A new FRAME-based Substrate node, ready for hacking.
A fresh FRAME-based Substrate node, ready for hacking :rocket:
Follow the steps below to get started with the Node Template, or get it up and running right from your browser in just a few clicks using the Substrate Playground :hammerandwrench:
direnv allowand lorri
First, complete the basic Rust setup instructions.
Use Rust's native
cargocommand to build and launch the template node:
cargo run --release -- --dev --tmp
cargo runcommand 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:
cargo runcommand 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:
Purge the development chain's state:
./target/release/node-template purge-chain --dev
Start the development chain with detailed logging:
RUST_BACKTRACE=1 ./target/release/node-template -ldebug --dev
Once the node template 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 template.
If you want to see the multi-node consensus algorithm in action, refer to our Start a Private Network tutorial.
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:
libp2pnetworking stack to allow the nodes in the network to communicate with one another.
There are several files in the
nodedirectory - 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
testnet_genesisfunctions, 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.
After the node has been built, refer to the embedded documentation to learn more about the capabilities and configuration parameters that it exposes:
In Substrate, the terms "runtime" and "state transition function" are analogous - they refer to the core logic of the blockchain that is responsible for validating blocks and executing the state changes they define. The Substrate project in this repository uses the FRAME framework to construct a blockchain runtime. FRAME allows runtime developers to declare domain-specific logic in modules called "pallets". At the heart of FRAME is a helpful macro language that makes it easy to create pallets and flexibly compose them to create blockchains that can address a variety of needs.
Review the FRAME runtime implementation included in this template and note the following:
impl $PALLET_NAME::Config for Runtime.
construct_runtime!macro, which is part of the core FRAME Support library.
A FRAME pallet is compromised of a number of blockchain primitives:
Configconfiguration interface is used to define the types and parameters upon which a FRAME pallet depends.
Then run the following command to start a single node development chain.
This command will firstly compile your code, and then start a local development network. You can also replace the default command (
cargo build --release && ./target/release/node-template --dev --ws-external) by appending your own. A few useful ones are as follow.
# Run Substrate node without re-compiling ./scripts/docker_run.sh ./target/release/node-template --dev --ws-external
Purge the local dev chain
./scripts/docker_run.sh ./target/release/node-template purge-chain --dev
Check whether the code is compilable
./scripts/docker_run.sh cargo check