Introduce chain spec generator

CHANGELOG.md

@@ -4,6 +4,12 @@ Changelog for the runtimes governed by the Polkadot Fellowship.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+
+### Added
+
+- Introduce chain spec generator ([polkadot-fellows/runtimes#78](https://github.com/polkadot-fellows/runtimes/pull/78))
+
 ## [1.0.0] 22.10.2023
 
 ### Changed

Cargo.toml

@@ -9,6 +9,7 @@ license = "GPL-3.0-only" # TODO <https://github.com/polkadot-fellows/runtimes/is
 resolver = "2"
 
 members = [
+	"chain-spec-generator",
 	"relay/kusama",
 	"relay/kusama/constants",
 	"relay/polkadot",

chain-spec-generator/Cargo.toml

@@ -0,0 +1,35 @@
+[package]
+name = "chain-spec-generator"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+repository.workspace = true
+license.workspace = true
+
+[dependencies]
+clap = { version = "4.4.4", features = [ "derive" ] }
+hex-literal = "0.4.1"
+serde_json = "1.0.107"
+
+polkadot-runtime = { path = "../relay/polkadot" }
+polkadot-runtime-constants = { path = "../relay/polkadot/constants" }
+kusama-runtime = { package = "staging-kusama-runtime", path = "../relay/kusama" }
+kusama-runtime-constants = { path = "../relay/kusama/constants" }
+
+sc-chain-spec = "22.0.0"
+polkadot-runtime-parachains = "2.0.0"
+polkadot-primitives = "2.0.0"
+sp-consensus-babe = "0.27.0"
+sp-authority-discovery = "21.0.0"
+sp-core = "23.0.0"
+pallet-staking = "23.0.0"
+sc-consensus-grandpa = "0.14.0"
+pallet-im-online = "22.0.0"
+sp-runtime = "26.0.0"
+sp-consensus-beefy = "8.0.0"
+
+[features]
+runtime-benchmarks = [
+	"kusama-runtime/runtime-benchmarks",
+	"polkadot-runtime/runtime-benchmarks",
+]

chain-spec-generator/src/main.rs

@@ -0,0 +1,54 @@
+use clap::Parser;
+use sc_chain_spec::ChainSpec;
+use std::collections::HashMap;
+
+mod relay_chain_specs;
+
+#[derive(Parser)]
+struct Cli {
+	/// The chain spec to generate.
+	chain: String,
+
+	/// Generate the chain spec as raw?
+	#[arg(long)]
+	raw: bool,
+}
+
+fn main() -> Result<(), String> {
+	let cli = Cli::parse();
+
+	let supported_chains =
+		HashMap::<_, Box<dyn Fn() -> Result<Box<dyn ChainSpec>, String>>>::from([
+			(
+				"polkadot-dev",
+				Box::new(|| relay_chain_specs::polkadot_development_config()) as Box<_>,
+			),
+			(
+				"polkadot-local",
+				Box::new(|| relay_chain_specs::polkadot_local_testnet_config()) as Box<_>,
+			),
+			("kusama-dev", Box::new(|| relay_chain_specs::kusama_development_config()) as Box<_>),
+			(
+				"kusama-local",
+				Box::new(|| relay_chain_specs::kusama_local_testnet_config()) as Box<_>,
+			),
+		]);
+
+	if let Some(function) = supported_chains.get(&*cli.chain) {
+		let chain_spec = (*function)()?.as_json(cli.raw)?;
+		print!("{chain_spec}");
+		Ok(())
+	} else {
+		if cli.chain.ends_with(".json") {
+			let chain_spec = relay_chain_specs::from_json_file(&cli.chain)?.as_json(cli.raw)?;
+			print!("{chain_spec}");
+			Ok(())
+		} else {
+			let supported = supported_chains.keys().enumerate().fold(String::new(), |c, (n, k)| {
+				let extra = (n + 1 < supported_chains.len()).then(|| ", ").unwrap_or("");
+				format!("{c}{k}{extra}")
+			});
+			Err(format!("Unknown chain, only supported: {supported} or a json file"))
+		}
+	}
+}