Crate pallet_example_mbm

Multi-Block Migrations Example Pallet

This pallet serves as a minimal example of a pallet that uses the Multi-Block Migrations Framework. You can observe how to configure it in a runtime in the kitchensink-runtime crate.

Introduction and Purpose

The primary purpose of this pallet is to demonstrate the concept of Multi-Block Migrations in Substrate. It showcases the migration of values from in the MyMap storage map a u32 to a u64 data type using the SteppedMigration implementation from the migrations::v1 module.

The MyMap storage item is defined in this pallet, and is aliased to v0::MyMap in the migrations::v1 module.

How to Read the Documentation

To access and navigate this documentation in your browser, use the following command:

• cargo doc --package pallet-example-mbm --open

This documentation is organized to help you understand the pallet’s components, features, and migration process.

Example Usage

To use this pallet and understand multi-block migrations, you can refer to the migrations::v1 module, which contains a step-by-step migration example.

Pallet Structure

The pallet is structured as follows:

• migrations: Contains migration-related modules and migration logic.
  • v1: Demonstrates the migration process for changing the data type in the storage map.
• pallet: Defines the pallet configuration and storage items.

Migration Safety

When working with migrations, it’s crucial to ensure the safety of your migrations. The preferred tool to test migrations is try-runtime-cli. Support will be added to dry-run MBMs once they are stable (tracked: https://github.com/paritytech/try-runtime-cli/issues/17).

Re-exports

• pub use pallet::*;

Modules

• migrations
• pallet
  The pallet module in each FRAME pallet hosts the most important items needed to construct this pallet.