从组织内部的角度来看,服务编制和服务编排之间的区别是什么?
我认为编排在内部非常适合高度分散的组织。您不需要中央业务流程执行器。这有利于每个组织子单元的独立成长和发展。
(我赞同编配与编排问题的解释: http://geekexplains.blogspot.com/2008/07/ways-of-combining-web-services.html)
服务可以区分为原子服务和由其他服务组成的服务。这样的作曲被称为“配器”。有时是工作流,有时是业务流程。例如,BPEL是一种编排语言,但自称为“业务流程执行语言”。
没有要求服务必须按层次结构组合。这意味着两个服务可以相互通信。在它们之间运行的协议被称为“编排”。它可能是两个服务,但通常会涉及两个以上的服务。编排中的每个服务都可以视为伙伴服务的编排器。参与编排的每个服务都可以实现为编排/工作流/流程。
编制显示每个服务的完整行为,而编排则组合每个服务的接口行为描述。
一篇区分编排、接口行为、提供者行为和编排的优秀科学文章如下: 杜马。面向服务的设计:一个多视角的方法。国际合作信息系统杂志,2004,13,337-368
当您可以控制流程中的所有参与者时——当它们都在一个控制域中并且您可以指定活动流时,编排非常有用。当然,当您指定将在您拥有控制权的组织内部实施的业务流程时,这是最常见的情况。
编排是一种指定两个或多个参与方如何协调其活动和过程以共享信息和价值的方法——其中任何一方都不能控制其他参与方的过程,或者可能对这些过程没有任何可见性。当需要跨控制/可见性领域进行协调时,使用编排。在一个简单的场景中,您可以把编排想象成一个网络协议。它规定了各方之间可接受的请求和响应模式。
基本技术(如XML、SOAP、WSDL)提供了将服务作为实体来描述、定位和调用的方法。然而,这些技术并没有提供关于服务在更复杂的协作中的角色的丰富行为细节。此协作包括一系列活动和活动之间的关系,这些活动和关系构建业务流程。有两种方法构建此流程:服务编制和服务编排。
服务编制
服务编制表示一个集中的可执行业务流程(编配器),用于协调不同服务之间的交互。协调器负责调用和组合服务。
所有参与服务之间的关系由单个端点(即组合服务)描述。编制包括管理各个服务之间的事务。业务流程为服务组合采用集中式方法。
服务编排
服务编排是参与服务的全局描述,由两个或多个端点之间的消息交换、交互规则和协议定义。编排为服务组合使用了分散的方法。
编排描述了多个服务之间的交互,其中编排表示从一方的角度进行控制。这意味着编排与编排在控制所涉及服务之间交互的逻辑应该驻留的位置上有所不同。
In orchestration, there is a conductor and there are instrument players. Players play according to how conductor conducts. If conductor is replaced, the harmonic expression will be different i.e. it is still the same play (service) but with a different outcome. For example, to provide a financial arrangement proposal, the orchestration service will conduct by asking (invoking) each player (entity or utility service, e.g. credit check) to play (return results or adjust/update its playing) according to conductor's template (business rules). In choreography, there is a choreographer and there are groups of dancers. Choreography is a direction, but each group of dancers is autonomous in how to realize that direction.
因为线程已经很老了,但仍然在为那些像我一样在这里跌跌撞撞地寻找这个问题的人写信。在面向服务的体系结构(SOA)中,这是一个备受争议的问题,初学者需要更清晰的解释。
业务流程:可执行过程
Used in private business processes A central process (which can be another Web service) takes control of the involved Web services and coordinates the execution of different operations on the Web services involved in the operation The involved Web services do not "know" (and do not need to know) that they are involved in a composition process and that they are taking part in a higher-level business process. Only the central coordinator of the orchestration is aware of this goal, so the orchestration is centralized with explicit definitions of operations and the order of invocation of Web services.
编排:多方合作
相反,编排不依赖于中央协调器。 相反,编排中涉及的每个Web服务都确切地知道 何时执行其操作以及与谁进行交互。 编舞是一种专注于交流的协作 公共业务流程中的消息。 编排的所有参与者都需要了解业务 流程、要执行的操作、要交换的消息和定时 信息交换。
编排与编排
从组合Web服务以执行业务的角度来看 流程、编排是一种更灵活的范式,并且具有 与编舞相比,以下优点: 组件过程的协调由一个 已知的协调员。 Web服务可以在它们不知道的情况下被合并 正在参与一个更大的业务流程。 在出现故障时,可以设置备用场景。
Andrei和其他人很好地解释了什么是编排,什么是编排。对于软件架构师在这两种选择之间进行选择,比较它们的不同质量也是很重要的。
配器优于舞蹈编排
Reliability: Orchestration platforms have built-in support for error handling and transaction management (compensating transactions). In choreography, custom-developed workflow and error handling tends to be more error-prone. Also, choreography is often event-driven and much of the processing is asynchronous. Therefore, choreography may require undo/correction events that add complexity to the solution. Modifiability: Creating and changing process workflows and complex service compositions is easier in the visual BPM tools found in orchestration platforms. You gain in "process visibility".
编舞优于编曲
性能:由于工作流脚本解释和编制平台本身的附加层,编制会引起性能开销。 成本:编排不需要额外的中间件或语言,它们有相关的学习曲线和治理负担。
EDIT
如果编配器元素没有采用高可用性机制,编配解决方案可能会引入SPOF。谢谢@Deepak在评论中指出这一点。
Service orchestration: you put together several services by a fixed logic. This logic is described at a single place. You can imagine a team of people with a manager doing micro-management. The manager precisly tells what, when and who should do. The team members do not care of the entire goal of the job, the manager combines the outputs into a single deliverable. A practical example is a BPEL process. BPEL process contains the logic, can invoke several services and combine their responses into a single service response.
Service choreography: the decision logic is distributed, with no centralized point. You can imagine a home, where everybody aims for the common good and works pro-actively without micro-management. Or you can imagine a human body, where different members are interdependent and work for the common goal. A practical example is event driven processing, where an agent is activated by an event and does its job. All the agents make a system together. There is no centralized logic. Choreography possibilities may go farther beyond orchestration as it is more aligned with the real world.
我的观点是,我们不需要对这两者进行太多区分,因为我们需要关注业务逻辑。在单点逻辑可以完成工作的地方,我们进行编排。如果一个问题不能被集中的逻辑覆盖,我们就不得不编排。这就是为什么我们经常在IT中遇到编排,而编排更多地是一个学术概念和一个研究主题。我们经常在不知情的情况下编舞,就像在现实世界中一样。
编配和编排都是大规模的过程形式主义的两种哲学,即协作空间。协作空间是一个行业的正式表示,例如健康行业、食品行业、汽车行业或... .因此,在您决定编排它们或使用编排来提供对终端消费者有意义的需求之前,您应该有一些小规模的能够使用某种交流语言的服务提供者。
编排通常遵循分布式系统中著名的中间件。IT行业中一些很好的工具例子可以是Juju, Zapier IFTTT。您可以对所使用的服务进行集中控制、听觉、修改和故障排除。
Choreography is more decentralized than orchestration in the sense that it accepts more autonomous collaborators. For example bitcoin network is a collection of service providers called nodes which collectively provide a Defi service namely distributed ledger functionality to its service end-consumers. But this does not have any centralized authority in charge, and there is no total-view over whole network. There is just a consensus machanism that if respected candidate service provider joins the network and participate in end-consumer service provision. Anywhere you need to attack trusted third party and its side effects such as corruption, an orchestration would not suffice.
同样,任何行业参与者之间的任何协作都可能受到编排或编排的影响,因此我希望将示例仅限于IT行业不会造成误导。
我还可以补充一点,命名暗示了两者与舞台表演的相似之处。在管弦乐队中,如果每个乐器演奏者都跟随指挥,他/她就能与其他成员和谐相处。另一方面,类似于编舞中的舞台舞蹈,没有指挥,每个舞台舞者只与他/她的搭档协调(最好是作为同伴),没有单一的协调领导。但两者仍然向观众呈现和谐。
One can use both choreography and orchestration is the same system as we have done in our product. Various actors performing various tasks dispatched to them are choreographed by the event pub/sub system via events they generate. For example, when a prime mover carrying a container arrives at a warehouse, that event, which is subscribed by the warehouse manager app, prompts the warehouse manager to activate the resources to unload the cargo. But when exceptions happen, such as the forklift to carry the load breaks down, that event starts an orchestration engine (a workflow processor) to orchestrate the task for various actors as per the exception handling workflow to handle the exception.