How can i upload an iOS build using post build script in cloud build ?

I have a project in cloud build and I'm trying to use post build script for ios but I didn't have success when trying to use a push.sh

!/bin/bash

echo "Uploading IPA to Appstore Connect..."

if xcrun altool --upload-app -f $path -u $ITUNES_USERNAME -p $ITUNES_PASSWORD ; then echo "Upload IPA to Appstore Connect finished with success" else echo "Upload IPA to Appstore Connect failed" fi