Automatically calculate public_addr field for dynamic apps (#10941). (

#10943) (#11139)

* Autodiscover public_addr for dynamic apps.

lib/service/service.go

@@ -4011,7 +4011,8 @@ func getPublicAddr(authClient auth.ReadAppsAccessPoint, a App) (string, error) {
 	for {
 		select {
 		case <-ticker.C:
-			publicAddr, err := findPublicAddr(authClient, a)
+			publicAddr, err := app.FindPublicAddr(authClient, a.PublicAddr, a.Name)
+
 			if err == nil {
 				return publicAddr, nil
 			}
@@ -4021,37 +4022,6 @@ func getPublicAddr(authClient auth.ReadAppsAccessPoint, a App) (string, error) {
 	}
 }
 
-// findPublicAddr tries to resolve the public address of the proxy of this cluster.
-func findPublicAddr(authClient auth.ReadAppsAccessPoint, a App) (string, error) {
-	// If the application has a public address already set, use it.
-	if a.PublicAddr != "" {
-		return a.PublicAddr, nil
-	}
-
-	// Fetch list of proxies, if first has public address set, use it.
-	servers, err := authClient.GetProxies()
-	if err != nil {
-		return "", trace.Wrap(err)
-	}
-	if len(servers) == 0 {
-		return "", trace.BadParameter("cluster has no proxied registered, at least one proxy must be registered for application access")
-	}
-	if servers[0].GetPublicAddr() != "" {
-		addr, err := utils.ParseAddr(servers[0].GetPublicAddr())
-		if err != nil {
-			return "", trace.Wrap(err)
-		}
-		return fmt.Sprintf("%v.%v", a.Name, addr.Host()), nil
-	}
-
-	// Fall back to cluster name.
-	cn, err := authClient.GetClusterName()
-	if err != nil {
-		return "", trace.Wrap(err)
-	}
-	return fmt.Sprintf("%v.%v", a.Name, cn.GetClusterName()), nil
-}
-
 // newHTTPFileSystem creates a new HTTP file system for the web handler.
 // It uses external configuration to make the decision
 func newHTTPFileSystem() (http.FileSystem, error) {

lib/srv/app/watcher.go

@@ -18,11 +18,13 @@ package app
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/gravitational/teleport"
 	"github.com/gravitational/teleport/api/types"
+	"github.com/gravitational/teleport/lib/auth"
 	"github.com/gravitational/teleport/lib/services"
-
+	"github.com/gravitational/teleport/lib/utils"
 	"github.com/gravitational/trace"
 )
 
@@ -82,7 +84,11 @@ func (s *Server) startResourceWatcher(ctx context.Context) (*services.AppWatcher
 		for {
 			select {
 			case apps := <-watcher.AppsC:
-				s.monitoredApps.setResources(apps)
+				appsWithAddr := make(types.Apps, 0, len(apps))
+				for _, app := range apps {
+					appsWithAddr = append(appsWithAddr, s.guessPublicAddr(app))
+				}
+				s.monitoredApps.setResources(appsWithAddr)
 				select {
 				case s.reconcileCh <- struct{}{}:
 				case <-ctx.Done():
@@ -97,6 +103,52 @@ func (s *Server) startResourceWatcher(ctx context.Context) (*services.AppWatcher
 	return watcher, nil
 }
 
+// guessPublicAddr will guess PublicAddr for given application if it is missing, based on proxy information and app name.
+func (s *Server) guessPublicAddr(app types.Application) types.Application {
+	if app.GetPublicAddr() != "" {
+		return app
+	}
+	appCopy := app.Copy()
+	pubAddr, err := FindPublicAddr(s.c.AccessPoint, app.GetPublicAddr(), app.GetName())
+	if err == nil {
+		appCopy.Spec.PublicAddr = pubAddr
+	} else {
+		s.log.WithError(err).Errorf("Unable to find public address for app %q, leaving empty.", app.GetName())
+	}
+	return appCopy
+}
+
+// FindPublicAddr tries to resolve the public address of the proxy of this cluster.
+func FindPublicAddr(authClient auth.ReadAppsAccessPoint, appPublicAddr string, appName string) (string, error) {
+	// If the application has a public address already set, use it.
+	if appPublicAddr != "" {
+		return appPublicAddr, nil
+	}
+
+	// Fetch list of proxies, if first has public address set, use it.
+	servers, err := authClient.GetProxies()
+	if err != nil {
+		return "", trace.Wrap(err)
+	}
+	if len(servers) == 0 {
+		return "", trace.BadParameter("cluster has no proxy registered, at least one proxy must be registered for application access")
+	}
+	if servers[0].GetPublicAddr() != "" {
+		addr, err := utils.ParseAddr(servers[0].GetPublicAddr())
+		if err != nil {
+			return "", trace.Wrap(err)
+		}
+		return fmt.Sprintf("%v.%v", appName, addr.Host()), nil
+	}
+
+	// Fall back to cluster name.
+	cn, err := authClient.GetClusterName()
+	if err != nil {
+		return "", trace.Wrap(err)
+	}
+	return fmt.Sprintf("%v.%v", appName, cn.GetClusterName()), nil
+}
+
 func (s *Server) getResources() (resources types.ResourcesWithLabelsMap) {
 	return s.getApps().AsResources().ToMap()
 }