Introduction

In this tutorial, we will be using Ignite CLI to create a new blockchain. Ignite CLI is a command line interface that allows users to quickly and easily create blockchain networks. By using Ignite CLI, we can quickly create a new blockchain without having to manually set up all the necessary components.

Once we have created our blockchain with Ignite CLI, we will take a look at the directory structure and files that were created. This will give us an understanding of how the blockchain is organized and how the different components of the blockchain interact with each other.

By the end of this tutorial, you will have a basic understanding of how to use Ignite CLI to create a new blockchain, and you will have a high-level understanding of the directory structure and files that make up a blockchain. This knowledge will be useful as you continue to explore the world of blockchain development.

Creating a new blockchain

To create a new blockchain project with Ignite, you will need to run the following command:

ignite scaffold chain example

The ignite scaffold chain command will create a new blockchain in a new directory example.

The new blockchain is built using the Cosmos SDK framework and imports several standard modules to provide a range of functionality. These modules include staking, which enables a delegated Proof-of-Stake consensus mechanism, bank for facilitating fungible token transfers between accounts, and gov for on-chain governance. In addition to these modules, the blockchain also imports other modules from the Cosmos SDK framework.

The example directory contains the generated files and directories that make up the structure of a Cosmos SDK blockchain. This directory includes files for the chain's configuration, application logic, and tests, among others. It provides a starting point for developers to quickly set up a new Cosmos SDK blockchain and build their desired functionality on top of it.

By default, Ignite creates a new empty custom module with the same name as the blockchain being created (in this case, example) in the x/ directory. This module doesn't have any functionality by itself, but can serve as a starting point for building out the features of your application. If you don't want to create this module, you can use the --no-module flag to skip it.

Directory structure

In order to understand what the Ignite CLI has generated for your project, you can inspect the contents of the example/ directory.

The app/ directory contains the files that connect the different parts of the blockchain together. The most important file in this directory is app.go, which includes the type definition of the blockchain and functions for creating and initializing it. This file is responsible for wiring together the various components of the blockchain and defining how they will interact with each other.

The cmd/ directory contains the main package responsible for the command-line interface (CLI) of the compiled binary. This package defines the commands that can be run from the CLI and how they should be executed. It is an important part of the blockchain project as it provides a way for developers and users to interact with the blockchain and perform various tasks, such as querying the blockchain state or sending transactions.

The docs/ directory is used for storing project documentation. By default, this directory includes an OpenAPI specification file, which is a machine-readable format for defining the API of a software project. The OpenAPI specification can be used to automatically generate human-readable documentation for the project, as well as provide a way for other tools and services to interact with the API. The docs/ directory can be used to store any additional documentation that is relevant to the project.

The proto/ directory contains protocol buffer files, which are used to describe the data structure of the blockchain. Protocol buffers are a language- and platform-neutral mechanism for serializing structured data, and are often used in the development of distributed systems, such as blockchain networks. The protocol buffer files in the proto/ directory define the data structures and messages that are used by the blockchain, and are used to generate code for various programming languages that can be used to interact with the blockchain. In the context of the Cosmos SDK, protocol buffer files are used to define the specific types of data that can be sent and received by the blockchain, as well as the specific RPC endpoints that can be used to access the blockchain's functionality.

The testutil/ directory contains helper functions that are used for testing. These functions provide a convenient way to perform common tasks that are needed when writing tests for the blockchain, such as creating test accounts, generating transactions, and checking the state of the blockchain. By using the helper functions in the testutil/ directory, developers can write tests more quickly and efficiently, and can ensure that their tests are comprehensive and effective.

The x/ directory contains custom Cosmos SDK modules that have been added to the blockchain. Standard Cosmos SDK modules are pre-built components that provide common functionality for Cosmos SDK-based blockchains, such as support for staking and governance. Custom modules, on the other hand, are modules that have been developed specifically for the blockchain project and provide project-specific functionality.

The config.yml file is a configuration file that can be used to customize the blockchain during development. This file includes settings that control various aspects of the blockchain, such as the network's ID, account balances, and the node parameters.

The .github directory contains a GitHub Actions workflow that can be used to automatically build and release a blockchain binary. GitHub Actions is a tool that allows developers to automate their software development workflows, including building, testing, and deploying their projects. The workflow in the .github directory is used to automate the process of building the blockchain binary and releasing it, which can save time and effort for developers.

The readme.md file is a readme file that provides an overview of the blockchain project. This file typically includes information such as the project's name and purpose, as well as instructions on how to build and run the blockchain. By reading the readme.md file, developers and users can quickly understand the purpose and capabilities of the blockchain project and get started using it.

Starting a blockchain node

To start a blockchain node in development, you can run the following command:

ignite chain serve

The ignite chain serve command is used to start a blockchain node in development mode. It first compiles and installs the binary using the ignite chain build command, then initializes the blockchain's data directory for a single validator using the ignite chain init command. After that, it starts the node locally and enables automatic code reloading so that changes to the code can be reflected in the running blockchain without having to restart the node. This allows for faster development and testing of the blockchain.

Congratulations! 🥳 You have successfully created a brand-new Cosmos blockchain using the Ignite CLI. This blockchain uses the delegated proof of stake (DPoS) consensus algorithm, and comes with a set of standard modules for token transfers, governance, and inflation. Now that you have a basic understanding of your Cosmos blockchain, it's time to start building custom functionality. In the following tutorials, you will learn how to build custom modules and add new features to your blockchain, allowing you to create a unique and powerful decentralized application.