grafana/grafana-kiosk

package kiosk

import (
    "context"
    "time"

    "fmt"
    "log"
    "os"

    "github.com/chromedp/cdproto/cdp"
    "github.com/chromedp/cdproto/fetch"

    "github.com/chromedp/chromedp"

    "google.golang.org/api/idtoken"
)

// GrafanaKioskIDToken creates a chrome-based kiosk using a oauth2 authenticated account.
func GrafanaKioskIDToken(cfg *Config, messages chan string) {
    dir, err := os.MkdirTemp(os.TempDir(), "chromedp-kiosk")
    if err != nil {
        panic(err)
    }

    defer os.RemoveAll(dir)

    opts := generateExecutorOptions(dir, cfg)

    allocCtx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
    defer cancel()

    // also set up a custom logger
    taskCtx, cancel := chromedp.NewContext(allocCtx, chromedp.WithLogf(log.Printf))
    defer cancel()

    listenChromeEvents(taskCtx, cfg, targetCrashed)

    // ensure that the browser process is started
    if err := chromedp.Run(taskCtx); err != nil {
        panic(err)
    }

    // Give browser time to load
    log.Printf("Sleeping %d MS before navigating to url", cfg.General.PageLoadDelayMS)
    time.Sleep(time.Duration(cfg.General.PageLoadDelayMS) * time.Millisecond)

    var generatedURL = GenerateURL(cfg.Target.URL, cfg.General.Mode, cfg.General.AutoFit, cfg.Target.IsPlayList)

    log.Println("Navigating to ", generatedURL)

    log.Printf("Token is using audience %s and reading from %s", cfg.IDToken.Audience, cfg.IDToken.KeyFile)
    tokenSource, err := idtoken.NewTokenSource(context.Background(), cfg.IDToken.Audience, idtoken.WithCredentialsFile(cfg.IDToken.KeyFile))

    if err != nil {
        panic(err)
    }

    chromedp.ListenTarget(taskCtx, func(ev interface{}) {
        //nolint:gocritic // future events can be handled here
        switch ev := ev.(type) {
        case *fetch.EventRequestPaused:
            go func() {
                fetchReq := fetch.ContinueRequest(ev.RequestID)
                for k, v := range ev.Request.Headers {
                    fetchReq.Headers = append(fetchReq.Headers, &fetch.HeaderEntry{Name: k, Value: fmt.Sprintf("%v", v)})
                }
                token, err := tokenSource.Token()
                if err != nil {
                    panic(fmt.Errorf("idtoken.NewClient: %w", err))
                }
                fetchReq.Headers = append(fetchReq.Headers, &fetch.HeaderEntry{Name: "Authorization", Value: "Bearer " + token.AccessToken})
                err = fetchReq.Do(GetExecutor(taskCtx))
                if err != nil {
                    panic(fmt.Errorf("idtoken.NewClient fetchReq error: %w", err))
                }
            }()
        }
    })

    if err := chromedp.Run(taskCtx, enableFetch(generatedURL)); err != nil {
        panic(err)
    }

    // blocking wait
    for {
        messageFromChrome := <-messages
        if err := chromedp.Run(taskCtx,
            chromedp.Navigate(generatedURL),
        ); err != nil {
            panic(err)
        }
        log.Println("Chromium output:", messageFromChrome)
    }
}

// GetExecutor returns executor for chromedp
func GetExecutor(ctx context.Context) context.Context {
    c := chromedp.FromContext(ctx)

    return cdp.WithExecutor(ctx, c.Target)
}

func enableFetch(url string) chromedp.Tasks {
    return chromedp.Tasks{
        fetch.Enable(),
        chromedp.Navigate(url),
    }
}