[wildfly-dev] WFLY-2422 or simplifying the remote outbound connection configuration for server to server communication

[Wolf-Dieter Fink]

I start a request for simplifying the configuration for "in EE 
application" clients and get rid of extra cluster configuration and 
repeat properties many times.
Also the client should not need to have knowledge about the server 
topology, there is no need to know how many servers there are or whether 
they are clustered or not.

Starting point in EAP6/WF8 is a application configuration like this:
https://github.com/wildfly/quickstart/blob/master/ejb-multi-server/app-main/ear/src/main/application/META-INF/jboss-ejb-client.xml?

and a server side configuration like this:
             <subsystem xmlns="urn:jboss:domain:remoting:3.0">
                 <endpoint worker="default"/>
                 <http-connector name="http-remoting-connector" 
connector-ref="default" security-realm="ApplicationRealm"/>
                 <outbound-connections>
                     <remote-outbound-connection 
name="remote-ejb-connection-1" 
outbound-socket-binding-ref="remote-ejb-1" username="quickuser1" 
security-realm="ejb-security-realm-1" protocol="http-remoting">
                         <properties>
                             <property name="SASL_POLICY_NOANONYMOUS" 
value="false"/>
                             <property name="SSL_ENABLED" value="false"/>
                         </properties>
                     </remote-outbound-connection>
                     <remote-outbound-connection 
name="remote-ejb-connection-2" 
outbound-socket-binding-ref="remote-ejb-2" username="quickuser2" 
security-realm="ejb-security-realm-2" protocol="http-remoting">
                         <properties>
                             <property name="SASL_POLICY_NOANONYMOUS" 
value="false"/>
                             <property name="SSL_ENABLED" value="false"/>
                         </properties>
                     </remote-outbound-connection>
                 </outbound-connections>
             </subsystem>



Tomasz did some refactoring (WF9) to use a profile from the application 
perspective. The configuration is like this:

jboss-ejb-client.xml
     <client-context>
         <profile name="main-app"/>
     </client-context>

server profile:
                 <remote connector-ref="http-remoting-connector" 
thread-pool-name="default">
                     <profiles>
                         <profile name="main-app">
                             <remoting-ejb-receiver name="AppOneA" 
outbound-connection-ref="remote-ejb-connection-1"/>
                             <remoting-ejb-receiver name="AppTwoA" 
outbound-connection-ref="remote-ejb-connection-2"/>
                         </profile>
                     </profiles>
                 </remote>
....
             <subsystem xmlns="urn:jboss:domain:remoting:3.0">
                 <outbound-connections>
                     <remote-outbound-connection 
name="remote-ejb-connection-1" 
outbound-socket-binding-ref="remote-ejb-1" username="quickuser1" 
security-realm="ejb-security-realm-1" protocol="http-remoting">
                         <properties>
                             <property name="SASL_POLICY_NOANONYMOUS" 
value="false"/>
                             <property name="SSL_ENABLED" value="false"/>
                         </properties>
                     </remote-outbound-connection>
                     <remote-outbound-connection 
name="remote-ejb-connection-2" 
outbound-socket-binding-ref="remote-ejb-2" username="quickuser2" 
security-realm="ejb-security-realm-2" protocol="http-remoting">
                         <properties>
                             <property name="SASL_POLICY_NOANONYMOUS" 
value="false"/>
                             <property name="SSL_ENABLED" value="false"/>
                         </properties>
                     </remote-outbound-connection>
                 </outbound-connections>
             </subsystem>


With the current implementation there are some issues or 
concerns/enhancements
- profile does not work with clusters
- not possible to have multiple profiles
- the properties/user must be still repeated



 From my point of view
- a cluster need to have the same property configuration, also different 
users make no sense. Might work, but at least the cluster view will use 
the same user
- a similar group of servers for the same application should not have 
different properties/users as this will be error prone
- configuration should be as small and intuitive as possible

My initial idea was to have a jboss-ejb-client.xml which reference 
'applications' to connect, that is similar to profiles
The server side as followed (don't care about the exact XML elements or 
names)

             <subsystem xmlns="urn:jboss:domain:remoting:3.0">
                 <outbound-connections>
                     <profile name="App1" username="quickuser1" 
security-realm="ejb-security-realm-1" protocol="http-remoting">
                         <properties>
                             <property name="SASL_POLICY_NOANONYMOUS" 
value="false"/>
                             <property name="SSL_ENABLED" value="false"/>
                         </properties>
<outbound-sockets>remote-ejb-1,remote-ejb2</outbound-sockets> <!-- 
repeated elements seems better -->
                     </remote-outbound-connection>
                     <remote-outbound-connection 
name="remote-ejb-connection-X" 
outbound-socket-binding-ref="remote-ejb-X" username="quickuser2" 
security-realm="ejb-security-realm-2" protocol="http-remoting">
                         <properties>
                             <property name="SASL_POLICY_NOANONYMOUS" 
value="false"/>
                             <property name="SSL_ENABLED" value="false"/>
                         </properties>
                     </remote-outbound-connection>
                 </outbound-connections>
             </subsystem>

In this case the profile use the user/security and properties for all 
connections and the cluster as well. In this it is necessary to have the 
same configuration for all the servers in the profile-bunch.
Another option I thought about is to use the user/properties in 
<profile> as default and have the possibility to use a inner element 
remote-outbound-connection, or a reference to remote-outbound-connection 
which can override these, but I'm not sure whether this is needed.

We (Tomasz Adamski and me) had a discussion about this and, technically 
there is no problem with each approach.

But ...

I know that all the ejb-client stuff is subject to change and to prevent 
from incompatible changes which are changed in every version
and from unnecessary work if the code will be changed before it will be 
used at all
I think it will need to be discussed with others because of this.

cheers
Wolf