ipld-eth-server/examples/erc20_watcher/every_block/transformer.go

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// 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 every_block
import (
"fmt"
"github.com/vulcanize/vulcanizedb/examples/erc20_watcher"
"github.com/vulcanize/vulcanizedb/libraries/shared"
"github.com/vulcanize/vulcanizedb/pkg/core"
"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
"log"
"math/big"
)
type Transformer struct {
Getter ERC20GetterInterface
Repository ERC20RepositoryInterface
Config erc20_watcher.ContractConfig
}
func (t *Transformer) SetConfiguration(config erc20_watcher.ContractConfig) {
t.Config = config
}
type TokenSupplyTransformerInitializer struct {
Config erc20_watcher.ContractConfig
}
func (i TokenSupplyTransformerInitializer) NewTokenSupplyTransformer(db *postgres.DB, blockChain core.BlockChain) shared.Transformer {
getter := NewGetter(blockChain)
repository := ERC20TokenRepository{DB: db}
transformer := Transformer{
Getter: &getter,
Repository: &repository,
Config: i.Config,
}
return transformer
}
const (
FetchingBlocksError = "Error getting missing blocks starting at block number %d: %s"
GetSupplyError = "Error getting supply for block %d: %s"
CreateSupplyError = "Error inserting token_supply for block %d: %s"
)
type transformerError struct {
err string
blockNumber int64
msg string
}
func (te *transformerError) Error() string {
return fmt.Sprintf(te.msg, te.blockNumber, te.err)
}
func newTransformerError(err error, blockNumber int64, msg string) error {
e := transformerError{err.Error(), blockNumber, msg}
log.Println(e.Error())
return &e
}
func (t Transformer) Execute() error {
var upperBoundBlock int64
blockChain := t.Getter.GetBlockChain()
lastBlock := blockChain.LastBlock().Int64()
if t.Config.LastBlock == -1 {
upperBoundBlock = lastBlock
} else {
upperBoundBlock = t.Config.LastBlock
}
// Supply transformations:
// Fetch missing supply blocks
blocks, err := t.Repository.MissingSupplyBlocks(t.Config.FirstBlock, upperBoundBlock, t.Config.Address)
if err != nil {
return newTransformerError(err, t.Config.FirstBlock, FetchingBlocksError)
}
// Fetch supply for missing blocks
log.Printf("Gets totalSupply for %d blocks", len(blocks))
// For each block missing total supply, create supply model and feed the missing data into the repository
for _, blockNumber := range blocks {
totalSupply, err := t.Getter.GetTotalSupply(t.Config.Abi, t.Config.Address, blockNumber)
if err != nil {
return newTransformerError(err, blockNumber, GetSupplyError)
}
// Create the supply model
model := createTokenSupplyModel(totalSupply, t.Config.Address, blockNumber)
// Feed it into the repository
err = t.Repository.CreateSupply(model)
if err != nil {
return newTransformerError(err, blockNumber, CreateSupplyError)
}
}
return nil
}
func createTokenSupplyModel(totalSupply big.Int, address string, blockNumber int64) TokenSupply {
return TokenSupply{
Value: totalSupply.String(),
TokenAddress: address,
BlockNumber: blockNumber,
}
}