Important Terms

As the Open Component Model (OCM) revolves around components, it is essential to establish a common understanding of the fundamental terminology employed throughout this website. The following section provides concise definitions of key terms, laying the groundwork for the documentation and tutorials that follow.

For a comprehensive exploration of every aspect of this topic, please refer to the OCM Specification OCM Specification and its Glossary.

Components in OCM#

The concept of a Component can vary widely, often defined with very specific views on granularity or other technical attributes. OCM takes a different approach, focusing on the intended purpose and overall meaning of components.

In OCM, Components group a set of semantically related Component Versions. Each Component Version is uniquely and globally identified by a Component Identity and can reference other Components. A Component Version can also contain Artifacts and a formal description on how to access them. These Artifacts come in two categories: resources, which describe the payload (e.g.,OCI images), and sources, which describe the input for creating resources (e.g., source code).

OCM Coordinates#

OCM Coordinates are used to reference OCM Component Versions and Artifacts within OCM Component Versions. Coordinates referring to an OCM Component Version are also called Component Identity, whereas relative Coordinates referring to an artifact are called Artifact Identity. Component Identities are globally unique and may be used to refer to full Component Versions. Artifact Identities are always relative to a Component Version and may only be used in conjunction with a Component Identity.

In detail:

Component Identity#

• Component Name: Identifies a component. Must start with URL-prefix that should be controlled by the owner of the component to avoid collisions.
• Component Version: If used with a Component name, identifies a specific Component Version. Must adhere to “relaxed SemVer” (major, minor (+ optional patch level) - optional v-prefix).

Artifact Identity#

Within a Component Version, all Artifacts must have a unique identity. Every Source Identity or Resource Identity always includes a name that typically expresses the intended purpose.

Artifacts may also have additional extraIdentity attributes that contribute to their identities. extraIdentity attributes are string-to-string maps.

Examples#

Assuming there is a component named example.org/my-component with two versions, 1.2.3 and 1.3.0, declaring a resource with the name my-resource, the following OCM Coordinates can be used to reference different elements:

• example.org/my-component: all versions of the component (1.2.3 + 1.3.0)
• example.org/my-component:1.2.3: version 1.2.3 of the component
• example.org/my-component:1.2.3:resource/my-resource: my-resource as declared by the component version