# Polkadot SDK's Minimal Template Polkadot SDK Logo Polkadot SDK Logo > This is a minimal template for creating a blockchain based on Polkadot SDK. > > This template is automatically updated after releases in the main [Polkadot SDK monorepo](https://github.com/paritytech/polkadot-sdk).
## Table of Contents - [Intro](#intro) - [Template Structure](#template-structure) - [Getting Started](#getting-started) - [Starting a Minimal Template Chain](#starting-a-minimal-template-chain) - [Omni Node](#omni-node) - [Minimal Template Node](#minimal-template-node) - [Zombienet with Omni Node](#zombienet-with-omni-node) - [Zombienet with Minimal Template Node](#zombienet-with-minimal-template-node) - [Connect with the Polkadot-JS Apps Front-End](#connect-with-the-polkadot-js-apps-front-end) - [Takeaways](#takeaways) - [Contributing](#contributing) - [Getting Help](#getting-help) ## Intro - ๐Ÿค This template is a minimal (in terms of complexity and the number of components) template for building a blockchain node. - ๐Ÿ”ง Its runtime is configured with a single custom pallet as a starting point, and a handful of ready-made pallets such as a [Balances pallet](https://paritytech.github.io/polkadot-sdk/master/pallet_balances/index.html). - ๐Ÿ‘ค The template has no consensus configured - it is best for experimenting with a single node network. ## Template Structure A Polkadot SDK based project such as this one consists of: - ๐Ÿงฎ the [Runtime](./runtime/README.md) - the core logic of the blockchain. - ๐ŸŽจ the [Pallets](./pallets/README.md) - from which the runtime is constructed. - ๐Ÿ’ฟ a [Node](./node/README.md) - the binary application (which is not part of the cargo default-members list and is not compiled unless building the entire workspace). ## Getting Started - ๐Ÿฆ€ The template is using the Rust language. - ๐Ÿ‘‰ Check the [Rust installation instructions](https://www.rust-lang.org/tools/install) for your system. - ๐Ÿ› ๏ธ Depending on your operating system and Rust version, there might be additional packages required to compile this template - please take note of the Rust compiler output. Fetch minimal template code: ```sh git clone https://github.com/paritytech/polkadot-sdk-minimal-template.git minimal-template cd minimal-template ``` ## Starting a Minimal Template Chain ### Omni Node [Omni Node](https://paritytech.github.io/polkadot-sdk/master/polkadot_sdk_docs/reference_docs/omni_node/index.html) can be used to run the minimal template's runtime. `polkadot-omni-node` binary crate usage is described at a high-level [on crates.io](https://crates.io/crates/polkadot-omni-node). #### Install `polkadot-omni-node` Please see installation section on [crates.io/omni-node](https://crates.io/crates/polkadot-omni-node). #### Build `minimal-template-runtime` ```sh cargo build -p minimal-template-runtime --release ``` #### Install `staging-chain-spec-builder` Please see the installation section at [`crates.io/staging-chain-spec-builder`](https://crates.io/crates/staging-chain-spec-builder). #### Use chain-spec-builder to generate the chain_spec.json file ```sh chain-spec-builder create --relay-chain "dev" --para-id 1000 --runtime \ target/release/wbuild/minimal-template-runtime/minimal_template_runtime.wasm named-preset development ``` **Note**: the `relay-chain` and `para-id` flags are extra bits of information required to configure the node for the case of representing a parachain that is connected to a relay chain. They are not relevant to minimal template business logic, but they are mandatory information for Omni Node, nonetheless. #### Run Omni Node Start Omni Node in development mode (sets up block production and finalization based on manual seal, sealing a new block every 3 seconds), with a minimal template runtime chain spec. ```sh polkadot-omni-node --chain --dev ``` ### Minimal Template Node #### Build both node & runtime ```sh cargo build --workspace --release ``` ๐Ÿณ Alternatively, build the docker image which builds all the workspace members, and has as entry point the node binary: ```sh docker build . -t polkadot-sdk-minimal-template ``` #### Start the `minimal-template-node` The `minimal-template-node` has dependency on the `minimal-template-runtime`. It will use the `minimal_template_runtime::WASM_BINARY` constant (which holds the WASM blob as a byte array) for chain spec building, while starting. This is in contrast to Omni Node which doesn't depend on a specific runtime, but asks for the chain spec at startup. ```sh --tmp --consensus manual-seal-3000 # or via docker docker run --rm polkadot-sdk-minimal-template ``` ### Zombienet with Omni Node #### Install `zombienet` We can install `zombienet` as described [here](https://paritytech.github.io/zombienet/install.html#installation), and `zombienet-omni-node.toml` contains the network specification we want to start. #### Update `zombienet-omni-node.toml` with a valid chain spec path Before starting the network with zombienet we must update the network specification with a valid chain spec path. If we need to generate one, we can look up at the previous section for chain spec creation [here](#use-chain-spec-builder-to-generate-the-chain_specjson-file). Then make the changes in the network specification like so: ```toml # ... chain = "dev" chain_spec_path = "" default_args = ["--dev"] # .. ``` #### Start the network ```sh zombienet --provider native spawn zombienet-omni-node.toml ``` ### Zombienet with `minimal-template-node` For this one we just need to have `zombienet` installed and run: ```sh zombienet --provider native spawn zombienet-multi-node.toml ``` ### Connect with the Polkadot-JS Apps Front-End - ๐ŸŒ You can interact with your local node using the hosted version of the [Polkadot/Substrate Portal](https://polkadot.js.org/apps/#/explorer?rpc=ws://localhost:9944). - ๐Ÿช A hosted version is also available on [IPFS](https://dotapps.io/). - ๐Ÿง‘โ€๐Ÿ”ง You can also find the source code and instructions for hosting your own instance in the [`polkadot-js/apps`](https://github.com/polkadot-js/apps) repository. ### Takeaways Previously minimal template's development chains: - โŒ Started in a multi-node setup will produce forks because minimal lacks consensus. - ๐Ÿงน Do not persist the state. - ๐Ÿ’ฐ Are pre-configured with a genesis state that includes several pre-funded development accounts. - ๐Ÿง‘โ€โš–๏ธ One development account (`ALICE`) is used as `sudo` accounts. ## Contributing - ๐Ÿ”„ This template is automatically updated after releases in the main [Polkadot SDK monorepo](https://github.com/paritytech/polkadot-sdk). - โžก๏ธ Any pull requests should be directed to this [source](https://github.com/paritytech/polkadot-sdk/tree/master/templates/minimal). - ๐Ÿ˜‡ Please refer to the monorepo's [contribution guidelines](https://github.com/paritytech/polkadot-sdk/blob/master/docs/contributor/CONTRIBUTING.md) and [Code of Conduct](https://github.com/paritytech/polkadot-sdk/blob/master/docs/contributor/CODE_OF_CONDUCT.md). ## Getting Help - ๐Ÿง‘โ€๐Ÿซ To learn about Polkadot in general, [Polkadot.network](https://polkadot.network/) website is a good starting point. - ๐Ÿง‘โ€๐Ÿ”ง For technical introduction, [here](https://github.com/paritytech/polkadot-sdk#-documentation) are the Polkadot SDK documentation resources. - ๐Ÿ‘ฅ Additionally, there are [GitHub issues](https://github.com/paritytech/polkadot-sdk/issues) and [Substrate StackExchange](https://substrate.stackexchange.com/).