Files
bdeb1337 d7342d6096 feat: workout-suggester, weather-aware workouts from a local Gemma
Go + Templ + HTMX app that checks the weather (Open-Meteo, MET Norway
fallback), scores run/ride/walk with plain rules, and has a local
open-weight model (Gemma 4 E2B via any OpenAI-compatible server) write
the plan. Routes are loops from your door (BRouter) plus signposted
OpenStreetMap routes (Overpass), with GPX export.
2026-10-11 19:29:58 +02:00

407 lines
12 KiB
Go

// Package web serves the app: Templ pages, HTMX fragments and an SSE
// endpoint that streams the coach's replies token by token.
package web
import (
"bytes"
"context"
"embed"
"errors"
"fmt"
"log/slog"
"net/http"
"strconv"
"strings"
"sync"
"time"
"github.com/a-h/templ"
"git.b0b.be/bdeb/workout-suggester/internal/coach"
"git.b0b.be/bdeb/workout-suggester/internal/config"
"git.b0b.be/bdeb/workout-suggester/internal/llm"
"git.b0b.be/bdeb/workout-suggester/internal/routes"
"git.b0b.be/bdeb/workout-suggester/internal/session"
"git.b0b.be/bdeb/workout-suggester/internal/weather"
"git.b0b.be/bdeb/workout-suggester/internal/web/views"
)
//go:embed static
var staticFS embed.FS
const (
sessionCookie = "ws_sid"
maxFormLen = 8 << 10
routesTimeout = 30 * time.Second
)
// Server is the web app.
type Server struct {
cfg config.Config
llm *llm.Client
weather *weather.Client
routes *routes.Client
store *session.Store
log *slog.Logger
}
// New wires a server from config. cacheDir keeps OpenStreetMap lookups
// between runs; empty disables that.
func New(cfg config.Config, cacheDir string, log *slog.Logger) *Server {
hc := &http.Client{Timeout: 45 * time.Second}
return &Server{
cfg: cfg,
llm: &llm.Client{
BaseURL: cfg.BaseURL,
APIKey: cfg.APIKey,
Model: cfg.Model,
HTTP: &http.Client{}, // per-request deadlines come from contexts
},
weather: &weather.Client{ForecastURL: cfg.ForecastURL, GeocodeURL: cfg.GeocodeURL, HTTP: hc},
routes: &routes.Client{URLs: strings.Fields(cfg.OverpassURL), BRouterURL: cfg.BRouterURL, HTTP: hc, CacheDir: cacheDir},
store: session.NewStore(),
log: log,
}
}
// Handler returns the app's routes.
func (s *Server) Handler() http.Handler {
mux := http.NewServeMux()
mux.Handle("GET /static/", http.FileServerFS(staticFS))
mux.HandleFunc("GET /{$}", s.index)
mux.HandleFunc("GET /health", s.health)
mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) { w.Write([]byte("ok")) })
mux.HandleFunc("POST /plan", s.plan)
mux.HandleFunc("GET /routes", s.routesCard)
mux.HandleFunc("GET /gpx/{id}", s.gpx)
mux.HandleFunc("POST /ask", s.ask)
mux.HandleFunc("GET /stream/{id}", s.stream)
return s.withSession(mux)
}
// Run serves until ctx is cancelled, then shuts down gracefully.
func (s *Server) Run(ctx context.Context) error {
srv := &http.Server{
Addr: s.cfg.Addr,
Handler: s.Handler(),
ReadHeaderTimeout: 10 * time.Second,
// No WriteTimeout: replies stream for as long as the model talks.
// LLM_TIMEOUT bounds each reply instead.
}
go func() {
t := time.NewTicker(10 * time.Minute)
defer t.Stop()
for {
select {
case <-ctx.Done():
return
case <-t.C:
s.store.Prune(12 * time.Hour)
}
}
}()
errc := make(chan error, 1)
go func() { errc <- srv.ListenAndServe() }()
s.log.Info("workout-suggester listening", "url", "http://"+s.cfg.Addr, "llm", s.cfg.BaseURL, "model", s.cfg.Model)
select {
case err := <-errc:
return err
case <-ctx.Done():
shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
return srv.Shutdown(shutdownCtx)
}
}
type ctxKey struct{}
// withSession gives every browser a random session cookie.
func (s *Server) withSession(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
sid := ""
if c, err := r.Cookie(sessionCookie); err == nil && len(c.Value) == 32 {
sid = c.Value
} else {
sid = session.NewID()
http.SetCookie(w, &http.Cookie{
Name: sessionCookie,
Value: sid,
Path: "/",
HttpOnly: true,
SameSite: http.SameSiteLaxMode,
})
}
next.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), ctxKey{}, sid)))
})
}
func sessionID(r *http.Request) string {
sid, _ := r.Context().Value(ctxKey{}).(string)
return sid
}
func (s *Server) render(w http.ResponseWriter, r *http.Request, c templ.Component) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
if err := c.Render(r.Context(), w); err != nil {
s.log.Error("render", "err", err)
}
}
func (s *Server) index(w http.ResponseWriter, r *http.Request) {
d := views.PageData{DefaultPlace: s.cfg.DefaultPlace}
if conv := s.store.Get(sessionID(r)); conv != nil {
p := conv.Plan()
d.Plan, d.Messages = &p, conv.Messages()
}
s.render(w, r, views.Page(d))
}
func (s *Server) health(w http.ResponseWriter, r *http.Request) {
ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
defer cancel()
model, err := s.llm.ResolveModel(ctx)
if err == nil && s.cfg.Model != "" {
_, err = s.llm.Models(ctx) // configured model: still check the server is up
}
h := views.HealthInfo{OK: err == nil, Model: model}
if err != nil {
h.Err = err.Error()
}
s.render(w, r, views.Health(h))
}
// parseRequest reads the form into a coach request, with safe defaults.
func parseRequest(r *http.Request) coach.Request {
req := coach.Request{
Activity: coach.Activity(r.FormValue("activity")),
Intensity: coach.Intensity(r.FormValue("intensity")),
Note: strings.TrimSpace(r.FormValue("note")),
}
switch req.Activity {
case coach.Run, coach.Ride, coach.Walk, coach.Indoor:
default:
req.Activity = coach.Any
}
switch req.Intensity {
case coach.Easy, coach.Moderate, coach.Hard:
default:
req.Intensity = coach.Moderate
}
req.Minutes, _ = strconv.Atoi(r.FormValue("minutes"))
req.Minutes = min(240, max(15, req.Minutes))
if len(req.Note) > 200 {
req.Note = req.Note[:200]
}
return req
}
// plan checks the weather, scores the options and starts the coach's reply.
func (s *Server) plan(w http.ResponseWriter, r *http.Request) {
r.Body = http.MaxBytesReader(w, r.Body, maxFormLen)
if err := r.ParseForm(); err != nil {
s.render(w, r, views.Error("That form was too big."))
return
}
req := parseRequest(r)
ctx, cancel := context.WithTimeout(r.Context(), 15*time.Second)
defer cancel()
var p coach.Plan
lat, errLat := strconv.ParseFloat(r.FormValue("lat"), 64)
lon, errLon := strconv.ParseFloat(r.FormValue("lon"), 64)
switch place := strings.TrimSpace(r.FormValue("place")); {
case errLat == nil && errLon == nil && lat >= -90 && lat <= 90 && lon >= -180 && lon <= 180:
p.At = routes.Point{Lat: lat, Lon: lon}
case place != "":
pl, err := s.weather.Geocode(ctx, place)
if err != nil {
s.log.Warn("geocode", "err", err)
s.render(w, r, views.Error("Couldn't find that place. Check the spelling, or tap 📍 Here."))
return
}
p.Place, p.At = pl.Name, routes.Point{Lat: pl.Lat, Lon: pl.Lon}
default:
s.render(w, r, views.Error("Where are you? Type a town or tap 📍 Here."))
return
}
f, err := s.weather.Forecast(ctx, p.At.Lat, p.At.Lon)
if err != nil {
s.log.Warn("forecast", "err", err)
s.render(w, r, views.Error("Couldn't get the weather right now. Are you online?"))
return
}
p.Forecast, p.Request, p.Assessment = f, req, coach.Assess(f, req)
conv, _ := s.store.Start(sessionID(r), p)
s.render(w, r, views.PlanView(conv.Plan(), conv.Messages()))
}
// loadRoutes looks up routes for the plan's pick once per plan. Concurrent
// callers (the routes card and the first reply) share one Overpass request.
func (s *Server) loadRoutes(ctx context.Context, conv *session.Conversation) coach.Plan {
p := conv.Plan()
if p.RoutesLoaded || p.Assessment.Pick == coach.Indoor {
return p
}
ctx, cancel := context.WithTimeout(ctx, routesTimeout)
defer cancel()
// Loops from the door (BRouter) and signposted routes (Overpass) at once.
kind := p.Assessment.Pick.RouteKind()
var (
loops []routes.Suggestion
loopsErr error
wg sync.WaitGroup
)
wg.Go(func() {
loops, loopsErr = s.routes.Loops(ctx, kind, p.At, p.Assessment.TargetKm, p.Forecast.Now.WindDirection)
})
area, err := s.routes.Near(ctx, p.At.Lat, p.At.Lon)
wg.Wait()
if loopsErr != nil {
s.log.Warn("loops", "err", loopsErr)
}
if err != nil {
s.log.Warn("routes", "err", err)
}
conv.UpdatePlan(func(p *coach.Plan) {
if p.RoutesLoaded {
return
}
p.RoutesLoaded = true
p.Routes = loops[:min(2, len(loops))]
if err == nil {
p.Routes = append(p.Routes, routes.Suggest(area, kind, p.Assessment.TargetKm, p.At, 4-len(p.Routes))...)
if j, km, ok := area.NearestJunction(kind, p.At); ok && km < 2 {
p.Junction = &coach.JunctionInfo{Ref: j.Ref, Kind: kind, Km: km}
}
}
if len(p.Routes) == 0 && err != nil {
p.RoutesErr = err.Error()
}
})
return conv.Plan()
}
func (s *Server) routesCard(w http.ResponseWriter, r *http.Request) {
conv := s.store.Get(sessionID(r))
if conv == nil {
s.render(w, r, views.Error("This plan expired. Ask again."))
return
}
s.render(w, r, views.RoutesCard(s.loadRoutes(r.Context(), conv)))
}
func (s *Server) gpx(w http.ResponseWriter, r *http.Request) {
id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
route, ok := s.routes.Route(id)
if err != nil || !ok {
http.NotFound(w, r)
return
}
w.Header().Set("Content-Type", "application/gpx+xml")
w.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="osm-%d.gpx"`, id))
routes.WriteGPX(w, route)
}
func (s *Server) ask(w http.ResponseWriter, r *http.Request) {
r.Body = http.MaxBytesReader(w, r.Body, maxFormLen)
text := strings.TrimSpace(r.FormValue("message"))
conv := s.store.Get(sessionID(r))
switch {
case conv == nil:
s.render(w, r, views.Error("This plan expired. Ask again from the top."))
return
case text == "" || len(text) > 1000:
http.Error(w, "message is empty or too long", http.StatusBadRequest)
return
}
user, reply := conv.Ask(text)
s.render(w, r, views.Exchange(user, reply))
}
// stream generates a reply and pushes it to the browser as server-sent
// events. EventSource reconnects automatically, so a reply that is already
// claimed or finished is answered with its current state instead of being
// generated twice.
func (s *Server) stream(w http.ResponseWriter, r *http.Request) {
id := r.PathValue("id")
conv := s.store.Get(sessionID(r))
w.Header().Set("Content-Type", "text/event-stream")
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("X-Accel-Buffering", "no") // don't let reverse proxies buffer
sse := &sseWriter{w: w, rc: http.NewResponseController(w)}
lost := session.Message{ID: id, Role: "assistant", State: session.Done,
Err: "This reply was lost, probably because the server restarted. Please ask again."}
if conv == nil {
sse.component(r.Context(), "done", views.MessageView(lost))
return
}
// The first reply should know the routes, so wait for them (cached
// after the first lookup, and shared with the routes card).
if conv.IsFirstReply(id) {
s.loadRoutes(r.Context(), conv)
}
prompt, msg, ok := conv.Claim(id)
if !ok {
if msg.ID == "" {
msg = lost
}
sse.component(r.Context(), "done", views.MessageView(msg))
return
}
ctx, cancel := context.WithTimeout(r.Context(), s.cfg.Timeout)
defer cancel()
start := time.Now()
err := s.llm.Stream(ctx, prompt, func(delta string) error {
conv.Append(id, delta)
return sse.component(ctx, "token", views.Token(delta))
})
if r.Context().Err() != nil { // browser went away; keep what we have
conv.Finish(id, errors.New("interrupted"))
return
}
switch {
case errors.Is(err, context.DeadlineExceeded):
err = fmt.Errorf("reply took longer than %s and was cut off", s.cfg.Timeout)
case err != nil:
s.log.Warn("generation failed", "err", err)
err = errors.New("the local model didn't answer. Is your model server running?")
default:
s.log.Debug("reply done", "id", id, "took", time.Since(start))
}
sse.component(r.Context(), "done", views.MessageView(conv.Finish(id, err)))
}
type sseWriter struct {
w http.ResponseWriter
rc *http.ResponseController
}
// component sends one rendered Templ component as a named SSE event.
func (s *sseWriter) component(ctx context.Context, event string, c templ.Component) error {
var buf bytes.Buffer
if err := c.Render(ctx, &buf); err != nil {
return err
}
var b strings.Builder
b.WriteString("event: " + event + "\n")
for _, line := range strings.Split(buf.String(), "\n") {
b.WriteString("data: " + line + "\n")
}
b.WriteString("\n")
if _, err := s.w.Write([]byte(b.String())); err != nil {
return err
}
return s.rc.Flush()
}