Materialised cache without a rebuild path

errormaterialised-cache-without-rebuild-path

A cache holding materialised views has to be rebuildable from a durable store or a worker. With nothing feeding it, a cold cache is a permanent gap rather than a slow start.

Severity: error
Selects: every node of kind cache
Components in scope: 37

What it checks

It looks at every node of kind cache, and fires when:

— all of these hold:
— the node's `materialised` is true
— this does not hold:
— the node has at least one incoming edge from a sql-database, nosql-database, worker or stream

Message

Cache '{{node.id}}' holds materialised data but nothing durable or no worker feeds it. It cannot be rebuilt after loss.

{{node.id}} style paths are filled in from the node, the edge or the design the finding is about.

Applies to · 37 components

Cache cache

Tripped by · 12

Reference designs whose broken twin names this rule in its header. The gate reads the same header, and fails when a rule no design trips.

cloudflare-edgereference etsy-searchreference google-mapsreference hotel-reservationreference khan-academy-goliathreference proximity-servicereference reddit-feedreference tiktok-recommendationreference twitter-timelinereference wikipediareference x-recommendationreference zerodha-kitereference

Source

1# yaml-language-server: $schema=../schema/rule.schema.json
2# A cache holding materialised views (timelines, feeds, precomputed lists) must be rebuildable
3# from a durable source or a worker. With no such in-edge, a cold cache is a permanent gap.
4# Tripped by: designs/twitter-timeline.broken.yaml
5schemaVersion: "1"
6type: "rule"
7id: "materialised-cache-without-rebuild-path"
8severity: "error"
9select:
10  node:
11    kind: "cache"
12when:
13  all:
14    - prop: "materialised"
15      equals: true
16    - not:
17        hasEdge:
18          direction: "in"
19          peerKind: ["sql-database", "nosql-database", "worker", "stream"]
20message: "Cache '{{node.id}}' holds materialised data but nothing durable or no worker feeds it. It cannot be rebuilt after loss."

The same page as markdown, for an agent: /catalogue/rules/materialised-cache-without-rebuild-path.md