The regular expression syntax used is from JavaScript (more specifically, ECMA 262).
Only the values that match this template will be accepted. The pattern keyword lets you define a regular expression template for the string value. Tools that do not support a specific format may default back to the type alone, as if the format is not specified. Tools can use the format to validate the input or to map the value to a specific type in the chosen programming language.
However, format is an open value, so you can use any formats, even not those defined by the OpenAPI Specification, such as:
In any case, in this article I’m going to show how to reference pipeline variables in an Azure Pipelines CI/CD multi-stage YAML file. Or maybe you’ve been doing this awhile and found the variables guidance to be less than clear. Maybe you’re just getting started with the relatively new YAML experience in Azure Pipelines. If you made it past that long and technical article title then you are here for a purpose.