PRABATH'S TECH BLOG

Some scenarios we need to select different backend pools based on some attributes in the request. Nginx has that capability to selecting different backend pools based on the request header value. To accomplish this in Nginx you can use the following code in your configuration. upstream gold { server 127.0.0.1:8080; server 127.0.0.1:8081; server 127.0.0.1:8082; } upstream platinum { server 127.0.0.1:8083; server 127.0.0.1:8084; server 127.0.0.1:8085; } upstream silver { server 127.0.0.1:8086; server 127.0.0.1:8087; } # map to different upstream backends based on header map $customer_type $pool { default "gold"; platinum "platinum"; silver "silver"; } server { listen 80; server_name localhost; location / { proxy_pass http://$pool; #standard proxy settings proxy_set_header X-Real-IP $remote_addr; proxy_redirect off; p...

When it comes to Microservices architecture, the deployment of Microservices plays a critical role and has the following key requirements. Ability to deploy/un-deploy independently from other Microservices. Developers never need to coordinate the deployment of changes that are local to their service. These kinds of changes can be deployed as soon as they have been tested. The UI team can, for example, perform A|B testing and rapidly iterate on UI changes. The Microservices Architecture pattern makes continuous deployment possible. Must be able to scale at each Microservices level (a given service may get more traffic than other services). Monolithic applications are difficult to scale individual portions of the application. If one service is memory intensive and another CPU intensive, the server must be provisioned with enough memory and CPU to handle the baseline load for each service. This can get expensive if each server needs high amount of CPU and RAM, and is exacerbated i...

In the typical filter or handler pattern  we have set of data and filters/handlers. We are filtering the available data set using available filters. These filters may have some dependencies(In business case this could be the sequence dependency or data dependency) like filter 2 depends on filter 1 and some filters does not have dependency with others. With the existing approach, some time consuming filters are designed to use several threads to process the received records parallely to improve the performance. However we are executing each filter one after another.  Even Though we are using multiple threads for high time consuming filters, we need to wait until all the record finish to execute the next filter. Sometimes we need to populate some data from database for filters but with the existing architecture we need to wait until the relevant filter is executed. We can improve this by using non blocking approach as much as possible. Following diagram shows the ...

In the software world, application monitoring is critical for the administrators as well as for the maintenance(Application support) teams. Obviously monitoring is very useful for the administrators. They need to monitor the realtime behavior of the application to give uninterrupted service to the end users, but monitoring is even important to the support teams to track down the issues of the applications. Doing support is the most important phase of the software development life cycle after delivering the product. End Users reported  different kind of issues and support engineers need some informations which are related to the application behaviour to solve the issues. Some issues are domain related and we can simply recreate the issues in our local environment. Fixing the issue is not a big deal if we could reproduce the same behavior in our local setup but some issues are not easy to replicate in the local environment because those aren’t continuously happening in the ...

As a company or individually, you may need to deliver your goods from one place to another place. The most important thing is selecting the suited shipment mode for your logistics. Following are the major modes of shipments.  1. Ground Land or "ground" shipping can be done by train or truck.In order to take air and sea shipments,   ground transportion is required to take the cargo from its place of origin to the airport or seaport .it is not always possible to establish a production facility near ports due to limited coastlines of countries. 2. Air Cargo is transported by air in specialized cargo aircraft or in the luggage compartments of     passenger aircraft 3. Ship Shipping is done by commercial ships. Merchant shipping is the lifeblood of the world economy,   carrying 90% of international trade with 102,194 commercial ships worldwide 4. Intermodal Intermodal freight transport refers to shipments that involve more than one mode....

1. Download JConsole topthreads Plugin. 2. Add following entries to the PRODUCT_HOME/bin/wso2server.sh     -Dcom.sun.management.jmxremote \     -Dcom.sun.management.jmxremote.port=PORT \     -Dcom.sun.management.jmxremote.ssl=false \     -Dcom.sun.management.jmxremote.authenticate=false \     -Djava.rmi.server.hostname=IP_ADDRESS \ Define your IP_ADDRESS address and PORT (port should be not used anywhere in that instance) 3. Run the JConsole using following command.     jconsole -pluginpath PATH_TO_JAR/topthreads-1.1.jar 4. Copy "JMXServerManager JMX Service URL" from the wso2carbon logs after restart the Wso2 Server (Eg:- service:jmx:rmi://localhost:11111/jndi/rmi://localhost:9999/jmxrmi) to the Remote process with the username and password. 5. Under Top Threads tab you can monitor the thread CPU usage.

We cannot use cipertool to automate encryption process for the selected elements in the jndi.properties file, because we can only specify Xpath notation here, but still we can use the manual process. Sample  [ESB_home]/repository/conf/ jndi.properties  file # register some connection factories # connectionfactory.[jndiname] = [ConnectionURL] connectionfactory.QueueConnectionFactory = amqp://admin:admin@clientID/carbon?brokerlist ='tcp://localhost:5672' # register some queues in JNDI using the form # queue.[jndiName] = [physicalName] queue.MyQueue = example.MyQueue # register some topics in JNDI using the form # topic.[jndiName] = [physicalName] topic.MyTopic = example.MyTopic 1. Enable secure valut in the ESB sh ciphertool.sh -Dconfigure 2.   Go to the [ESB_home]/bin and execute the following command to generate the encrypted value for the clear text  password. sh ciphertool.sh 3.   It will prompt following  console fo...

This blog post assumes that the user who reads has some basic understanding of SSL tunneling and the basic message flow of the ESB. If you are not familiar with the concepts of the SSL tunneling you can refer my previous blog post about the SSL tunneling and you can get detail idea about the message flow from this article . I will give brief introduction about the targetHandler for understand concepts easily. As you may already know TargetHandler(TH) is responsible for handling requests and responses for the backend side. It is maintaining status (REQUEST_READY, RESPONSE_READY .. ,etc) based on the events which fired by the IOReactor and executing relevant methods. As the example if a response which is coming from the backend side hits to the ESB, IOReactor fire the responseRecived method in the targetHandler side. Followings are the basic methods contain in the target handler and their responsibilities. Connect: -  This is executed when new outgoing connection needed. ...

You want to be able to access some restricted destinations and/or ports with some applications from your computer but you are on a restricted network (corporate) - Even using a Torrent client. How to overcome this limitation?  What if backend service is secure one? We can use SSL tunneling for overcome above issue. What is the SSL tunneling? SSL tunneling is when an Internal client application requests a web object using HTTPS on port 8080 through the proxy server.  An example of this is when you are using online shopping. The internet connection to the target relevant e-commerce website  is tunneled to by you through proxy server. The key word here is through. The client communicates with the target web server directly after the initial connection has been established by proxy server, by means of communication within the SSL tunnel that has been created after SSL negotiation has taken place. How it's working? The client makes a tunneling...

Synapse handler is new feature which come with the ESB 4.9.0. It provide abstract handler implementation to the users. User can create their own concrete handlers which is executing in the synapse layer. Main intention of this blog post is to explain how to write synapse handler and explain basic theoretical background. 1. What is the handler? Handlers are basically talking with the chain of responsibility pattern. Chain of responsibility allows a number of classes to attempt to handle a request independently of any other object along the chain. Once the request is handled, it completes it's journey through the chain. The Handler defines the interface which required to handle the request and concreteHandlers handle request in a specific manner that they are responsible for. 2. What is Synapse handler? Synapse handler is providing abstract handle implementation which executes in the following four scenarios. 1. Request in flow This is exe...