How to configure hotswap-agent.properties with weblogic?

[zenglian]

I'm using maven + weblogic 12c.

What I did:

(1) installed dcevmlight for jdk1.8.0-112 v8 as altjvm.

(2) add below line in setDomainEnv.cmd, version is 1.0.1-SNAPSHOT

set JAVA_OPTIONS=%JAVA_OPTIONS% -XXaltjvm=dcevm -javaagent:G:\programs\java\hotswap-agent.jar

(3) put hotswap-agent.properties in src/main/resources, where g:/a/b/c/d/target/classes is the target path of mvn compile.

extraClasspath=G:/a/b/c/d/target/classes
autoHotswap=true
autoHotswap.port=8453

(4) run "mvn clean install" to package the classes under g:/a/b/c/d/class into lib1.jar and deploy it to weblogic server. hotswap-agent.properties is in the root of jar file.

(5) edit a java file and run "mvn -o compile".

I'm expecting the modified class is reloaded by weblogic server, but nothing happens. What's wrong with the above steps?

From weblogic console, I see a lot of messages like "HOTSWAP AGENT: 20:46:01.274 INFO (org.hotswap.agent.watch.nio.TreeWatcherNIO) - Registering directory target C:\oracle\fmwhome12\user_projects\domains\base_domain\servers\AdminServer\tmp_WL_user\MyApp\kd1vs via watched: C:\oracle\fmwhome12\user_projects\domains\base_domain\servers\AdminServer\tmp_WL_user\MyApp", but I could not find the string "g:/a/b/c/d/target/classes" I defined in hotswap-agent.properties.

Thanks.

[rs-renato]

I also would like to know..

[jp295m]

I think HotSwapAgent does not support Weblogic. Can someone confirm?

[skybber]

You are right, it does not support.

[Kladdkaka]

Hi! I would like to try to get hotswapagent working with weblogic, have there been any progress or anything that is helpful to start off with?

[skybber]

Unfortunately nobody is working on it now.

[ramuece09]

Hi! Do we have any updates on this? Is the current version HotswapAgent works with web logic? Please confirm

[skybber]

Probably it does not work.

[Kladdkaka]

For @ramuece09 and anyone who might be interested, a while ago I tried to write a plugin to enable weblogic support, if I recall correctly I kind of got it to work, although it was quite buggy and I have completely forgot how I configured weblogic, and I think some weird JVM crash also happened, although that could have been that weblogics built-in fastswap was enabled or something.

package org.hotswap.agent.plugin.weblogic

import org.hotswap.agent.annotation.Init
import org.hotswap.agent.annotation.OnClassLoadEvent
import org.hotswap.agent.javassist.*
import org.hotswap.agent.logging.AgentLogger
import org.hotswap.agent.util.classloader.HotswapAgentClassLoaderExt
import org.hotswap.agent.util.classloader.WatchResourcesClassLoader

/**
 * ModuleClassLoaderTransformer
 */
class ModuleClassLoaderTransformer {
    @Init
    var moduleClassLoader: ClassLoader? = null

    companion object {
        protected var LOGGER = AgentLogger.getLogger(ModuleClassLoaderTransformer::class.java)

        @OnClassLoadEvent(classNameRegexp = "weblogic.utils.classloaders.ChangeAwareClassLoader")
        @Throws(NotFoundException::class, CannotCompileException::class)
        @JvmStatic
        fun transformChangeAwareClassLoader(classPool: ClassPool, ctClass: CtClass) {
            LOGGER.error("transformChangeAwareClassLoader: ${ctClass.simpleName}")

            val src = """$currentClassName.logMessage("ChangeAwareClassLoaderConstructor -> " + $1.toString());"""

            ctClass.getDeclaredConstructor(arrayOf(
                    classPool["weblogic.utils.classloaders.ClassFinder"],
                    CtClass.booleanType,
                    classPool["java.lang.ClassLoader"]
            )).insertBefore(src)
        }

        @OnClassLoadEvent(classNameRegexp = "weblogic.utils.classloaders.MultiClassFinder")
        @Throws(NotFoundException::class, CannotCompileException::class)
        @JvmStatic
        fun transformMultiClassFinder(classPool: ClassPool, ctClass: CtClass) {
            LOGGER.error("MultiClassFinder: ${ctClass.simpleName}")

            val srcAddFinder = """$currentClassName.logMessage("MultiClassFinder#addFinder -> " + $1.toString());"""

            ctClass.getDeclaredMethod("addFinder", arrayOf(classPool["weblogic.utils.classloaders.ClassFinder"])).insertBefore(
                    srcAddFinder
            )
            val srcAddFinderFirst = """$currentClassName.logMessage("MultiClassFinder#addFinderFirst -> " + $1.toString());"""

            ctClass.getDeclaredMethod("addFinderFirst", arrayOf(classPool["weblogic.utils.classloaders.ClassFinder"])).insertBefore(
                    srcAddFinderFirst
            )
        }

        @OnClassLoadEvent(classNameRegexp = "weblogic.utils.classloaders.CompositeWebAppFinder")
        @Throws(NotFoundException::class, CannotCompileException::class)
        @JvmStatic
        fun transformCompositeWebAppFinder(classPool: ClassPool, ctClass: CtClass) {
            LOGGER.error("MultiClassFinder: ${ctClass.simpleName}")
            val src = """$currentClassName.logMessage("CompositeWebAppFinder#addLibraryFinder -> " + $1.toString());"""
            ctClass.getDeclaredMethod("addLibraryFinder", arrayOf(classPool["weblogic.utils.classloaders.ClassFinder"])).insertBefore(
                    src
            )
        }

        @OnClassLoadEvent(classNameRegexp = "weblogic.utils.classloaders.GenericClassLoader")
        @Throws(NotFoundException::class, CannotCompileException::class)
        @JvmStatic
        fun transformGenericClassLoader(classPool: ClassPool, ctClass: CtClass) {
            LOGGER.error("transformGenericClassLoader: ${ctClass.simpleName}")

            val ctHaClassLoader = classPool[HotswapAgentClassLoaderExt::class.java.name]
            ctClass.addInterface(ctHaClassLoader)

            val setExtraClassPath = "$\$ha\$setExtraClassPath"

            val srcSetExtraClassPath = """
            public void $setExtraClassPath(java.net.URL[] extraClassPath) {
                $currentClassName.logMessage("okokok -> " + extraClassPath[0].toString());
                try {
                    weblogic.utils.classloaders.MultiClassFinder multiClassFinder = new weblogic.utils.classloaders.MultiClassFinder();
                    for (int i = 0; i < extraClassPath.length; i++) {
                        try {
                            java.net.URL url = extraClassPath[i];
                            java.io.File root = new java.io.File(url.getPath());
                            weblogic.utils.classloaders.IndexedDirectoryClassFinder indexedDirectoryClassFinder = new weblogic.utils.classloaders.IndexedDirectoryClassFinder(root);
                            multiClassFinder.addFinder(indexedDirectoryClassFinder);
                        } catch (java.lang.Exception e) {
                            $currentClassName.logException(e);
                        }
                    }
                    this.addClassFinderFirst(multiClassFinder);
                    $currentClassName.logMessage("classpathzlol -> " + this.getClassPath());
                } catch (java.lang.Exception e) {
                    $currentClassName.logException(e);
                }
            }
            """.trimIndent()

            ctClass.addMethod(CtNewMethod.make(
                    srcSetExtraClassPath,
                    ctClass
            ))

            val setWatchResourceLoader = "$\$ha\$setWatchResourceLoader"

            val srcSetWatchResourceLoader = """
            public void $setWatchResourceLoader(${WatchResourcesClassLoader::class.java.name} watchResourceLoader) {
                $currentClassName.logMessage("WatchResourcesClassLoader -> " + watchResourceLoader.toString());
            }
            """.trimIndent()

            ctClass.addMethod(CtNewMethod.make(
                    srcSetWatchResourceLoader,
                    ctClass
            ))
        }

        @JvmStatic
        fun logMessage(str: String) {
            LOGGER.error("logMessage: $str")
        }

        @JvmStatic
        fun logException(ex: Exception?) {
            LOGGER.error("logException", ex)
        }
    }
}

private val currentClassName: String
    get() {
        return ModuleClassLoaderTransformer::class.java.name
    }

Although I must say that I am quite new to the Java world still, I think I had only worked with Java for 1.5 year or something when I wrote that, so there is probably some stupid mistake that I did :)

[skybber]

It looks OK for me, could you please turn it to Java code and make plugin?

[ramuece09]

@Kladdkaka It's really sounds good. I'm a Java freak.. Let me pitch this when I get some time. Thanks for the update. Share if you have any specific error message

[tporeba]

@skybber @ramuece09 I translated the plugin draft by @Kladdkaka into Java and it does work. For now I just tested some basic paths of reloading existing class or adding a new one with WLS12 - and it is OK, it works even for EJB classes.

See:

• PR Weblogic plugin #418
• snapshot jar https:/tporeba/HotswapAgent/releases/tag/1.4.2-SNAPSHOT%2Bweblogic