add some runtime constants

src/commands/runtime.rs

 use crate::*;
 
-pub async fn runtime_info(_data: Data) -> () {
-	// TODO get information from runtime
-	// certification duration for example
-	println!("TODO");
-	()
+pub async fn runtime_info(data: Data) -> () {
+	let api = data.client();
+
+	// certifications
+	let cert_period = api
+		.constants()
+		.at(&runtime::constants().cert().cert_period())
+		.unwrap();
+	let max_by_issuer = api
+		.constants()
+		.at(&runtime::constants().cert().max_by_issuer())
+		.unwrap();
+	let validity_period = api
+		.constants()
+		.at(&runtime::constants().cert().validity_period())
+		.unwrap();
+
+	println!("certification period: {cert_period} blocks");
+	println!("max certs by issuer: {max_by_issuer}");
+	println!("certification validity: {validity_period} blocks");
+
+	// account
+	let new_account_price = api
+		.constants()
+		.at(&runtime::constants().account().new_account_price())
+		.unwrap();
+	// balances
+	let existential_deposit = api
+		.constants()
+		.at(&runtime::constants().balances().existential_deposit())
+		.unwrap();
+
+	println!(
+		"new account price: {}",
+		data.format_balance(new_account_price)
+	);
+	println!(
+		"existential deposit: {}",
+		data.format_balance(existential_deposit)
+	);
 }

src/data.rs

@@ -103,7 +103,10 @@ impl Data {
 	/// build a client from url
 	// TODO get client from a pre-defined list
 	pub async fn build_client(mut self) -> Self {
-		self.client = Some(Client::from_url(&self.args.url).await.expect("needed"));
+		self.client = Some(Client::from_url(&self.args.url).await.expect(&format!(
+			"could not establish connection with the server {}",
+			self.args.url
+		)));
 		self
 	}
 	/// build an indexer if not disabled

src/main.rs

@@ -563,7 +563,10 @@ async fn main() -> Result<(), GcliError> {
 		)
 		.await
 		.unwrap(),
-		Subcommand::RuntimeInfo => commands::runtime::runtime_info(data).await,
+		Subcommand::RuntimeInfo => {
+			data = data.build_client().await.fetch_system_properties().await?;
+			commands::runtime::runtime_info(data).await;
+		}
 		Subcommand::Indexer(subcommand) => indexer::handle_command(data, subcommand).await?,
 	}