Intercept methods with logic based on annotations
fuudtor...@gmail.com
I want to extract some aop-like things that are spread all around my code into Instrumentation(s).
For example:
public class MyController{
public void authUser(@MdcValue("account") String account, ...){
...
}
}
I want to intercept all methods that have at least one parameter annotated with @MdcValue and put such parameters into logging context.
There are many such methods thus it should work as fast as current non-extracted implementation:
public class MyController{
public void authUser(String account, ...){
try (MdcCloseable ignored = Mdc.put("account", account)){
...
}
}
}
Because of performance reasons I do not want to parse annotations or construct Method instance on each call.
I implemented first solution. I use
intercept(
Advice
.withCustomMapping()
.bind(InjectRandomId.class, new RandomIdInjector())
.to(MdcValueProcessor.class)
)
RandomIdInjector used to add unique id to each method and be able to store actions it map:
public class MdcValueProcessor {
private static final ConcurrentMap<String, MdcProcessor> idToProcessor = new ConcurrentHashMap<>();
@Advice.OnMethodEnter
public static AutoCloseable onMethodEnter(
@Advice.Origin("#t") String instrumentedClass, // #t means class name. @e can inject Method but it will require Class.getDeclaredMethod call on each request. Let's optimize
@Advice.Origin() String methodAsString, // no params means Method.toString - the simplest way - use method.toString to distinguish methods with different signatures
@InjectRandomId String id, // this id will be uniq for each instrumented method
@Advice.AllArguments Object[] allArguments) throws Exception {
return onMethodEnterImpl(instrumentedClass, methodAsString, id, allArguments);
}
@Advice.OnMethodExit(onThrowable = Throwable.class) // on regular exit and on any exception
public static void onMethodExit(@Advice.Enter AutoCloseable closeMdc) throws Exception {
closeMdc.close();
}
// this method is intended to help with debug because @Advice.OnMethodEnter will be inlined and line info will be loss.
// It should be public because it will be invoked from inline code
public static AutoCloseable onMethodEnterImpl(String clazz, String method, String id, @Advice.AllArguments Object[] values) {
...
}
}
Now I want to optimize and clear this code.
I want to inject static final Processors[] field to intstrumented class and initialize it on clinit.
I can add field with:
.defineField("processors", Object[].class, FieldManifestation.FINAL, Visibility.PUBLIC, Ownership.STATIC)
But I do not know how to move further.
Q1: How to add <clinit> with static field initialization?
Q2: How to pass this field to Advice?
Thankyou.
Feodor Bobin
fuudtor...@gmail.com
Rafael Winterhalter
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fuudtor...@gmail.com
1. I want use final field (to maintain concurrency guarantees). Thus I need to initialize field in clinit block. How can I add it with bytebuddy?
2. I want use random field name. I need FieldDescription to inject field to Advice, don't I? How can get FieldDescription from AgentBuilder.defineField?
Thank you,
Feodor
Rafael Winterhalter
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Fedor Bobin
Feodor
Rafael Winterhalter
Fedor Bobin
I am getting
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