聊聊skywalking的AbstractPlatformTransactionManagerInstrumentation

序

本文主要研究一下skywalking的AbstractPlatformTransactionManagerInstrumentation

AbstractPlatformTransactionManagerInstrumentation

skywalking-6.6.0/apm-sniffer/optional-plugins/optional-spring-plugins/spring-tx-plugin/src/main/java/org/apache/skywalking/apm/plugin/spring/transaction/define/AbstractPlatformTransactionManagerInstrumentation.java

public class AbstractPlatformTransactionManagerInstrumentation extends ClassInstanceMethodsEnhancePluginDefine {

    @Override
    public ConstructorInterceptPoint[] getConstructorsInterceptPoints() {
        return new ConstructorInterceptPoint[0];
    }

    @Override
    public InstanceMethodsInterceptPoint[] getInstanceMethodsInterceptPoints() {
        return new InstanceMethodsInterceptPoint[]{
            new InstanceMethodsInterceptPoint() {
                @Override
                public ElementMatcher<MethodDescription> getMethodsMatcher() {
                    return named("getTransaction");
                }

                @Override
                public String getMethodsInterceptor() {
                    return "org.apache.skywalking.apm.plugin.spring.transaction.GetTransactionMethodInterceptor";
                }

                @Override
                public boolean isOverrideArgs() {
                    return false;
                }
            }, new InstanceMethodsInterceptPoint() {
                @Override
                public ElementMatcher<MethodDescription> getMethodsMatcher() {
                    return named("commit").or(named("rollback"));
                }

                @Override
                public String getMethodsInterceptor() {
                    return "org.apache.skywalking.apm.plugin.spring.transaction.EndTransactionMethodInterceptor";
                }

                @Override
                public boolean isOverrideArgs() {
                    return false;
                }
            }
        };
    }

    @Override
    public ClassMatch enhanceClass() {
        return byName("org.springframework.transaction.support.AbstractPlatformTransactionManager");
    }
}

• AbstractPlatformTransactionManagerInstrumentation繼承了ClassInstanceMethodsEnhancePluginDefine，其getInstanceMethodsInterceptPoints方法建立了InstanceMethodsInterceptPoint數組，其中一個InstanceMethodsInterceptPoint的getMethodsMatcher爲named("getTransaction")，getMethodsInterceptor返回org.apache.skywalking.apm.plugin.spring.transaction.GetTransactionMethodInterceptor；另一個InstanceMethodsInterceptPoint的getMethodsMatcher爲named("commit").or(named("rollback")，getMethodsInterceptor返回的是org.apache.skywalking.apm.plugin.spring.transaction.EndTransactionMethodInterceptor；其enhanceClass方法返回的是byName("org.springframework.transaction.support.AbstractPlatformTransactionManager")

ClassInstanceMethodsEnhancePluginDefine

skywalking-6.6.0/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/interceptor/enhance/ClassInstanceMethodsEnhancePluginDefine.java

public abstract class ClassInstanceMethodsEnhancePluginDefine extends ClassEnhancePluginDefine {

    /**
     * @return null, means enhance no static methods.
     */
    @Override
    public StaticMethodsInterceptPoint[] getStaticMethodsInterceptPoints() {
        return null;
    }

}

• ClassInstanceMethodsEnhancePluginDefine繼承了ClassEnhancePluginDefine，其getStaticMethodsInterceptPoints方法返回null

ClassEnhancePluginDefine

skywalking-6.6.0/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/interceptor/enhance/ClassEnhancePluginDefine.java

public abstract class ClassEnhancePluginDefine extends AbstractClassEnhancePluginDefine {
    private static final ILog logger = LogManager.getLogger(ClassEnhancePluginDefine.class);

    /**
     * New field name.
     */
    public static final String CONTEXT_ATTR_NAME = "_$EnhancedClassField_ws";

    /**
     * Begin to define how to enhance class. After invoke this method, only means definition is finished.
     *
     * @param typeDescription target class description
     * @param newClassBuilder byte-buddy's builder to manipulate class bytecode.
     * @return new byte-buddy's builder for further manipulation.
     */
    @Override
    protected DynamicType.Builder<?> enhance(TypeDescription typeDescription,
        DynamicType.Builder<?> newClassBuilder, ClassLoader classLoader,
        EnhanceContext context) throws PluginException {
        newClassBuilder = this.enhanceClass(typeDescription, newClassBuilder, classLoader);

        newClassBuilder = this.enhanceInstance(typeDescription, newClassBuilder, classLoader, context);

        return newClassBuilder;
    }

    /**
     * Enhance a class to intercept constructors and class instance methods.
     *
     * @param typeDescription target class description
     * @param newClassBuilder byte-buddy's builder to manipulate class bytecode.
     * @return new byte-buddy's builder for further manipulation.
     */
    private DynamicType.Builder<?> enhanceInstance(TypeDescription typeDescription,
        DynamicType.Builder<?> newClassBuilder, ClassLoader classLoader,
        EnhanceContext context) throws PluginException {
        ConstructorInterceptPoint[] constructorInterceptPoints = getConstructorsInterceptPoints();
        InstanceMethodsInterceptPoint[] instanceMethodsInterceptPoints = getInstanceMethodsInterceptPoints();
        String enhanceOriginClassName = typeDescription.getTypeName();
        boolean existedConstructorInterceptPoint = false;
        if (constructorInterceptPoints != null && constructorInterceptPoints.length > 0) {
            existedConstructorInterceptPoint = true;
        }
        boolean existedMethodsInterceptPoints = false;
        if (instanceMethodsInterceptPoints != null && instanceMethodsInterceptPoints.length > 0) {
            existedMethodsInterceptPoints = true;
        }

        /**
         * nothing need to be enhanced in class instance, maybe need enhance static methods.
         */
        if (!existedConstructorInterceptPoint && !existedMethodsInterceptPoints) {
            return newClassBuilder;
        }

        /**
         * Manipulate class source code.<br/>
         *
         * new class need:<br/>
         * 1.Add field, name {@link #CONTEXT_ATTR_NAME}.
         * 2.Add a field accessor for this field.
         *
         * And make sure the source codes manipulation only occurs once.
         *
         */
        if (!context.isObjectExtended()) {
            newClassBuilder = newClassBuilder.defineField(CONTEXT_ATTR_NAME, Object.class, ACC_PRIVATE | ACC_VOLATILE)
                .implement(EnhancedInstance.class)
                .intercept(FieldAccessor.ofField(CONTEXT_ATTR_NAME));
            context.extendObjectCompleted();
        }

        /**
         * 2. enhance constructors
         */
        if (existedConstructorInterceptPoint) {
            for (ConstructorInterceptPoint constructorInterceptPoint : constructorInterceptPoints) {
                if (isBootstrapInstrumentation()) {
                    newClassBuilder = newClassBuilder.constructor(constructorInterceptPoint.getConstructorMatcher()).intercept(SuperMethodCall.INSTANCE
                        .andThen(MethodDelegation.withDefaultConfiguration()
                            .to(BootstrapInstrumentBoost.forInternalDelegateClass(constructorInterceptPoint.getConstructorInterceptor()))
                        )
                    );
                } else {
                    newClassBuilder = newClassBuilder.constructor(constructorInterceptPoint.getConstructorMatcher()).intercept(SuperMethodCall.INSTANCE
                        .andThen(MethodDelegation.withDefaultConfiguration()
                            .to(new ConstructorInter(constructorInterceptPoint.getConstructorInterceptor(), classLoader))
                        )
                    );
                }
            }
        }

        /**
         * 3. enhance instance methods
         */
        if (existedMethodsInterceptPoints) {
            for (InstanceMethodsInterceptPoint instanceMethodsInterceptPoint : instanceMethodsInterceptPoints) {
                String interceptor = instanceMethodsInterceptPoint.getMethodsInterceptor();
                if (StringUtil.isEmpty(interceptor)) {
                    throw new EnhanceException("no InstanceMethodsAroundInterceptor define to enhance class " + enhanceOriginClassName);
                }
                ElementMatcher.Junction<MethodDescription> junction = not(isStatic()).and(instanceMethodsInterceptPoint.getMethodsMatcher());
                if (instanceMethodsInterceptPoint instanceof DeclaredInstanceMethodsInterceptPoint) {
                    junction = junction.and(ElementMatchers.<MethodDescription>isDeclaredBy(typeDescription));
                }
                if (instanceMethodsInterceptPoint.isOverrideArgs()) {
                    if (isBootstrapInstrumentation()) {
                        newClassBuilder =
                            newClassBuilder.method(junction)
                                .intercept(
                                    MethodDelegation.withDefaultConfiguration()
                                        .withBinders(
                                            Morph.Binder.install(OverrideCallable.class)
                                        )
                                        .to(BootstrapInstrumentBoost.forInternalDelegateClass(interceptor))
                                );
                    } else {
                        newClassBuilder =
                            newClassBuilder.method(junction)
                                .intercept(
                                    MethodDelegation.withDefaultConfiguration()
                                        .withBinders(
                                            Morph.Binder.install(OverrideCallable.class)
                                        )
                                        .to(new InstMethodsInterWithOverrideArgs(interceptor, classLoader))
                                );
                    }
                } else {
                    if (isBootstrapInstrumentation()) {
                        newClassBuilder =
                            newClassBuilder.method(junction)
                                .intercept(
                                    MethodDelegation.withDefaultConfiguration()
                                        .to(BootstrapInstrumentBoost.forInternalDelegateClass(interceptor))
                                );
                    } else {
                        newClassBuilder =
                            newClassBuilder.method(junction)
                                .intercept(
                                    MethodDelegation.withDefaultConfiguration()
                                        .to(new InstMethodsInter(interceptor, classLoader))
                                );
                    }
                }
            }
        }

        return newClassBuilder;
    }

    /**
     * Enhance a class to intercept class static methods.
     *
     * @param typeDescription target class description
     * @param newClassBuilder byte-buddy's builder to manipulate class bytecode.
     * @return new byte-buddy's builder for further manipulation.
     */
    private DynamicType.Builder<?> enhanceClass(TypeDescription typeDescription,
        DynamicType.Builder<?> newClassBuilder, ClassLoader classLoader) throws PluginException {
        StaticMethodsInterceptPoint[] staticMethodsInterceptPoints = getStaticMethodsInterceptPoints();
        String enhanceOriginClassName = typeDescription.getTypeName();
        if (staticMethodsInterceptPoints == null || staticMethodsInterceptPoints.length == 0) {
            return newClassBuilder;
        }

        for (StaticMethodsInterceptPoint staticMethodsInterceptPoint : staticMethodsInterceptPoints) {
            String interceptor = staticMethodsInterceptPoint.getMethodsInterceptor();
            if (StringUtil.isEmpty(interceptor)) {
                throw new EnhanceException("no StaticMethodsAroundInterceptor define to enhance class " + enhanceOriginClassName);
            }

            if (staticMethodsInterceptPoint.isOverrideArgs()) {
                if (isBootstrapInstrumentation()) {
                    newClassBuilder = newClassBuilder.method(isStatic().and(staticMethodsInterceptPoint.getMethodsMatcher()))
                        .intercept(
                            MethodDelegation.withDefaultConfiguration()
                                .withBinders(
                                    Morph.Binder.install(OverrideCallable.class)
                                )
                                .to(BootstrapInstrumentBoost.forInternalDelegateClass(interceptor))
                        );
                } else {
                    newClassBuilder = newClassBuilder.method(isStatic().and(staticMethodsInterceptPoint.getMethodsMatcher()))
                        .intercept(
                            MethodDelegation.withDefaultConfiguration()
                                .withBinders(
                                    Morph.Binder.install(OverrideCallable.class)
                                )
                                .to(new StaticMethodsInterWithOverrideArgs(interceptor))
                        );
                }
            } else {
                if (isBootstrapInstrumentation()) {
                    newClassBuilder = newClassBuilder.method(isStatic().and(staticMethodsInterceptPoint.getMethodsMatcher()))
                        .intercept(
                            MethodDelegation.withDefaultConfiguration()
                                .to(BootstrapInstrumentBoost.forInternalDelegateClass(interceptor))
                        );
                } else {
                    newClassBuilder = newClassBuilder.method(isStatic().and(staticMethodsInterceptPoint.getMethodsMatcher()))
                        .intercept(
                            MethodDelegation.withDefaultConfiguration()
                                .to(new StaticMethodsInter(interceptor))
                        );
                }
            }

        }

        return newClassBuilder;
    }
}

• ClassEnhancePluginDefine繼承了AbstractClassEnhancePluginDefine，其enhance方法先執行enhanceClass(typeDescription, newClassBuilder, classLoader)，後執行enhanceInstance(typeDescription, newClassBuilder, classLoader, context)，最後返回newClassBuilder；enhanceClass方法遍歷staticMethodsInterceptPoints，經過newClassBuilder.method(isStatic().and(staticMethodsInterceptPoint.getMethodsMatcher())).intercept方法加強newClassBuilder；enhanceInstance方法主要用於加強CONTEXT_ATTR_NAME字段、constructors、instance methods

GetTransactionMethodInterceptor

skywalking-6.6.0/apm-sniffer/optional-plugins/optional-spring-plugins/spring-tx-plugin/src/main/java/org/apache/skywalking/apm/plugin/spring/transaction/GetTransactionMethodInterceptor.java

public class GetTransactionMethodInterceptor implements InstanceMethodsAroundInterceptor {
    @Override
    public void beforeMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
                             MethodInterceptResult result) throws Throwable {
        if (allArguments[0] == null) {
            AbstractSpan span = ContextManager.createLocalSpan(Constants.OPERATION_NAME_SPRING_TRANSACTION_NO_TRANSACTION_DEFINITION_GIVEN);
            span.setComponent(ComponentsDefine.SPRING_TX);
            return;
        }
        TransactionDefinition definition = (TransactionDefinition) allArguments[0];
        AbstractSpan span = ContextManager.createLocalSpan(Constants.OPERATION_NAME_SPRING_TRANSACTION_GET_TRANSACTION_METHOD + buildOperationName(definition.getName()));
        span.tag(Constants.TAG_SPRING_TRANSACTION_ISOLATION_LEVEL, String.valueOf(definition.getIsolationLevel()));
        span.tag(Constants.TAG_SPRING_TRANSACTION_PROPAGATION_BEHAVIOR, String.valueOf(definition.getPropagationBehavior()));
        span.tag(Constants.TAG_SPRING_TRANSACTION_TIMEOUT, String.valueOf(definition.getTimeout()));
        span.setComponent(ComponentsDefine.SPRING_TX);
    }

    @Override
    public Object afterMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
                              Object ret) throws Throwable {
        ContextManager.stopSpan();
        return ret;
    }

    @Override
    public void handleMethodException(EnhancedInstance objInst, Method method, Object[] allArguments,
                                      Class<?>[] argumentsTypes, Throwable t) {
        ContextManager.activeSpan().errorOccurred().log(t);
    }

    private String buildOperationName(String transactionDefinitionName) {
        if (!Config.Plugin.SpringTransaction.SIMPLIFY_TRANSACTION_DEFINITION_NAME) {
            return transactionDefinitionName;
        }
        String[] ss = transactionDefinitionName.split("\\.");

        int simplifiedLength = ss.length - 2;
        if (simplifiedLength < 0) {
            return transactionDefinitionName;
        }
        StringBuilder name = new StringBuilder();
        for (int i = 0; i < ss.length - 1; i++) {
            name.append(i < simplifiedLength ? ss[i].charAt(0) : ss[i]).append(".");
        }
        return name.append(ss[ss.length - 1]).toString();
    }
}

• GetTransactionMethodInterceptor實現了InstanceMethodsAroundInterceptor接口，其beforeMethod方法會獲取TransactionDefinition，而後經過ContextManager.createLocalSpan建立span，而後設置Constants.TAG_SPRING_TRANSACTION_ISOLATION_LEVEL、Constants.TAG_SPRING_TRANSACTION_PROPAGATION_BEHAVIOR、Constants.TAG_SPRING_TRANSACTION_TIMEOUT這幾個tag；afterMethod方法執行ContextManager.stopSpan()；handleMethodException方法則執行ContextManager.activeSpan().errorOccurred().log(t)

EndTransactionMethodInterceptor

skywalking-6.6.0/apm-sniffer/optional-plugins/optional-spring-plugins/spring-tx-plugin/src/main/java/org/apache/skywalking/apm/plugin/spring/transaction/EndTransactionMethodInterceptor.java

public class EndTransactionMethodInterceptor implements InstanceMethodsAroundInterceptor {
    @Override
    public void beforeMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
                             MethodInterceptResult result) throws Throwable {
        AbstractSpan span = ContextManager.createLocalSpan(Constants.OPERATION_NAME_SPRING_TRANSACTION_PREFIX + method.getName());
        TransactionStatus status = (TransactionStatus) allArguments[0];
        span.tag(Constants.TAG_SPRING_TRANSACTION_IS_NEW_TRANSACTION, String.valueOf(status.isNewTransaction()));
        span.tag(Constants.TAG_SPRING_TRANSACTION_HAS_SAVEPOINT, String.valueOf(status.hasSavepoint()));
        span.tag(Constants.TAG_SPRING_TRANSACTION_ROLLBACK_ONLY, String.valueOf(status.isRollbackOnly()));
        span.tag(Constants.TAG_SPRING_TRANSACTION_IS_COMPLETED, String.valueOf(status.isCompleted()));
        span.setComponent(ComponentsDefine.SPRING_TX);
    }

    @Override
    public Object afterMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
                              Object ret) throws Throwable {
        ContextManager.stopSpan();
        return ret;
    }

    @Override
    public void handleMethodException(EnhancedInstance objInst, Method method, Object[] allArguments,
                                      Class<?>[] argumentsTypes, Throwable t) {
        ContextManager.activeSpan().errorOccurred().log(t);
    }
}

• EndTransactionMethodInterceptor實現了InstanceMethodsAroundInterceptor接口，其beforeMethod方法經過ContextManager.createLocalSpan建立span，而後獲取TransactionStatus，以後設置Constants.TAG_SPRING_TRANSACTION_IS_NEW_TRANSACTION、Constants.TAG_SPRING_TRANSACTION_HAS_SAVEPOINT、Constants.TAG_SPRING_TRANSACTION_ROLLBACK_ONLY、Constants.TAG_SPRING_TRANSACTION_IS_COMPLETED這幾個tag；其afterMethod方法執行ContextManager.stopSpan()；其handleMethodException方法執行ContextManager.activeSpan().errorOccurred().log(t)

小結

AbstractPlatformTransactionManagerInstrumentation繼承了ClassInstanceMethodsEnhancePluginDefine，其getInstanceMethodsInterceptPoints方法建立了InstanceMethodsInterceptPoint數組，其中一個InstanceMethodsInterceptPoint的getMethodsMatcher爲named("getTransaction")，getMethodsInterceptor返回org.apache.skywalking.apm.plugin.spring.transaction.GetTransactionMethodInterceptor；另一個InstanceMethodsInterceptPoint的getMethodsMatcher爲named("commit").or(named("rollback")，getMethodsInterceptor返回的是org.apache.skywalking.apm.plugin.spring.transaction.EndTransactionMethodInterceptor；其enhanceClass方法返回的是byName("org.springframework.transaction.support.AbstractPlatformTransactionManager")

doc

• AbstractPlatformTransactionManagerInstrumentation