Bastian Köcher
f3bf5c1acd
The `xcm` crate was renamed to `staging-xcm` to be able to publish it to crates.io as someone as squatted `xcm`. The problem with this rename is that the `TypeInfo` includes the crate name which ultimately lands in the metadata. The metadata is consumed by downstream users like `polkadot-js` or people building on top of `polkadot-js`. These people are using the entire `path` to find the type in the type registry. Thus, their code would break as the type path would now be [`staging_xcm`, `VersionedXcm`] instead of [`xcm`, `VersionedXcm`]. This pull request fixes this by renaming the path segment `staging_xcm` to `xcm`. This requires: https://github.com/paritytech/scale-info/pull/197 --------- Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Timestamp Module
The Timestamp module provides functionality to get and set the on-chain time.
Overview
The Timestamp module allows the validators to set and validate a timestamp with each block.
It uses inherents for timestamp data, which is provided by the block author and validated/verified by other validators. The timestamp can be set only once per block and must be set each block. There could be a constraint on how much time must pass before setting the new timestamp.
NOTE: The Timestamp module is the recommended way to query the on-chain time instead of using an approach based on block numbers. The block number based time measurement can cause issues because of cumulative calculation errors and hence should be avoided.
Interface
Dispatchable Functions
set- Sets the current time.
Public functions
get- Gets the current time for the current block. If this function is called prior to setting the timestamp, it will return the timestamp of the previous block.
Config Getters
MinimumPeriod- Gets the minimum (and advised) period between blocks for the chain.
Usage
The following example shows how to use the Timestamp module in your custom module to query the current timestamp.
Prerequisites
Import the Timestamp module into your custom module and derive the module configuration trait from the timestamp trait.
Get current timestamp
use pallet_timestamp::{self as timestamp};
#[frame_support::pallet]
pub mod pallet {
use super::*;
use frame_support::pallet_prelude::*;
use frame_system::pallet_prelude::*;
#[pallet::pallet]
pub struct Pallet<T>(_);
#[pallet::config]
pub trait Config: frame_system::Config + timestamp::Config {}
#[pallet::call]
impl<T: Config> Pallet<T> {
#[pallet::weight(0)]
pub fn get_time(origin: OriginFor<T>) -> DispatchResult {
let _sender = ensure_signed(origin)?;
let _now = <timestamp::Pallet<T>>::get();
Ok(())
}
}
}
Example from the FRAME
The Session module uses the Timestamp module for session management.
Related Modules
License: Apache-2.0