/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cloudtrace.instrument.thrift;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import cloudtrace.instrument.Span;
import cloudtrace.instrument.Trace;
import cloudtrace.instrument.Tracer;
import cloudtrace.thrift.TInfo;
/**
* To move trace data from client to server, the RPC call must be annotated to take a TInfo object as its first argument. The user can simply pass null, so long
* as they wrap their Client and Service objects with these functions.
*
* <pre>
* Trace.on("remoteMethod");
* Iface c = new Client();
* c = TraceWrap.client(c);
* c.remoteMethod(null, arg2, arg3);
* Trace.off();
* </pre>
*
* The wrapper will see the annotated method and send or re-establish the trace information.
*
* Note that the result of these calls is a Proxy object that conforms to the basic interfaces, but is not your concrete instance.
*
*/
public class TraceWrap {
@SuppressWarnings("unchecked")
public static <T> T service(final T instance) {
InvocationHandler handler = new InvocationHandler() {
@Override
public Object invoke(Object obj, Method method, Object[] args) throws Throwable {
if (args == null || args.length < 1 || args[0] == null || !(args[0] instanceof TInfo)) {
return method.invoke(instance, args);
}
Span span = Trace.trace((TInfo) args[0], method.getName());
try {
return method.invoke(instance, args);
} catch (InvocationTargetException ex) {
throw ex.getCause();
} finally {
span.stop();
}
}
};
return (T) Proxy.newProxyInstance(instance.getClass().getClassLoader(), instance.getClass().getInterfaces(), handler);
}
@SuppressWarnings("unchecked")
public static <T> T client(final T instance) {
InvocationHandler handler = new InvocationHandler() {
@Override
public Object invoke(Object obj, Method method, Object[] args) throws Throwable {
if (args == null || args.length < 1 || args[0] != null) {
return method.invoke(instance, args);
}
Class<?> klass = method.getParameterTypes()[0];
if (TInfo.class.isAssignableFrom(klass)) {
args[0] = Tracer.traceInfo();
}
Span span = Trace.start("client:" + method.getName());
try {
return method.invoke(instance, args);
} catch (InvocationTargetException ex) {
throw ex.getCause();
} finally {
span.stop();
}
}
};
return (T) Proxy.newProxyInstance(instance.getClass().getClassLoader(), instance.getClass().getInterfaces(), handler);
}
}