1 alias gssh='gcloud compute ssh'

     2 

     3 _gssh() {

     4   local cur=${COMP_WORDS[COMP_CWORD]}

     5   [[ "$cur" = -* ]] && return 0

     6   local hosts=$(gcloud compute instances list --format='value(name)')

     7   COMPREPLY=( $(compgen -W "$hosts" -- "$cur") )

     8   return 0

     9 }

    10 

    11 complete -F _gssh gssh