Spock

Centralized cache for blockchain data

Features

scrape any data available on blockchain (events, tx data, traces)
easily provide semantic layers on top
ensure data consistency

Installation

npm install spock-etl

Usage

Spock exposes CLI interface like:

spock-etl etl|migrate|validate|api yourconfig.js|ts

Commands

migrate — launches database migrations (core and defined in config)
etl — launches ETL process (long running process)
api — run general GraphQL api exposing database schema api
validate-logs — task to check logs against Google BigQueryData
validate-jobs - checks if there are no errored jobs (transformers or extractors)

Response caching

We can automatically cache slow graphql queries. To enable it add: VL_GRAPHQL_CACHING_ENABLED=true env variable or in your config:

  api: {
    responseCaching: {
      enabled: true,
      duration: "15 seconds" // default
    };
  };

Query whitelisting

Probably you don't want users to issue any query on GraphQL API. That's why we support query whitelisting.

Enable it by:

{
  // ...
  api: {
    whitelisting: {
      enabled: true,
      whitelistedQueriesDir: "./queries",
      bypassSecret: "SECRET VALUE 123",
    },
  }
}

We rely on special operationName (part of request's body) parameter to match requested query with a query that is defined in whitelistedQueriesDir.

You can bypass whole mechanism (for example to test new queries) by providing bypassSecret as devMode in request's body.

Ethereum node considerations

spock pulls all the data from ethereum node. Nodes can differ greatly between each other, and some are simply not reliable / consistent. Based on our tests:

Alchemy works
Infura DOESN'T WORK. Sometimes it can randomly return empty sets for getLogs calls
Self hosted nodes should work (not tested yet) but keep in mind that vulcan can generate quite a lot of network calls (around 500k daily)

Development

yarn build — build everything
yarn build:watch - build and watch
yarn test:fix - run tests, auto fix all errors

Tip: Use yarn link to link packages locally.

PostgreSQL for development

Start

docker-compose up -d

Stop (data preserved)

docker-compose stop

Down (data lost)

docker-compose down

Logging

We use consola for logging. By default it will log everything. To adjust logging levels set VL_LOGGING_LEVEL. env variable. Ex. use VL_LOGGING_LEVEL=4 to omit detailed db logs (most verbose).

Sentry integration

Configure sentry by providing environmental variables:

SENTRY_DSN=...
SENTRY_ENV=production

We will only report critical errors (ie. stopped jobs).

sirhill/spock