api/app.go
func appLog(w http.ResponseWriter, r *http.Request, t auth.Token) error {
	var err error
	var lines int
	if l := r.URL.Query().Get("lines"); l != "" {
		lines, err = strconv.Atoi(l)
		if err != nil {
			msg := `Parameter "lines" must be an integer.`
			return &errors.HTTP{Code: http.StatusBadRequest, Message: msg}
		}
	} else {
		return &errors.HTTP{Code: http.StatusBadRequest, Message: `Parameter "lines" is mandatory.`}
	}
	w.Header().Set("Content-Type", "application/x-json-stream")
	source := r.URL.Query().Get("source")
	unit := r.URL.Query().Get("unit")
	follow := r.URL.Query().Get("follow")
	appName := r.URL.Query().Get(":app")
	filterLog := app.Applog{Source: source, Unit: unit}
	a, err := getAppFromContext(appName, r)
	if err != nil {
		return err
	}
	allowed := permission.Check(t, permission.PermAppReadLog,
		contextsForApp(&a)...,
	)
	if !allowed {
		return permission.ErrUnauthorized
	}
	logs, err := a.LastLogs(lines, filterLog)
	if err != nil {
		return err
	}
	encoder := json.NewEncoder(w)
	err = encoder.Encode(logs)
	if err != nil {
		return err
	}
	if follow != "1" {
		return nil
	}
	closeChan := r.Context().Done()
	l, err := app.NewLogListener(&a, filterLog)
	if err != nil {
		return err
	}
	logTracker.add(l)
	defer func() {
		logTracker.remove(l)
		l.Close()
	}()
	logChan := l.ListenChan()
	for {
		var logMsg app.Applog
		var chOpen bool
		select {
		case <-closeChan:
			return nil
		case logMsg, chOpen = <-logChan:
		}
		if !chOpen {
			return nil
		}
		err := encoder.Encode([]app.Applog{logMsg})
		if err != nil {
			break
		}
	}
	return nil
}
func appLog(w http.ResponseWriter, r *http.Request, t auth.Token) error {
	var err error
	var lines int
	if l := r.URL.Query().Get("lines"); l != "" {
		lines, err = strconv.Atoi(l)
		if err != nil {
			msg := `Parameter "lines" must be an integer.`
			return &errors.HTTP{Code: http.StatusBadRequest, Message: msg}
		}
	} else {
		return &errors.HTTP{Code: http.StatusBadRequest, Message: `Parameter "lines" is mandatory.`}
	}
	w.Header().Set("Content-Type", "application/x-json-stream")
	source := r.URL.Query().Get("source")
	unit := r.URL.Query().Get("unit")
	follow := r.URL.Query().Get("follow")
	appName := r.URL.Query().Get(":app")
	filterLog := app.Applog{Source: source, Unit: unit}
	a, err := getAppFromContext(appName, r)
	if err != nil {
		return err
	}
	allowed := permission.Check(t, permission.PermAppReadLog,
		contextsForApp(&a)...,
	)
	if !allowed {
		return permission.ErrUnauthorized
	}
	logs, err := a.LastLogs(lines, filterLog)
	if err != nil {
		return err
	}
	encoder := json.NewEncoder(w)
	err = encoder.Encode(logs)
	if err != nil {
		return err
	}
	if follow != "1" {
		return nil
	}
	closeChan := r.Context().Done()
	l, err := app.NewLogListener(&a, filterLog)
	if err != nil {
		return err
	}
	logTracker.add(l)
	defer func() {
		logTracker.remove(l)
		l.Close()
	}()
	logChan := l.ListenChan()
	for {
		var logMsg app.Applog
		var chOpen bool
		select {
		case <-closeChan:
			return nil
		case logMsg, chOpen = <-logChan:
		}
		if !chOpen {
			return nil
		}
		err := encoder.Encode([]app.Applog{logMsg})
		if err != nil {
			break
		}
	}
	return nil
}
// title: app log
// path: /apps/{app}/log
// method: GET
// produce: application/x-json-stream
// responses:
//   200: Ok
//   400: Invalid data
//   401: Unauthorized
//   404: App not found