From a1014224d32151dbba7083eb03d8e500beb67f4c Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Thu, 18 Mar 2021 21:49:12 +0100
Subject: garage node configure --replace <old_node_id> <new_node_id>

---
 src/garage/cli.rs | 64 +++++++++++++++++++++++++++++++------------------------
 1 file changed, 36 insertions(+), 28 deletions(-)

diff --git a/src/garage/cli.rs b/src/garage/cli.rs
index 21bafebd..886cf384 100644
--- a/src/garage/cli.rs
+++ b/src/garage/cli.rs
@@ -6,6 +6,7 @@ use serde::{Deserialize, Serialize};
 use structopt::StructOpt;
 
 use garage_util::error::Error;
+use garage_util::data::UUID;
 use garage_util::time::*;
 
 use garage_rpc::membership::*;
@@ -82,6 +83,10 @@ pub struct ConfigureNodeOpt {
 	/// Optionnal node tag
 	#[structopt(short = "t", long = "tag")]
 	tag: Option<String>,
+
+	/// Replaced node(s): list of node IDs that will be removed from the current cluster
+	#[structopt(long = "replace")]
+	replace: Vec<String>,
 }
 
 #[derive(StructOpt, Debug)]
@@ -379,6 +384,24 @@ pub async fn cmd_status(
 	Ok(())
 }
 
+pub fn find_matching_node(cand: impl std::iter::Iterator<Item=UUID>, pattern: &str) -> Result<UUID, Error> {
+	let mut candidates = vec![];
+	for c in cand {
+		if hex::encode(&c).starts_with(&pattern) {
+			candidates.push(c);
+		}
+	}
+	if candidates.len() != 1 {
+		Err(Error::Message(format!(
+			"{} nodes match '{}'",
+			candidates.len(),
+			pattern,
+		)))
+	} else {
+		Ok(candidates[0])
+	}
+}
+
 pub async fn cmd_configure(
 	rpc_cli: RpcAddrClient<Message>,
 	rpc_host: SocketAddr,
@@ -392,18 +415,7 @@ pub async fn cmd_configure(
 		resp => return Err(Error::Message(format!("Invalid RPC response: {:?}", resp))),
 	};
 
-	let mut candidates = vec![];
-	for adv in status.iter() {
-		if hex::encode(&adv.id).starts_with(&args.node_id) {
-			candidates.push(adv.id);
-		}
-	}
-	if candidates.len() != 1 {
-		return Err(Error::Message(format!(
-			"{} matching nodes",
-			candidates.len()
-		)));
-	}
+	let added_node = find_matching_node(status.iter().map(|x| x.id), &args.node_id)?;
 
 	let mut config = match rpc_cli
 		.call(&rpc_host, &Message::PullConfig, ADMIN_RPC_TIMEOUT)
@@ -413,7 +425,14 @@ pub async fn cmd_configure(
 		resp => return Err(Error::Message(format!("Invalid RPC response: {:?}", resp))),
 	};
 
-	let new_entry = match config.members.get(&candidates[0]) {
+	for replaced in args.replace.iter() {
+		let replaced_node = find_matching_node(config.members.keys().cloned(), replaced)?;
+		if config.members.remove(&replaced_node).is_none() {
+			return Err(Error::Message(format!("Cannot replace node {:?} as it is not in current configuration", replaced_node)));
+		}
+	}
+
+	let new_entry = match config.members.get(&added_node) {
 		None => NetworkConfigEntry {
 			datacenter: args
 				.datacenter
@@ -430,7 +449,7 @@ pub async fn cmd_configure(
 		},
 	};
 
-	config.members.insert(candidates[0].clone(), new_entry);
+	config.members.insert(added_node, new_entry);
 	config.version += 1;
 
 	rpc_cli
@@ -456,27 +475,16 @@ pub async fn cmd_remove(
 		resp => return Err(Error::Message(format!("Invalid RPC response: {:?}", resp))),
 	};
 
-	let mut candidates = vec![];
-	for (key, _) in config.members.iter() {
-		if hex::encode(key).starts_with(&args.node_id) {
-			candidates.push(*key);
-		}
-	}
-	if candidates.len() != 1 {
-		return Err(Error::Message(format!(
-			"{} matching nodes",
-			candidates.len()
-		)));
-	}
+	let deleted_node = find_matching_node(config.members.keys().cloned(), &args.node_id)?;
 
 	if !args.yes {
 		return Err(Error::Message(format!(
 			"Add the flag --yes to really remove {:?} from the cluster",
-			candidates[0]
+			deleted_node
 		)));
 	}
 
-	config.members.remove(&candidates[0]);
+	config.members.remove(&deleted_node);
 	config.version += 1;
 
 	rpc_cli
-- 
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