mirror of https://github.com/grafana/grafana.git
110 lines
2.9 KiB
Go
110 lines
2.9 KiB
Go
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package frontend
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import (
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"context"
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"net"
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"net/http"
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"time"
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"github.com/grafana/dskit/services"
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"github.com/grafana/grafana/pkg/infra/log"
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"github.com/grafana/grafana/pkg/setting"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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type frontendService struct {
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*services.BasicService
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cfg *setting.Cfg
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httpServ *http.Server
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log log.Logger
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errChan chan error
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promGatherer prometheus.Gatherer
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}
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func ProvideFrontendService(cfg *setting.Cfg, promGatherer prometheus.Gatherer) (*frontendService, error) {
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s := &frontendService{
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cfg: cfg,
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log: log.New("frontend-server"),
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promGatherer: promGatherer,
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}
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s.BasicService = services.NewBasicService(s.start, s.running, s.stop)
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return s, nil
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}
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func (s *frontendService) start(ctx context.Context) error {
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s.httpServ = s.newFrontendServer(ctx)
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s.errChan = make(chan error)
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go func() {
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s.errChan <- s.httpServ.ListenAndServe()
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}()
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return nil
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}
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func (s *frontendService) running(ctx context.Context) error {
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select {
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case <-ctx.Done():
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return nil
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case err := <-s.errChan:
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return err
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}
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}
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func (s *frontendService) stop(failureReason error) error {
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s.log.Info("stopping frontend server", "reason", failureReason)
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if err := s.httpServ.Shutdown(context.Background()); err != nil {
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s.log.Error("failed to shutdown frontend server", "error", err)
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return err
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}
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return nil
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}
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func (s *frontendService) newFrontendServer(ctx context.Context) *http.Server {
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s.log.Info("starting frontend server", "addr", ":"+s.cfg.HTTPPort)
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router := http.NewServeMux()
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router.Handle("/metrics", promhttp.HandlerFor(s.promGatherer, promhttp.HandlerOpts{EnableOpenMetrics: true}))
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router.HandleFunc("/", s.handleRequest)
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server := &http.Server{
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// 5s timeout for header reads to avoid Slowloris attacks (https://thetooth.io/blog/slowloris-attack/)
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ReadHeaderTimeout: 5 * time.Second,
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Addr: ":" + s.cfg.HTTPPort,
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Handler: router,
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BaseContext: func(_ net.Listener) context.Context { return ctx },
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}
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return server
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}
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func (s *frontendService) handleRequest(writer http.ResponseWriter, request *http.Request) {
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// This should:
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// - get correct asset urls from fs or cdn
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// - generate a nonce
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// - render them into the index.html
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// - and return it to the user!
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s.log.Info("handling request", "method", request.Method, "url", request.URL.String())
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htmlContent := `<!DOCTYPE html>
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<html>
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<head>
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<title>Grafana Frontend Server</title>
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<style>
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body {
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font-family: sans-serif;
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}
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</style>
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</head>
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<body>
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<h1>Grafana Frontend Server</h1>
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<p>This is a simple static HTML page served by the Grafana frontend server module.</p>
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</body>
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</html>`
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writer.Header().Set("Content-Type", "text/html; charset=utf-8")
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_, err := writer.Write([]byte(htmlContent))
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if err != nil {
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s.log.Error("could not write to response", "err", err)
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}
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}
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