Rule engine

MSR uses a rule engine to evaluate policies, such as tag pruning and image enforcement.

The rule engine supports the following operators:

  • greater than or equals

  • greater than

  • equals

  • not equals

  • less than or equals

  • less than

  • starts with

  • ends with

  • contains

  • one of

  • not one of

  • matches

  • before

  • after


The matches operator conforms subject fields to a user-provided regular expression (regex). The regex for matches must follow the specification in the official Go documentation: Package syntax.

Each of the following policies uses the rule engine: