grafana/cue/scuemata/scuemata.cue
sam boyer 96473004db
Refactor dashboard scuemata to introduce composition slots, allow unspecified panels to validate, and re-enable devenv validation (#38727)
* Re-enable devenv dashboard validation

* Open up dashboard schema composition points

* Introduce composition space at front of scuemata

* Refactor go code to use new composition structure

* Bunch of small cleanups in dashboard.cue

* Enable both base and dist tests of devenv

* Get rid of obsolete CUE loading hacks

* Skip weird failures on these tests

Really don't seem to be testing for what we intend them to be testing
for.
2021-09-06 18:53:42 -04:00

62 lines
2.6 KiB
CUE

package scuemata
// A family is a collection of schemas that specify a single kind of object,
// allowing evolution of the canonical schema for that kind of object over time.
//
// The schemas are organized into a list of Lineages, which are themselves ordered
// lists of schemas where each schema with its predecessor in the lineage.
//
// If it is desired to define a schema with a breaking schema relative to its
// predecessors, a new Lineage must be created, as well as a Migration that defines
// a mapping to the new schema from the latest schema in prior Lineage.
//
// The version number of a schema is not controlled by the schema itself, but by
// its position in the list of lineages - e.g., 0.0 corresponds to the first
// schema in the first lineage.
#Family: {
compose?: {...}
lineages: [#Lineage, ...#Lineage]
migrations: [...#Migration]
let lseq = lineages[len(lineages)-1]
latest: #LastSchema & {_p: lseq}
}
// A Lineage is a non-empty list containing an ordered series of schemas that
// all describe a single kind of object, where each schema is backwards
// compatible with its predecessor.
#Lineage: [{...}, ...{...}]
#LastSchema: {
_p: #Lineage
_p[len(_p)-1]
}
// A Migration defines a relation between two schemas, "_from" and "_to". The
// relation expresses any complex mappings that must be performed to
// transform an input artifact valid with respect to the _from schema, into
// an artifact valid with respect to the _to schema. This is accomplished
// in two stages:
// 1. A Migration is initially defined by passing in schemas for _from and _to,
// and mappings that translate _from to _to are defined in _rel.
// 2. A concrete object may then be unified with _to, resulting in its values
// being mapped onto "result" by way of _rel.
//
// This is the absolute simplest possible definition of a Migration. It's
// incumbent on the implementor to manually ensure the correctness and
// completeness of the mapping. The primary value in defining such a generic
// structure is to allow comparably generic logic for migrating concrete
// artifacts through schema changes.
//
// If _to isn't backwards compatible (accretion-only) with _from, then _rel must
// explicitly enumerate every field in _from and map it to a field in _to, even
// if they're identical. This is laborious for anything outside trivially tiny
// schema. We'll want to eventually add helpers for whitelisting or blacklisting
// of paths in _from, so that migrations of larger schema can focus narrowly on
// the points of actual change.
#Migration: {
from: {...}
to: {...}
rel: {...}
result: to & rel
}