YiDB (Configuration Management System) is a high performance metadata-driven persistence and query service for configuration data with supporting of RESTful API and client lib (Java, Python). YiDB is a generic system that be used for cloud configuration, as well other software needs for configuration. As a by-product, YiDB can be a persistence solution for real-time state data as well. Moreover, YiDB supports multiple data repositories for desired data isolation.

The metadata model is based on object-oriented paradigm that can support graph/tree data model. The metadata can contain two types of field: attribute field define payload of entity and relationship field define relationship between entity. The metadata is extensible by inheritance: child metadata can inherit fields from parent metadata.

The persistence service provides CRUD API for the runtime entity of metadata. The entity can be flat-structure or embedded-structure that conformed to the metadata definition. Besides the basic functionality, it also supports some advanced features: version based optimistic locking, audit tracing, reference integrity, security access control of data, branching and advanced data browser.

The query service provides an imperative style query language that defines the traversal path of graph/tree data model. The query language supports Boolean filter, attribute selection and implicit join that will extract a tree result from graph data set. For example, ApplicationService[@name = "comp-iq"].groups[@name = "columns"].groups[@name = "col1"].serviceInstances will return service instances under column 1 of comp-iq application. The query language also provides SQL like utilities such as sort, limit, skip, hint, explain and etc.

YiDB also comes with a system management utility to maintain system healthiness includes monitoring metrics (e.g. API latency / qps) and throttling low-priority API under overload status. The whole system is available to be deployed independently.