Simplify local cluster script

Author: erikgrinaker

Diff for: README.md

@@ -34,7 +34,7 @@ With a [Rust compiler](https://www.rust-lang.org/tools/install) installed, a loc
 cluster can be started on `localhost` ports `9601` to `9605`:
 
 ```
-$ (cd clusters/local && ./run.sh)
+$ ./cluster/run.sh
 ```
 
 A command-line client can be built and used with the node on `localhost` port `9605`:

Diff for: cluster/run.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+#
+# This script builds and runs a 5-node toyDB cluster listening on ports
+# 9601-9605. Config and data is stored under the toydb* directories.
+# To connect a toysql client to node 5 on port 9605, run:
+#
+# cargo run --release --bin toysql
+
+set -euo pipefail
+
+# Change into the script directory.
+cd "$(dirname $0)"
+
+# Build toyDB and toySQL using release optimizations.
+cargo build --release --bin toydb
+cargo build --release --bin toysql
+
+# Start nodes 1-5 in the background, prefixing their output with the node ID.
+echo "Starting 5 nodes on ports 9601-9605. To connect to node 5, run:"
+echo "cargo run --release --bin toysql"
+echo ""
+
+for ID in 1 2 3 4 5; do
+    (cargo run -q --release -- -c toydb$ID/toydb.yaml 2>&1 | sed -e "s/\\(.*\\)/toydb$ID \\1/g") &
+done
+
+# Wait for the background processes to exit. Kill all toyDB processes when the
+# script exits (e.g. via Ctrl-C).
+trap 'kill $(jobs -p)' EXIT
+wait < <(jobs -p)