Websockets on Spring boot website hosted on Azure returns Error 503/403 - spring-boot

Question

I have built a webapp on Spring Boot using Spring Security with Azure AD authentication and Websockets to communicate with clients. Locally this works perfectly but when i deploy it as an Azure Web App the Websocket connection fails with Error 503 and 403.
I've tried searching both here and Google for answers. Some of the answers point to an App setting where you can toggle websocket support in the web app on Azure but that setting is not there anymore. A lot of solutions i found are about 5 years old and not much relevant to my situation.
I'll share some code but it's pretty basic and mostly fetched from the guides online from Microsoft and Spring.
Jacascript that connect to the websocket endpoint:
stompClient = Stomp.over(socket);
stompClient.connect({}, onConnected, onError);
My websocketconfiguration:
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;
#Configuration
#EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/ws").setAllowedOrigins("*").withSockJS();
}
#Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.setApplicationDestinationPrefixes("/app");
registry.enableSimpleBroker("/topic");
}
}
Websecurity configuration:
#EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
#Autowired
private OAuth2UserService<OidcUserRequest, OidcUser> oidcUserService;
#Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.anyRequest().authenticated()
.and()
.oauth2Login()
.userInfoEndpoint()
.oidcUserService(oidcUserService);
http.headers().frameOptions().disable();
}
}
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.5.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.groupId</groupId>
<artifactId>artifactId</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Name</name>
<description>This is a description</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>com.microsoft.azure</groupId>
<artifactId>azure-active-directory-spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-oauth2-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-oauth2-jose</artifactId>
</dependency>
<dependency>
<groupId>org.thymeleaf.extras</groupId>
<artifactId>thymeleaf-extras-springsecurity5</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>com.microsoft.azure</groupId>
<artifactId>azure-webapp-maven-plugin</artifactId>
<version>1.5.4</version>
<configuration>
<deploymentType>jar</deploymentType>
<!-- configure app to run on port 80, required by App Service -->
<appSettings>
<property>
<name>JAVA_OPTS</name>
<value>-Dserver.port=80</value>
</property>
</appSettings>
<!-- Web App information -->
<resourceGroup>myResourceGroup</resourceGroup>
<appName>myAppName</appName>
<region>myRegion</region>
<pricingTier>S1</pricingTier>
<!-- Java Runtime Stack for Web App on Linux -->
<linuxRuntime>jre8</linuxRuntime>
</configuration>
</plugin>
</plugins>
</build>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.microsoft.azure</groupId>
<artifactId>azure-spring-boot-bom</artifactId>
<version>2.1.2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
</project>
I expect the websocket to connect as it does locally but i get this 503 error message reply:
Content-Length: 260
Content-Type: text/html
ETag: "5ce7bd82-104"
Server: nginx
Date: Fri, 31 May 2019 07:59:58 GMT
Followed by these:
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Transfer-Encoding: chunked
Content-Type: application/json;charset=UTF-8
Expires: 0
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Date: Fri, 31 May 2019 07:59:59 GMT
Edit:
If i go to the requested url directly i get an error saying Can "Upgrade" only to "WebSocket".
Edit2:
If i tail my web app logs in the Azure client this message pops up:
0 transport error)], stompSubProtocol[processed CONNECT(0)-CONNECTED(0)-DISCONNECT(0)], stompBrokerRelay[null], inboundChannel[pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 975], outboundChannel[pool
size = 0, active threads = 0, queued tasks = 0, completed tasks = 325], sockJsScheduler[pool size = 1, active threads = 1, queued tasks = 1, completed tasks = 53124]```

Answer 1

It sounds like you might be running a web app container if the web socket setting is not visible.
 
To enable the WebSocket please run the below cmdlet for your site and let us know your results.
 
az webapp config set --web-sockets-enabled true --name <sitename> --resource-group <resourcegroupname>

Answer 2

Revisiting this after a couple of months. We hosted the app on another service and tried to deploy yet again to Azure just for kicks, and websockets worked.
I have not done any changes to the app or in azure.