Crate polkadot_sdk_frame

FRAME

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Framework for Runtime Aggregation of Modularized Entities: Substrate’s State Transition Function (Runtime) Framework.

Usage

This crate is organized into 3 stages:

1. preludes: prelude, testing_prelude, runtime::prelude, benchmarking::prelude, and weights_prelude.
2. domain-specific modules, like traits, hashing, arithmetic and derive.
3. Accessing frame/substrate dependencies directly: deps.

The main intended use of this crate is through preludes, which re-export most of the components needed for pallet development. Domain-specific modules serve as a backup for organization, and deps provides direct access to all dependencies if needed.

Example Usage

use polkadot_sdk_frame as frame;

#[frame::pallet]
pub mod pallet {
	use frame::prelude::*;
	// ^^ using the prelude!

	#[pallet::config]
	pub trait Config: frame_system::Config {}

	#[pallet::pallet]
	pub struct Pallet<T>(_);
}

#[cfg(test)]
pub mod tests {
	use frame::testing_prelude::*;
}

#[cfg(feature = "runtime-benchmarks")]
pub mod benchmarking {
	use frame::benchmarking::prelude::*;
}

pub mod runtime {
	use frame::runtime::prelude::*;
}

Features

This crate uses a runtime feature to include all types and tools needed to build FRAME-based runtimes. For runtime development, import it as:

polkadot-sdk-frame = { version = "foo", features = ["runtime"] }

If you just want to build a pallet instead, import it as

polkadot-sdk-frame = { version = "foo" }

Prelude Relationships

The preludes have overlapping imports for convenience:

• testing_prelude includes prelude and runtime::prelude
• runtime::prelude includes prelude
• benchmarking::prelude includes prelude

Naming

Please note that this crate can only be imported as polkadot-sdk-frame or frame. This is due to compatibility matters with frame-support.

A typical pallet’s Cargo.toml using this crate looks like:

[dependencies]
codec = { features = ["max-encoded-len"], workspace = true }
scale-info = { features = ["derive"], workspace = true }
frame = { workspace = true, features = ["runtime"] }

[features]
default = ["std"]
std = [
	"codec/std",
	"scale-info/std",
	"frame/std",
]
runtime-benchmarks = [
	"frame/runtime-benchmarks",
]
try-runtime = [
	"frame/try-runtime",
]

Documentation

For more detailed documentation and examples, see polkadot_sdk_frame.

Re-exports

pub use frame_support::pallet;

pub use frame_support::pallet_macros::import_section;

pub use frame_support::pallet_macros::pallet_section;

pub use log;

Modules

account

All account management related traits.

arithmetic

The arithmetic types used for safe math.

benchmarking

Prelude to be included in the benchmarking.rs of a pallet.

deps

Access to all of the dependencies of this crate. In case the prelude re-exports are not enough, this module can be used.

derive

All derive macros used in frame.

hashing

All hashing related components.

pallet_macros

Macros used within the main pallet macro.

prelude

The main prelude of FRAME.

runtime

All of the types and tools needed to build FRAME-based runtimes.

testing_prelude

The main testing prelude of FRAME.

token

All token related types and traits.

traits

All traits often used in FRAME pallets.

transaction

This is already part of the prelude.

try_runtime

weights_prelude

Prelude to be included in the weight.rs of each pallet.

Attribute Macros

storage_alias

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