lib.rs

// This file is part of Substrate.

// Copyright (C) 2020-2022 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! # Remote Externalities
//!
//! An equivalent of `sp_io::TestExternalities` that can load its state from a remote substrate
//! based chain, or a local state snapshot file.

use codec::{Decode, Encode};

use log::*;
use serde::de::DeserializeOwned;
use sp_core::{
	hashing::twox_128,
	hexdisplay::HexDisplay,
	storage::{
		well_known_keys::{is_default_child_storage_key, DEFAULT_CHILD_STORAGE_KEY_PREFIX},
		ChildInfo, ChildType, PrefixedStorageKey, StorageData, StorageKey,
	},
};
pub use sp_io::TestExternalities;
use sp_runtime::{traits::Block as BlockT, StateVersion};
use std::{
	fs,
	path::{Path, PathBuf},
	sync::Arc,
};
use substrate_rpc_client::{
	rpc_params, ws_client, BatchRequestBuilder, ChainApi, ClientT, StateApi, WsClient,
};

type KeyValue = (StorageKey, StorageData);
type TopKeyValues = Vec<KeyValue>;
type ChildKeyValues = Vec<(ChildInfo, Vec<KeyValue>)>;

const LOG_TARGET: &str = "remote-ext";
const DEFAULT_TARGET: &str = "wss://rpc.polkadot.io:443";
const BATCH_SIZE: usize = 1000;
const PAGE: u32 = 1000;

/// The execution mode.
#[derive(Clone)]
pub enum Mode<B: BlockT> {
	/// Online. Potentially writes to a cache file.
	Online(OnlineConfig<B>),
	/// Offline. Uses a state snapshot file and needs not any client config.
	Offline(OfflineConfig),
	/// Prefer using a cache file if it exists, else use a remote server.
	OfflineOrElseOnline(OfflineConfig, OnlineConfig<B>),
}

impl<B: BlockT> Default for Mode<B> {
	fn default() -> Self {
		Mode::Online(OnlineConfig::default())
	}
}

/// Configuration of the offline execution.
///
/// A state snapshot config must be present.
#[derive(Clone)]
pub struct OfflineConfig {
	/// The configuration of the state snapshot file to use. It must be present.
	pub state_snapshot: SnapshotConfig,
}

/// Description of the transport protocol (for online execution).
#[derive(Debug, Clone)]
pub enum Transport {
	/// Use the `URI` to open a new WebSocket connection.
	Uri(String),
	/// Use existing WebSocket connection.
	RemoteClient(Arc<WsClient>),
}

impl Transport {
	fn as_client(&self) -> Option<&WsClient> {
		match self {
			Self::RemoteClient(client) => Some(client),
			_ => None,
		}
	}

	// Open a new WebSocket connection if it's not connected.
	async fn map_uri(&mut self) -> Result<(), &'static str> {
		if let Self::Uri(uri) = self {
			log::debug!(target: LOG_TARGET, "initializing remote client to {:?}", uri);

			let ws_client = ws_client(uri).await.map_err(|e| {
				log::error!(target: LOG_TARGET, "error: {:?}", e);
				"failed to build ws client"
			})?;

			*self = Self::RemoteClient(Arc::new(ws_client))
		}

		Ok(())
	}
}

impl From<String> for Transport {
	fn from(uri: String) -> Self {
		Transport::Uri(uri)
	}
}

impl From<Arc<WsClient>> for Transport {
	fn from(client: Arc<WsClient>) -> Self {
		Transport::RemoteClient(client)
	}
}

/// Configuration of the online execution.
///
/// A state snapshot config may be present and will be written to in that case.
#[derive(Clone)]
pub struct OnlineConfig<B: BlockT> {
	/// The block hash at which to get the runtime state. Will be latest finalized head if not
	/// provided.
	pub at: Option<B::Hash>,
	/// An optional state snapshot file to WRITE to, not for reading. Not written if set to `None`.
	pub state_snapshot: Option<SnapshotConfig>,
	/// The pallets to scrape. If empty, entire chain state will be scraped.
	pub pallets: Vec<String>,
	/// Transport config.
	pub transport: Transport,
	/// Lookout for child-keys, and scrape them as well if set to true.
	pub scrape_children: bool,
}

impl<B: BlockT> OnlineConfig<B> {
	/// Return rpc (ws) client.
	fn rpc_client(&self) -> &WsClient {
		self.transport
			.as_client()
			.expect("ws client must have been initialized by now; qed.")
	}
}

impl<B: BlockT> Default for OnlineConfig<B> {
	fn default() -> Self {
		Self {
			transport: Transport::Uri(DEFAULT_TARGET.to_owned()),
			at: None,
			state_snapshot: None,
			pallets: vec![],
			scrape_children: true,
		}
	}
}

impl<B: BlockT> From<String> for OnlineConfig<B> {
	fn from(s: String) -> Self {
		Self { transport: s.into(), ..Default::default() }
	}
}

/// Configuration of the state snapshot.
#[derive(Clone)]
pub struct SnapshotConfig {
	/// The path to the snapshot file.
	pub path: PathBuf,
}

impl SnapshotConfig {
	pub fn new<P: Into<PathBuf>>(path: P) -> Self {
		Self { path: path.into() }
	}
}

impl From<String> for SnapshotConfig {
	fn from(s: String) -> Self {
		Self::new(s)
	}
}

impl Default for SnapshotConfig {
	fn default() -> Self {
		Self { path: Path::new("SNAPSHOT").into() }
	}
}

/// Builder for remote-externalities.
pub struct Builder<B: BlockT> {
	/// Custom key-pairs to be injected into the externalities. The *hashed* keys and values must
	/// be given.