Documentation
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Overview ¶
Package mapsstyle is a server-side pull-through cache for MapLibre style assets served by the graywolf-maps Worker. The browser hits /api/maps/style/{path}; on disk-miss, graywolf fetches from upstream once, writes the body to <TileCacheDir>/style/, and serves it. The next request comes off disk — including after a reboot, from a different browser, or from a LAN guest.
No startup network: graywolf does NOT pre-fetch on boot. The first online browser request is the trigger. A new user with internet sees a working map immediately; a never-online user sees a broken map (which is the correct visible failure mode — they have no tiles either). See docs/wiki/system-topology.md for the offline maps story.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func RewriteStyleJSON ¶
RewriteStyleJSON rewrites absolute maps.nw5w.com URLs inside a style.json payload to point at the local proxy prefix (e.g. "/api/maps/style"). Rewritten fields:
- top-level "glyphs" (URL template)
- top-level "sprite" (URL base)
- sources.*.url that points at maps.nw5w.com/tiles.json
Other source types (raster-dem on s3.amazonaws.com) are left untouched.
Types ¶
type Cache ¶
type Cache struct {
// contains filtered or unexported fields
}
Cache is a disk-backed pull-through cache for MapLibre style assets. Concurrent reads are safe; in-flight upstream fetches for the same asset are coalesced (stampede protection).
func (*Cache) Get ¶
Get returns the body + content-type for rel. Tries disk first; on miss, fetches upstream and writes to disk before returning. Returns an error if the path is unsafe or both disk + upstream are unavailable.
Concurrent Gets for the same rel coalesce: the first caller fetches, subsequent callers wait and re-read from disk.
func (*Cache) PrewarmGlyphs ¶
PrewarmGlyphs reads the cached style.json from disk, discovers fontstacks via `text-font` layer keys, and fetches every glyph range 0..prewarmMaxRange for each fontstack. Per fontstack, after prewarmStop404 consecutive 404s the walk bails on that stack.
Serial by design: each range is fetched in order so the consecutive-404 counter advances correctly. The total wall-clock is bounded by the caller's context (the map-download piggyback uses a 5-minute deadline). Best-effort — returns the first genuine error, callers log and move on.
Idempotent — files already on disk are skipped.
func (*Cache) SetPrewarmLimits ¶
SetPrewarmLimits overrides the defaults for PrewarmGlyphs. Tests use it to avoid running through 1000+ ranges per case.
type Config ¶
type Config struct {
// BaseURL is the maps worker root, e.g. https://maps.nw5w.com.
BaseURL string
// CacheDir is the directory holding cached assets. Callers should
// pass <TileCacheDir>/style so the catalog, downloads, and style
// cache all coexist under TileCacheDir without colliding.
CacheDir string
// TokenProvider returns the current bearer token; called per fetch
// so re-registration rotates the token without restart. May be nil
// (tests). An empty token sends no ?t= parameter.
TokenProvider func(context.Context) string
// LocalPrefix is the URL prefix the browser uses to reach this
// cache (e.g. "/api/maps/style"). Used to rewrite absolute upstream
// URLs inside style.json so the served copy points at the local
// proxy. Required for style.json correctness.
LocalPrefix string
// Logger defaults to slog.Default().
Logger *slog.Logger
// HTTPClient is the upstream HTTP client. Defaults to a 5s-timeout
// client; tests override with httptest-provided clients (no
// timeout) or a custom timeout. The 5s default bounds the worst
// case where the upstream is slow and the browser is waiting.
HTTPClient *http.Client
}
Config configures a Cache.
Source Files