Detailed description is on https://www.the-swamp.info/blog/connecting-cloud-functions-compute-engine/
Coomands to execute in order to setup everything:
create_network.sh
in case you don't want to use default VPC network, you can create custom
mandatory step is to create firewall to allow communication to Redis database
create_vm.sh
create_vpc_connector.sh
cf\deploy_cf.sh