Enterprise Application Integration and Enterprise Serivce Bus

Enterprise Application Integration

• Integrating systems and applications together
• Get software systems to work in perfect synchronism with each other
• Not limited to integration within an organization
• Integrating with customer applications
• Integrating with supplier/partner applications
• Integrating with public services

By using EAI, we have got another problem that how can we talk to each different services which develop on different technologies, different languages, different protocols, different platforms, different message formats and different QoS requirements (security, reliability). ESB is the rescue for this problem. 

Now we will see how can we use ESB to resolve this problem. Think a real scenario. A Chinese girl is joining who does not know English in your classroom. Think you know only Englis and you don't know Chinese. So how can you communicate with that Chinese girl? In this scenario, you can a friend who knows Chinese and English. Through that, you can easily communicate with that girl. This is cost and time effective as you don't need to study Chinese. 

Now we can apply this solution to the software industry. Let's assume, you are developing a business application for buying a dress. There you need to talk to Sales System, Customer System, and Inventory system. In this example, let's assume sales system built using SOAP protocol (Exposing SOAP services). Customer system using XML based REST services and Inventory system using JSON-based REST services. Now you need to deal with multiple protocols. Here we can use ESB as the rescue. 

What is ESB?

The normal bus is used to transfer from one place to another place. In ESB, you need to pass your message to ESB, ESB will pass your message to a destination. Also if destination sends a response, ESB will take that response and deliver to you. In the previous example, sales system will send the soap message to ESB. ESB will take this message and convert it to XML based REST message to the cusomer system. You may connect to multiple application through ESB. But you only need to do one simple connection which calls ESB only. ESB will talk to rest of the applications.

Introduction to SOA (Service Oriented Architecture)

Hi all,

In this blog, we will see about What is SOA in a simple way with real world examples.

Before coming to the point what is SOA, we need to know why SOA is needed and why it had been evolved. For this, we will go with simple real world example. Think about an old radio. In there everything is integrated such as FM radio, The cassette player, the speaker ... But if we want a double cassette player or CD player, we have to change the whole thing again and again. But with modular applications, each part is independent. We can add other items to the already available thing. There should be a way to communicate with each component.

Let's apply this scenario to the software industry. Initially, we used standalone application which is run on one computer and do one job. Database, UI, everything is in the simple computer. Then there was a requirement that multiple users need to access at the same time. For that, we got Client Server architecture. This means you have the front end on your machine and database logic & rest of the things in the different machine which is called as a server. Every client calls the same server machine. Then requirements had been grown. So people moved to different architecture 'Multi-tier architecture'. The front end is on your machine. Business logic implemented in different server and DB is on another server. After that people decided to go in distributed applications. For example, one application does a part of the job, another application does that's job and the third application does another job. By integrating all these jobs, you can fulfill your requirement. That means different services and different responsibilities owned by the different applications.

Here you have other problem that how can we inter-connect with these applications. Practically application A can run on the Linux which is implemented using JAVA, Application B runs on windows which are implemented in C#. Here JAVA application needs to communicate with the C# application. So we need the new model. To overcome this scenario we came u with SOA model. SOA means Service Oriented Architecture.

So we need to know what is service? When we connect to the application, the application may not expose everything that it can do. But it may expose certain functionalities to the world. For example, Hotel reservation system may expose register, login, get booking details and book rooms. But all other private functions will keep privately. When they expose the functionalities,  we called it as service. We depend on multiple services to achieve a specific goal. This is what service oriented architecture.

"A set of principles and practices for modeling enterprise business functions as services or micro services which have following attributes."

The features of SOA are

• Standardized: Support open standards.
• Loose Coupling: Need to give required data to the interface and expects the response. Processing will be handling by the service.
• Stateless: The Service does not maintain state between invocation
• Reusable
• Autonomic
• Abstract
• Discoverable

Couples of example for SOA

• The supply chain management system should keep an eye on the inventory management system
• Decision support systems cannot help make useful decisions without insight to all the aspects of the business

In next blog, we will see some more about SOA and WSO2 ESB.

Working with cloud instances in WSO2

Hi all,

I had a chance to work with cloud instances in WSO2 environment. There are four instances which are created in ubuntu environment. I have had cluster set up of four nodes in cloud.

In this blog I am not going to explain the cluster setup. Here there will be a brief explanation of cloud instances and how can we handle it.

When we are creating cloud instance we will get a key for that. After that we need to change mode of the file by following command.

    change key file permission : chmod 600 <file>

Then we can  start the instance by specifying the IP address of the node. 

    ssh -i <key file> ubuntu@<IP>

When we starting it, it will ask passpharase for key. we need to give that value.

Now we have started the cloud instance.

The cloud instance will look like pure computer when we buy it (Except OS might be installed). So we need to all other things from the terminal.

• Command to download from a web link.
  
  sudo apt wget <link>
  
• To install unzip
  
  sudo apt get unzip
  
• Need to install JAVA as same as installing JAVA in ubuntu [1]
  
• If you want to copy from local machine to cloud instance, you can use sftp.
  
  Need to start sftp in the cloud instance.
  
            sftp -i <key file> ubuntu@<IP>
  
  Copy file
  
            put <FROM> <TO>

References

 [1] https://www.digitalocean.com/community/tutorials/how-to-install-java-on-ubuntu-with-apt-get

RabbitMQ SSL connection Using RabbitMQ Event Adpter in WSO2 CEP- Part 2

stHi all,


This is the continuous blog of this blog. In the previous blog we saw about rabbitMQ broker side configuration. Here we are going to see about specifying CEP side Configuration. RabbitMQ Receiver is an extension for the CEP. So we need to download it and put it into the CEP. Those are given below.

Steps 

1.  Please visit this link to download RabbitMQ Receiver extension.
2. Download rabbitmq client jar from this link. 
3. Place the extension .jar file into the <CEP_HOME>/repository/components/dropins directory which you downloaded in step 1.
4. Place the rabbitmq client .jar file into the <CEP_HOME>/repository/components/lib directory which you downloaded in step 2.
5. Start the CEP Server by going to directory <CEP_HOME>/bin in terminal and giving command like sh ./wso2server.sh
6. Create a Stream in CEP. Refer more here.
7. Go to Main => Manage => Receiver to open the Available Receivers page and then click Add Event Receiver in the management console. You can get the management console by visiting the https://172.17.0.1:9443/carbon
8. Select Input Event Adapter Type as rabbitmq.
9. Then you will get a page like below.

   9. Then you need to specify values for the properties given above. Here I have mentioned important and  mandatory properties' values.

• Host Name: localhost
• Host Port: 5671
• Username: guest
• Password: guest
• Queue Name: testsslqueue
• Exchange Name: testsslexchange
• SSL Enabled: True
• SSL Keystore Location: ../client/keycert.p12
• SSL Keystore Type: PKCS12
• SSL Keystore Password: MySecretPassword
• SSL Truststore Location: ../rabbitstore (These are the values we took from the part 1 blog step 5)
• SSL Truststore Type: JKS
• SSL Truststore Password: rabbitstore (The password is the one we used when we are key tool command in Step 5)
• Connection SSL Version: SSL

After specifying above values, select the stream you had add in step 3 and save it. 

Then if there is a message in the queue you mentioned in RabbitMQ broker, you will get it into the CEP. The data from the queue can be used in further in Execution plan for processing and we can publish it.

Introduction to WSO2 BPS

We can use WSO2 BPS for efficient business Process Management by allowing easy deploy of business processes written using either WS-BPEL standard or BPMN 2.0 standard.

Business Process: Collection of related and structured activities or tasks, that meants a business use case and produces a specific service or output. A process may have zero or more well-defined inputs and an output.

Process Initiator: The person or Apps who initiates business process.

Human task: In here human interaction is involved in business process.

BPEL: It is an XML-based language used for the definition and execution of business. Composing of web services and orchestration.

BPMN: Graphical notation of business processes.

Simple BPEL Process Modeling

• Download BPS product.
• Go to <BPS_HOME> -> bin through terminal and execute sh ./wso2server.sh command.
• Install the plug-in with pre-packaged Eclipse - This method uses a complete plug-in installation with pre-packaged Eclipse, so that you do not have to install Eclipse separately. On the WSO2 BPS product page, click Tooling and then download the distribution according to your operating system under the Eclipse JavaEE Mars + BPS Tooling 3.6.0 section.
• Then we need to create carbon Composite Application Project. These steps clearly mentioned in https://docs.wso2.com/display/BPS360/BPEL+Guide

 

JAVA Flight Recorder with WSO2 Products

Brief JAVA Flight Recorder

A profiling and event collection framework built into the Oracle JDK. It gathers low level information about the JVM and application behavior without performance impact (less than 2%). With Java Flight Recorder system administrators and developers have a new way to diagnose production issues. JFR provides a way to collect events from a Java application from the OS layer, the JVM, and all the way up to the Java application. The collected events include thread latency events such as sleep, wait, lock contention, I/O, GC, and method profiling. JFR can be enabled by default and continuously collect low level data from Java applications in production environments. This will allow a much faster turnaround time for system administrators and developers when a production issue occurs. Rather than turning on data gathering after the fact, the continuously collected JFR data is simply written to disk and the analysis can be done on data collected from the application leading up to the issue, rather than data collected afterwards. We can use this JFR to do long run testing in effective way.

Here we will see using JFR to do long run testing to WSO2 products through JMC (JAVA Mission Control). Here I am taking WSO2 CEP as WSO2 Product.

•  Go to <CEP_HOME>/bin and open wso2server.sh using gedit.
• In that you can see $JAVACMD. Below that add these to enable JFR
•  -XX:+UnlockCommercialFeatures \
•   -XX:+FlightRecorder \
• Start WSO2 CEP by using sh ./wso2server.sh in terminal.
• Then start JMC by clicking on that. You can see this org.wso2.carbon.bootstrap.Bootstrap in that UI like below.

• Right click on org.wso2.carbon.bootstrap.Bootstrap and click on start Flight Recording. Following window will be appear.

• Then go to next steps and do your  relevant changes and click on Finish.
• After specific time you mentioned you will get a .jfr file you can see the memory growth, cpu usage..... in that.
• You can open this .jfr file anytime.
  
  Thanks all :)

RabbitMQ SSL connection Using RabbitMQ Event Adpter in WSO2 CEP- Part 1

Hi all,

I am writing this blog by assuming you are familiar with RabbitMQ Broker. Here I mainly focus on Securing the connection between RabbirMQ Message Broker and WSO2 CEP. That means how to receive secure messages from RabbitMQ Broker from WSO2 CEP Receiver. The use case here going to explain is, CEP is going to act as a consumer and consumes messages from RabbitMQ server. So simply CEP will act as a Client and RabbitMQ Server Will act as the Server.

 Introduction to RabbitMQ SSL connection

In normal connection we send messages without secure. But some confidential information like credit card number, we can not send without secure. For that purpose, we use SSL. SSL stands for Secure Sockets Layer. SSL allows sensitive information to be transmitted securely. This layer ensures that all data passed between the server and client remain private and integral. SSL is an industry standard. SSL is a security protocol. Protocols describe how algorithms should be used. In this case, the SSL protocol determines variables of the encryption for both the link and the data being transmitted.

Steps 

1.  As First Step we need to create own certificate Authority.
   
   • For that in terminal and go to specific folder (location) by using cd command.
   • Then use below commands.
   • $ mkdir testca
   • $ cd testca
   • $ mkdir certs private
   • $ chmod 700 private
   • $ echo 01 > serial
   • $ touch index.txt
   • Then create a new file using the following command, inside the tesca directory.  
   • $ gedit openssl.cnf
     
     When we using this commanda file will open in gedit. So copy and paste following thing and save it.
     
     

     [ ca ]
     default_ca = testca
     
     [ testca ]
     dir = .
     certificate = $dir/cacert.pem
     database = $dir/index.txt
     new_certs_dir = $dir/certs
     private_key = $dir/private/cakey.pem
     serial = $dir/serial
     
     default_crl_days = 7
     default_days = 365
     default_md = sha256
     
     policy = testca_policy
     x509_extensions = certificate_extensions
     
     [ testca_policy ]
     commonName = supplied
     stateOrProvinceName = optional
     countryName = optional
     emailAddress = optional
     organizationName = optional
     organizationalUnitName = optional
     
     [ certificate_extensions ]
     basicConstraints = CA:false
     
     [ req ]
     default_bits = 2048
     default_keyfile = ./private/cakey.pem
     default_md = sha256
     prompt = yes
     distinguished_name = root_ca_distinguished_name
     x509_extensions = root_ca_extensions
     
     [ root_ca_distinguished_name ]
     commonName = hostname
     
     [ root_ca_extensions ]
     basicConstraints = CA:true
     keyUsage = keyCertSign, cRLSign
     
     [ client_ca_extensions ]
     basicConstraints = CA:false
     keyUsage = digitalSignature
     extendedKeyUsage = 1.3.6.1.5.5.7.3.2
     
     [ server_ca_extensions ]
     basicConstraints = CA:false
     keyUsage = keyEncipherment
     extendedKeyUsage = 1.3.6.1.5.5.7.3.1
     

     • Now we can generate the key and certificates that our test Certificate Authority will use. Still within the testca directory:

       $ openssl req -x509 -config openssl.cnf -newkey rsa:2048 -days 365 -out cacert.pem -outform PEM -subj /CN=MyTestCA/ -nodes

       $ openssl x509 -in cacert.pem -out cacert.cer -outform DER

   
   
2.  Generating certificate and key for the Server
• Apply following commands. (Assuming you are still in testca folder)

• $ cd ..
  $ ls
  testca
  $ mkdir server
  $ cd server
  $ openssl genrsa -out key.pem 2048
  $ openssl req -new -key key.pem -out req.pem -outform PEM -subj /CN=$(hostname)/O=server/ -nodes
  $ cd ../testca
  $ openssl ca -config openssl.cnf -in ../server/req.pem -out ../server/cert.pem -notext -batch -extensions server_ca_extensions
  $ cd ../server
  $ openssl pkcs12 -export -out keycert.p12 -in cert.pem -inkey key.pem -passout pass:MySecretPassword

   
3.  Generating certificate and key for the client
•  Apply following commands.

• $ cd ..
  $ ls
  server testca
  $ mkdir client
  $ cd client
  $ openssl genrsa -out key.pem 2048
  $ openssl req -new -key key.pem -out req.pem -outform PEM -subj /CN=$(hostname)/O=client/ -nodes
  $ cd ../testca
  $ openssl ca -config openssl.cnf -in ../client/req.pem -out ../client/cert.pem -notext -batch -extensions client_ca_extensions
  $ cd ../client
  $ openssl pkcs12 -export -out keycert.p12 -in cert.pem -inkey key.pem -passout pass:MySecretPassword

   
4. Configuring RabbitMQ Server
   To enable the SSL support in RabbitMQ, we need to provide to RabbitMQ the location of the root certificate, the server's certificate file, and the server's key. We also need to tell it to listen on a socket that is going to be used for SSL connections, and we need to tell it whether it should ask for clients to present certificates, and if the client does present a certificate, whether we should accept the certificate if we can't establish a chain of trust to it.
   
   For that we need to create file inside "/etc/rabbitmq". You have to name the file as "rabbitmq.config". Inside the file copy and paste following configuration.
   
   

   [
     {rabbit, [
        {ssl_listeners, [5671]},
        {ssl_options, [{cacertfile,"/path/to/testca/cacert.pem"},
                       {certfile,"/path/to/server/cert.pem"},
                       {keyfile,"/path/to/server/key.pem"},
                       {verify,verify_peer},
                       {fail_if_no_peer_cert,false}]}
      ]}
   ].

5. Trust the Client's Root CA
   Use the following command.

   $ cat testca/cacert.pem >> all_cacerts.pem

   To validating certificate use below command.

   keytool -import -alias server1 -file /path/to/server/cert.pem -keystore /path/to/rabbitstore

   
   If you want study more about this configuration, go to this link. Now we have finished configuration in server side and created certificates. In my next blog, I will continue this blog by specifying CEP side Configuration. :)