Conditional check in yaml file to show the proper content - yaml

Question

How can I check if / else in yaml file.
like:
if %{attribute}
attributes:
shipping_comment: Shipping comment / Instructions
else
attributes:
shipping_date: Date

Answer 1

YAML is a data serialisation language, so it's not meant to contain if/else style executable statements: that's the responsibility of the programming language you're using.
A simple example in Ruby to determine which config string from a YAML file to output could be defining your YAML config file as follows:
data.yml
attributes:
shipping_comment: Shipping comment / Instructions
shipping_date: Date
Then, in your program, read the file in and run the conditional there:
shipping.rb
#!/usr/bin/env ruby
require 'yaml'
config = YAML.load_file('data.yml')
attribute = true # your attribute to check here
if attribute
puts config['attributes']['shipping_comment']
else
puts config['attributes']['shipping_date']
end

Answer 2

Out of the box .yaml files won't include any conditional logic, as Paul Fioravanti says:
YAML is a data serialisation language, so it's not meant to contain if/else style executable statements: that's the responsibility of the programming language you're using.
However, there are some cases, such as Infrastructure as Code where you might not have the luxury of Paul's solution. In these cases, most decent Infrastructure tools provide an inbuilt way of achieving conditional logic.
Since it appears that infra is not the area you're looking in, I won't go into detail on how to write each tools solution, but for anyone that end's up here like I did, docs such as these helped me and may prove useful for you:
Ansible
CloudFormation

Answer 3

This is a little late for the original poster, but may be of use to others: The Azure implementation of the YAML parser does support conditional checks. For example, the following YAML in an azure-pipeline.yml:
#azure-pipeline.yml
parameters:
- name: testCondition
displayName: 'Use experimental build process?'
type: boolean
default: true
steps:
- ${{ if eq(parameters.testCondition, true) }}:
- bash: echo 'true'
- ${{ if not(eq(parameters.testCondition, true)) }}:
- bash: echo 'false'
will evaluate the value of the testCondition parameter. When run, the bash task will echo "true", something like this: