ethwal

A simple library for creating Ethereum based flat file datasets.

Usage

The library consists of two main components, Writer and Reader. Each reader and writer needs to specify dataset name and path. The name is used to identify the dataset, and the path is used to specify the directory where the dataset is stored. They may use json or cbor encoding for the data as well as zstd compression. The other custom encoders and compressors can be added by implementing the ethwal.Encoder and ethwal.Compressor interfaces.

The writer supports file roll over strategies such as: rolling over every Nth block, or after writing a certain amount of data.

Writer

package main
import (
"fmt""github.com/0xsequence/ethwal""github.com/ethereum/go-ethereum/common""github.com/ethereum/go-ethereum/core/types"
)
funcmain() {
w, err:= ethwal.NewWriter[[]types.Log](ethwal.Options{
Dataset: ethwal.Dataset{
Name: "event-logs",
Path: "data",
},
FileRollPolicy: ethwal.NewFileSizeRollPolicy(128<<10), /* 128 KB */
})
iferr!=nil {
fmt.Println(err)
return
}
fori:=0; i<1000; i++ {
err=w.Write(ethwal.Block[[]types.Log]{
Number: uint64(i),
Hash: "0x123",
Data: []types.Log{
{
Address: common.HexToAddress("0x123"),
Topics: []common.Hash{
common.HexToHash("0x123"),
},
Data: []byte("0x123"),
},
},
})
iferr!=nil {
fmt.Println(err)
return
}
}
// Close the writerw.Close()
}
}

Reader

package main
import (
"fmt""io""github.com/0xsequence/ethwal""github.com/ethereum/go-ethereum/core/types"
)
funcmain() {
r, err:= ethwal.NewReader[[]types.Log](ethwal.Options{
Dataset: ethwal.Dataset{
Name: "event-logs",
Path: "data",
},
})
iferr!=nil {
fmt.Println(err)
return
}
// Read all the blocksvarb ethwal.Block[[]types.Log]
forb, err=r.Read(); err==nil; b, err=r.Read() {
fmt.Println(b.Number)
fmt.Println(b.Hash)
fmt.Println(b.Data)
}
iferr!=nil&&err!=io.EOF {
fmt.Println(err)
return
}
// Close the readerr.Close()
}

CLI examples

Read ethwal from local fs

$ ./ethwalcat --mode=read --path=./../indexer-data/db-logwal-new/137/v3/ --from=20000001 --to=20000005 --decompressor=zstd
{"blockHash":"0x90220f1f2d13248bef5ed31739b3625cb3696061ce891070ee7768dd6f94474f","blockNum":20000001,"blockTS":1633732467,"blockData":null}
{"blockHash":"0xb1db1d89202cee5cbc99f537ee0107e0d175d7f458e5c566657b644a3b205843","blockNum":20000002,"blockTS":1633732469,"blockData":null}
{"blockHash":"0x1c475400153bcfb8c1558cadc4fa94ed00ba28282fd63f13e0193e7a5e651d20","blockNum":20000003,"blockTS":1633732471,"blockData":null}
{"blockHash":"0xed17a5cfa53dffe8489c2f0dbea7d64cf732b3ef1d235ba3438a41154935b110","blockNum":20000004,"blockTS":1633732473,"blockData":null}

Transcode ethwal from local cbor zstd to local json not compressed

./ethwalcat --mode=read --path=./../indexer-data/db-logwal-new/137/v3/ --from=20000001 --to=20000005 --decompressor=zstd | ./ethwalcat --mode=write --path=./ --encoder=json --compressor=none

Read transcoded ethwal

$ ./ethwalcat --mode=read --path=./ --decoder=json --decompressor=none
{"blockHash":"0x90220f1f2d13248bef5ed31739b3625cb3696061ce891070ee7768dd6f94474f","blockNum":20000001,"blockTS":1633732467,"blockData":null}
{"blockHash":"0xb1db1d89202cee5cbc99f537ee0107e0d175d7f458e5c566657b644a3b205843","blockNum":20000002,"blockTS":1633732469,"blockData":null}
{"blockHash":"0x1c475400153bcfb8c1558cadc4fa94ed00ba28282fd63f13e0193e7a5e651d20","blockNum":20000003,"blockTS":1633732471,"blockData":null}
{"blockHash":"0xed17a5cfa53dffe8489c2f0dbea7d64cf732b3ef1d235ba3438a41154935b110","blockNum":20000004,"blockTS":1633732473,"blockData":null}

Read ethwal from Google Cloud Bucket

$ ./ethwalcat --mode=read --google-cloud-bucket=sequence-dev-cluster-indexer-wal --path=./polygon-db-logwal/137/v2 --decompressor=zstd --from=1455120 --to=1455130
{"blockHash":"0x0000000000000000000000000000000000000000000000000000000000000000","blockNum":1455120,"blockTS":0,"blockData":null}