first cut of weather

Author: erh

README.md

@@ -55,6 +55,35 @@ With the default `draft = 6 ft`:
 | `0 – 2×draft`  | DEPVS | saturated blue      |
 | `≥ 2×draft`    | DEPDW | white (safe water)  |
 
+### Optional wind overlay
+
+The chartplotter can show animated wind particles using
+[sakitam-fdd/wind-layer](https://github.com/sakitam-fdd/wind-layer). It's wired
+up as a togglable layer (off by default) and appears in the layers panel as
+`wind` once the package is installed and wind data is published.
+
+Wind data is served by the bundled NOAA weather cache at
+`/noaa-weather/gfs/latest.json` (see below). The cache fetches the latest
+GFS 0.25° UGRD/VGRD at 10 m above ground from NOMADS, parses the GRIB2
+inline, and writes the JSON shape `ol-wind` consumes. No external
+converter required — `grib2json`, ecCodes, Java, etc. are *not* needed.
+
+To enable:
+
+1. `npm install` (the `ol-wind` package is already listed in `package.json`).
+2. Rebuild the frontend (`npm run build`) and reload — toggle `wind` on
+   from the layers panel.
+
+If `ol-wind` is missing or NOMADS is unreachable the chartplotter logs a
+warning and leaves the layer out — nothing else breaks.
+
+### NOAA weather endpoints
+
+| Path                              | Purpose                                                                                                              |
+| --------------------------------- | -------------------------------------------------------------------------------------------------------------------- |
+| `/noaa-weather/gfs/latest.json`   | Latest GFS 0.25° UGRD + VGRD at 10 m, two-record JSON shaped for `ol-wind`. Disk-cached under `<root>/noaa-weather/`, soft TTL 90 min with stale-while-revalidate. Fetches the most recent published GFS cycle from NOMADS (walks back in 6 h steps until one returns 200). |
+| `/noaa-weather/stats`             | JSON cache stats: hits, refreshes, errors, current file size and mtime.                                              |
+
 ### Debug endpoints
 
 | Path                                          | Purpose                                                                                                          |

module.go

@@ -11,6 +11,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"go.viam.com/rdk/components/generic"
 	"go.viam.com/rdk/logging"
@@ -68,6 +69,51 @@ func resolveCacheRoot(configured string) string {
 	return filepath.Join(base, "viam-chartplotter")
 }
 
+// withCookiePathRoot wraps an http.Handler so any Set-Cookie headers
+// it writes that don't already specify a Path get `Path=/` appended.
+// Required because vmodutils's cookie middleware doesn't set Path
+// and Go's default-Path-from-request-URL behaviour fans out the same
+// cookie into a copy per tile path.
+func withCookiePathRoot(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(&cookiePathRootWriter{ResponseWriter: w}, r)
+	})
+}
+
+type cookiePathRootWriter struct {
+	http.ResponseWriter
+	wroteHeader bool
+}
+
+func (w *cookiePathRootWriter) fixCookies() {
+	cookies := w.Header().Values("Set-Cookie")
+	if len(cookies) == 0 {
+		return
+	}
+	w.Header().Del("Set-Cookie")
+	for _, c := range cookies {
+		if !strings.Contains(strings.ToLower(c), "path=") {
+			c = c + "; Path=/"
+		}
+		w.Header().Add("Set-Cookie", c)
+	}
+}
+
+func (w *cookiePathRootWriter) WriteHeader(code int) {
+	if !w.wroteHeader {
+		w.wroteHeader = true
+		w.fixCookies()
+	}
+	w.ResponseWriter.WriteHeader(code)
+}
+
+func (w *cookiePathRootWriter) Write(b []byte) (int, error) {
+	if !w.wroteHeader {
+		w.WriteHeader(http.StatusOK)
+	}
+	return w.ResponseWriter.Write(b)
+}
+
 // StartChartplotterServer wires the static frontend, the NOAA WMS caching proxy, and
 // the ENC catalog/store handlers, and starts an HTTP server on the given port.
 // draftFt is the boat's draft in feet — drives the depth-shading bands at
@@ -87,6 +133,15 @@ func StartChartplotterServer(
 	if err != nil {
 		return nil, err
 	}
+	// vmodutils.PrepInModuleServer installs a cookie middleware that
+	// calls http.SetCookie(w, &http.Cookie{Name, Value}) without
+	// setting Path — Go then fills in the request URL's directory as
+	// the default Path. That means every tile URL gets its own copy of
+	// `api-key` / `api-key-id` / `host` cookies, fanning out into
+	// hundreds of duplicates per session. Wrap the server handler so
+	// any outgoing Set-Cookie gets a global Path=/ if it doesn't
+	// already specify one.
+	server.Handler = withCookiePathRoot(server.Handler)
 
 	root := resolveCacheRoot(cacheRoot)
 
@@ -128,6 +183,18 @@ func StartChartplotterServer(
 	encHandlers.Register(mux)
 	logger.Infof("noaa enc store: %s (default draft=%.1f ft)", encDir, draftFt)
 
+	// NOAA GFS weather cache. Serves /noaa-weather/gfs/latest.json which
+	// the frontend wind layer (ol-wind) consumes. Disk cache lives under
+	// <root>/noaa-weather/.
+	weatherDir := filepath.Join(root, "noaa-weather")
+	weatherCache, err := NewWeatherCache(weatherDir, logger.Sublogger("weather"))
+	if err != nil {
+		logger.Warnf("weather cache disabled: %v", err)
+	} else {
+		weatherCache.Register(mux)
+		logger.Infof("noaa weather cache: %s", weatherDir)
+	}
+
 	// Per-process instance ID. The frontend polls /version and reloads when it
 	// changes, so the browser picks up a new build/restart without manual refresh.
 	instanceID := newInstanceID()