decentraland / atlas-server / 39959757456

94%

Build Type

push

github

Committed by web-flow

Commit Message

feat: cache the map images at the cdn and in memory (#156)

Stacked on #155 (base `feat/render-worker-pool`); retarget to `master`
once #155 merges.

**Problem.** Every PNG route was served with `public, max-age=120`
(minimap/estatemap 600) and Cloudflare keys on the full URL, so the same
deterministic images were re-rendered every couple of minutes. Clients
ask for a small fixed set: unity-explorer 49
`/v1/map.png?…&width=1020&height=1020&size=20` URLs per session (no disk
cache), bevy-explorer ~400 grid-snapped `768x768&size=16` ones,
places/discovery/marketplace thumbnails per-place
`/v2/map.png?…selected=…` and per-parcel/estate `map.png`.

**Changes**
- Every image has a data-derived version, the same on every replica:
images without `on-sale`/`listed-for-rent` follow a **land version**
(fingerprint of tile types, estates and borders; unchanged by prices,
orders, rentals), images with them an **overlay version** (land version
+ each listed tile's price, order expiration and rental expiration).
Both are in `/v2/tiles/info` (`landVersion`, `overlayVersion`);
`lastUpdatedAt` is unchanged.
- 200s carry a weak `ETag` (`W/"<version>-<hash of the normalized
request>"`) and `public, max-age=60, s-maxage=300,
stale-while-revalidate=86400`; no `Last-Modified`, so revalidation is by
`If-None-Match` (lists, weak, `*`), answered with a 304 before any
render slot is taken. `?v=` equal to the image's version gets `public,
max-age=31536000, immutable`; any other `v` is served normally. The PNG
routes no longer go through the last-modified middleware. 400/500/503
keep their headers.
- Each PNG request takes one map snapshot (`getSnapshot()`: the served
tiles with both versions, captured together; records are swapped, never
changed) before any await, and the version, cache key, estate lookup and
render job all read from it, so an image always matches its ETag even if
the map refreshes while the render waits for a thread. Overlays are
drawn from the data alone; exp... (continued)

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