[Feature Request] `az pipelines preview` command

[brittandeyoung]

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I would like the ability to generate fully expanded azure pipelines templates using the Pipelines Preview API. The az pipelines command does not have a preview subcommand.

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I would like the az pipelines preview command to be added which would allow providing an azure pipelines YML file and would return the fully expanded pipeline YAML file.

ideally, you would provide id, branch instead of actual YAML to the command, but also allowing a yamlOverride would be nice as well.

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We are wanting a way to programmatically receive a fully expanded Azure pipelines YAML.

[brittandeyoung]

For those out there wanting the same functionality. I found a method to make this api call using the build in az devops invoke command as a work around until the command is added. Here is an example:

az devops invoke --organization "https://dev.azure.com/myorg/" --area pipelines --resource preview --api-version 7.1 --http-method POST --in-file ./temp-in-file.json --route-parameters pipelineId=1111111 project=MyProject

Here is what the temp-in-file.json would look like:

{
    "resources": {
        "repositories": {
            "self": {
                "refName": "main"
            }
        }
    },
    "previewRun": true
}

You can update the refName inside the json to get the fully expanded YAML for a specific branch.