EthereumSamurai

Ethereum Indexer

Structure

EthereumSamurai consists of two parts: API and Indexing job. API is EthereumSamurai project. Indexing job is EthereumSamurai.Indexer project.

Dependencies

It depends on:

1. MongoDB where all data is stored.
2. Ethereum go-client is a source of data from blockchain.
3. RabbitMQ serves to notify external services about indexing events and to process erc20 contracts

Configuration

Both project can recieve configuration via http request to configuration service or via environment variables. Configuration Model is described by IBaseSettings interface.

To configure indexing job you should pass additional configuration(see appsettings.json in EthereumSamurai.Indexer):

"IndexerInstanceSettings": { "IndexerId": "FirstIndexer", "ThreadAmount": 4, "StartBlock": 0, "StopBlock": null, ... },

If application exits before indexing is completed you can restart it and it would start indexing from the last synced point(points if ThreadAmount > 1).

• IndexerId - any string. If you want to run multiple indexers on several VM.
• ThreadAmount - amount of threads for that particular indexer instance.
• StartBlock - block from which indexing starts
• StopBlock - stop the indexing instance on the block with BlockNumber == StopBlock(Leave it null or skip in configuration)

Example from docker-compose.yml configuration file services:

jobrunner:

environment:

 ConnectionStrings__ConnectionString: https://ethereum.samurai,settings.com
 
 IndexerInstanceSettings__BalancesStartBlock: '0'
 
 IndexerInstanceSettings__ContractsIndexerThreadAmount: '1'
 
 IndexerInstanceSettings__IndexBalances: 'true'
 
 IndexerInstanceSettings__IndexBlocks: 'true'
 
 IndexerInstanceSettings__IndexContracts: 'true'
 
 IndexerInstanceSettings__IndexerId: TestIndexer
 
 IndexerInstanceSettings__SendEventsToRabbit: 'true'
 
 IndexerInstanceSettings__StartBlock: '1'
 
 IndexerInstanceSettings__StopBlock: ''
 
 IndexerInstanceSettings__ThreadAmount: '1'

image: lykkedev/lykke-ethereum-indexer-jobs:test

version: '2.0'

Logic behind ThreadAmount

Example: If last BlockNumber on the blockchain is 100 and the indexer instance has the next configuration:

• ThreadAmount = 2;
• StartBlock = 0;
• StopBlock is not set or is null; In that case indexing jobs would process blockchain in two threads in the next ways:

1. First thread would process blocks in the range 1 - 50.
2. The other one would process blocks in the range 51 - ... and would download new blocks and deal with blockchain forks until the application is stopped.