Improve bin/server

bin/server

@@ -1,8 +1,28 @@
-cd bin/dither && \
-	ROOT=/Users/dce/code/davideisinger.com/content \
-	KEY=/Users/dce/code/davideisinger.com/secret.key \
-	bundle exec ruby dither.rb &
+#!/usr/bin/env bash
+set -euo pipefail
 
-sleep 1
+repo_root=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
+dither_dir="${repo_root}/bin/dither"
+
+pushd "${dither_dir}" >/dev/null
+ROOT="${repo_root}/content" KEY="${repo_root}/secret.key" bundle exec ruby dither.rb &
+dither_pid=$!
+popd >/dev/null
+
+cleanup() {
+	if kill -0 "${dither_pid}" 2>/dev/null; then
+		kill "${dither_pid}" 2>/dev/null || true
+		wait "${dither_pid}" 2>/dev/null || true
+	fi
+}
+trap cleanup EXIT INT TERM
+
+# Wait until the dither server is listening instead of guessing with sleep.
+for _ in {1..50}; do
+	if (echo >/dev/tcp/localhost/4567) >/dev/null 2>&1; then
+		break
+	fi
+	sleep 0.1
+done
 
 DITHER_SERVER=http://localhost:4567 hugo server