Compile-time weaving support for aspects

[jefftap]

Hi, I am attempting to make use of TimedAspect via AspectJ compile-time weaving using the aspectj-maven-plugin. When the aspect code is executed, it throws one of the two errors, depending on what is being executed:

java.lang.NoSuchMethodError: io.micrometer.core.aop.TimedAspect.aspectOf()Lio/micrometer/core/aop/TimedAspect

java.lang.NoSuchMethodException: io.micrometer.core.aop.TimedAspect.aspectOf()

This usually indicates that the AspectJ weaver has not properly processed the aspect code. I am not sure if this is a problem with my own code/configuration, or if it's an issue in Micrometer's jar. The aspect works perfectly fine using Spring AOP, but I would prefer to use AspectJ weaving with @Timed to allow it access to private/protected methods and the other various benefits one gets from AspectJ integration.

Relevant information:

• micrometer-core version: 1.1.1
• Spring Boot version: 2.1.1.RELEASE
• AspectJ verison: 1.9.2
• Java version: 1.8
• aspectj-maven-plugin version: 1.11

aspectj-maven-plugin configuration:

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>aspectj-maven-plugin</artifactId>
                <version>1.11</version>
                <configuration>
                    <complianceLevel>1.8</complianceLevel>
                    <source>1.8</source>
                    <target>1.8</target>
                    <showWeaveInfo>true</showWeaveInfo>
                    <Xlint>ignore</Xlint>
                    <aspectLibraries>
                        <aspectLibrary>
                            <groupId>org.springframework</groupId>
                            <artifactId>spring-aspects</artifactId>
                        </aspectLibrary>
                        <aspectLibrary>
                            <groupId>io.micrometer</groupId>
                            <artifactId>micrometer-core</artifactId>
                        </aspectLibrary>
                    </aspectLibraries>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>test-compile</goal>
                        </goals>
                    </execution>
                </executions>
                <dependencies>
                    <dependency>
                        <groupId>org.aspectj</groupId>
                        <artifactId>aspectjtools</artifactId>
                        <version>${aspectj.version}</version>
                    </dependency>
                </dependencies>
            </plugin>

[jkschneider]

Have you added aspectj weaving to the build section of your POM?

<build>
<plugins>
  <plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>aspectj-maven-plugin</artifactId>
    <executions>
      <execution>
        <goals>
          <goal>compile</goal> 
        </goals>
      </execution>
    </executions>
  </plugin>
</plugins>

[jefftap]

Yes. The aspectj-maven-plugin configuration I posted in my initial post is under <build>/<plugins>.

[jefftap]

My current hypothesis is that the build.gradle file needs the aspectj plugin applied to it. This should cause the Micrometer build to use ajc, which should process the aspect.

[jefftap]

Also, one way to work around this is to write your own aspect that weaves around an annotation and use the Timer methods in there. It still needs to be coupled with Spring, though. Inject the MeterRegistry as a dependency. The bean should be declared in the Spring configuration using the Aspects.aspectOf method to pull in the AspectJ instance, and Spring handles the injection from there.

[izeye]

I don't have much expertise on AspectJ but after some quick research, it seems to require a similar configuration to spring-aspects to support compile-time weaving as already pointed out by @jefftap although I'm not sure there's any plan for compile-time weaving support.

[jefftap]

Looks like spring-aspects.jar compiles with ajc, then. I think the solution to this ticket is to either compile Micrometer with ajc, or improve the documentation on how to get Micrometer to work properly with AspectJ. I can write a small addition to the documentation explaining this, if desired.

[ewencluley]

I am running into the exact same issue as @jefftap. While the compile time weaving seems to succeed, at runtime the aspectOf methods are not there on the TimedAspect classes. The documentation for micrometer suggests the @Timed annotation should be supported using compile time aspectj weaving. (https://micrometer.io/docs/concepts#_the_code_timed_code_annotation)

use in your application either through compile/load time AspectJ weaving or through framework facilities that interpret AspectJ aspects

Would be great to have some documentation on how to get this working.

[Phil-Ba]

I didn't manage to get this working with CTW. As far as I understood it, it seems that micrometer-core is not compiled with the ajc and thus the aspects are missing the required factory methods.
The only solution I found, was to do LTW and have the micrometer-core classes also be woven during load time.
Another solution would be the recompile the micrometer-core jar with the aspectj maven plugin, but this also requires all dependencies...

[Exidex]

The issue still persist. As noted higher it could be resolved by using LTW, but in my case it is not an option because I do not have access to the deployment setup, and the only option is CTW which doesn't work with this library

[innovationhub-asia]

Same issue here, CTW does not work. Is there any plan to support it properly, so CTW will work ?

[venushka]

I've had the same issue with CTW, although I got around this by wrapping the aspect like this for now.

@Aspect
public class MetricsAspect {
  @Around("execution (@io.micrometer.core.annotation.Timed * *.*(..))")
  public Object timedMethod(ProceedingJoinPoint pjp) throws Throwable {
    final TimedAspect timeAspect = new TimedAspect(MetricsServlet.getRegistry());
    return timeAspect.timedMethod(pjp);
  }
}

and adding the following to the aop.xml

<aspectj>
  <aspects>
    <aspect name="com.venushka.metrics.MetricsAspect"/>
  </aspects>
</aspectj>

It would be great if this works out of the box for CTW.