云计算环境下软件服务开放市场中间件构造与演化关键技术研究

As an exchange foundation of cloud software services, the cloud marketplace plays an important role to promote the capability and creativity of cloud services. However, existing cloud marketplaces are usually based on online stores operated by some particular companies. Users are usually required to get involved in their particular ecosystems, seriously restricting their creativity and competition. Moreover, these marketplaces lack efficient and flexible service publishing and discovery mechanisms. Therefore, this makes them difficult to handle a huge number of dynamic cloud service exchanges efficiently. To address this issue, we propose in this project an open cloud marketplace middleware system for cloud software services based on a service publishing and subscription model. This model extends traditional content-based distributed publish/subscribe paradigm. By introducing the matching mechanism of multidimensional contents such as service functionality, service behavior, and quality of service etc, a new distributed publish/subscribe paradigm for service publishing and subscription is proposed. This new paradigm allows service providers to publish their services to and allows service consumers to subscribe needed services from distributed overlay networks based on service descriptions and requirements (including service functionality, behavior, quality etc). New filter-based routing algorithms supporting behavior covering are developed to optimize the storage of service descriptions and service requirements to speed up their matching. Moreover, the middleware system can also make self-adaption to adjust and optimize the overlay network based on service exchange information. In this way, the middleware system is able to support a huge number of dynamic service exchanges in the cloud environment with the aid of the efficient and flexible service publishing and discovery mechanism.

云服务市场是软件服务交易使用的基础，是促进和提升云计算服务及创新能力的重要保障。然而，现有云服务市场由单一企业所主导，限制用户于其服务生态圈，缺乏高效灵活的服务发布与查找机制，严重制约竞争力和创新能力，难于满足海量动态云服务交易需求。为了解决这个难题，本课题研究开放云服务市场中间件系统的构造及探索其演化机制。通过扩展传统基于线性内容匹配的分布式发布/订阅模式，提出一种服务发布与订阅模型，创建服务行为、服务质量等多维度非线性内容匹配和路由机制，研发基于分布式服务发布/订阅模型的开放云服务市场中间件系统及其软件体系结构、动态构造演化技术和路由匹配算法。该系统允许用户把多维度服务描述发布到分布式节点之上，并通过基于服务行为覆盖的路由算法自动优化服务描述的存储路径和匹配效率，实现灵活高效的服务发布与服务查找。同时，该系统能够根据市场交易需求对其节点自动调整和动态演化，保障海量用户平等参与服务交易。

本项目主要针对云计算环境下云服务市场服务发布与服务订阅的难题，设计和构造一个开放云服务市场中间件系统，开发新的服务发布与服务查找方法、融合软件系统自适应动态演化机制，为实现一个健康、可信、高效、良性发展的开放云服务市场提供软件技术支持。具体而言，1）项目研究了一种基于Pub/Sub的分布式服务市场体系结构，既能兼顾服务注册信息存储效率，又能兼顾服务查找效率，方便收集和分享市场操作元数据，而且还具有较好的可扩展性，从而解决海量用户操作性能瓶颈问题，保障所有用户平等参与服务交易，满足开放云服务市场需求。2）项目组提出了一种基于Pub/Sub的分布式云服务发布订阅方法，采用有限状态自动机描述云服务发布和云服务订阅，在服务订阅路由过程中逐步匹配和分解订阅，沿着路由路径缓存匹配结果，复用已有的分解和匹配结果，基于云服务行为覆盖过滤重复的路由及匹配过程，提高云服务订阅路由和匹配效率。