kitchensink_runtime/
constants.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// 	http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
17
18//! A set of constant values used in substrate runtime.
19
20/// Money matters.
21pub mod currency {
22	use node_primitives::Balance;
23
24	pub const MILLICENTS: Balance = 1_000_000_000;
25	pub const CENTS: Balance = 1_000 * MILLICENTS; // assume this is worth about a cent.
26	pub const DOLLARS: Balance = 100 * CENTS;
27
28	pub const fn deposit(items: u32, bytes: u32) -> Balance {
29		items as Balance * 15 * CENTS + (bytes as Balance) * 6 * CENTS
30	}
31}
32
33/// Time.
34pub mod time {
35	use node_primitives::{BlockNumber, Moment};
36
37	/// Since BABE is probabilistic this is the average expected block time that
38	/// we are targeting. Blocks will be produced at a minimum duration defined
39	/// by `SLOT_DURATION`, but some slots will not be allocated to any
40	/// authority and hence no block will be produced. We expect to have this
41	/// block time on average following the defined slot duration and the value
42	/// of `c` configured for BABE (where `1 - c` represents the probability of
43	/// a slot being empty).
44	/// This value is only used indirectly to define the unit constants below
45	/// that are expressed in blocks. The rest of the code should use
46	/// `SLOT_DURATION` instead (like the Timestamp pallet for calculating the
47	/// minimum period).
48	///
49	/// If using BABE with secondary slots (default) then all of the slots will
50	/// always be assigned, in which case `MILLISECS_PER_BLOCK` and
51	/// `SLOT_DURATION` should have the same value.
52	///
53	/// <https://research.web3.foundation/Polkadot/protocols/block-production/Babe#6-practical-results>
54	pub const MILLISECS_PER_BLOCK: Moment = 3000;
55	pub const SECS_PER_BLOCK: Moment = MILLISECS_PER_BLOCK / 1000;
56
57	// NOTE: Currently it is not possible to change the slot duration after the chain has started.
58	//       Attempting to do so will brick block production.
59	pub const SLOT_DURATION: Moment = MILLISECS_PER_BLOCK;
60
61	// 1 in 4 blocks (on average, not counting collisions) will be primary BABE blocks.
62	pub const PRIMARY_PROBABILITY: (u64, u64) = (1, 4);
63
64	// NOTE: Currently it is not possible to change the epoch duration after the chain has started.
65	//       Attempting to do so will brick block production.
66	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = 10 * MINUTES;
67	pub const EPOCH_DURATION_IN_SLOTS: u64 = {
68		const SLOT_FILL_RATE: f64 = MILLISECS_PER_BLOCK as f64 / SLOT_DURATION as f64;
69
70		(EPOCH_DURATION_IN_BLOCKS as f64 * SLOT_FILL_RATE) as u64
71	};
72
73	// These time units are defined in number of blocks.
74	pub const MINUTES: BlockNumber = 60 / (SECS_PER_BLOCK as BlockNumber);
75	pub const HOURS: BlockNumber = MINUTES * 60;
76	pub const DAYS: BlockNumber = HOURS * 24;
77}
kitchensink_runtime/constants.rs

kitchensink_runtime/
constants.rs
