Add automatic peer discovery from Consul

src/rpc/consul.rs

@@ -0,0 +1,52 @@
+use std::net::{IpAddr, SocketAddr};
+
+use hyper::client::Client;
+use hyper::StatusCode;
+use hyper::{Body, Method, Request};
+use serde::Deserialize;
+
+use garage_util::error::Error;
+
+#[derive(Deserialize, Clone)]
+struct ConsulEntry {
+	#[serde(alias = "Address")]
+	address: String,
+	#[serde(alias = "ServicePort")]
+	service_port: u16,
+}
+
+pub async fn get_consul_nodes(
+	consul_host: &str,
+	consul_service_name: &str,
+) -> Result<Vec<SocketAddr>, Error> {
+	let url = format!(
+		"http://{}/v1/catalog/service/{}",
+		consul_host, consul_service_name
+	);
+	let req = Request::builder()
+		.uri(url)
+		.method(Method::GET)
+		.body(Body::default())?;
+
+	let client = Client::new();
+
+	let resp = client.request(req).await?;
+	if resp.status() != StatusCode::OK {
+		return Err(Error::Message(format!("HTTP error {}", resp.status())));
+	}
+
+	let body = hyper::body::to_bytes(resp.into_body()).await?;
+	let entries = serde_json::from_slice::<Vec<ConsulEntry>>(body.as_ref())?;
+
+	let mut ret = vec![];
+	for ent in entries {
+		let ip = ent
+			.address
+			.parse::<IpAddr>()
+			.map_err(|e| Error::Message(format!("Could not parse IP address: {}", e)))?;
+		ret.push(SocketAddr::new(ip, ent.service_port));
+	}
+	debug!("Got nodes from Consul: {:?}", ret);
+
+	Ok(ret)
+}