sp_session/
lib.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//! Substrate core types around sessions.
19
20#![cfg_attr(not(feature = "std"), no_std)]
21
22extern crate alloc;
23
24use codec::{Decode, DecodeWithMemTracking, Encode};
25
26#[cfg(feature = "std")]
27use sp_api::ProvideRuntimeApi;
28#[cfg(feature = "std")]
29use sp_runtime::traits::Block as BlockT;
30
31use alloc::vec::Vec;
32use sp_staking::SessionIndex;
33use Debug;
34
35pub mod runtime_api;
36pub use runtime_api::*;
37
38/// Number of validators in a given session.
39pub type ValidatorCount = u32;
40
41/// Proof of membership of a specific key in a given session.
42#[derive(
43	Encode,
44	Decode,
45	DecodeWithMemTracking,
46	Clone,
47	Eq,
48	PartialEq,
49	Default,
50	Debug,
51	scale_info::TypeInfo,
52)]
53pub struct MembershipProof {
54	/// The session index on which the specific key is a member.
55	pub session: SessionIndex,
56	/// Trie nodes of a merkle proof of session membership.
57	pub trie_nodes: Vec<Vec<u8>>,
58	/// The validator count of the session on which the specific key is a member.
59	pub validator_count: ValidatorCount,
60}
61
62/// A utility trait to get a session number. This is implemented for
63/// `MembershipProof` below to fetch the session number the given session
64/// membership proof is for. It is useful when we need to deal with key owner
65/// proofs generically (i.e. just typing against the `KeyOwnerProofSystem`
66/// trait) but still restrict their capabilities.
67pub trait GetSessionNumber {
68	fn session(&self) -> SessionIndex;
69}
70
71/// A utility trait to get the validator count of a given session. This is
72/// implemented for `MembershipProof` below and fetches the number of validators
73/// in the session the membership proof is for. It is useful when we need to
74/// deal with key owner proofs generically (i.e. just typing against the
75/// `KeyOwnerProofSystem` trait) but still restrict their capabilities.
76pub trait GetValidatorCount {
77	fn validator_count(&self) -> ValidatorCount;
78}
79
80impl GetSessionNumber for sp_core::Void {
81	fn session(&self) -> SessionIndex {
82		Default::default()
83	}
84}
85
86impl GetValidatorCount for sp_core::Void {
87	fn validator_count(&self) -> ValidatorCount {
88		Default::default()
89	}
90}
91
92impl GetSessionNumber for MembershipProof {
93	fn session(&self) -> SessionIndex {
94		self.session
95	}
96}
97
98impl GetValidatorCount for MembershipProof {
99	fn validator_count(&self) -> ValidatorCount {
100		self.validator_count
101	}
102}
103
104/// Generate the initial session keys with the given seeds, at the given block and store them in
105/// the client's keystore.
106#[cfg(feature = "std")]
107pub fn generate_initial_session_keys<Block, T>(
108	client: std::sync::Arc<T>,
109	at: Block::Hash,
110	seeds: Vec<String>,
111	keystore: sp_keystore::KeystorePtr,
112) -> Result<(), sp_api::ApiError>
113where
114	Block: BlockT,
115	T: ProvideRuntimeApi<Block>,
116	T::Api: SessionKeys<Block>,
117{
118	use sp_api::{ApiError, ApiExt};
119
120	if seeds.is_empty() {
121		return Ok(())
122	}
123
124	let mut runtime_api = client.runtime_api();
125
126	let version = runtime_api.api_version::<dyn SessionKeys<Block>>(at)?.ok_or_else(|| {
127		ApiError::Application(Box::from("Could not find `SessionKeys` runtime api"))
128	})?;
129
130	runtime_api.register_extension(sp_keystore::KeystoreExt::from(keystore));
131
132	for seed in seeds {
133		let seed = Some(seed.as_bytes().to_vec());
134
135		if version < 2 {
136			#[allow(deprecated)]
137			runtime_api.generate_session_keys_before_version_2(at, seed.clone())?;
138		} else {
139			// `owner` isn't important here as we don't need a `proof`.
140			runtime_api.generate_session_keys(at, vec![], seed.clone())?;
141		}
142	}
143
144	Ok(())
145}
sp_session/lib.rs

sp_session/
lib.rs
