4. Vendor runtime support over submodule + symlink

Status

Accepted

Context

An IOC instance needs its runtime-support file-set: StreamDevice protocol files, AreaDetector plugin sets, support *.ibek.support.yaml, and the associated .proto/.protocol/.template/.db. Historically these were consumed by pointing the instance at a central support module via a git submodule and symlinks into it.

That coupling made “what is this IOC actually running?” hard to answer from the committed instance alone: the answer depended on the submodule commit and on whatever the symlinks resolved to in the build image, so a pattern’s version was tied to the image rather than to the instance.

Decision

Consume runtime support as per-instance vendored copies, pinned by a runtime-lock.yaml at the instance root, instead of submodule + symlink.

ibek pattern add|update|check|restore|schema copies a pattern’s file-set from a central library (e.g. ibek-runtime-streamdevice, ibek-runtime-support) into the instance’s config/, prepends a deterministic # Vendored from <source>@<version> — DO NOT EDIT header, and records each file’s SHA-256 in the lock. A self-contained ioc.schema.json is generated per instance by merging the vendored support entities into the image’s published base schema.

Consequences

• An instance gains a version axis for its support that is independent of the image: the committed lock answers “what is this IOC running?” with cryptographic certainty.

• Vendored files are real files (not symlinks) and carry a DO-NOT-EDIT header; ibek pattern check enforces their integrity against the lock so accidental edits are caught.

• config/ remains the Kubernetes ConfigMap payload (runtime inputs only, bounded by the ConfigMap size limit), now self-contained rather than resolved through a submodule at build time.

• The central libraries become the single upstream source for patterns; see ADR 3 for how their tags relate to the lock.