#
pezkuwi_sdk_docs/pezkuwi_sdk/
frame_runtime.rs

    1//! # FRAME
    2//!
    3//! ```no_compile
    4//!   ______   ______    ________   ___ __ __   ______
    5//!  /_____/\ /_____/\  /_______/\ /__//_//_/\ /_____/\
    6//!  \::::_\/_\:::_ \ \ \::: _  \ \\::\| \| \ \\::::_\/_
    7//!   \:\/___/\\:(_) ) )_\::(_)  \ \\:.      \ \\:\/___/\
    8//!    \:::._\/ \: __ `\ \\:: __  \ \\:.\-/\  \ \\::___\/_
    9//!     \:\ \    \ \ `\ \ \\:.\ \  \ \\. \  \  \ \\:\____/\
    10//!      \_\/     \_\/ \_\/ \__\/\__\/ \__\/ \__\/ \_____\/
    11//! ```
    12//!
    13//! > **F**ramework for **R**untime **A**ggregation of **M**odularized **E**ntities: Substrate's
    14//! > State Transition Function (Runtime) Framework.
    15//!
    16//! ## Introduction
    17//!
    18//! As described in [`crate::reference_docs::wasm_meta_protocol`], at a high-level Substrate-based
    19//! blockchains are composed of two parts:
    20//!
    21//! 1. A *runtime* which represents the state transition function (i.e. "Business Logic") of a
    22//! blockchain, and is encoded as a WASM blob.
    23//! 2. A node whose primary purpose is to execute the given runtime.
    24#![doc = simple_mermaid::mermaid!("../../../mermaid/substrate_simple.mmd")]
    25//!
    26//! *FRAME is the Substrate's framework of choice to build a runtime.*
    27//!
    28//! FRAME is composed of two major components, **pallets** and a **runtime**.
    29//!
    30//! ## Pallets
    31//!
    32//! A pallet is a unit of encapsulated logic. It has a clearly defined responsibility and can be
    33//! linked to other pallets. In order to be reusable, pallets shipped with FRAME strive to only care
    34//! about its own responsibilities and make as few assumptions about the general runtime as
    35//! possible. A pallet is analogous to a _module_ in the runtime.
    36//!
    37//! A pallet is defined as a `mod pallet` wrapped by the [`frame::pallet`] macro. Within this macro,
    38//! pallet components/parts can be defined. Most notable of these parts are:
    39//!
    40//! - [Config](frame::pallet_macros::config), allowing a pallet to make itself configurable and
    41//!   generic over types, values and such.
    42//! - [Storage](frame::pallet_macros::storage), allowing a pallet to define onchain storage.
    43//! - [Dispatchable function](frame::pallet_macros::call), allowing a pallet to define extrinsics
    44//!   that are callable by end users, from the outer world.
    45//! - [Events](frame::pallet_macros::event), allowing a pallet to emit events.
    46//! - [Errors](frame::pallet_macros::error), allowing a pallet to emit well-formed errors.
    47//!
    48//! Some of these pallet components resemble the building blocks of a smart contract. While both
    49//! models are programming state transition functions of blockchains, there are crucial differences
    50//! between the two. See [`crate::reference_docs::runtime_vs_smart_contract`] for more.
    51//!
    52//! Most of these components are defined using macros, the full list of which can be found in
    53//! [`frame::pallet_macros`].
    54//!
    55//! ### Example
    56//!
    57//! The following example showcases a minimal pallet.
    58#![doc = docify::embed!("src/pezkuwi_sdk/frame_runtime.rs", pallet)]
    59//!
    60//! ## Runtime
    61//!
    62//! A runtime is a collection of pallets that are amalgamated together. Each pallet typically has
    63//! some configurations (exposed as a `trait Config`) that needs to be *specified* in the runtime.
    64//! This is done with [`frame::runtime::prelude::construct_runtime`].
    65//!
    66//! A (real) runtime that actually wishes to compile to WASM needs to also implement a set of
    67//! runtime-apis. These implementation can be specified using the
    68//! [`frame::runtime::prelude::impl_runtime_apis`] macro.
    69//!
    70//! ### Example
    71//!
    72//! The following example shows a (test) runtime that is composing the pallet demonstrated above,
    73//! next to the [`frame::prelude::frame_system`] pallet, into a runtime.
    74#![doc = docify::embed!("src/pezkuwi_sdk/frame_runtime.rs", runtime)]
    75//!
    76//! ## More Examples
    77//!
    78//! You can find more FRAME examples that revolve around specific features at [`pallet_examples`].
    79//!
    80//! ## Alternatives 🌈
    81//!
    82//! There is nothing in the Substrate's node side code-base that mandates the use of FRAME. While
    83//! FRAME makes it very simple to write Substrate-based runtimes, it is by no means intended to be
    84//! the only one. At the end of the day, any WASM blob that exposes the right set of runtime APIs is
    85//! a valid Runtime form the point of view of a Substrate client (see
    86//! [`crate::reference_docs::wasm_meta_protocol`]). Notable examples are:
    87//!
    88//! * writing a runtime in pure Rust, as done in [this template](https://github.com/JoshOrndorff/frameless-node-template).
    89//! * writing a runtime in AssemblyScript, as explored in [this project](https://github.com/LimeChain/subsembly).
    90
    91/// A FRAME based pallet. This `mod` is the entry point for everything else. All
    92/// `#[pallet::xxx]` macros must be defined in this `mod`. Although, frame also provides an
    93/// experimental feature to break these parts into different `mod`s. See [`pallet_examples`] for
    94/// more.
    95#[docify::export]
    96#[frame::pallet(dev_mode)]
    97pub mod pallet {
    98	use frame::prelude::*;
    99
    100	/// The configuration trait of a pallet. Mandatory. Allows a pallet to receive types at a
    101	/// later point from the runtime that wishes to contain it. It allows the pallet to be
    102	/// parameterized over both types and values.
    103	#[pallet::config]
    104	pub trait Config: frame_system::Config {
    105		/// A type that is not known now, but the runtime that will contain this pallet will
    106		/// know it later, therefore we define it here as an associated type.
    107		#[allow(deprecated)]
    108		type RuntimeEvent: IsType<<Self as frame_system::Config>::RuntimeEvent> + From<Event<Self>>;
    109
    110		/// A parameterize-able value that we receive later via the `Get<_>` trait.
    111		type ValueParameter: Get<u32>;
    112
    113		/// Similar to [`Config::ValueParameter`], but using `const`. Both are functionally
    114		/// equal, but offer different tradeoffs.
    115		const ANOTHER_VALUE_PARAMETER: u32;
    116	}
    117
    118	/// A mandatory struct in each pallet. All functions callable by external users (aka.
    119	/// transactions) must be attached to this type (see [`frame::pallet_macros::call`]). For
    120	/// convenience, internal (private) functions can also be attached to this type.
    121	#[pallet::pallet]
    122	pub struct Pallet<T>(PhantomData<T>);
    123
    124	/// The events that this pallet can emit.
    125	#[pallet::event]
    126	pub enum Event<T: Config> {}
    127
    128	/// A storage item that this pallet contains. This will be part of the state root trie
    129	/// of the blockchain.
    130	#[pallet::storage]
    131	pub type Value<T> = StorageValue<Value = u32>;
    132
    133	/// All *dispatchable* call functions (aka. transactions) are attached to `Pallet` in a
    134	/// `impl` block.
    135	#[pallet::call]
    136	impl<T: Config> Pallet<T> {
    137		/// This will be callable by external users, and has two u32s as a parameter.
    138		pub fn some_dispatchable(
    139			_origin: OriginFor<T>,
    140			_param: u32,
    141			_other_para: u32,
    142		) -> DispatchResult {
    143			Ok(())
    144		}
    145	}
    146}
    147
    148/// A simple runtime that contains the above pallet and `frame_system`, the mandatory pallet of
    149/// all runtimes. This runtime is for testing, but it shares a lot of similarities with a *real*
    150/// runtime.
    151#[docify::export]
    152pub mod runtime {
    153	use super::pallet as pallet_example;
    154	use frame::{prelude::*, testing_prelude::*};
    155
    156	// The major macro that amalgamates pallets into `enum Runtime`
    157	construct_runtime!(
    158		pub enum Runtime {
    159			System: frame_system,
    160			Example: pallet_example,
    161		}
    162	);
    163
    164	// These `impl` blocks specify the parameters of each pallet's `trait Config`.
    165	#[derive_impl(frame_system::config_preludes::TestDefaultConfig)]
    166	impl frame_system::Config for Runtime {
    167		type Block = MockBlock<Self>;
    168	}
    169
    170	impl pallet_example::Config for Runtime {
    171		type RuntimeEvent = RuntimeEvent;
    172		type ValueParameter = ConstU32<42>;
    173		const ANOTHER_VALUE_PARAMETER: u32 = 42;
    174	}
    175}