Simple-Blockchain

A blockchain project built to gain understanding on the fundamental workings of blockchain.

Features

• Each instance of blockchain server will have its own wallet of initial balance $500, along with a private and public key.
  • User could then create transactions specifying the recipient address and the amount.
  • Transactions created would be signed with the wallet's private key and submitted to the blockchain's transaction pool.
• A new block can be added to the blockchain when a blockchain server successfully "mines" a new block.
  • For each transaction in the transaction pool, the blockchain server that is doing the mining work will verify the transaction and for the valid transactions, it will be added into a new block in the blockchain.
  • When a new block is successfully added into the blockchain, the miner will be rewarded. The transaction that will send the mining reward to the miner will be included in the new block's data.
• Instances of the application can be synchronized (blockchain state & transactions in transaction pool) with each other using Websockets. Refer to section below on how to achieve this.
• CD pipeline to deploy to Google Cloud Run is set up using GitHub actions.

How to Run Program Conveniently

After cloning the repo, run docker-compose up at the root directory to directly spin up 3 blockchain server nodes that are synchronized with each other.

How to Run Program Manually

Head to the /cmd/blockchain directory and enter the command go run ..

There are also two environment variables, HTTP_PORT and PEERS that can be specified along with running go run ..

• HTTP_PORT specifies the port that the current blockchain listens to
• PEERS specifies the addresses of the servers that the current blockchain has to establish websocket connections to.

Example, if we have one blockchain server A running on address http://localhost:8080, we could start another blockchain server B which could connect to server A to synchronize blockchain updates. The command to start server B could be something like HTTP_PORT=8081 PEERS=localhost:8080 go run ..

Swagger docs would also be available at {hostname}/swagger/index.html.

How to Run All Tests

From the root directory, enter command go clean -testcache && go test ./... to run all tests in the project recursively.

How to Update Swagger Docs

From the root directory of the project, run swag init -d ./cmd/blockchain -o ./cmd/docs --parseDependency.