Crate frame_system[][src]

System Module

The System module provides low-level access to core types and cross-cutting utilities. It acts as the base layer for other pallets to interact with the Substrate framework components.

Overview

The System module defines the core data types used in a Substrate runtime. It also provides several utility functions (see Module) for other FRAME pallets.

In addition, it manages the storage items for extrinsics data, indexes, event records, and digest items, among other things that support the execution of the current block.

It also handles low-level tasks like depositing logs, basic set up and take down of temporary storage entries, and access to previous block hashes.

Interface

Dispatchable Functions

The System module does not implement any dispatchable functions.

Public Functions

See the Module struct for details of publicly available functions.

Signed Extensions

The System module defines the following extensions:

Lookup the runtime aggregator file (e.g. node/runtime) to see the full list of signed extensions included in a chain.

Usage

Prerequisites

Import the System module and derive your module’s configuration trait from the system trait.

Example - Get extrinsic count and parent hash for the current block

use frame_support::{decl_module, dispatch};
use frame_system::{self as system, ensure_signed};

pub trait Trait: system::Trait {}

decl_module! {
	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
		#[weight = 0]
		pub fn system_module_example(origin) -> dispatch::DispatchResult {
			let _sender = ensure_signed(origin)?;
			let _extrinsic_count = <system::Module<T>>::extrinsic_count();
			let _parent_hash = <system::Module<T>>::parent_hash();
			Ok(())
		}
	}
}

Modules

offchain

Module helpers for off-chain calls.

Structs

Account

The full account information for a particular account ID.

AccountInfo

Information of an account.

BlockHash

Map of block numbers to block hashes.

CallKillAccount

Event handler which calls kill_account when it happens.

CallOnCreatedAccount

Event handler which calls on_created_account when it happens.

ChainContext
CheckEra

Check for transaction mortality.

CheckGenesis

Genesis hash check to provide replay protection between different networks.

CheckMortality

Check for transaction mortality.

CheckNonce

Nonce check and increment to give replay protection for transactions.

CheckSpecVersion

Ensure the runtime version registered in the transaction is the same as at present.

CheckTxVersion

Ensure the transaction version registered in the transaction is the same as at present.

CheckWeight

Block resource (weight) limit check.

EnsureNever
EnsureNone
EnsureOneOf

The “OR gate” implementation of EnsureOrigin.

EnsureRoot
EnsureSigned
EnsureSignedBy
EventRecord

Record of an event happening.

GenesisConfig

Genesis config for the module, allow to build genesis storage.

LastRuntimeUpgrade

Stores the spec_version and spec_name of when the last runtime upgrade happened.

LastRuntimeUpgradeInfo

Stores the spec_version and spec_name of when the last runtime upgrade happened.

Module

Enums

Call

Dispatchable calls.

Error

Error for the System module

InitKind

A type of block initialization to perform.

Phase

A phase of a block’s execution.

RawEvent

Events for this module.

RawOrigin

Origin for the System module.

RefStatus

Reference status; can be either referenced or unreferenced.

Traits

Trait
WeightInfo

Functions

ensure_none

Ensure that the origin o represents an unsigned extrinsic. Returns Ok or an Err otherwise.

ensure_root

Ensure that the origin o represents the root. Returns Ok or an Err otherwise.

ensure_signed

Ensure that the origin o represents a signed extrinsic (i.e. transaction). Returns Ok with the account that signed the extrinsic or an Err otherwise.

extrinsics_data_root

Compute the trie root of a list of extrinsics.

extrinsics_root

Compute the trie root of a list of extrinsics.

split_inner

Split an option into two constituent options, as defined by a splitter function.

Type Definitions

DigestItemOf
DigestOf
Event

RawEvent specialized for the configuration Trait

Key
KeyValue
Origin

Exposed trait-generic origin type.

RefCount

Type used to encode the number of references an account has.