[KARAF-7804] Cannot register more than one HTTP proxy

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.5.0, 4.4.6
• Component/s: karaf
• Target Version/s: 4.5.0, 4.4.6
• Assignee: Jean-Baptiste Onofré
• Reporter: Aleksy Wróblewski
• Created: 26/Jan/24 13:06
• Updated: 28/Mar/24 13:44
• Resolved: 28/Mar/24 13:44

Description

When you register more than one proxy into ProxyService, it crashes with the following exception:

 

org.osgi.service.http.NamespaceException: ServletModel{id=ServletModel-49,name='org.apache.karaf.http.core.internal.proxy.ProxyServlet',alias='/kb',urlPatterns=[/kb/*],servlet=org.apache.karaf.http.core.internal.proxy.ProxyServlet@6bad2ac1,contexts=[

{HS,OCM-48,default,/}]} can't be registered. ServletContextModel\{id=ServletContextModel-2,contextPath='/'} already contains servlet named org.apache.karaf.http.core.internal.proxy.ProxyServlet: ServletModel{id=ServletModel-47,name='org.apache.karaf.http.core.internal.proxy.ProxyServlet',alias='/webconsole',urlPatterns=[/webconsole/*],servlet=org.apache.karaf.http.core.internal.proxy.ProxyServlet@4ce53d9c,contexts=[\{HS,OCM-48,default,/}

]}

 

The important part: already contains servlet named org.apache.karaf.http.core.internal.proxy.ProxyServlet

 

This is because servlet-name is not specified when registering a new ProxyServlet into HttpService. So PAX-WEB defaults to the fully qualified class name, as specified in HTTP whiteboard spec section 140.4. (https://docs.osgi.org/specification/osgi.cmpn/7.0.0/service.http.whiteboard.html#service.http.whiteboard-i21223311). But the class name is the same for subsequent Servlets, so there is a conflict.

This is also easy to see when you modify org.apache.karaf.itests.HttpTest.testProxy to register two proxies and check if both are registered:

@Test
public void testProxy() throws Exception {
executeCommand("http:proxy-add /test1 http://karaf.apache.org");
executeCommand("http:proxy-add /test2 http://karaf.apache.org"); // not added

String output = executeCommand("http:proxy-balancing-list");
System.out.println(output);
assertContains("random", output);
assertContains("round-robin", output);

output = executeCommand("http:proxy-list");
System.out.println(output);
assertContains("/test1", output);
assertContains("/test2", output); // fails
}