scripts: allow cloud-init script to accept a custom output file

When running manual tests locally, it is sometimes necessary to
generate a cloud-init file at a custom path instead of defaulting
to /tmp. This is useful for developers and higher-level management
layers where files in /tmp may be cleaned up automatically.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

scripts/create-cloud-init.sh

@@ -1,8 +1,37 @@
 #!/usr/bin/env bash
 set -ex
 
-rm -f /tmp/ubuntu-cloudinit.img
-mkdosfs -n CIDATA -C /tmp/ubuntu-cloudinit.img 8192
-mcopy -oi /tmp/ubuntu-cloudinit.img -s test_data/cloud-init/ubuntu/local/user-data ::
-mcopy -oi /tmp/ubuntu-cloudinit.img -s test_data/cloud-init/ubuntu/local/meta-data ::
-mcopy -oi /tmp/ubuntu-cloudinit.img -s test_data/cloud-init/ubuntu/local/network-config ::
+usage() {
+    echo "Usage: $0 [-o|--output <output_file>]"
+    echo ""
+    echo "Options:"
+    echo "  -o, --output    Specify output file path (default: /tmp/ubuntu-cloudinit.img)"
+    echo "  -h, --help      Show this help message"
+}
+
+OUTPUT_FILE=/tmp/ubuntu-cloudinit.img
+
+while [ "$1" != "" ]; do
+    echo "Processing argument: $1"
+    case $1 in
+    -o | --output)
+        OUTPUT_FILE=$2
+        shift # Remove argument (-o) name from `$@`
+        shift # Remove argument value (file path) from `$@`
+        ;;
+    -h | --help)
+        usage # run usage function on help
+        exit 0
+        ;;
+    *)
+        usage # run usage function if wrong argument provided
+        exit 1
+        ;;
+    esac
+done
+
+rm -f "$OUTPUT_FILE"
+mkdosfs -n CIDATA -C "$OUTPUT_FILE" 8192
+mcopy -oi "$OUTPUT_FILE" -s test_data/cloud-init/ubuntu/local/user-data ::
+mcopy -oi "$OUTPUT_FILE" -s test_data/cloud-init/ubuntu/local/meta-data ::
+mcopy -oi "$OUTPUT_FILE" -s test_data/cloud-init/ubuntu/local/network-config ::