add flag to disable root endpoint

Author: stroebitzer

.github/workflows/build_and_push.yaml

@@ -19,17 +19,11 @@ jobs:
         run: make build
       # - name: Lint Dockerfiles
       #   run: make docker-lint
-
-      # TODO remove this after quay creds are set
-      - name: Build all Docker Images
-        run: make docker-build-all
-
-      # - name: Login to Quay
-      #   uses: docker/login-action@v3
-      #   with:
-      #     registry: quay.io
-      #     username: ${{ secrets.QUAY_USERNAME }}
-      #     password: ${{ secrets.QUAY_ROBOT_TOKEN }}
-
-      # - name: Push all Docker Images
-      #   run: make docker-push-all
+      - name: Login to Quay
+        uses: docker/login-action@v3
+        with:
+          registry: quay.io
+          username: ${{ secrets.QUAY_USERNAME }}
+          password: ${{ secrets.QUAY_ROBOT_TOKEN }}
+      - name: Push all Docker Images
+        run: make docker-push-all

README.md

@@ -10,7 +10,6 @@ The aim of this application is to be used in the context of trainings for Docker
 
 <img width="500" alt="Screenshot 2025-06-04 at 15 40 30" src="https://github.com/user-attachments/assets/7cafc452-4f21-4202-8379-2a983ecbf122" />
 
-
 ## Available Endpoints
 
 > **_NOTE:_** The application offers the following endpoints on port **8080**
@@ -50,6 +49,8 @@ If everything is fine the application will respond with a 200 status code, if no
 | `leak cpu`          | Leak CPU                                                            |
 | `request <url>`     | Request a URL, e.g., `request https://www.kubermatic.com/`          |
 | `delay / <seconds>` | Set delay for the root endpoint (`/`) in seconds, e.g., `delay / 5` |
+| `disable /`         | The root endpoint (`/`) will respond with a 503 status code         |
+| `enable /`          | The root endpoint (`/`) will respond with a 200 status code         |
 
 > **_INSIDE A CONTAINER_** If you want to send commands to the application you have to use of `docker attach my-training-application-container`. The container als has to have `tty` enabled.
 
@@ -65,8 +66,8 @@ spec:
     - name: training-application
       image: quay.io/kubermatic-labs/training-application:3.0.0
       imagePullPolicy: Always
-      tty: true # <= add those flags
-      stdin: true # <= add those flags
+      tty: true # <= add this flag
+      stdin: true # <= add this flag
       ports:
         - name: http
           containerPort: 8080
@@ -123,12 +124,19 @@ spec:
 - **Default Value**: "not set"
 - **Usage**: via config file or via the environment variable `APP_COLOR`
 
+### `rootEnabled`
+
+- **Description**: Flag to indicate if the root endpoint (`/`) is enabled or not
+- **Type**: bool
+- **Default Value**: true
+- **Usage**: configurable via the commands `enable /` and `disable /`
+
 ### `rootDelaySeconds`
 
 - **Description**: For delaying requests to the root endpoint
 - **Type**: int
 - **Default Value**: 0
-- **Usage**: via config file or via the command `delay / <seconds>`, eg "delay / 10"
+- **Usage**: via the command `delay / <seconds>`, eg "delay / 10"
 
 ### `startUpDelaySeconds`
 

src/cli.go

@@ -108,6 +108,12 @@ func (cli *cli) executeCommand(command string) error {
 			return fmt.Errorf("error on converting delay string '%s' to int: %s", delayString, err)
 		}
 		log.Infof("Set delay for the root endpoint ('/') to '%d' seconds", cli.config.rootDelaySeconds)
+	} else if strings.HasPrefix(command, "disable /") {
+		cli.config.rootEnabled = false
+		log.Info("Disabled the root endpoint ('/')")	
+	} else if strings.HasPrefix(command, "enable /") {
+		cli.config.rootEnabled = true
+		log.Info("Enabled the root endpoint ('/')")	
 	} else {
 		return fmt.Errorf("unknown command '%s'", command)
 	}

src/config.go

@@ -16,6 +16,7 @@ type appConfig struct {
 	configFilePath       string
 	alive                bool
 	ready                bool
+	rootEnabled					 bool
 	rootDelaySeconds     int
 	startUpDelaySeconds  int
 	tearDownDelaySeconds int
@@ -32,6 +33,7 @@ func (appConfig *appConfig) logAppConfig() {
 	log.Infof("     configFilePath:            %v", appConfig.configFilePath)
 	log.Infof("     ready:                     %v", appConfig.ready)
 	log.Infof("     alive:                     %v", appConfig.alive)
+	log.Infof("     / enabled:                 %v", appConfig.rootEnabled)
 	log.Infof("     / delay seconds:           %d", appConfig.rootDelaySeconds)
 	log.Infof("     startup delay seconds:     %d", appConfig.startUpDelaySeconds)
 	log.Infof("     teardown delay seconds:    %d", appConfig.tearDownDelaySeconds)
@@ -49,6 +51,7 @@ func newAppConfig(configFilePath string) *appConfig {
 		configFilePath:       configFilePath,
 		alive:                true,
 		ready:                false,
+		rootEnabled: true,
 		rootDelaySeconds:     0,
 		startUpDelaySeconds:  0,
 		tearDownDelaySeconds: 0,
@@ -72,7 +75,6 @@ func (appConfig *appConfig) initAppConfig(isReady bool) {
 	appConfig.applicationMessage = getAppConfigStringValue(fileConfig, "message", "APP_MESSAGE", "not set")
 	appConfig.color = getAppConfigStringValue(fileConfig, "color", "APP_COLOR", "not set")
 	appConfig.logToFileOnly = getAppConfigBoolValue(fileConfig, "logToFileOnly", "", false)
-	appConfig.rootDelaySeconds = getAppConfigIntValue(fileConfig, "rootDelaySeconds", "", 0)
 	appConfig.startUpDelaySeconds = getAppConfigIntValue(fileConfig, "startUpDelaySeconds", "", 0)
 	appConfig.tearDownDelaySeconds = getAppConfigIntValue(fileConfig, "tearDownDelaySeconds", "", 0)
 	catMode := getAppConfigBoolValue(fileConfig, "catMode", "", false)
@@ -94,7 +96,7 @@ func getAppConfigStringValue(fileConfig *properties.Properties, fileConfigProper
 	if fileConfig == nil {
 		return defaultValue
 	}
-	return fileConfig.GetString(fileConfigProperty, "")
+	return fileConfig.GetString(fileConfigProperty, defaultValue)
 }
 
 func getAppConfigBoolValue(fileConfig *properties.Properties, fileConfigProperty, envVarName string, defaultValue bool) bool {
@@ -113,11 +115,14 @@ func getAppConfigBoolValue(fileConfig *properties.Properties, fileConfigProperty
 		return defaultValue
 	}
 	fileConfigPropertyValue := fileConfig.GetString(fileConfigProperty, "")
+	if fileConfigPropertyValue == "" {
+		return defaultValue
+	}
 	value, err := strconv.ParseBool(fileConfigPropertyValue)
 	if err != nil {
 		log.Errorf("could not convert file configuration property named '%s' with value '%s' to bool:", fileConfigProperty, fileConfigPropertyValue)
 		return defaultValue
-	}
+	} 
 	return value
 }
 
@@ -137,6 +142,9 @@ func getAppConfigIntValue(fileConfig *properties.Properties, fileConfigProperty,
 		return defaultValue
 	}
 	fileConfigPropertyValue := fileConfig.GetString(fileConfigProperty, "")
+	if fileConfigPropertyValue == "" {
+		return defaultValue
+	}
 	value, err := strconv.Atoi(fileConfigPropertyValue)
 	if err != nil {
 		log.Errorf("could not convert file configuration property named '%s' with value '%s' to int:", fileConfigProperty, fileConfigPropertyValue)

src/server.go

@@ -38,6 +38,10 @@ func (s *server) run() {
 
 func (s *server) handleRoot(w http.ResponseWriter, r *http.Request) {
 	log.Info("Request to root endpoint ('/')")
+	if !s.config.rootEnabled {
+		w.WriteHeader(http.StatusServiceUnavailable)
+		log.Info("Root endpoint ('/') responded with Status Code 503 Service Unavailable due to root endpoint is disabled")
+	} else {
 	if s.config.rootDelaySeconds > 0 {
 		for i := 0; i < s.config.rootDelaySeconds; i++ {
 			log.Infof("Delayed Response for %d of %d seconds", i+1, s.config.rootDelaySeconds)
@@ -67,12 +71,13 @@ func (s *server) handleRoot(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprintf(w, "Hostname: %s<br>", hostName)
 
 	if s.config.catImageUrl != "" {
-		fmt.Fprint(w, "<h2>The promised cute cat</h2>")
+		fmt.Fprint(w, "<h2>The cute cat</h2>")
 		fmt.Fprintf(w, "<img src='%s' width='500px'></img>", s.config.catImageUrl)
 	}
 
 	fmt.Fprint(w, "</body></htlml>")
 }
+}
 
 func (s *server) handleLiveness(w http.ResponseWriter, r *http.Request) {
 	log.Info("Request to liveness endpoint ('/liveness')")

training-application.conf

@@ -6,4 +6,3 @@ logToFileOnly = false
 catMode = false
 startUpDelaySeconds = 0
 tearDownDelaySeconds = 0
-rootDelaySeconds = 0