ipld-eth-server/examples/erc20_watcher/every_block/repository.go
Elizabeth Engelman 7ee253b2a3 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
2018-06-27 14:41:51 -05:00

92 lines
2.6 KiB
Go

// 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/pkg/datastore/postgres"
"log"
)
type ERC20RepositoryInterface interface {
Create(supply TokenSupply) error
MissingBlocks(startingBlock int64, highestBlock int64) ([]int64, error)
}
type TokenSupplyRepository struct {
*postgres.DB
}
type repositoryError struct {
err string
msg string
blockNumber int64
}
func (re *repositoryError) Error() string {
return fmt.Sprintf(re.msg, re.blockNumber, re.err)
}
func newRepositoryError(err error, msg string, blockNumber int64) error {
e := repositoryError{err.Error(), msg, blockNumber}
log.Println(e.Error())
return &e
}
const (
GetBlockError = "Error fetching block number %d: %s"
InsertTokenSupplyError = "Error inserting token_supply for block number %d: %s"
MissingBlockError = "Error finding missing token_supply records starting at block %d: %s"
)
func (tsp *TokenSupplyRepository) Create(supply TokenSupply) error {
var blockId int
err := tsp.DB.Get(&blockId, `SELECT id FROM blocks WHERE number = $1 AND eth_node_id = $2`, supply.BlockNumber, tsp.NodeID)
if err != nil {
return newRepositoryError(err, GetBlockError, supply.BlockNumber)
}
_, err = tsp.DB.Exec(
`INSERT INTO token_supply (supply, token_address, block_id)
VALUES($1, $2, $3)`,
supply.Value, supply.TokenAddress, blockId)
if err != nil {
return newRepositoryError(err, InsertTokenSupplyError, supply.BlockNumber)
}
return nil
}
func (tsp *TokenSupplyRepository) MissingBlocks(startingBlock int64, highestBlock int64) ([]int64, error) {
blockNumbers := make([]int64, 0)
err := tsp.DB.Select(
&blockNumbers,
`SELECT number FROM BLOCKS
LEFT JOIN token_supply ON blocks.id = block_id
WHERE block_id ISNULL
AND eth_node_id = $1
AND number >= $2
AND number <= $3
LIMIT 20`,
tsp.NodeID,
startingBlock,
highestBlock,
)
if err != nil {
return []int64{}, newRepositoryError(err, MissingBlockError, startingBlock)
}
return blockNumbers, err
}