Unify error enums in substrate and ethereum clients with thiserror …

…(#1094)

* Unify error enums in substrate and ethereum clients with `thiserror`

Related to paritytech/parity-bridges-common#857

* Add license pre-amble

* rustfmt

* Fix spelling

bridges/relays/bin-ethereum/Cargo.toml

@@ -21,6 +21,7 @@ libsecp256k1 = { version = "0.7", default-features = false, features = ["hmac"]
 log = "0.4.14"
 num-traits = "0.2"
 serde_json = "1.0.64"
+thiserror = "1.0.26"
 
 # Bridge dependencies
 

bridges/relays/bin-ethereum/src/error.rs

@@ -0,0 +1,38 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+// Parity Bridges Common is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// Parity Bridges Common is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// You should have received a copy of the GNU General Public License
+// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+use crate::rpc_errors::RpcError;
+use thiserror::Error;
+
+/// Result type used by PoA relay.
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Ethereum PoA relay errors.
+#[derive(Error, Debug)]
+pub enum Error {
+	/// Failed to decode initial header.
+	#[error("Error decoding initial header: {0}")]
+	DecodeInitialHeader(codec::Error),
+	/// RPC error.
+	#[error("{0}")]
+	Rpc(#[from] RpcError),
+	/// Failed to read genesis header.
+	#[error("Error reading Substrate genesis header: {0:?}")]
+	ReadGenesisHeader(relay_substrate_client::Error),
+	/// Failed to read initial GRANDPA authorities.
+	#[error("Error reading GRANDPA authorities set: {0:?}")]
+	ReadAuthorities(relay_substrate_client::Error),
+	/// Failed to deploy bridge contract to Ethereum chain.
+	#[error("Error deploying contract: {0:?}")]
+	DeployContract(RpcError),
+}

bridges/relays/bin-ethereum/src/ethereum_deploy_contract.rs

@@ -15,6 +15,7 @@
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
 use crate::{
+	error::{Error, Result},
 	ethereum_client::{bridge_contract, EthereumHighLevelRpc},
 	rpc_errors::RpcError,
 };
@@ -104,20 +105,20 @@ pub async fn run(params: EthereumDeployContractParams) {
 async fn prepare_initial_header(
 	sub_client: &SubstrateClient<Rialto>,
 	sub_initial_header: Option<Vec<u8>>,
-) -> Result<(RialtoHeaderId, Vec<u8>), String> {
+) -> Result<(RialtoHeaderId, Vec<u8>)> {
 	match sub_initial_header {
 		Some(raw_initial_header) => {
 			match rialto_runtime::Header::decode(&mut &raw_initial_header[..]) {
 				Ok(initial_header) =>
 					Ok((HeaderId(initial_header.number, initial_header.hash()), raw_initial_header)),
-				Err(error) => Err(format!("Error decoding initial header: {}", error)),
+				Err(error) => Err(Error::DecodeInitialHeader(error)),
 			}
 		},
 		None => {
 			let initial_header = sub_client.header_by_number(Zero::zero()).await;
 			initial_header
 				.map(|header| (HeaderId(Zero::zero(), header.hash()), header.encode()))
-				.map_err(|error| format!("Error reading Substrate genesis header: {:?}", error))
+				.map_err(|error| Error::ReadGenesisHeader(error))
 		},
 	}
 }
@@ -127,14 +128,13 @@ async fn prepare_initial_authorities_set(
 	sub_client: &SubstrateClient<Rialto>,
 	sub_initial_header_hash: rialto_runtime::Hash,
 	sub_initial_authorities_set: Option<Vec<u8>>,
-) -> Result<OpaqueGrandpaAuthoritiesSet, String> {
+) -> Result<OpaqueGrandpaAuthoritiesSet> {
 	let initial_authorities_set = match sub_initial_authorities_set {
 		Some(initial_authorities_set) => Ok(initial_authorities_set),
 		None => sub_client.grandpa_authorities_set(sub_initial_header_hash).await,
 	};
 
-	initial_authorities_set
-		.map_err(|error| format!("Error reading GRANDPA authorities set: {:?}", error))
+	initial_authorities_set.map_err(|error| Error::ReadAuthorities(error))
 }
 
 /// Deploy bridge contract to Ethereum chain.
@@ -145,7 +145,7 @@ async fn deploy_bridge_contract(
 	initial_header: Vec<u8>,
 	initial_set_id: u64,
 	initial_authorities: Vec<u8>,
-) -> Result<(), String> {
+) -> Result<()> {
 	eth_client
 		.submit_ethereum_transaction(
 			params,
@@ -160,5 +160,5 @@ async fn deploy_bridge_contract(
 			),
 		)
 		.await
-		.map_err(|error| format!("Error deploying contract: {:?}", error))
+		.map_err(|error| Error::DeployContract(error))
 }

bridges/relays/bin-ethereum/src/ethereum_exchange.rs

@@ -339,7 +339,7 @@ pub async fn run(params: EthereumExchangeParams) {
 async fn run_single_transaction_relay(
 	params: EthereumExchangeParams,
 	eth_tx_hash: H256,
-) -> Result<(), String> {
+) -> anyhow::Result<()> {
 	let EthereumExchangeParams { eth_params, sub_params, sub_sign, instance, .. } = params;
 
 	let eth_client = EthereumClient::try_connect(eth_params).await.map_err(RpcError::Ethereum)?;
@@ -354,7 +354,9 @@ async fn run_single_transaction_relay(
 		bridge_instance: instance,
 	};
 
-	relay_single_transaction_proof(&source, &target, eth_tx_hash).await
+	relay_single_transaction_proof(&source, &target, eth_tx_hash)
+		.await
+		.map_err(Into::into)
 }
 
 async fn run_auto_transactions_relay_loop(

bridges/relays/bin-ethereum/src/ethereum_exchange_submit.rs

@@ -16,6 +16,7 @@
 
 //! Submitting Ethereum -> Substrate exchange transactions.
 
+use anyhow::anyhow;
 use bp_eth_poa::{
 	signatures::{secret_to_address, SignTransaction},
 	UnsignedTransaction,
@@ -47,10 +48,10 @@ pub async fn run(params: EthereumExchangeSubmitParams) {
 	let EthereumExchangeSubmitParams { eth_params, eth_sign, eth_nonce, eth_amount, sub_recipient } =
 		params;
 
-	let result: Result<_, String> = async move {
+	let result: anyhow::Result<_> = async move {
 		let eth_client = EthereumClient::try_connect(eth_params)
 			.await
-			.map_err(|err| format!("error connecting to Ethereum node: {:?}", err))?;
+			.map_err(|err| anyhow!("error connecting to Ethereum node: {:?}", err))?;
 
 		let eth_signer_address = secret_to_address(&eth_sign.signer);
 		let sub_recipient_encoded = sub_recipient;
@@ -59,7 +60,7 @@ pub async fn run(params: EthereumExchangeSubmitParams) {
 			None => eth_client
 				.account_nonce(eth_signer_address)
 				.await
-				.map_err(|err| format!("error fetching acount nonce: {:?}", err))?,
+				.map_err(|err| anyhow!("error fetching acount nonce: {:?}", err))?,
 		};
 		let gas = eth_client
 			.estimate_gas(CallRequest {
@@ -70,7 +71,7 @@ pub async fn run(params: EthereumExchangeSubmitParams) {
 				..Default::default()
 			})
 			.await
-			.map_err(|err| format!("error estimating gas requirements: {:?}", err))?;
+			.map_err(|err| anyhow!("error estimating gas requirements: {:?}", err))?;
 		let eth_tx_unsigned = UnsignedTransaction {
 			nonce,
 			gas_price: eth_sign.gas_price,
@@ -84,7 +85,7 @@ pub async fn run(params: EthereumExchangeSubmitParams) {
 		eth_client
 			.submit_transaction(eth_tx_signed)
 			.await
-			.map_err(|err| format!("error submitting transaction: {:?}", err))?;
+			.map_err(|err| anyhow!("error submitting transaction: {:?}", err))?;
 
 		Ok(eth_tx_unsigned)
 	}