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