rss-tools/app/app.go (view raw)
| 1 | package app |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "fmt" |
| 6 | "log/slog" |
| 7 | "net/http" |
| 8 | "os" |
| 9 | "strings" |
| 10 | "sync" |
| 11 | "time" |
| 12 | |
| 13 | "go.etcd.io/bbolt" |
| 14 | ) |
| 15 | |
| 16 | type App struct { |
| 17 | mux *http.ServeMux |
| 18 | workers []func(context.Context) error |
| 19 | shutdowns []func(context.Context) |
| 20 | wg *sync.WaitGroup |
| 21 | db *bbolt.DB |
| 22 | scraperClient *http.Client |
| 23 | |
| 24 | // TODO: cacher, each scrapper should be able to get it's own cacher |
| 25 | Config *Config |
| 26 | Client *http.Client |
| 27 | Logger *slog.Logger |
| 28 | } |
| 29 | |
| 30 | func New(cfg *Config, db *bbolt.DB) *App { |
| 31 | return &App{ |
| 32 | mux: http.NewServeMux(), |
| 33 | workers: nil, |
| 34 | wg: &sync.WaitGroup{}, |
| 35 | db: db, |
| 36 | scraperClient: &http.Client{Timeout: 10 * time.Second}, |
| 37 | |
| 38 | Logger: slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug, AddSource: false})), |
| 39 | Client: &http.Client{Timeout: 31 * time.Second}, |
| 40 | Config: cfg, |
| 41 | } |
| 42 | } |
| 43 | |
| 44 | // Route registers a global route. pattern syntax is the same as in [http.ServeMux].HandlerFunc |
| 45 | func (a App) Route(pattern string, handler http.HandlerFunc) { |
| 46 | a.mux.HandleFunc(pattern, handler) |
| 47 | } |
| 48 | |
| 49 | // AddWorker adds background worker |
| 50 | func (a *App) AddWorker(worker func(ctx context.Context) error) { |
| 51 | a.workers = append(a.workers, worker) |
| 52 | } |
| 53 | |
| 54 | // AddShutdown registers a shutdown hook that will be called when the app stops. |
| 55 | // Shutdown hooks are called in reverse order of registration. |
| 56 | func (a *App) AddShutdown(fn func(ctx context.Context)) { |
| 57 | a.shutdowns = append(a.shutdowns, fn) |
| 58 | } |
| 59 | |
| 60 | const ( |
| 61 | defaultScraperUserAgent = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36" |
| 62 | defaultScraperAccept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8" |
| 63 | ) |
| 64 | |
| 65 | // Get is intended for scraping sources; API SDK calls should use [App.Client] directly. |
| 66 | func (a *App) Get(ctx context.Context, url string) (*http.Response, error) { |
| 67 | req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil) |
| 68 | if err != nil { |
| 69 | return nil, err |
| 70 | } |
| 71 | req.Header.Set("User-Agent", defaultScraperUserAgent) |
| 72 | req.Header.Set("Accept", defaultScraperAccept) |
| 73 | return a.scraperClient.Do(req) |
| 74 | } |
| 75 | |
| 76 | // Start starts an app and with all it's registered sources |
| 77 | func (a *App) Start(ctx context.Context) error { |
| 78 | // workers |
| 79 | for _, worker := range a.workers { |
| 80 | a.wg.Add(1) |
| 81 | go func(w func(context.Context) error) { |
| 82 | defer a.wg.Done() |
| 83 | if err := w(ctx); err != nil { |
| 84 | a.Logger.ErrorContext(ctx, "worker exited with an error", "err", err) |
| 85 | } |
| 86 | }(worker) |
| 87 | } |
| 88 | |
| 89 | // http server |
| 90 | handler := a.recoverMiddleware(a.mux) |
| 91 | handler = a.loggingMiddleware(handler) |
| 92 | if strings.TrimSpace(a.Config.AuthToken) != "" { |
| 93 | handler = a.authMiddleware(handler) |
| 94 | } |
| 95 | |
| 96 | httpSrv := &http.Server{ |
| 97 | Addr: fmt.Sprintf(":%d", a.Config.Port), // fixme |
| 98 | Handler: handler, |
| 99 | } |
| 100 | |
| 101 | go func() { |
| 102 | go func() { |
| 103 | <-ctx.Done() |
| 104 | shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second) |
| 105 | defer cancel() |
| 106 | httpSrv.Shutdown(shutdownCtx) |
| 107 | }() |
| 108 | }() |
| 109 | |
| 110 | a.Logger.Info("starting http server", "port", a.Config.Port) |
| 111 | if err := httpSrv.ListenAndServe(); err != http.ErrServerClosed { |
| 112 | return err |
| 113 | } |
| 114 | |
| 115 | a.wg.Wait() |
| 116 | |
| 117 | shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second) |
| 118 | defer cancel() |
| 119 | for _, fn := range a.shutdowns { |
| 120 | fn(shutdownCtx) |
| 121 | } |
| 122 | |
| 123 | return nil |
| 124 | } |