herodotusdev / l2-indexer

Indexer for Ethereum Layer 2s (OP Stack rollups, Arbitrum, etc...)

L2 Indexer

This repo implements an indexer whose role is to watch for L2 rollups events emitted on Ethereum and index the Output Roots into a database for querying later -- providing examples for Arbitrum, Optimism, Base, Zora chain

Supported Networks

Type	Network	Network Detail	Support
Arbitrum	Arbitrum	mainnet	✅
Arbitrum	Arbitrum	sepolia	✅
OP Stack	Base	mainnet	✅
OP Stack	Base	sepolia	✅
Optimism	Optimism	mainnet	✅
Optimism	Optimism	sepolia	✅
OP Stack	Zora	mainnet	✅

Architecture

1. Monitor Events: Run monitoring service that gets network spec as pm2 config. It keeps track OP Stack rollup & Arbitrum that emitted block hash preimage(Output Root) on the L1 contract.
2. L2 Micro Service: Rust HTTP micro-service provides L2 information including block hash requested by block number.

Monitoring service:

Monitor events (OutputProposed) from L1 contract. Retrieve output_root

First check table is exist. If it's exist, get latest L1 block that stored in db, and use this block number as from_block filter. If it's not exist, create table and query all events from 0 to latest block - BLOCK_DELAY.

Monitor service will pull every POLL_PERIOD. If POLL_PERIOD is longer than block creation time, the service algorithm is already ensure to get not duplicated event. Here is the example log:

example log

output_root = 0x43949a1178f9fbcd851c5f6103603d7f7df0c05e399d09c7edb96ef4281a9d25, l2OutputIndex = 2873, l2BlockNumber = 110408263, l1Blocknumber = 18276691, l1Timestamp = 1696416911, l1_transaction_hash=0xbf90fd89af4a580695abd69bccce1ed3ef426e72021ee3c7e0aad2f4b3d8375d, l1_transaction_index=195, L1_block_hash=0x3d05fd1575b8b38b08a1e8d2a4253b09fba7e01f72e66e8c19eec0a3b39bc62f
from 18276743 to 18276747, 0 pools found!
from 18276748 to 18276752, 0 pools found!
from 18276753 to 18276757, 0 pools found!

Block number -> Output Index mapper Microservice

Request with l2_block_number, network_name return l2_output_root and l2_block_number. In this case, we can query the database directly:

  SELECT l2_output_root, l2_output_index, l2_block_number, l1_timestamp, l1_transaction_hash, l1_block_number, l1_transaction_index, l1_block_hash
            FROM optimism
            WHERE l2_block_number >= $1
            ORDER BY l2_block_number ASC
            LIMIT 1;

So that it return the nearest, but newer blocknumber from what was requested.

Endpoint:

http://127.0.0.1:8000/output-root?network=optimism_sepolia&l2_block=1

How to run

1. Use the setup script

./setup.sh

2. When developing rebuild and restart the services

./restart.sh

3. Check the logs, start, stop services manually, etc. - use pm2

4. Cleanup everything

./cleanup.sh

License

l2_indexer is licensed under the GNU General Public License v3.0.

---

Herodotus Dev Ltd - 2024

l2-indexer's Issues

Possible SQL injection point?

https://github.com/HerodotusDev/opstack_indexer/blob/a058388150d7a75cb5cc4bc66057e2caf3d53714/crates/monitor_events/src/main.rs#L61C28-L61C28

Do not parse strings directly into your sql query. Prone to SQL injection attacks.

Recommend using ORMs

Alloy Migration

migration from ethers-rs to alloy-rs
https://github.com/alloy-rs/alloy