Compile-time and load-time weaving support for aspects

build.gradle

@@ -126,7 +126,7 @@ subprojects {
 
 
             javadoc {
-                if (project.name.contains('samples')) {
+                if (project.name.contains('samples') || project.name.contains("-test-aspectj")) {
                     enabled = false
                 } else {
                     configure(options) {
@@ -289,7 +289,7 @@ subprojects {
     }
 
     // Do not publish some modules
-    if (!['samples', 'benchmarks', 'micrometer-osgi-test', 'concurrency-tests'].find { project.name.contains(it) }) {
+    if (!['samples', 'benchmarks', 'micrometer-osgi-test', 'concurrency-tests', 'micrometer-test-aspectj-ctw', 'micrometer-test-aspectj-ltw'].find { project.name.contains(it) }) {
         apply plugin: 'com.netflix.nebula.maven-publish'
         apply plugin: 'com.netflix.nebula.maven-manifest'
         apply plugin: 'com.netflix.nebula.maven-developer'
@@ -337,7 +337,7 @@ subprojects {
 
             check.dependsOn("testModules")
 
-            if (!(project.name in [])) { // add projects here that do not exist in the previous minor so should be excluded from japicmp
+            if (!(project.name in ['micrometer-test-aspectj-ltw', 'micrometer-test-aspectj-ctw'])) { // add projects here that do not exist in the previous minor so should be excluded from japicmp
                 apply plugin: 'me.champeau.gradle.japicmp'
                 apply plugin: 'de.undercouch.download'
 

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ activemq-artemis = "2.34.0"
 application-insights = "2.6.4"
 archunit = "1.3.0"
 asmForPlugins = "7.3.1"
-aspectjweaver = "1.9.22.1"
+aspectjweaver = "1.9.20.1"
 assertj = "3.26.0"
 awaitility = "4.2.1"
 caffeine = "2.9.3"
@@ -89,6 +89,7 @@ activemqArtemisJunit5 = { module = "org.apache.activemq:artemis-junit-5", versio
 applicationInsights = { module = "com.microsoft.azure:applicationinsights-core", version.ref = "application-insights" }
 archunitJunit5 = { module = "com.tngtech.archunit:archunit-junit5", version.ref = "archunit" }
 asmForPlugins = { module = "org.ow2.asm:asm", version.ref = "asmForPlugins" }
+aspectjrt = { module = "org.aspectj:aspectjrt", version.ref = "aspectjweaver" }
 aspectjweaver = { module = "org.aspectj:aspectjweaver", version.ref = "aspectjweaver" }
 assertj = { module = "org.assertj:assertj-core", version.ref = "assertj" }
 awaitility = { module = "org.awaitility:awaitility", version.ref = "awaitility" }
@@ -232,3 +233,4 @@ plugin-bnd = "biz.aQute.bnd:biz.aQute.bnd.gradle:6.4.0"
 kotlin19 = { id = "org.jetbrains.kotlin.jvm", version = "1.9.23" }
 kotlin17 = { id = "org.jetbrains.kotlin.jvm", version = "1.7.22" }
 jcstress = { id = "io.github.reyerizo.gradle.jcstress", version = "0.8.15" }
+aspectj = { id = 'io.freefair.aspectj.post-compile-weaving', version = '8.6' }

micrometer-core/build.gradle

@@ -1,5 +1,6 @@
 plugins {
     alias(libs.plugins.kotlin19)
+    alias(libs.plugins.aspectj)
     id 'me.champeau.mrjar' version "0.1.1"
 }
 
@@ -81,7 +82,8 @@ dependencies {
     }
 
     // Aspects
-    optionalApi 'org.aspectj:aspectjweaver'
+    optionalApi libs.aspectjrt
+    java11RuntimeOnly libs.aspectjrt
 
     // instrumentation options
     optionalApi 'io.dropwizard.metrics:metrics-core' // TODO move dropwizard out of core module? DropwizardMeterRegistry for e.g. JMX registry
@@ -209,6 +211,8 @@ dependencies {
     testImplementation 'io.grpc:grpc-inprocess'
     testImplementation 'io.grpc:grpc-testing-proto'
     testImplementation 'com.squareup.retrofit2:retrofit'
+
+    testImplementation 'org.aspectj:aspectjweaver'
 }
 
 task shenandoahTest(type: Test) {

micrometer-core/src/main/java/io/micrometer/core/aop/CountedAspect.java

@@ -167,7 +167,7 @@ public CountedAspect(MeterRegistry registry, Function<ProceedingJoinPoint, Itera
         this.shouldSkip = shouldSkip;
     }
 
-    @Around("@within(io.micrometer.core.annotation.Counted) and not @annotation(io.micrometer.core.annotation.Counted)")
+    @Around("@within(io.micrometer.core.annotation.Counted) && !@annotation(io.micrometer.core.annotation.Counted) && execution(* *(..))")
     @Nullable
     public Object countedClass(ProceedingJoinPoint pjp) throws Throwable {
         if (shouldSkip.test(pjp)) {
@@ -202,7 +202,7 @@ public Object countedClass(ProceedingJoinPoint pjp) throws Throwable {
      * @return Whatever the intercepted method returns.
      * @throws Throwable When the intercepted method throws one.
      */
-    @Around(value = "@annotation(counted)", argNames = "pjp,counted")
+    @Around(value = "@annotation(counted) && execution(* *(..))", argNames = "pjp,counted")
     @Nullable
     public Object interceptAndRecord(ProceedingJoinPoint pjp, Counted counted) throws Throwable {
         if (shouldSkip.test(pjp)) {

micrometer-core/src/main/java/io/micrometer/core/aop/TimedAspect.java

@@ -161,7 +161,7 @@ public TimedAspect(MeterRegistry registry, Function<ProceedingJoinPoint, Iterabl
         this.shouldSkip = shouldSkip;
     }
 
-    @Around("@within(io.micrometer.core.annotation.Timed) and not @annotation(io.micrometer.core.annotation.Timed)")
+    @Around("@within(io.micrometer.core.annotation.Timed) && !@annotation(io.micrometer.core.annotation.Timed) && execution(* *(..))")
     @Nullable
     public Object timedClass(ProceedingJoinPoint pjp) throws Throwable {
         if (shouldSkip.test(pjp)) {

micrometer-observation/build.gradle

@@ -1,3 +1,7 @@
+plugins {
+    alias(libs.plugins.aspectj)
+}
+
 description 'Module containing Observation related code'
 
 jar {
@@ -21,7 +25,7 @@ dependencies {
     optionalApi 'javax.servlet:javax.servlet-api'
 
     // Aspects
-    optionalApi 'org.aspectj:aspectjweaver'
+    optionalApi libs.aspectjrt
 
     // log monitoring
     testImplementation 'ch.qos.logback:logback-classic'
@@ -42,4 +46,5 @@ dependencies {
 
     testImplementation 'org.assertj:assertj-core'
     testImplementation 'org.awaitility:awaitility'
+    testImplementation 'org.aspectj:aspectjweaver'
 }

micrometer-observation/src/main/java/io/micrometer/observation/Observations.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2024 VMware, Inc.
+ *
+ * Licensed 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
+ *
+ * https://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 io.micrometer.observation;
+
+import io.micrometer.common.lang.Nullable;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Generator of observations bound to a static global registry. For use especially in
+ * places where dependency injection of {@link ObservationRegistry} is not possible for an
+ * instrumented type.
+ *
+ * @author Marcin Grzejszczak
+ * @since 1.14.0
+ */
+public final class Observations {
+
+    private static final ObservationRegistry initialRegistry = ObservationRegistry.create();
+
+    private static final DelegatingObservationRegistry globalRegistry = new DelegatingObservationRegistry(
+            initialRegistry);
+
+    private Observations() {
+        throw new UnsupportedOperationException("You can't instantiate a utility class");
+    }
+
+    /**
+     * Sets a registry as the global registry.
+     * @param registry Registry to set.
+     */
+    public static void setRegistry(ObservationRegistry registry) {
+        globalRegistry.setDelegate(registry);
+    }
+
+    /**
+     * Resets registry to the original, empty one.
+     */
+    public static void resetRegistry() {
+        globalRegistry.setDelegate(initialRegistry);
+    }
+
+    /**
+     * Retrieves the current global instance.
+     * @return Global registry.
+     */
+    public static ObservationRegistry getGlobalRegistry() {
+        return globalRegistry;
+    }
+
+    private static final class DelegatingObservationRegistry implements ObservationRegistry {
+
+        private final AtomicReference<ObservationRegistry> delegate = new AtomicReference<>(ObservationRegistry.NOOP);
+
+        DelegatingObservationRegistry(ObservationRegistry delegate) {
+            setDelegate(delegate);
+        }
+
+        void setDelegate(ObservationRegistry delegate) {
+            this.delegate.set(Objects.requireNonNull(delegate, "Delegate must not be null"));
+        }
+
+        @Nullable
+        @Override
+        public Observation getCurrentObservation() {
+            return delegate.get().getCurrentObservation();
+        }
+
+        @Nullable
+        @Override
+        public Observation.Scope getCurrentObservationScope() {
+            return delegate.get().getCurrentObservationScope();
+        }
+
+        @Override
+        public void setCurrentObservationScope(@Nullable Observation.Scope current) {
+            delegate.get().setCurrentObservationScope(current);
+        }
+
+        @Override
+        public ObservationConfig observationConfig() {
+            return delegate.get().observationConfig();
+        }
+
+        @Override
+        public boolean isNoop() {
+            return delegate.get().isNoop();
+        }
+
+    }
+
+}

micrometer-observation/src/main/java/io/micrometer/observation/aop/ObservedAspect.java

@@ -19,6 +19,7 @@
 import io.micrometer.common.lang.Nullable;
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationRegistry;
+import io.micrometer.observation.Observations;
 import io.micrometer.observation.annotation.Observed;
 import io.micrometer.observation.ObservationConvention;
 import org.aspectj.lang.ProceedingJoinPoint;
@@ -84,6 +85,11 @@ public class ObservedAspect {
 
     private final Predicate<ProceedingJoinPoint> shouldSkip;
 
+    // For Compile Time Weaving
+    public ObservedAspect() {
+        this(Observations.getGlobalRegistry(), null, DONT_SKIP_ANYTHING);
+    }
+
     public ObservedAspect(ObservationRegistry registry) {
         this(registry, null, DONT_SKIP_ANYTHING);
     }
@@ -105,7 +111,7 @@ public ObservedAspect(ObservationRegistry registry,
         this.shouldSkip = shouldSkip;
     }
 
-    @Around("@within(io.micrometer.observation.annotation.Observed) and not @annotation(io.micrometer.observation.annotation.Observed)")
+    @Around("@within(io.micrometer.observation.annotation.Observed) && !@annotation(io.micrometer.observation.annotation.Observed) && execution(* *.*(..))")
     @Nullable
     public Object observeClass(ProceedingJoinPoint pjp) throws Throwable {
         if (shouldSkip.test(pjp)) {

micrometer-observation/src/test/java/io/micrometer/observation/aop/ObservedAspectTests.java

@@ -364,7 +364,8 @@ void skipPredicateShouldTakeEffectForClass() {
     void ignoreClassLevelAnnotationIfMethodLevelPresent() {
         registry.observationConfig().observationHandler(new ObservationTextPublisher());
 
-        AspectJProxyFactory pf = new AspectJProxyFactory(new ObservedClassLevelAnnotatedService());
+        ObservedClassLevelAnnotatedService annotatedService = new ObservedClassLevelAnnotatedService();
+        AspectJProxyFactory pf = new AspectJProxyFactory(annotatedService);
         pf.addAspect(new ObservedAspect(registry));
 
         ObservedClassLevelAnnotatedService service = pf.getProxy();

settings.gradle

@@ -31,7 +31,7 @@ include 'micrometer-commons', 'micrometer-core', 'micrometer-observation'
     project(":micrometer-samples-$sample").projectDir = new File(rootProject.projectDir, "samples/micrometer-samples-$sample")
 }
 
-include 'micrometer-test', 'micrometer-observation-test'
+include 'micrometer-test', 'micrometer-observation-test', 'micrometer-test-aspectj-ltw', 'micrometer-test-aspectj-ctw'
 
 ['atlas', 'prometheus', 'prometheus-simpleclient', 'datadog', 'elastic', 'ganglia', 'graphite', 'health', 'jmx', 'influx', 'otlp', 'statsd', 'new-relic', 'cloudwatch2', 'signalfx', 'wavefront', 'dynatrace', 'azure-monitor', 'humio', 'appoptics', 'kairos', 'stackdriver', 'opentsdb'].each { sys ->
     include "micrometer-registry-$sys"

tests/micrometer-test-aspectj-ctw/build.gradle

@@ -0,0 +1,19 @@
+plugins {
+    id 'java'
+    alias(libs.plugins.aspectj)
+}
+
+description 'AspectJ compile-time weaving test for Micrometer aspects'
+
+dependencies {
+    implementation project(':micrometer-core')
+    aspect project(':micrometer-core')
+    aspect project(':micrometer-observation')
+
+    testImplementation libs.junitJupiter
+    testImplementation libs.assertj
+}
+
+test {
+    useJUnitPlatform()
+}

tests/micrometer-test-aspectj-ctw/src/main/java/io/micrometer/test/ctw/MeasuredClass.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2024 VMware, Inc.
+ *
+ * Licensed 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
+ *
+ * https://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 io.micrometer.test.ctw;
+
+import io.micrometer.core.annotation.Counted;
+import io.micrometer.core.annotation.Timed;
+import io.micrometer.observation.annotation.Observed;
+
+@Observed
+@Counted
+@Timed
+public class MeasuredClass {
+
+    @Timed
+    public void timedMethod() {
+    }
+
+    @Counted
+    public void countedMethod() {
+    }
+
+    @Observed
+    public void observedMethod() {
+    }
+
+    public void classLevelTimedMethod() {
+    }
+
+    public void classLevelCountedMethod() {
+    }
+
+    public void classLevelObservedMethod() {
+    }
+
+}

tests/micrometer-test-aspectj-ctw/src/main/java/io/micrometer/test/ctw/package-info.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2024 VMware, Inc.
+ *
+ * Licensed 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
+ *
+ * https://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.
+ */
+@NonNullApi
+@NonNullFields
+package io.micrometer.test.ctw;
+
+import io.micrometer.common.lang.NonNullApi;
+import io.micrometer.common.lang.NonNullFields;