Chapter 2. Introduction to Service Registry rules

This chapter introduces the optional rules used to govern registry content and provides details on the available rule types:

2.1. Rules for registry content

To govern the evolution of registry content, you can configure optional rules for artifact content added to the registry. All configured global rules or artifact rules must pass before a new artifact version can be uploaded to the registry. Configured artifact rules override any configured global rules.

The goal of these rules is to prevent invalid content from being added to the registry. For example, content can be invalid for the following reasons:

  • Invalid syntax for a given artifact type (for example, AVRO or PROTOBUF)
  • Valid syntax, but semantics violate a specification
  • Incompatibility, when new content includes breaking changes relative to the current artifact version

You can add these optional content rules using the Service Registry web console, REST API commands, or a Java client application.

2.2. When rules are applied

Rules are applied only when content is added to the registry. This includes the following REST operations:

  • Adding an artifact
  • Updating an artifact
  • Adding an artifact version

If a rule is violated, Service Registry returns an HTTP error. The response body includes the violated rule and a message showing what went wrong.

Note

If no rules are configured for an artifact, the set of currently configured global rules are applied, if any.

2.3. How rules work

Each rule has a name and optional configuration information. The registry storage maintains the list of rules for each artifact and the list of global rules. Each rule in the list consists of a name and a set of configuration properties, which are specific to the rule implementation.

A rule is provided with the content of the current version of the artifact (if one exists) and the new version of the artifact being added. The rule implementation returns true or false depending on whether the artifact passes the rule. If not, the registry reports the reason why in an HTTP error response. Some rules might not use the previous version of the content. For example, compatibility rules use previous versions, but syntax or semantic validity rules do not.

Additional resources

For more details, see Section 8.2, “Service Registry content rule types”.