blockbook/workshop/blockbook.md

Blockbook Introduction

• backend for Suite
• essential for Suite to work
• supports multiple coins - around 80 officially, and much more unofficially
• github repository is quite popular - 700 forks, 700 stars - https://github.com/trezor/blockbook
• public UI - https://btc1.trezor.io/

Building blocks of Blockbook

Go language

• developed by Google
• statically typed, compiled language
• can do concurrent programming (goroutines)
• good bindings for RocksDB
• error handling is explicit - no exceptions, no try-catch

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ZeroMQ

• messaging library
• listens for hashblock and hashtx events/notifications/messages from bitcoind and runs a callback function (sends notifications to subscribers)
• used in bchain/mq.go

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RocksDB

• used in db/rocksdb.go

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Bitcoin RPC (bitcoind)

• used in bchain/coins/btc/bitcoinrpc.go

Backend software components/parts

• programming language
  • Go
  • good for concurrent programming - goroutines, channels
  • support for RocksDB
  • explicit error handling - no exceptions
  • capital letters for public functions, variables, etc.
• main entrypoint/loop
  • according to CLI args, does some things
  • blockbook.go
• configurations
  • one config per coin - configs/coins/bitcoin.json - RPC details, ports
  • build/blockchaincfg.json - coin + server configurations
  • blockbook.go taking CLI args
• modularization
  • the core is blockchain agnostic, bitcoin specified an RPC client interface, all coins implement this interface - with the possibility of default implementations
• db
  • RocksDB - db/rocksdb.go
  • column families, no tables
  • key-value store of bytes, very fast and efficient
• data source
  • bitcoind RPC for blockchain data, ZeroMQ for notifications
  • coingecko API for fiat rates
• data synchronization
  • initial sync
  • incremental sync
  • reorg handling
• application states
  • synchronizing, ready for requests, DB inconsistent
• dev environment
  • dev server, local development
• logging
  • glog ... INFO, WARNING, ERROR
• monitoring
  • external, via internal API
• reporting / metrics
  • Prometheus - metrics, Grafana - dashboards
  • common/metrics.go
• REST API
  • /server/public.go - ConnectFullPublicInterface
• websocket API
  • server/websocket.go - requestHandlers
• admin interface / internal dashboard
  • very small now
  • server/internal.go
• frontend / UI
  • /, /test-websocket.html
• cron jobs / scheduled / periodic tasks
  • fetching fiat rates
• authentication/authorization
  • not used, only for the admin interface
• caching
  • saving used transactions in RocksDB
• testing
  • unit tests, integration tests
  • go test -tags=unittest ./db
• deployment
  • Debian packages, Debian servers, bare-metal, no cloud
• CI/CD
  • Github Actions, previously Gitlab CI
• security
• backups
• scaling
• performance
• error handling
• rate limiting
• load balancing
• cloudflare
• messaging systems
• localization
• documentation
  • docs folder
• support
• server resources
• reliability
• developers
• contributors
• repository
• users
• clients

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Schedule

• 1. Diagram introduction - 5 minutes
• 2. Backend terms brainstorming - 10 minutes
• 3. Backend terms discussing + code + diagrams - 45 minutes Break - 5 minutes
• 4. Installing dependencies - 15 minutes
• 5. Installing and running local regtest bitcoind - 15 minutes
• 6. Running local Blockbook connected to local regtest - 15 minutes Break - 5 minutes
• 7. Playing with code, implementing some API and UI changes - 60 minutes