Use Rust's native cargo command to build and launch the HODL node:

cargo run --release -- --dev --tmp

The cargo run command will perform an initial build. Use the following command to build the node without launching it:

cargo build --release

Once the project has been built, the following command can be used to explore all parameters and subcommands:

./target/release/node-hodl -h

The provided cargo run command will launch a temporary node and its state will be discarded after you terminate the process. After the project has been built, there are other ways to launch the node.

This command will start the single-node development chain with persistent state:

./target/release/node-hodl --dev

Purge the development chain's state:

./target/release/node-hodl purge-chain --dev

Start the development chain with detailed logging:

RUST_BACKTRACE=1 ./target/release/node-hodl -ldebug --dev

Once the node is running locally, you can connect it with Polkadot-JS Apps front-end to interact with your chain. Click here connecting the Apps to your local node.

A Substrate project such as this consists of a number of components that are spread across a few directories.

A blockchain node is an application that allows users to participate in a blockchain network. Substrate-based blockchain nodes expose a number of capabilities:

• Networking: Substrate nodes use the libp2p networking stack to allow the nodes in the network to communicate with one another.
• Consensus: Blockchains must have a way to come to consensus on the state of the network. Substrate makes it possible to supply custom consensus engines and also ships with several consensus mechanisms that have been built on top of Web3 Foundation research.
• RPC Server: A remote procedure call (RPC) server is used to interact with Substrate nodes.

There are several files in the node directory - take special note of the following:

• chain_spec.rs: A chain specification is a source code file that defines a Substrate chain's initial (genesis) state. Chain specifications are useful for development and testing, and critical when architecting the launch of a production chain. Take note of the development_config and testnet_genesis functions, which are used to define the genesis state for the local development chain configuration. These functions identify some well-known accounts and use them to configure the blockchain's initial state.
• service.rs: This file defines the node implementation. Take note of the libraries that this file imports and the names of the functions it invokes. In particular, there are references to consensus-related topics, such as the longest chain rule, the Aura block authoring mechanism and the GRANDPA finality gadget.