Examples: only terminate vtadmin if it was started

examples/common/lib/utils.sh

@@ -139,6 +139,31 @@ function wait_for_healthy_shard() {
 	wait_for_shard_vreplication_engine "${keyspace}" "${shard}"
 }
 
+# Stop the specified vtadmin binary name using the provided PID file.
+# Example:
+#  stop_vtadmin_process "vtadmin-web" "$VTDATAROOT/tmp/vtadmin-web.pid"
+function stop_vtadmin_process() {
+  if [[ -z ${1} || -z ${2} ]]; then
+    fail "A binary name and PID file must be specified when attempting to shutdown vtadmin"
+  fi
+
+  local binary_name="${1}"
+  local pidfile="${2}"
+  local pid=""
+
+  if [[ -e "${pidfile}" ]]; then
+    pid=$(cat "${pidfile}")
+    echo "Stopping ${binary_name}..."
+    kill "${pid}"
+    # Wait for the process to terminate
+    while ps -p "${pid}" > /dev/null; do
+      sleep 1
+    done
+  else
+    echo "Skipping stopping ${binary_name} because the specified PID file (${pidfile}) does not exist."
+  fi
+}
+
 # Print error message and exit with error code.
 function fail() {
 	echo "ERROR: ${1}"

examples/common/scripts/vtadmin-down.sh

@@ -1,9 +1,20 @@
 #!/bin/bash
 
-source "$(dirname "${BASH_SOURCE[0]:-$0}")/../env.sh"
+# Copyright 2023 The Vitess Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
-echo "Stopping vtadmin-web..."
-kill -9 "$(cat "$VTDATAROOT/tmp/vtadmin-web.pid")"
+source "$(dirname "${BASH_SOURCE[0]:-$0}")/../env.sh"
 
-echo "Stopping vtadmin-api..."
-kill -9 "$(cat "$VTDATAROOT/tmp/vtadmin-api.pid")"
+stop_vtadmin_process "vtadmin-web" "$VTDATAROOT/tmp/vtadmin-web.pid"
+stop_vtadmin_process "vtadmin-api" "$VTDATAROOT/tmp/vtadmin-api.pid"