Crate frame_support_procedural

source ·
Expand description

Proc macro of Support code for the runtime.

Macros

Attribute Macros

  • call_index
    Each dispatchable may also be annotated with the #[pallet::call_index($idx)] attribute, which explicitly defines the codec index for the dispatchable function in the Call enum.
  • compact
    Compact encoding for arguments can be achieved via #[pallet::compact]. The function must return a DispatchResultWithPostInfo or DispatchResult.
  • config
    The mandatory attribute #[pallet::config] defines the configurable options for the pallet.
  • constant
    The #[pallet::constant] attribute can be used to add an associated type trait bounded by Get from pallet::config into metadata, e.g.:
  • disable_frame_system_supertrait_check
    To bypass the frame_system::Config supertrait check, use the attribute pallet::disable_frame_system_supertrait_check, e.g.:
  • error
    The #[pallet::error] attribute allows you to define an error enum that will be returned from the dispatchable when an error occurs. The information for this error type is then stored in metadata.
  • event
    The #[pallet::event] attribute allows you to define pallet events. Pallet events are stored under the system / events key when the block is applied (and then replaced when the next block writes it’s events).
  • extra_constants
    Allows you to define some extra constants to be added into constant metadata.
  • generate_deposit
    The attribute #[pallet::generate_deposit($visibility fn deposit_event)] generates a helper function on Pallet that handles deposit events.
  • generate_storage_info
    To generate the full storage info (used for PoV calculation) use the attribute #[pallet::generate_storage_info], e.g.:
  • generate_store
    To generate a Store trait associating all storages, annotate your Pallet struct with the attribute #[pallet::generate_store($vis trait Store)], e.g.:
  • genesis_build
    The #[pallet::genesis_build] attribute allows you to define how genesis_configuration is built. This takes as input the GenesisConfig type (as self) and constructs the pallet’s initial state.
  • genesis_config
    The #[pallet::genesis_config] attribute allows you to define the genesis configuration for the pallet.
  • getter
    The optional attribute #[pallet::getter(fn $my_getter_fn_name)] allows you to define a getter function on Pallet.
  • hooks
    The #[pallet::hooks] attribute allows you to specify a Hooks implementation for Pallet that specifies pallet-specific logic.
  • inherent
    The #[pallet::inherent] attribute allows the pallet to provide some inherent. An inherent is some piece of data that is inserted by a block authoring node at block creation time and can either be accepted or rejected by validators based on whether the data falls within an acceptable range.
  • origin
    The #[pallet::origin] attribute allows you to define some origin for the pallet.
  • pallet
    The pallet struct placeholder #[pallet::pallet] is mandatory and allows you to specify pallet information.
  • require_transactional
  • storage
    The #[pallet::storage] attribute lets you define some abstract storage inside of runtime storage and also set its metadata. This attribute can be used multiple times.
  • storage_alias
  • storage_prefix
    The optional attribute #[pallet::storage_prefix = "SomeName"] allows you to define the storage prefix to use. This is helpful if you wish to rename the storage field but don’t want to perform a migration.
  • storage_version
    Because the pallet::pallet macro implements GetStorageVersion, the current storage version needs to be communicated to the macro. This can be done by using the pallet::storage_version attribute:
  • transactional
    Execute the annotated function in a new storage transaction.
  • type_value
    The #[pallet::type_value] attribute lets you define a struct implementing the Get trait to ease the use of storage types. This attribute is meant to be used alongside #[pallet::storage] to define a storage’s default value. This attribute can be used multiple times.
  • unbounded
    The optional attribute #[pallet::unbounded] declares the storage as unbounded. When implementating the storage info (when #[pallet::generate_storage_info] is specified on the pallet struct placeholder), the size of the storage will be declared as unbounded. This can be useful for storage which can never go into PoV (Proof of Validity).
  • validate_unsigned
    The #[pallet::validate_unsigned] attribute allows the pallet to validate some unsigned transaction:
  • weight
    Each dispatchable needs to define a weight with #[pallet::weight($expr)] attribute, the first argument must be origin: OriginFor<T>.
  • whitelist_storage
    The optional attribute #[pallet::whitelist_storage] will declare the storage as whitelisted from benchmarking. Doing so will exclude reads of that value’s storage key from counting towards weight calculations during benchmarking.

Derive Macros

  • CloneNoBound
    Derive Clone but do not bound any generic. Docs are at frame_support::CloneNoBound.
  • DebugNoBound
    Derive Debug but do not bound any generics. Docs are at frame_support::DebugNoBound.
  • DefaultNoBound
    derive Default but do no bound any generic. Docs are at frame_support::DefaultNoBound.
  • EqNoBound
    derive Eq but do no bound any generic. Docs are at frame_support::EqNoBound.
  • PalletError
  • PartialEqNoBound
    Derive PartialEq but do not bound any generic. Docs are at frame_support::PartialEqNoBound.
  • RuntimeDebugNoBound
    Derive Debug, if std is enabled it uses frame_support::DebugNoBound, if std is not enabled it just returns "<stripped>". This behaviour is useful to prevent bloating the runtime WASM blob from unneeded code.