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

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.
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

Use the setup script

./setup.sh

When developing rebuild and restart the services

./restart.sh

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

./cleanup.sh

License

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

Herodotus Dev Ltd - 2024