| package main |
| |
| import ( |
| "context" |
| "flag" |
| "fmt" |
| "net/http" |
| "os" |
| "time" |
| |
| "github.com/go-chi/chi/v5" |
| "go.skia.org/infra/go/common" |
| "go.skia.org/infra/go/httputils" |
| "go.skia.org/infra/go/sklog" |
| "go.skia.org/infra/go/sser" |
| "k8s.io/client-go/kubernetes" |
| "k8s.io/client-go/rest" |
| ) |
| |
| // flags |
| var ( |
| local = flag.Bool("local", false, "Running locally if true. As opposed to in production.") |
| port = flag.String("port", ":8000", "HTTP service address (e.g., ':8000')") |
| sserPort = flag.Int("sser_port", 7000, "Server-Sent Events peer connection port.") |
| promPort = flag.String("prom_port", ":20000", "Metrics service address (e.g., ':10110')") |
| namespace = flag.String("namespace", "default", "Namespace this application is running in.") |
| labelSelector = flag.String("label_selector", "app=sserexample", "Label selector for peers of this application.") |
| ) |
| |
| const page = `<!DOCTYPE html> |
| <html> |
| <head> |
| <title></title> |
| <meta charset="utf-8" /> |
| </head> |
| <body> |
| <pre></pre> |
| <script type="text/javascript" charset="utf-8"> |
| const pre = document.querySelector('pre'); |
| const evtSource = new EventSource('/_/sse?stream=counter'); |
| const messages = []; |
| evtSource.onmessage = (event) => { |
| messages.push(event.data); |
| while (messages.length > 10) { |
| messages.shift(); |
| } |
| pre.textContent = messages.join('\n'); |
| }; |
| </script> |
| </body> |
| </html> |
| ` |
| |
| func index(w http.ResponseWriter, r *http.Request) { |
| w.Header().Set("Context-Type", "text/html") |
| _, err := w.Write([]byte(page)) |
| if err != nil { |
| sklog.Errorf("write index page: %s", err) |
| } |
| } |
| |
| func main() { |
| ctx := context.Background() |
| common.InitWithMust( |
| "sserexample", |
| common.PrometheusOpt(promPort), |
| ) |
| |
| var peerFinder sser.PeerFinder |
| if !*local { |
| config, err := rest.InClusterConfig() |
| if err != nil { |
| sklog.Fatal(err) |
| } |
| clientset, err := kubernetes.NewForConfig(config) |
| if err != nil { |
| sklog.Fatal(err) |
| } |
| |
| peerFinder, err = sser.NewPeerFinder(clientset, *namespace, *labelSelector) |
| if err != nil { |
| sklog.Fatal(err) |
| } |
| } else { |
| peerFinder = sser.NewPeerFinderLocalhost() |
| } |
| |
| sserServer, err := sser.New(*sserPort, peerFinder) |
| if err != nil { |
| sklog.Fatal(err) |
| } |
| err = sserServer.Start(ctx) |
| if err != nil { |
| sklog.Fatal(err) |
| } |
| |
| r := chi.NewRouter() |
| r.HandleFunc("/", index) |
| r.HandleFunc("/_/sse", sserServer.ClientConnectionHandler(ctx)) |
| |
| var h http.Handler = r |
| if !*local { |
| h = httputils.HealthzAndHTTPS(h) |
| } |
| |
| hostname, err := os.Hostname() |
| if err != nil { |
| sklog.Fatal(err) |
| } |
| |
| count := 0 |
| go func() { |
| for range time.Tick(time.Second) { |
| count++ |
| if err := sserServer.Send(ctx, "counter", fmt.Sprintf("%s - %d", hostname, count)); err != nil { |
| sklog.Errorf("failed to send: %s", err) |
| } |
| } |
| }() |
| |
| http.Handle("/", h) |
| sklog.Info("Ready to serve.") |
| sklog.Fatal(http.ListenAndServe(*port, nil)) |
| } |
