Hi Sandeep,
thank you for your answer!
Ok so I tried to change my project and adding a simple class like this:
package com.test.ext;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.knox.gateway.config.Configure;
import org.apache.knox.gateway.config.Default;
import org.apache.knox.gateway.dispatch.AbstractGatewayDispatch;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class MyDispatch extends AbstractGatewayDispatch {
private static final Logger LOG =
LoggerFactory.getLogger(MyDispatch.class);
@Override
public void destroy() {
LOG.debug("******* destroy()");
}
@Configure
protected void customMethod(@Default("Test") String test) {
LOG.debug("******* @Configure customMethod(): {}", test);
}
@Override
public void doGet(URI url, HttpServletRequest request,
HttpServletResponse response)
throws IOException, URISyntaxException {
LOG.debug("******* doGet() request: {}, {}",
request.getMethod(), new URI(request.getRequestURI()));
super.doGet(url, request, response);
}
}
made the ".jar" and put in the "ext" folder.
Executed the REST request again:
curl -i -k -u admin:admin-password -X GET
'https://localhost:8443/gateway/sandbox/webhdfs/v1/?op=LISTSTATUS'
and I expected to see some logs, e.g. from the "doGet()" method (I'm not
sure about the "@Configure" method, when should a method with that
annotation be executed?), but it seems it does not see the class.
So I tried to configure my topology to use the dispatch (as written on [1]):
<service>
<role>WEBHDFS</role>
<url>http://hadoop-namenode:50070/webhdfs</url>
<dispatch>
<classname>com.test.ext.MyDispatch</classname>
<use-two-way-ssl>false</use-two-way-ssl>
</dispatch>
</service>
and after saving logs say:
ERROR knox.gateway (GatewayFilter.java:doFilter(170)) - Gateway
processing failed: javax.servlet.ServletException:
org.apache.shiro.subject.ExecutionException:
java.security.PrivilegedActionException: javax.servlet.ServletException:
javax.servlet.ServletException: java.lang.ClassNotFoundException:
com.test.ext.MyDispatch
javax.servlet.ServletException:
org.apache.shiro.subject.ExecutionException:
java.security.PrivilegedActionException: javax.servlet.ServletException:
javax.servlet.ServletException: *java.lang.ClassNotFoundException:
com.test.ext.MyDispatch*
so it's not seeing my class.
What am I missing?
Thank you!
Matteo
[1] https://knox.apache.org/books/knox-1-3-0/dev-guide.html#service.xml
On 14/03/19 20:47, Sandeep Moré wrote:
Hello Matteo,
I don't think this is a right way to add filters to Knox, if you want
to add some custom logic between your Knox and the backend you can
write custom dispatch [1]
you can add this new jar in the ext folder and it should be picked up
by Knox on start-up.
[1]
https://knox.apache.org/books/knox-1-3-0/dev-guide.html#Custom+Dispatch+Dependency+Injection
On Thu, Mar 14, 2019 at 12:52 PM Matteo Alessandroni
<[email protected] <mailto:[email protected]>> wrote:
Hi,
I'm trying to add a filter on a Knox instance so that I'll be able
to add a custom logic to (every / specific) REST requests to Knox.
I thought to use the "Class Path" feature [1], so I created a
Maven Java project, generated a ".jar" file and placed it in the
"$GATEWAY_HOME/ext" folder
Then, I thought it was necessary to link my custom class [2] on
the "gateway.xml" files of the resources I wanted, e.g.
./data/deployments/sandbox.topo.16977ef2478/%2F/WEB-INF/gateway.xml
added:
<filter>
<role>rewrite</role>
<name>url-rewrite</name>
<class>com.test.knox.MyUrlRewriteServletFilter</class>
</filter>
then I made a REST request to Knox:
curl -i -k -u admin:admin-password -X GET
'https://localhost:8443/gateway/sandbox/webhdfs/v1/?op=LISTSTATUS'
but my filter is not called at all (I cannot see the log) and I'm
not sure whether it's because the class is not loaded or the
filter is placed in the wrong place or whatever.
On [4] you can see the project I have built.
So my questions are:
* what am I doing wrong or missing?
* is there a better way to do that? I just need to add a logic
when executing REST requests to Knox and make another REST
call to an external service I need.
Thank you!
Regards,
Matteo
[1] https://knox.apache.org/books/knox-1-2-0/dev-guide.html#Class+Path
[2]
https://github.com/mat-ale/apache-knox-filter/blob/master/src/main/java/com/plainid/ext/MyUrlRewriteServletFilter.java
[3]
[4] https://github.com/mat-ale/apache-knox-filter
