try-runtime-cli: 'instant' snapshots, threading refactor, better progress logs (#14057)

* remote externalities refactor

* remove redundant logs

* use const for parallel requests

* prefer functional

* improve variable naming

* handle requests error

* use overlayedchanges

* Revert "use overlayedchanges"

This reverts commit c0ddb87a5abdd52207597f5df66cbbdf9d79badc.

* Revert "Revert "use overlayedchanges""

This reverts commit 1d49362d9b999c045c8f970a0ab8b486bc47a90a.

* Revert "Revert "Revert "use overlayedchanges"""

This reverts commit 06df786488d94f249e9abccffac4af445f76e5a7.

* backup/load raw storage values

* test raw storage drain and restore

* update snapshot tests

* improve logs

* clippy suggestions

* address comments

* fix example

* fix test

* clippy

substrate/primitives/state-machine/src/testing.rs

@@ -27,7 +27,7 @@ use crate::{
 	StorageTransactionCache, StorageValue, TrieBackendBuilder,
 };
 
-use hash_db::Hasher;
+use hash_db::{HashDB, Hasher};
 use sp_core::{
 	offchain::testing::TestPersistentOffchainDB,
 	storage::{
@@ -160,6 +160,34 @@ where
 		self.extensions.register(ext);
 	}
 
+	/// Sets raw storage key/values and a root.
+	///
+	/// This can be used as a fast way to restore the storage state from a backup because the trie
+	/// does not need to be computed.
+	pub fn from_raw_snapshot(&mut self, raw_storage: Vec<(H::Out, Vec<u8>)>, storage_root: H::Out) {
+		for (k, v) in raw_storage {
+			self.backend.backend_storage_mut().emplace(k, hash_db::EMPTY_PREFIX, v);
+		}
+		self.backend.set_root(storage_root);
+	}
+
+	/// Drains the underlying raw storage key/values and returns the root hash.
+	///
+	/// Useful for backing up the storage in a format that can be quickly re-loaded.
+	///
+	/// Note: This DB will be inoperable after this call.
+	pub fn into_raw_snapshot(mut self) -> (Vec<(H::Out, Vec<u8>)>, H::Out) {
+		let raw_key_values = self
+			.backend
+			.backend_storage_mut()
+			.drain()
+			.into_iter()
+			.map(|(k, v)| (k, v.0))
+			.collect::<Vec<(H::Out, Vec<u8>)>>();
+
+		(raw_key_values, *self.backend.root())
+	}
+
 	/// Return a new backend with all pending changes.
 	///
 	/// In contrast to [`commit_all`](Self::commit_all) this will not panic if there are open
@@ -362,6 +390,46 @@ mod tests {
 		assert_eq!(H256::from_slice(ext.storage_root(Default::default()).as_slice()), root);
 	}
 
+	#[test]
+	fn raw_storage_drain_and_restore() {
+		// Create a TestExternalities with some data in it.
+		let mut original_ext =
+			TestExternalities::<BlakeTwo256>::from((Default::default(), Default::default()));
+		original_ext.insert(b"doe".to_vec(), b"reindeer".to_vec());
+		original_ext.insert(b"dog".to_vec(), b"puppy".to_vec());
+		original_ext.insert(b"dogglesworth".to_vec(), b"cat".to_vec());
+		let child_info = ChildInfo::new_default(&b"test_child"[..]);
+		original_ext.insert_child(child_info.clone(), b"cattytown".to_vec(), b"is_dark".to_vec());
+		original_ext.insert_child(child_info.clone(), b"doggytown".to_vec(), b"is_sunny".to_vec());
+
+		// Drain the raw storage and root.
+		let root = *original_ext.backend.root();
+		let (raw_storage, storage_root) = original_ext.into_raw_snapshot();
+
+		// Load the raw storage and root into a new TestExternalities.
+		let mut recovered_ext =
+			TestExternalities::<BlakeTwo256>::from((Default::default(), Default::default()));
+		recovered_ext.from_raw_snapshot(raw_storage, storage_root);
+
+		// Check the storage root is the same as the original
+		assert_eq!(root, *recovered_ext.backend.root());
+
+		// Check the original storage key/values were recovered correctly
+		assert_eq!(recovered_ext.backend.storage(b"doe").unwrap(), Some(b"reindeer".to_vec()));
+		assert_eq!(recovered_ext.backend.storage(b"dog").unwrap(), Some(b"puppy".to_vec()));
+		assert_eq!(recovered_ext.backend.storage(b"dogglesworth").unwrap(), Some(b"cat".to_vec()));
+
+		// Check the original child storage key/values were recovered correctly
+		assert_eq!(
+			recovered_ext.backend.child_storage(&child_info, b"cattytown").unwrap(),
+			Some(b"is_dark".to_vec())
+		);
+		assert_eq!(
+			recovered_ext.backend.child_storage(&child_info, b"doggytown").unwrap(),
+			Some(b"is_sunny".to_vec())
+		);
+	}
+
 	#[test]
 	fn set_and_retrieve_code() {
 		let mut ext = TestExternalities::<BlakeTwo256>::default();