Groovy 3.0 YamlBuilder

list-to-yaml.groovy

import groovy.yaml.YamlBuilder

def counts = [ 1, 2, 3 ]
def yaml = new YamlBuilder()
yaml(counts)

assert yaml.toString() == '''\
---
- 1
- 2
- 3
'''

map-to-yaml.groovy

import groovy.yaml.YamlBuilder

def config = [ name: 'orders-api', sidecars: ['cadvisor', 'metricbeat', 'xray'] ]
def yaml = new YamlBuilder()
yaml(config)

assert yaml.toString() == '''\
---
name: "orders-api"
sidecars:
- "cadvisor"
- "metricbeat"
- "xray"
'''

object-to-yaml.groovy

import groovy.yaml.YamlBuilder

class Person { int age; List languages; String name; }

def person = new Person(age: 30, name:'Claude', languages: ['English', 'French'])
def yaml = new YamlBuilder()
yaml(person)

assert yaml.toString() == '''\
---
- languages:
  - "English"
  - "French"
  age: 30
  name: "Claude"
'''