MODCLUSTER-798 Fix handling of offseted ports

[jajik]

https://issues.redhat.com/browse/MODCLUSTER-798

This PR makes it work when portOffset for tomcats 8.5 and 9.0. No fix is required for tomcat-10.1 which seems strange, however, I was not able to determine why tomcat-10.1 behaves differently. Because of this I believe the fix can be made better by someone who understand the codebase better.

This is the server.xml I used

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN" address="127.0.0.1" portOffset="port_offset">
  <Listener className="org.jboss.modcluster.container.catalina.standalone.ModClusterListener"
              connectorPort="8080"
              advertise="false"
              stickySession="true"
              stickySessionForce="false"
              stickySessionRemove="true"
              proxyList="127.0.0.1:6666" />
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <GlobalNamingResources>
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

  <Service name="Catalina">
    <Connector port="8080" protocol="HTTP/1.1"
               address="127.0.0.1"
               connectionTimeout="20000"
               redirectPort="8443"
               portOffset="port_offset" />
    
    <Connector protocol="AJP/1.3"
               address="127.0.0.1"
               port="8009"
               secretRequired="false"
               redirectPort="8443"
               portOffset="port_offset" />
   
    <Engine name="Catalina" defaultHost="localhost">

      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">

        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>
    </Engine>
  </Service>
</Server>

with tomcat1 running on 127.0.0.1:8080 (offset 0) and tomcat2 on 127.0.0.1:8081 (offset 1). Without these changes, proxy gets CONFIG message for tomcat2 with port 8080. Alternatively, I could change connectorPort for tomcat2 to 8081, but that would cause some issues in createProxyConnector function (e.g., connectorPort.equals(connector.getPort())).

Edit: Fix formatting.

[rhusar]

Looks like portOffset is not widely used setting since noone reported this bug before. Anyway, I ll have a look, but the general fix looks about right.

[jajik]

Thanks a lot! (I would be more confident about the fix if tomcat-10.1 would require it too.)

[rhusar]

Thanks @jajik - I could reproduce this with Tomcat 10 no problem. That needs fixing too - replaced by #762

[jajik]

Ok, glad to hear that, now it makes sense 🙂