Artifactory 5.5.1元数据写入时出现ConcurrentModificationException问题求助

我之前碰到过一模一样的问题，这个ConcurrentModificationException的根源很明确：你在同步的afterCreate钩子中执行了会触发同类钩子的操作。具体来说，当你往stage-release仓库上传构件时，钩子会触发repositories.copy把构件复制到release仓库，而这个复制操作本身又会触发release仓库的afterCreate钩子——此时原钩子的执行还没完成，插件系统正在遍历钩子动作集合，新的钩子触发会修改这个集合，直接导致Guava的LinkedHashMultimap抛出并发修改异常。

解决方案1：用异步任务执行复制操作 #

把复制逻辑放到异步任务里，让当前的afterCreate钩子先执行完毕，再异步处理复制，这样就不会干扰正在遍历的钩子集合。修改后的代码如下：

import org.artifactory.exception.CancelException
import org.artifactory.repo.RepoPathFactory
import org.artifactory.api.context.ContextHelper

storage {
    afterCreate { item ->
        def repoKey = item.repoPath.repoKey
        if (repoKey == 'stage-release') {
            def sourcePath = RepoPathFactory.create(repoKey, item.repoPath.path)
            def destPath = RepoPathFactory.create('release', item.repoPath.path)
            
            echo "ID is " + item.repoPath.id
            if (!repositories.exists(destPath)) {
                echo "MISSING artifact in the release repo, scheduling async copy"
                // 提交异步任务执行复制逻辑
                def executions = ContextHelper.get().beanForType(org.artifactory.api.execution.Executions.class)
                executions.submitAsync("Copy artifact from stage-release to release", {
                    repositories.copy(sourcePath, destPath)
                })
            } else {
                echo "FOUND the artifact in the release repo so no need to copy"
            }
        }
    }
}

def echo(str) {
    log.warn "########################### " + str;
}

解决方案2：复制时直接禁用拦截器（更简洁） #

Artifactory 5.x的Groovy API支持在复制操作时禁用拦截器，这样复制构件到release仓库时不会触发afterCreate钩子，从根源上避免循环触发和并发问题。修改复制那一行代码即可：

import org.artifactory.exception.CancelException
import org.artifactory.repo.RepoPathFactory

storage {
    afterCreate { item ->
        def SourcePath = RepoPathFactory.create('stage-release', item.repoPath.path)
        def DestPath = RepoPathFactory.create('release', item.repoPath.path)
        if (item.repoPath.repoKey == 'stage-release') {
            echo " ID is " + item.repoPath.id
            if (repositories.exists(DestPath)) {
                echo "FOUND the artifact in the release repo so no need to copy"
            } else {
                echo "MISSING artifact in the release repo so copying it over"
                // 添加参数禁用复制时的钩子触发
                repositories.copy(SourcePath, DestPath, [suppressInterceptors: true])
            }
        }
    }
}

def echo(str) {
    log.warn "########################### " + str;
}

为什么升级后才出现问题？ #

Artifactory升级到5.5.1后，插件系统的钩子执行机制做了并发安全的强化校验——升级前可能没有这么严格的检测，所以钩子的循环触发没有抛出异常，但实际上这种写法本身就存在线程安全隐患，只是之前没暴露出来而已。

内容的提问来源于stack exchange，提问作者Raj