implement failover to backup db

core/parentchain/light-client/src/io.rs

@@ -126,13 +126,47 @@ impl<B: Block, LightClientState: Decode + Encode + Debug> LightClientSealing
 	// unseals db with automatic failover to db backup
 	fn unseal(&self) -> Result<LightClientState> {
 		Ok(unseal(self.db_path())
-			.or(unseal(self.backup_path()))
+			.or_else(|e| {
+				warn!(
+					"can't unseal db at {:?}. error {:?}. trying backup at {:?}",
+					self.db_path(),
+					e,
+					self.backup_path()
+				);
+				// create a copy because we will overwrite the db in the next step
+				fs::copy(self.db_path(), self.db_path().with_extension("cantunseal")).and_then(
+					|_| {
+						fs::copy(self.backup_path(), self.db_path()).and_then(|_| {
+							unseal(self.db_path()).map_err(|e| {
+								warn!("{:?}", e);
+								e
+							})
+						})
+					},
+				)
+			})
 			.map(|b| Decode::decode(&mut b.as_slice()))??)
 	}
 
-	// checks if either the db or its backup can be opened
+	// checks if either the db or its backup can be opened in opaque mode (no unseal)
 	fn exists(&self) -> bool {
-		SgxFile::open(self.db_path()).or(SgxFile::open(self.backup_path())).is_ok()
+		debug!("check if db exists at {:?}", self.db_path());
+		fs::File::open(self.db_path())
+			.or_else(|e| {
+				warn!(
+					"can't open db at {:?}. error: {:?}. trying restore backup at {:?}",
+					self.db_path(),
+					e,
+					self.backup_path()
+				);
+				fs::copy(self.backup_path(), self.db_path())
+					.and_then(|_| fs::File::open(self.db_path()))
+					.map_err(|e| {
+						warn!("{:?}", e);
+						e
+					})
+			})
+			.is_ok()
 	}
 
 	fn path(&self) -> &Path {
@@ -261,9 +295,11 @@ where
 	OCallApi: EnclaveOnChainOCallApi,
 	LightClientSeal: LightClientSealing<LightClientState = LightValidationState<B>>,
 {
+	trace!("[{:?}]  init light client db", parentchain_id);
 	if !seal.exists() {
 		info!(
-			"[Enclave] ChainRelay DB for parachain validator not found, creating new! {}",
+			"[{:?}] ChainRelay DB for parachain validator not found, creating new! {}",
+			parentchain_id,
 			seal.path().display()
 		);
 		let validator = init_parachain_validator::<B, OCallApi>(
@@ -276,6 +312,7 @@ where
 	}
 
 	let validation_state = seal.unseal()?;
+	info!("unseal success");
 	let genesis_hash = validation_state.genesis_hash()?;
 
 	let init_state = if genesis_hash == params.genesis_header.hash() {

enclave-runtime/src/initialization/parentchain/mod.rs

@@ -44,7 +44,7 @@ use itc_parentchain::{
 };
 use itp_component_container::ComponentInitializer;
 use itp_settings::worker_mode::ProvideWorkerMode;
-
+use log::*;
 use std::{path::PathBuf, vec::Vec};
 
 mod common;
@@ -61,6 +61,10 @@ pub(crate) fn init_parentchain_components<WorkerModeProvider: ProvideWorkerMode>
 ) -> Result<Vec<u8>> {
 	match ParentchainInitParams::decode(&mut encoded_params.as_slice())? {
 		ParentchainInitParams::Parachain { id, shard, params } => {
+			info!(
+				"[{:?}] initializing parachain parentchain components for shard: {:?}",
+				id, shard
+			);
 			let shard_creation_info = get_shard_creation_info_internal(shard)?;
 
 			// todo: query timestamp of creation header to give a creation reference to target_a/b as well in order to fast-sync
@@ -104,6 +108,10 @@ pub(crate) fn init_parentchain_components<WorkerModeProvider: ProvideWorkerMode>
 			}
 		},
 		ParentchainInitParams::Solochain { id, shard, params } => {
+			info!(
+				"[{:?}] initializing solochain parentchain components for shard: {:?}",
+				id, shard
+			);
 			let shard_creation_info = get_shard_creation_info_internal(shard)?;
 			// todo: query timestamp of creation header to give a creation reference to target_a/b as well in order to fast-sync
 			match id {

enclave-runtime/src/lib.rs

@@ -394,8 +394,6 @@ pub unsafe extern "C" fn init_parentchain_components(
 	latest_header: *mut u8,
 	latest_header_size: usize,
 ) -> sgx_status_t {
-	info!("Initializing light client!");
-
 	let encoded_params = slice::from_raw_parts(params, params_size);
 	let latest_header_slice = slice::from_raw_parts_mut(latest_header, latest_header_size);