int64) {
+	fr.MissingBlockNumbers = missingBlocks
+}
+
+type FailureRepository struct {
+	createFail           bool
+	missingBlocksFail    bool
+	missingBlocksNumbers []int64
+}
+
+func (fr *FailureRepository) Create(supply every_block.TokenSupply) error {
+	if fr.createFail {
+		return TestError
+	} else {
+		return nil
+	}
+}
+
+func (fr *FailureRepository) MissingBlocks(startingBlock int64, highestBlock int64) ([]int64, error) {
+	if fr.missingBlocksFail {
+		return []int64{}, TestError
+	} else {
+		return fr.missingBlocksNumbers, nil
+	}
+}
+
+func (fr *FailureRepository) SetCreateFail(fail bool) {
+	fr.createFail = fail
+}
+
+func (fr *FailureRepository) SetMissingBlocksFail(fail bool) {
+	fr.missingBlocksFail = fail
+}
+
+func (fr *FailureRepository) SetMissingBlocks(missingBlocks []int64) {
+	fr.missingBlocksNumbers = missingBlocks
+}
+
+type Blockchain struct {
+	FetchedAbi             string
+	FetchedContractAddress string
+	FetchedMethod          string
+	FetchedMethodArg       interface{}
+	FetchedResult          interface{}
+	FetchedBlockNumber     int64
+	lastBlock              *big.Int
+}
+
+func (fb *Blockchain) FetchContractData(abiJSON string, address string, method string, methodArg interface{}, result interface{}, blockNumber int64) error {
+	fb.FetchedAbi = abiJSON
+	fb.FetchedContractAddress = address
+	fb.FetchedMethod = method
+	fb.FetchedMethodArg = methodArg
+	fb.FetchedResult = result
+	fb.FetchedBlockNumber = blockNumber
+	return nil
+}
+
+func (fb *Blockchain) GetBlockByNumber(blockNumber int64) (core.Block, error) {
+	panic("implement me")
+}
+
+func (fb *Blockchain) GetLogs(contract core.Contract, startingBlockNumber *big.Int, endingBlockNumber *big.Int) ([]core.Log, error) {
+	panic("implement me")
+}
+
+func (fb *Blockchain) LastBlock() *big.Int {
+	return fb.lastBlock
+}
+
+func (fb *Blockchain) Node() core.Node {
+	panic("implement me")
+}
+
+func (fb *Blockchain) SetLastBlock(lastBlock *big.Int) {
+	fb.lastBlock = lastBlock
+}
+
+type FailureBlockchain struct {
+	lastBlock *big.Int
+}
+
+func (FailureBlockchain) FetchContractData(abiJSON string, address string, method string, methodArg interface{}, result interface{}, blockNumber int64) error {
+	return errors.New("TestError")
+}
+
+func (FailureBlockchain) GetBlockByNumber(blockNumber int64) (core.Block, error) {
+	panic("implement me")
+}
+
+func (FailureBlockchain) GetLogs(contract core.Contract, startingBlockNumber *big.Int, endingBlockNumber *big.Int) ([]core.Log, error) {
+	panic("implement me")
+}
+
+func (fb FailureBlockchain) LastBlock() *big.Int {
+	return fb.lastBlock
+}
+
+func (FailureBlockchain) Node() core.Node {
+	panic("implement me")
+}
+
+func (fb *FailureBlockchain) SetLastBlock(lastBlock *big.Int) {
+	fb.lastBlock = lastBlock
+}