Crate polkadot_sdk_frame::prelude::frame_system

frame_system’s parent crate, which is mandatory in all pallets build with this crate.

Conveniently, the keyword frame_system is in scope as one uses use polkadot_sdk_frame::prelude::*

System Pallet

The System pallet 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.

• Config

Overview

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

In addition, it manages the storage items for extrinsic data, indices, 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 pallet provides dispatchable functions that, with the exception of remark, manage low-level or privileged functionality of a Substrate-based runtime.

• remark: Make some on-chain remark.
• set_heap_pages: Set the number of pages in the WebAssembly environment’s heap.
• set_code: Set the new runtime code.
• set_code_without_checks: Set the new runtime code without any checks.
• set_storage: Set some items of storage.
• kill_storage: Kill some items from storage.
• kill_prefix: Kill all storage items with a key that starts with the given prefix.
• remark_with_event: Make some on-chain remark and emit an event.
• do_task: Do some specified task.
• authorize_upgrade: Authorize new runtime code.
• authorize_upgrade_without_checks: Authorize new runtime code and an upgrade sans verification.
• apply_authorized_upgrade: Provide new, already-authorized runtime code.

A Note on Upgrades

The pallet provides two primary means of upgrading the runtime, a single-phase means using set_code and a two-phase means using authorize_upgrade followed by apply_authorized_upgrade. The first will directly attempt to apply the provided code (application may have to be scheduled, depending on the context and implementation of the OnSetCode trait).

The authorize_upgrade route allows the authorization of a runtime’s code hash. Once authorized, anyone may upload the correct runtime to apply the code. This pattern is useful when providing the runtime ahead of time may be unwieldy, for example when a large preimage (the code) would need to be stored on-chain or sent over a message transport protocol such as a bridge.

The *_without_checks variants do not perform any version checks, so using them runs the risk of applying a downgrade or entirely other chain specification. They will still validate that the code meets the authorized hash.

Public Functions

See the Pallet struct for details of publicly available functions.

Signed Extensions

The System pallet defines the following extensions:

• CheckWeight: Checks the weight and length of the block and ensure that it does not exceed the limits.
• CheckNonce: Checks the nonce of the transaction. Contains a single payload of type T::Nonce.
• CheckEra: Checks the era of the transaction. Contains a single payload of type Era.
• CheckGenesis: Checks the provided genesis hash of the transaction. Must be a part of the signed payload of the transaction.
• CheckSpecVersion: Checks that the runtime version is the same as the one used to sign the transaction.
• CheckTxVersion: Checks that the transaction version is the same as the one used to sign the transaction.

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

Modules

• limits
  Block resource limits configuration structures.
• migrations
  Migrate the reference counting state.
• mocking
  Provide types to help defining a mock environment when testing pallets.
• offchain
  Module helpers for off-chain calls.
• pallet
  The pallet module in each FRAME pallet hosts the most important items needed to construct this pallet.
• pallet_prelude
  Prelude to be used alongside pallet macro, for ease of use.
• weights
  Autogenerated weights for frame_system

Structs

• AccountInfo
  Information of an account.
• ChainContext
• CheckEra
  Check for transaction mortality.
• CheckGenesis
  Genesis hash check to provide replay protection between different networks.
• CheckMortality
  Check for transaction mortality.
• CheckNonZeroSender
  Check to ensure that the sender is not the zero address.
• 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.
• CodeUpgradeAuthorization
  Information needed when a new runtime binary is submitted and needs to be authorized before replacing the current runtime.
• Consumer
  Event handler which registers a consumer when created.
• DispatchEventInfo
  Information about the dispatch of a call, to be displayed in the ExtrinsicSuccess and ExtrinsicFailed events.
• EnsureNever
  Always fail.
• EnsureNone
  Ensure the origin is None. i.e. unsigned transaction.
• EnsureRoot
  Ensure the origin is Root.
• EnsureRootWithSuccess
  Ensure the origin is Root and return the provided Success value.
• EnsureSigned
  Ensure the origin is any Signed origin.
• EnsureSignedBy
  Ensure the origin is Signed origin from the given AccountId.
• EnsureWithSuccess
  Ensure the origin is provided Ensure origin and return the provided Success value.
• EventRecord
  Record of an event happening.
• GenesisConfig
  Can be used to configure the genesis state of this pallet.
• LastRuntimeUpgradeInfo
  Stores the spec_version and spec_name of when the last runtime upgrade happened.
• Pallet
  The Pallet struct, the main type that implements traits and standalone functions within the pallet.
• Provider
  Event handler which registers a provider when created.
• SelfSufficient
  Event handler which registers a self-sufficient when created.

Enums

• Call
  Contains a variant per dispatchable extrinsic that this pallet has.
• DecRefStatus
  Some resultant status relevant to decrementing a provider/self-sufficient reference.
• Error
  Error for the System pallet
• Event
  Event for the System pallet.
• IncRefStatus
  Some resultant status relevant to incrementing a provider/self-sufficient reference.
• Phase
  A phase of a block’s execution.
• RawOrigin
  Origin for the System pallet.
• RefStatus
  Reference status; can be either referenced or unreferenced.

Traits

• Config
  Configuration trait of this pallet.
• ConsumerLimits
  Numeric limits over the ability to add a consumer ref using inc_consumers.
• DefaultConfig
  Based on Config. Auto-generated by #[pallet::config(with_default)]. Can be used in tandem with #[register_default_config] and #[derive_impl] to derive test config traits based on existing pallet config traits in a safe and developer-friendly way.
• ExtensionsWeightInfo
  Weight functions needed for frame_system_extensions.
• SetCode
  Do something when we should be setting the code.
• WeightInfo
  Weight functions needed for frame_system.

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.
• ensure_signed_or_root
  Ensure that the origin o represents either a signed extrinsic (i.e. transaction) or the root. Returns Ok with the account that signed the extrinsic, None if it was root, 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.
• unique
  Returns a 32 byte datum which is guaranteed to be universally unique. entropy is provided as a facility to reduce the potential for precalculating results.

Type Aliases

• Account
  The full account information for a particular account ID.
• AllExtrinsicsLen
  Total length (in bytes) for all extrinsics put together, for the current block.
• BlockHash
  Map of block numbers to block hashes.
• BlockWeight
  The current weight for the block.
• ConsumedWeight
  An object to track the currently used extrinsic weight in a block.
• InherentsApplied
  Whether all inherents have been applied.
• Key
• KeyValue
• LastRuntimeUpgrade
  Stores the spec_version and spec_name of when the last runtime upgrade happened.
• ModuleDeprecated
  Type alias to Pallet, to be used by construct_runtime.
• Origin
  Exposed trait-generic origin type.
• RefCount
  Type used to encode the number of references an account has.