Substrate relay stub (#376)

* substrate-relay: initial commit

* MillauHeaderApi and RialtoHeaderApi

* post-merge fixes + TODOs + compilation

bridges/relays/substrate/src/cli.rs

@@ -0,0 +1,65 @@
+// Copyright 2019-2020 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/>.
+
+//! Deal with CLI args of substrate-to-substrate relay.
+
+use structopt::StructOpt;
+
+/// Parse relay CLI args.
+pub fn parse_args() -> Command {
+	Command::from_args()
+}
+
+/// Substrate-to-Substrate relay CLI args.
+#[derive(StructOpt)]
+#[structopt(about = "Substrate-to-Substrate relay")]
+pub enum Command {
+	MillauHeadersToRialto {
+		#[structopt(flatten)]
+		millau: MillauConnectionParams,
+		#[structopt(flatten)]
+		rialto: RialtoConnectionParams,
+		#[structopt(flatten)]
+		rialto_sign: RialtoSigningParams,
+	},
+}
+
+macro_rules! declare_chain_options {
+	($chain:ident, $chain_prefix:ident) => {
+		paste::item! {
+			#[doc = $chain " connection params."]
+			#[derive(StructOpt)]
+			pub struct [<$chain ConnectionParams>] {
+				#[doc = "Connect to " $chain " node at given host."]
+				pub [<$chain_prefix _host>]: String,
+				#[doc = "Connect to " $chain " node at given port."]
+				pub [<$chain_prefix _port>]: u16,
+			}
+
+			#[doc = $chain " signing params."]
+			#[derive(StructOpt)]
+			pub struct [<$chain SigningParams>] {
+				#[doc = "The SURI of secret key to use when transactions are submitted to the " $chain " node."]
+				pub [<$chain_prefix _signer>]: String,
+				#[doc = "The password for the SURI of secret key to use when transactions are submitted to the " $chain " node."]
+				pub [<$chain_prefix _signer_password>]: Option<String>,
+			}
+		}
+	};
+}
+
+declare_chain_options!(Rialto, rialto);
+declare_chain_options!(Millau, millau);