Peeyush Tugnawat's Blog

Service Oriented Architecture: The Beginning

Sat, 21 Nov 2009 18:00:19 -0800

This was one of my early posts. Posting again based on the feedback I got from people looking for it. As I mentioned in the earlier post, following are the questions that I frequently encounter and was trying to find common sense answers for

I have heard about it so much, but what exactly is SOA? What is a Service?
What exactly do you mean when you say Service Oriented?
What do you mean by Composite Services?
What do you mean by Service Orchestration?
What is different about Service Oriented approach for Enterprise Integration?
How is one company's SOA different than the other?

So as I thought while posting my first blog entry I did take a step back and revisited the concepts from a common sense perspective to share my understanding. Here it is my experiment and thoughts shared...

Service Oriented Architecture: The Beginning

What is a Service?

Service means the performance of any duties or work for another. Service is provided by a service provider and consumed by the service consumer. Simple!

Think about it. We all use and provide services almost everyday in our day today life. Following are some examples of well-known services:

Service Provider: Government
Services Provided: Education Services, Infrastructure Services, Police and Fire Services, Postal Services, and other regulatory services

Service Provider: Financial Companies
Services Provided: Accounting Services, Banking Services, Tax Services, and auditing services

Service Provider: Utility Companies
Services Provided: Electricity Services, Gas Services, Communication Services, Water Services, and Waste Management services

Service Provider: Individuals
Services Provided: Employee Services (various roles), Medical Services, Law and Attorney Services

One of the formal definition of services in a business sense is "Service is any act or performance that one party can offer to another that is essentially in tangible and does not result in the ownership of anything."

What is service oriented?

Any approach simple or composite based on services and/or service-mix is service oriented. So is it anything new? No, Actually we already live in a service oriented world and Service oriented approach is so very common in our surroundings. It exists universally and is the most fundamental functional aspect of human life in our society. Service providers and consumers range from an individual person to giant multinational corporations. Most companies provide services that are outcome of services provided to them by individual employees and may be other companies. Service oriented societies and cultures demonstrate some common characteristics such as standard currencies, governance, service composition, and service orchestration.

Before we talk about Service Oriented approach for software architecture, let's see how some of the principles apply in real life example. Let's go through my example:

My Example of Service: Flight Service

I used to live in Denver and fly for work to customer locations frequently, the obvious real life example I was able to think of was of an airline and the service (flight) it provides. Let's take an example of a service I have used often, flight between Denver and San Francisco.

Thinking from service perspective, the airline I use is the Service Provider of the flight between Denver and San Francisco. Since I choose to pay for the flight and use the service, which makes me the service consumer.

In this example some of the things to note as they relate to SOA are the following:

Service Abstraction

The airline uses multiple services, goods, and equipments to provide this service to the customers. The service in itself is very complex technically and is composed of several other services. But from my perspective there is a well defined but simple interface to consume this service. All I need to care about is making the payment for ticket and be on time at the correct Airport and gate :)

I don't have to worry about paying the Airport for the services such as security, gate fees, air traffic control, and the airline in-flight services. I also don't worry about how the airline manages their employees, equipment, goods, and other services that they consume to provide me with this service.

This demonstrates the concept of abstraction. Services abstract the logic and implementation.

Service Loose Coupling

Abstraction promotes loose coupling of services. As services are modular, logic contained in them is independent of each other. Awareness of the service is enough for the services to interact and thus they are loosely coupled. They can change within their own boundaries without causing any change required to the consumer.

In my example, most of the individual services are loosely coupled and communicate using standard interfaces. The airline relies on the services provided by Airport for security and ATC, it does not actually know or have to interact with specific persons providing these services. Airport can very well replace the security and ATC personals and still provide the same service without any awareness required on the service consumers side. Loose coupling is one of the most important concepts of SOA.

Service Contract

Service should be defined and be agreed upon by the provider and consumer. My airline in this example agrees to provide me a seat in economy class, provide me with the standard in-flight service, and fly me from Denver airport's particular gate to the SFO airport. I agree to this service by buying the ticket using standard currency (USD in this case). I also agree to be physically present at the airport at the defined time, look up for the gate information, go through the security and walk to the defined gate. Besides the basic known things, there is a formal contract between me and airline (service provider and the consumer). Some of the standards components of service definition in our example are Airports, Flight Numbers, Currency, and Security.

Service Discovery

The airline that provide me this service is listed on my corporate travel web site as well as other standard and known interfaces and thus can be discovered by me or any other customer. The service should be discoverable.

Service Composition

The airline service is composed of several other services internally. To provide the service (flying between Denver and San Francisco) to me and other customers, the airline uses various services from multiple service providers. Following are the main category of services that are used by our airline to provide the flying service

Airport Services
Employee Services
Food Catering Services
Entertainment Services

Following diagram represents the Service that is composed of several other services. Thus the end service that I use is a composite service.

Like the diagram depicts, one service can be composed of multiple service components internally. There is a layer of abstraction and thus the consumer of the service does not need to know the details. SOA is based on the principle of Service Composition.

Service Orchestration

In a music world, the person orchestrating a music orchestra symphony decides what music instrument is to be played and when it plays what is the note that it should play. In our example, the flight service has to be perfectly orchestrated to provide the desired level of customer satisfaction. Our airline has to use internal and external services in an ordered and defined way as a process flow. Every service component like drinks, video, audio, announcements are well planned and orchestrated. The airline decides the process flow, execution, and timing of services that we noticed in the diagram above for service composition. Every process in the service has to be executed in a perfect order and style.

This is Service Orchestration and is a very important component of SOA.

Important Characteristics of Service Orientation

Based on my understanding I came up with the following main characteristics or Service Orientation

Service Discover-ability
Service Interactions and Amalgamation supported by Open Standards
Service Composition
Service Abstraction
Service Loose Coupling
And also importantly Service Real World Effects

What is Service Oriented Architecture?

If we are already living in a world that works based on service oriented approach, what is so different about applying it to software architecture? What is the entire buzz about?

SOA is a simple and common sense approach adopted from the way things work in our surroundings to the more complex, tightly coupled, and rigid world of software.

SOA as it relates to software paradigm is an agile architecture approach that is based on service-oriented principles of composition, abstraction, loose coupling, discover-ability, and amalgamation. SOA inherently empowers scalability, evolution of services, interoperability, reusability, and modularity.

Why is SOA Needed?

Simplicity is desired for the traditional and complex IT world. Better and common sense approaches should be enabled. SOA is needed for the following main reasons:

To provide seamless agility to business
To improve business process visibility
To simplify the current rigid and complex state of IT
To enhance efficiency and provide cost-effectiveness
To enable reusability factor
To provide better quality of service

How is one company's SOA different than the other?

SOA as such is not a product that can be bought, rather is an approach towards building modular software using service-oriented principles. There are tools that can be used to realize the service-oriented approach efficiently. Many companies provide tools for assisting enterprise software implementation based on services and service-oriented architecture approach. In case of Oracle, the components for SOA are bundled as SOA Suite which is a complete set of service infrastructure components for building, deploying, and managing SOAs.

Find more about Oracle SOA Suite

Silicon Valley Code Camp 09

Sun, 04 Oct 2009 15:53:35 -0800

Attended Silicon Valley Code Camp this weekend. They had great sessions for people interested at looking at real code. Met some wonderful people really passionate about technologies.

Oracle had some interesting sessions there too.

http://www.siliconvalley-codecamp.com/

Recommended!

ESB and java.security.PrivilegedActionException

Sat, 07 Mar 2009 09:34:50 -0800

I was running into ESB Invocation failures and was not able to invoke ESB processes from BPEL/ESB processes with the following error

"java.security.PrivilegedActionException: javax.xml.soap.SOAPException"

It was hard to find the root cause of this error as we were not using any soap header security mechanism as the error might suggest or imply.

If you are getting this exception and are not using any security mechanism, try to check for any unknown / special characters in the input message payload. In my case that was causing it to fail with the above error message, once I got rid of the special characters this error went away.

FOTY0001: type error

Fri, 27 Feb 2009 14:05:01 -0800

If you are using Cross References (using xref:lookupXRef1M) function in your integration processes (BPEL/ESB) and ever come across the following error

"XPath expression failed to execute.

Error while processing xpath expression, the expression is

Please verify the xpath query."

This exception can occur because of the following reasons:

The cross reference table with the given name is not found
The specified column names are not found
The specified reference value is empty
Multiple values are found

Oracle Technology Network (OTN) TechBlog

Tue, 24 Feb 2009 20:03:58 -0800

If you have not checked out the OTN TechBlog already, I would like to share this great resource blog from Justin Kestelyn. He is the OTN Editor-in-Chief.

Here is the link to his blog

http://blogs.oracle.com/otn/

Best Practices: SOA and Enterprise Applications

Sat, 21 Feb 2009 20:14:17 -0800

Oracle Fusion Middleware Best Practice Centers for Applications are great reference sources for information on Service Oriented Architecture for Enterprise Applications.

Following are the links to pages for each application:

Best Practice Center: Oracle E-Business Suite and Fusion Middleware

Best Practice Center: Oracle Siebel and Fusion Middleware

Best Practice Center: Oracle PeopleSoft and Fusion Middleware

Best Practice Center: Oracle JD Edwards and Fusion Middleware

I am also a contributor and so far have shared my experiences at Best Practice Center: Oracle E-Business Suite and Fusion Middleware. This blog is also listed there.

There is wealth of information available on these centers and comes from experts in their fields. Highly recommended!

Technorati

Fri, 20 Feb 2009 22:14:20 -0800

Technorati Profile

Cloud Computing

Sun, 08 Feb 2009 14:54:40 -0800

What is Cloud Computing?

Try searching for "cloud computing" in google and you get 16,200,000 results.

There is lot of interest about Cloud Computing and what it means as it applies to different aspects of computing paradigm. It is more than just Software as a Service (SaaS), which relates to hosted on-demand delivery of applications.

Based on my understanding, Cloud Computing is about applications, platform, infrastructure, and storage resources being available as services.

There are many interesting discussions about what it is and what should be the definition of "Cloud".

Instead of trying to coin yet another definition of "Cloud", I tried to find a somewhat formal but plausible definition. This is the closest one I found. It is from an article published in ACM SIGCOMM Computer Communication Review

"Clouds are a large pool of easily usable and accessible virtualized resources (such as hardware, development platforms and/or services). These resources can be dynamically re-configured to adjust to a variable load (scale), allowing also for an optimum resource utilization. This pool of resources is typically exploited by a pay-per-use model in which guarantees are offered by the Infrastructure Provider by means of customized SLAs."

"A Break in the Clouds: Towards a Cloud Definition", Luis M. Vaquero, Luis Rodero-Merino , Juan Caceres, Maik Lindner, ACM SIGCOMM Computer Communication Review 50 Volume 39, Number 1, January 2009

Oracle and Cloud Computing

Visit Oracle Cloud Computing Center to learn about Oracle's offering that allow enterprises to benefit from the developments taking place in the area of Cloud Computing.

Searching BPEL process instances by business keys

Fri, 06 Feb 2009 09:37:37 -0800

Out of the Box Search Capabilities

BPEL Console provides several out of the box features for searching the process instances using multiple search criteria. Following are the main search criteria that can be used within BPEL console

All the above are very powerful features for process administration.

Enterprise Integrations and Support

Enterprise integrations deal with business data and transactions. These integrations often have interactions between multiple layers. In case of a failed transaction at any layer, the support function personals can spend a great deal of time and energy on finding the issue and troubleshooting it. I wrote about this in one of my previous post "Service Oriented approach for ERP integration".

Now imagine a use case where thousands of messages are being processed every minute. Searching by some of the default criteria’s can result in multiple search results.

Lets take an example.

Custom Search Requirement Example

Lets assume that there is a BPEL process that processes orders in Oracle E-Business Suite. The order details are coming from an external application that is used by end users which in turn publishes to a JMS queue. The BPEL process picks up from the JMS queue and creates an Order in the EBS with the Order Number that comes from the message.

In the above example, if the end application does not receive an order confirmation, you can imagine there can be many reasons for that. One of them could be that the bpel process instance failed for some reason.

When it comes to tracking that order, the end application support will most likely call the support and mention that for this particular order (along with some sort of business key like the order number) there was no confirmation received.

In a production environment, there may be thousands of process instances. For our bpel support person to browse through the instances just by time can also take some time. But for him to be able to search the process instance by using a business key can prove to be extremely useful.

So the question from business user and administrator becomes

Can I search by Order Number?

The answer is YES.

Is there a simple way to do it?

Any one who has worked with application integration can relate to it and would agree with it. Now the question is “Is there a simple way to do it?”

The answer is YES.

Let’s Do It

Let's build one simple bpel process from scratch and find out how can we achieve this highly desirable functionality

Step 1

Right Click on your application and select “New Project” option

Select BPEL Process Project

Step 2

Name the process “SearchableUsingCustomKeyProcess

Step 3

For simplicity we will proceed with the default option

Step 4

So now we have a skeleton asynchronous BPEL process

Step 5

Click on SearchableUsingCustomKeyProcess.xsd

Change the name of the input to orderNumber

Step 6

Drag and drop a Java Embedding activity from the Process Activities drop down on right hand side

Name it “JavaEmbeddingToSetProcessTitle”

Step 7

Double click Java Embedding you just added

Add the following code

Step 7

Deploy the process on server

Step 8

Initiate the process from BPEL console with “1001” as input to the orderNumber field

Notice the instance title is different than the process name. This is because of the setTitle statement in our Java Embedding.

Click on Audit Flow and then on the Java activity to make sure that the instance ran without any errors

Step 10

Let’s see if we can search by our custom field (order number) that we want to search for out of many bpel process intances in the console

Click on Instances

Now put the following into the Title field under Locate Instances and click “Go”

“OrderEntryBPELProcess - OrderNumber:1001”

Notice how we are able to search for our particular order number (1001).

You can search for other order numbers easily by just replacing the end of the string with the order number. For example searching for the following string within the title field will search for order number “2001”

“OrderEntryBPELProcess - OrderNumber:2001”

Summary

Requirements related to searching for a process instance in BPEL console by using a custom field could be addressed by the approach demonstrated in this post.

This example demonstrates that it can be done and it can be done easily.

Java Embedding in BPEL Process

Fri, 30 Jan 2009 20:34:29 -0800

If you have a Java embedding in your BPEL process and have ever wondered where (if not domain.log) the output is written to if you do something like

System.out.println statement from your code within the java embedding

The output gets written to the file under /opmn/logs/default*.log

Siebel Record Locking with Web Services

Tue, 27 Jan 2009 22:03:28 -0800

Error: "The selected record has been modified by another user since it was retrieved"

Reason: The reason we were getting this error in our case was because of the custom scripts. Execution of custom scripts on the Business Components was slowing down the WriteRecord process. This was resulting in the record locking issue.

One way to know if custom scripts are causing this error is to disable all custom scripts (if any) and then try to run the web service to check if you still run into the same error. If yes, following references might help.

Related References:

Troubleshooting Workflow Process Execution Problems
http://download.oracle.com/docs/cd/B40099_02/books/BPFWorkflow/BPFWorkflow_Admin20.html

Defining an Error Exception to Handle an Update Conflict
http://download.oracle.com/docs/cd/B40099_02/books/BPFWorkflow/BPFWorkflow_Design22.html#wp1223641

ORABPEL-10902

Tue, 27 Jan 2009 22:01:36 -0800

I was getting this error when trying to deploy or compile a bpel project

Error:
[Error ORABPEL-10902]: compilation failed
[Description]: in "bpel.xml", XML parsing failed because "undefined part element.
In WSDL at

Please make sure the spelling of the element QName is correct and the WSDL import is complete.
".
[Potential fix]: n/a.

The problem was that the within my wsdl file the schema definition included an import statement and the schemaLocation attribute was not pointing to correct path

http://www.w3.org/2001/XMLSchema">
http://something:someport/MyXSD.xsd"/>

Once this was changed to correct url, the error went away.

Siebel Web Service Invocation Error

Mon, 07 Jul 2008 15:05:52 -0800

Issue: Error code: SBL-EAI-04313 while invoking a Sibel Web Service from BPEL.

Error Details:

“There is no active Web Service with operation named 'http://siebel.com/asi/:SiebelAccountInsert'.(SBL-EAI-04313”

      EAIObjMgr_enu_0024_25165939.log


            SBL-EAI-04313
            IDS_EAI_WS_OP_NOT_FOUND
            There is no active Web Service with operation named 'http://siebel.com/asi/:SiebelAccountInsert'.(SBL-EAI-04313)

Solution:

I was able to resolve this issue by doing the the following:

1. Login to Siebel

2. Browse to Administration - Web Services

3. Within Siebel WS Administration, make sure that the status of WS is ‘Active’

4. Make sure that the Binding is set to SOAP_DOC_LITERAL

5. and finally Clear the Cache by clicking the “Clear Cache” button

Service enable integration business services using Oracle Application adapter

Fri, 28 Mar 2008 12:22:54 -0800

To make the business service within E-Business Suite participate in your service oriented integration architecture as a web services. The integration approach used depends upon the requirements and the integration mechanism that is best suited to satisfy the requirements. To use one of the integration function in a SOA based solution (integration or composite process) is relatively simple with the help of Oracle Applications adapter by exposing them as web services. This enhances re-usability, extensibility, and faster design to deploy time frame.

Using EBS adapter has tremendous advantages. It exposes existing EBS Integration Interfaces as Web Services. The adapter inherently uses and leverages open standards, including J2CA, XML, WSIF, WSIL, and WSDL. Most importantly it dramatically reduces the time to design and develop a SOA based integration that interfaces with web service based integration interface for EBS.

E-Business Suite Integration: Using Irep to discover available business services

Thu, 27 Mar 2008 15:40:28 -0800

To plan your soa based integrations, the architects and business users need to know what services are available within ebs that can be leveraged to be a part of your information integration, business process integration or coming up with composite application spanning across enterprise silos.

The first step when planning and designing your integrations should be to use Oracle Irep. This will give you the details of the business services available within EBS and also the details of service end-points. IRep lets users easily discover the appropriate business service interface for integration with any system, application, or business partner.

It is a pre-built central catalog of information about the numerous public integration interfaces delivered with Oracle applications, known as business interfaces.

The key advantages of using Irep are

Helps in better integration planning by providing information to make informed decisions

Acts as single source of truth for the available business servicesEnhanced re-use of existing components

Assurance that you are using supported public interfaces

Using Irep

Go to http://irep.oracle.com/

If you are working on EBS R12: From the Navigator menu, select the Integration Repository responsibility, then click the Integration Repository link that appears.

Browse IRep

: You can browse Irep using the categories of product or by the integration standards you wish to leverage.

Search IRep:

IRep also lets you search using various search parameters. You can search by interface name, internal name, product family, interface type (concurrent program, web service, XML gateway map etc), product, and business entities.

In Release 12, the Oracle Integration Repository will ship as part of the E-Business Suite. As your instance is patched, the repository will automatically be updated with content appropriate for the precise revisions of interfaces in your environment. But until Release 12 is available, you can explore an on-line version of the Integration Repository for the 11i10 version of E-Business applications.