Blockchain in Go

Before you start

• Install Go in you machine.
• Install Code Editor VS CODE or IDE GO LAND
• Get Some Understanding of How Blockchain Works
• Below are some youtube video link will give you some context
  • How does a blockchain work - Simply Explained
  • Blockchain 101 - A Visual Demo
  • Blockchain 101 - Part 2 - Public / Private Keys and Signing
• If you are new to Go language follow the Cheat Sheet. You will get some understanding of Go syntax.

Local Setup

Clone the repository

$ git clone https://github.com/NearPrime/blockchain.git

Open the project directory

$ cd blockchain

Install the Go Dependency

$ go mod init blockchain

$ go get golang.org/x/crypto/ripemd160

$ go get github.com/boltdb/bolt

$ go get github.com/stretchr/testify/assert

Build the executable

$ go build

Cheers!! You have done with your local setup. You are ready to play with your blockchain.

Follow below steps to play around your blockchain

1. Set NODE_ID to 3000 export NODE_ID=3000 in the first terminal window.
2. Open two more terminal and set the NODE_ID to 3001 & 3002.
3. Create a wallet and a new blockchain for NODE 3000
   1. blockchain createwallet it will create a wallet and give you the wallet address.
   2. blockchain createblockchain -address CENTRAL_NODE CENTRAL_NODE is address of wallet you just created.
   3. After that, the blockchain will contain single genesis block. We need to save the block and use it in other nodes cp blockchain_3000.db blockchain_genesis.db
4. Go to the terminal NODE 3001. This will be a wallet node. Generate some addresses with blockchain createwallet. Let's call them as WALLET_1, WALLET_2, WALLET_3 for shake of understanding.
5. On terminal NODE 3000. Let's send some coins to the wallet addresses. We have to have -mine flag because initially there are no miner nodes in the network.
   1. $ blockchain send -from CENTRAL_NODE -to WALLET_1 -amount 10 -mine
   2. $ blockchain send -from CENTRAL_NODE -to WALLET_2 -amount 10 -mine
   3. Start the node blockchain startnode. This node must be running until the end of the scenario.
6. On terminal NODE 3001. Start the node’s blockchain with the genesis block saved above cp blockchain_genesis.db blockchain_3001.db.
   1. Run the Node blockchain startnode It’ll download all the blocks from the central node. To check that everything’s ok, stop the node and check the balances.
   2. blockchain getbalance -address WALLET_1 it will return Balance of 'WALLET_1': 10
   3. blockchain getbalance -address WALLET_2 it will return Balance of 'WALLET_2': 10
   4. blockchain getbalance -address CENTRAL_NODE you can check the balance of the CENTRAL_NODE address, because the node 3001 now has its blockchain.
7. On terminal NODE 3002. Generate a Wallet blockchain createwallet. This will be a miner node.
   1. Initialize the blockchain: cp blockchain_genesis.db blockchain_3002.db
   2. Start the node: blockchain startnode -miner MINER_WALLET
8. On terminal NODE 3001. Send some coins.
   1. blockchain send -from WALLET_1 -to WALLET_3 -amount 1
   2. blockchain send -from WALLET_2 -to WALLET_4 -amount 1
9. Quickly! Switch to the miner node NODE 3002 and see it mining a new block! Also, check the output of the central node.
10. On terminal NODE 3001. Switch to the wallet node.
    1. Start the wallet node: blockchain startnode. It’ll download the newly mined block.
    2. Now stop the node and check the balances using blockchain getbalance -address WALLET_1
11. blockchain listaddresses You can get all the addresses.
12. blockchain printchain It will return the complete chain.

Scripts

• blockchain getbalance -address {WALLET_ADDRESS} It will return the current balance of wallet.
• blockchain createblockchain -address {CENTRAL_NODE} CENTRAL_NODE is wallet address. It will create blockchain.
• blockchain createwallet it will create a wallet and returns the wallet address.
• blockchain listaddresses it will list all wallet address available on blockchain.
• blockchain printchain It will return the blockchain.
• blockchain send -from {WALLET_ADD_1} -to {WALLET_ADD_2} -amount {amount} It will used to send the coins from one wallet to another.
• blockchain startnode It will start the node. and download all the newly mined block.

Useful tips

• I've followed the below tutorial and the Blockchain Implementation is done as described in the following articles, It's good to follow if you want to get a good understanding of Code Base:*

1. Basic Prototype
2. Proof-of-Work
3. Persistence and CLI
4. Transactions 1
5. Addresses
6. Transactions 2
7. Network