I study SOA and webservices for a science paper. My state of knowledge is, that every SOA architcture needs a service broker.
Webservices are concrete implementations of a SOA, so do they have a service broker after? For example I create a webservice in asp.net which returns "hallo world" By Creating it, do I create a service broker too?
Don't let fool you by answers which are copy paste from Wikipedia :-)
Webservices are concrete implementations of a SOA
This assumption/statement is wrong. At least there is no direct relationship between SOA and webservices. SOA is an architectural paradigm where a webservice is a concrete technology (stack) based on WSDL and its result, the SOAP-protocol. Nothing more. Webservices may help to establish loosely coupled service landscape, which the SOA paradigm expects. But you could also build up a SOA landscape with other technology stacks (self-written hacks, RMI, even based on REST for instance).
Repository
The thing is: When you start building up your SOA-landscape, you (or others) will code services (i.e. webservices) where your service will have a technical contract (WSDL, WADL, ..) as a base for the implementation. Your clients will ask for it and you want it to store somewhere. This somewhere is usually a service repository. You could develop your own one, use the UDDI-standard or just buy one of products by the big vendors (IBM, TIBCO, Oracle etc).
Broker
A message broker within the SOA context is some piece of software, which supports the decoupling of the connected partner systems. Commonly it's called ESB (enterprise service bus). Also one of the goals of the SOA paradigm is, that the services can be used by anyone (reusability). Therefore you don't want to connect your services by P2P-connections (aka spaghetti architecture) - just imagine that one of the service participants changes it's hardware/IP: this would be a nightmare for all the connected partner systems. That's why the ESB was invented which acts between the service consumer and the service provider.
Typically, these ESB-products support a lot of technologies or -stacks/APIs like HTTP, JMS, REST etc.
Source: I work with a self-claimed SOA landscape and thousands of different (web-)services for a big company for a long time now.
A Web service is a set of related application functions that can be programmatically invoked over the Internet. Businesses can dynamically mix and match Web services to perform complex transactions with minimal programming. Web services allow buyers and sellers all over the world to discover each other, connect dynamically, and execute transactions in real time with minimal human interaction.
Web services are self-contained, self-describing modular applications that can be published, located, and invoked across the Web.
A network component in a Web Services architecture can play one or
more fundamental roles: service provider, service broker, and service
client.
Service brokers register and categorize published services and provide search services. For example, UDDI acts as a service broker for WSDL-described Web services.
Related
I’ve been learning a little bit about SOA and Oracle SOA Suite 12c, I barely understand that I can use BPEL Process in a SOA Project and that I cannot use it with Service Bus Project and that SOA Composites are deployed into the Oracle Enterprise Manager, while Service Bus Projects are deployed directly to the Oracle Service Bus.
My question is, does anyone know what are the differences between use SOA Projects and Service Bus Project even if I can consume services or use DBAdapter from any?
Is there any good reason to consume my soap, rest, dBadapters, etc in a BPEL Process in the SOA Project instead of doing it directly in my Service Bus Project?
Thanks in advance for you help,
:)
OSB is generally used whenever your flow is simple and light weight like- just DB call, web service call, message routing with few mappings. It can used as a proxy service (to hide the actual implementation) to the external system who is calling this proxy as a web service.
Whereas, SOA is preferred where the flow is complex with bulk transformation or heavy orchestration involving multiple intermediate calls to third party systems, etc.
You can go through the below link to get more information,
https://community.oracle.com/thread/1077167?start=0&tstart=0
Is it advicible to build the MSA based services on Oracle SOA or any other ESB suite for that matter? Is there any advantage or disadvantage?
If I am using Java, Spring and JPA over a message queue - say - RabbitMQ, I can achieve it in a more controlled environment with less recurring expenses. Of course will end up mixing tools like Drools or JBPM or similar to achieve things that may be OOTB (Out of the box) in the SOA Or ESB Suite. But scaling a specific service without paying licence fee for an additional environment should certainly be a good catch right?
Microservices architecture pattern applies to development of backend systems/services, whereas ESB (e.g. Oracle SOA Suite) is intended as an intermediary layer between consumers and backend services. Backend services contain rich application logic, whereas ESB services provide only intermediary functions like routing, transformation, orchestration etc.
ESB is not intended for rich application logic, though it's possible to do that.
Using ESB (e.g. Oracle SOA Suite) to host microservices is achievable, but you will get a big overhead comparing to limited functions and scalability. If you are looking for centralized API management (tracing, security etc.), you can put an API gateway into your architecture instead of full scale ESB.
they have many common features. but how the difference?
MOM allow asynchronous while SOA does not, this is the only difference?
SOA, Service Oriented Architecture, is an architecture that defines how to structure access to business information between different applications. In a nutshell, usually, one application needs something done with a piece of information (may it be an orderfile or anything else) that application has a need. Another application may be able to do the corresponding processing of that piece of information, hence it has a capability. The first application then Consumes the Service of the second application, which Provides the Service (no matter the underlying technology, which can be anything such as JMS, HTTP/SOAP, HTTP/REST, EMail, FTP, etc.). To make this work, a Contract between the first application and the Service has to be defined which clears such things out as Message Format (XSD or similar), Protocol (HTTP/SOAP? JMS?) etc.
MOM, Message Oriented Middleware, on the other hand is just a family of software/middleware platforms. They are actual implementations, and not a high-level concept like SOA. They can be used to implement a SOA architecture, an Event Driven architecture or other architectures. Usually, MOM enriches a set of applications with asynchronous messaging where a MOM server stores and forwards the messages. Often things such as transactions, guranteed delivery, fail-over, loose coupling and load balancing are built into MOM implementations. Examples of MOM are IBM WebSphere MQ, Apache ActiveMQ, RabbitMQ, JBoss HornetQ, etc.
Message oriented middleware (MOM) is a type of technology where as SOA is a type of architecture. Even though a lot of people think about web-service when they talk about SOA, you can use MOM to implement it as well (in fact in many cases that's the better option)
What's the difference between an RPC System, like Twitter's Finagle, and an Enterprise Service Bus, like Mule? What kind of problems are each of them good at solving?
I will try to answer this as a soft explanation, rather than a technical breakdown of features:
One may say that Finagle is a asynchronous messaging library that allows services to connect to one another freely (not tightly tied to architectural system integration standards) while supporting multiple protocols.
From the Finagle website:
Finagle is a network stack for the JVM that you can use to build asynchronous Remote Procedure Call (RPC) clients and servers in Java, Scala, or any JVM-hosted language. Finagle provides a rich set of protocol-independent tools.
An enterprise service bus (ESB), on the other hand, is a asynchronous messaging architecture which typically adheres to industry standards and protocols. An ESB promotes a system where message flow is controlled and routed between systems, and where servers can register their service and clients can register what messages they are interested in. The services offered by servers can be registered and versioned.
You will typically find Finagle being used somewhere between a website and backend services. But, you will typically find an ESB inside a large corporate, where it's responsible to integrating systems like finance, support, sales, etc.
Both solutions offer asynchronous messaging and buffering to various extends, but are not designed to solve the same problem. For ESB, you would probably think 'strict, enterprise', but for Finagle you would probably think 'flexible, web'.
Hope this helps
Update:
Not quite related, but if you are exploring this space, I would look at Kafka these days.
RPC and ESB are two architectural patterns. While RPC is usually a request-reply and synchronous in nature, an ESB works on the concept of messaging (simplified explanation) and of asynchronous in nature. ESB is the foundation for any SOA implementation. ESB enables loose coupling thus promoting true agility. A simplified example from implementation perspective is as follows:
A web service is a typical RPC. The consumer is tightly bound to the producer and any change in the contract on the producer side, will require changes on the consumer side.
In ESB, the service consumer doesn't invoke the service producer directly. It just puts the message in the bus and based on the rules (mediator), appropriate service producer will handle it. If the service consumer and service producer talk in different formats, ESB provides the facility to do the transformation (like formatting the zipcode as xxxxx-xxxx, splitting the name into first name and last name, etc.).
This is just simplified explanation. For more information, please check the following links:
Why do developers need an Enterprise Service Bus?
Enterprise Service Bus
Both solve completely different problems:
An ESB is an intermediation middleware that provides message transformation and routing, protocol adaptation and other value-add operations (like orchestration, guaranteed delivery, idempotent filtering...). It sits in-between your service consumers and providers and transparently (ie without any change in consumer or provider) provides its different features.
An RPC system provides client and server technologies for performing RPC operations.
I'd like to better understand the reasons for .NET's application server model compared to that used by most Java application servers.
In most cases I've seen with ASP.NET web applications, business logic is hosted in the web server's asp.net hosts processes. Another common approach is to have a physically or logically different tier which hosts your business objects and then are exposed as web services or accessed via mechanisms like WCF. The latter approach typically but not always seems to be used when higher scale is required. In the days of COM objects I've seen Microsoft Transaction Server (MTS) and later COM+ hosting used to host COM objects containing business logic, with MTS (theoretically) managing object lifetime, transactions, concurrency yada yada. This model largely seems to have disappeared in ASP.NET land.
In the Java world you might have Apache with Tomcat as the servlet container and your business objects hosted in Tomcat. In this case, Tomcat provides similar functionality to what MTS provided in the .NET world.
Several questions:
Why the fundamental difference in the Microsoft vs. Java approaches to application servers? This must have been an architecture/design choice when these frameworks were created.
What are the pros and cons of each approach?
Why did Microsoft move away from the MTS-hosting model (which is similar to the Tomcast servlet hosting model) to the more common current approach which is just to have business objects as part of the web server's ASP.NET process?
If you wanted to implement the MTS type approach or the Tomcat type approach in ASP.NET applications today I assume a common pattern would be to host business objects in some IIS process (possibly on some different physical or logical tier) and access via WCF (or standard asmx web services, whatever). Is this a correct assumption?
To my way of thinking, the primary difference is in the "open" approach vs. the "integrated stack" approach. Microsoft likes to provide everything as an integrated stack that all shares a common flavor and approach. Java is more friendly to the "bring your own x" model, where you may want to plug in your favorite application server, transaction manager, etc. Both technology stacks allow in-process invocation as well as remote invocation with varying levels of transaction support.
Really, WCF is not a new technology stack, but a reorganization and rebranding of existing elements of the .NET stack. Specifically, WCF took on the functions of .NET Remoting, Web Services, and distributed transactions.
You reference "the more common current approach which is just to have business objects as part of the web server's ASP.NET process." That is only common for non-distributed apps. It is a simple model that works well when all of your objects will reside on the same server. This follows Microsoft's "Scale Out" deployment model. Rather than segregating object tiers across servers, put everything but the database together on the web servers and then incrementally add identical, redundant servers to scale out the web-server layer.
Microsoft has been pushing hard lately on Service Oriented Architecture, which relies more heavily on WCF and remote invocation. This is seen as a key to the cloud strategy that would have people moving parts or all of their applications to flexible resources in the cloud (which MS would like to host with Azure and the like).