a bit o' spruce, from http://play.spruce.cf

spruce.json

{"flavor":"1.17.0","prune":["meta"],"env":["HOME=/home/user"],"cherry_pick":[],"yaml":[{"filename":"file1.yml","contents":"---\nips:\n- 1.2.3.4\n- 2.2.3.4\n\nport: 80\n\n# if we read from output, ips_with_port is a list instead of string\nips_with_port:\n  (( cartesian-product \"\\\"\" ips \":\" port \"\\\"\" ))\n\n# join failed\njoin_ips_with_port:\n  (( join \",\" ips_with_port ))\n\ntest_broker:\n  (( concat \"test=[\" join_ips_with_port \"]\" ))\n\n\n\n\n"}],"skip_eval":false,"fallback_append":false,"go_patch":false,"debug":false,"trace":false}