Azure Pipeline variable when to use explicit name and value attributes

Question

This doc mentions two ways to create a yml variable.

Explicit use of name and value attributes

variables:
- name: myvariable
  value: myvalue

Another approach is a short-hand key: value approach.

variables:
  myvariable: myvalue

I have noticed that if you're using variables for a template reference, you need to be explicit about the name and value. This will work.

variables:
- name: localTargetEnvironment
  value: dev 
- name: variablesTemplatePath
  value: ../shared/variables-${{ variables.localTargetEnvironment }}.yml    
- template: ${{ variables.variablesTemplatePath }}

But this will not work.

variables: 
  variablesTemplatePath: ../shared/variables-${{ variables.localTargetEnvironment }}.yml
- template: ${{ variables.variablesTemplatePath }}

When/why would I use one approach over another?

Hi, How about the issue? Does the answer below resolved your question? If not, would you please let me know the latest information about this issue? — Vito Liu, Apr 26 '21 at 14:42
@VitoLiu-MSFT, using `extends` seems to work but that doesn't explain when to use one syntax over the other. — duyn9uyen, May 17 '21 at 19:51
Hi, Just share the workaround with you, about this issue, we have report to the product team before, and the project team is investigating this issue, you could refer to this [ticket](https://developercommunity.visualstudio.com/t/conditional-variable-only-set-when-unrelated-varia/749897) for more details. — Vito Liu, May 25 '21 at 09:55

score 1 · Answer 1 · answered Apr 13 '21 at 08:30

YAML has two kinds of collection nodes: sequences and mappings. When you use -, you indicate a sequence item. Sequence items are the content of sequences.

You use sequences when the identifying attribute of the contained values is their position. For example, for jobs, you have a first job, a second job and so on. Their order is meaningful and important.

Mappings on the other hand are collections that contain key-value-pairs. The key usually being a scalar (i.e. a textual value, like pool or vmImage) and the value being any kind of YAML node. For mappings, the identifying attribute of a value is its key. For example for variables, their order is not important, but their name is.

In addition, yaml pipeline is strict with yaml format, thus you should not use sequences nodes and mappings node for variables in the same time, which will cause parsing error. See: Question about the hypens in a YAML file, when to use for details.

Why would a variable sequence work and a variable mapping not work in my example above? — duyn9uyen, Apr 13 '21 at 14:30

Vito Liu · Accepted Answer · 2021-04-22T06:25:34.870

0

You could add the filed extends and then try it again. Such as below:

    variables: 
      localTargetEnvironment: test
      variablesTemplatePath: test/${{ variables.localTargetEnvironment }}.yml
    
    extends:
      template: ${{ variables.variablesTemplatePath }}

Result:

edited Apr 22 '21 at 06:25

answered Apr 22 '21 at 06:06

Vito Liu

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Acceptable workaround. – duyn9uyen Dec 03 '22 at 13:35

Azure Pipeline variable when to use explicit name and value attributes

2 Answers2