Cloud computing applications on google app engine platform

GAE lets you write web applications based on the Google's infrastructure. Means you don't need to care about is the web page you are hosting like (including database), but just interested in developing applications in the APIprovided by Google. With  App Engine, you just upload your application, and it's available ready to serve your users.
Overview of Google App Engine

You can use your own domain name (e.g., as http://www.example.com/) through google apps. Or you can use sub-domain free appspot.com. GAE lets be a free host with 1 GB of storage capacity and allow 5 million monthly pageviews, pass this level you will have to pay the fee. Use The GAE, us from having to design the database, write SQL to query data, map data with the object. We just design the class and GAE automatically handle to work with the database. In summary, now you just have to think and write the most amazing application and then call on the whole world to use.

However, the downside of building apps on GAE is you will depend entirely on the Google technology and very hard to split off into a standalone application. Yahoo or Microsoft will never buy an application built on the Foundation of the opponent. Also, the investors are also very afraid when the assets of the company you put out into the hands of other people, whether it is Google.

GAE is Google launched on April 2008 Python language support. To April 2009, GAE has announced support for the second official language is Java, mark a big change in the way of building applications. Some other languages such as PHP can also run if installed together with the switch from PHP to Java.

GAE is modeled cloud computer PaaS platform. GAE allows customers to deploy to run web applications on Google's infrastructure. With the ease of construction, maintenance and scalable, GAE has been the development and deployment of business use.

With the cost of building and deploying the initial application is almost zero, customers to easily build on-demand applications. When the application has obtained profits and pass the level use of the customer only must pay the charge that his resources were used.

Development environment
An App Engine application meet the requirements. A web request will start when there is a user or the user's web browser sends a request to access the to the application via the HTTP protocol. When App Engine receives a request, it will correctly be intended application based on the domain name or subdomain of. appspot.com (provided free each application) or as a separate domain name we have registered and set up with Google Apps. App Engine selects a server from multiple servers to handle the request. Then, App Engine will send the requests received from users to the appropriate application to handle. After you have finished processing the applications will send data back to App Engine, App Engine will receive data feedback from the application and returned to users through a web browser. Under angle of view of the application environment, enforce only appear and exist when starting a request and will disappear when the request is met. App Engine provides a minimum 2 way data storage exists between the requirements, but the mechanism of this exist outside execution environment. Environments will not maintain state between requests, or at least for not wanting the status will be maintained between requests. App Engine can distribute traffic to many servers, because it needs to respond to many requests processed same reason, regardless of how much traffic will it handle at the same time.

GAE has itself mechanisms to manage the status of each requirement in each application as the Sandbox (developer unknown mechanism inside but support people develop the necessary services). This allows App  Engine to process a request to the server that it wishes its estimates in order to return the fastest response. No way to make sure that hardware on the same server will process the request twice, even when the request comes from a client, and to rather quickly. Sandboxcho allows App Engine to run multiple applications on the same server, in which the behavior of an application do not affect other applications. In addition to the limit access to the operating system, environmental enforcement also limited the use of the CPU and the remember. App Engine keeps this limited flexibility and more closely these limits to the use more resources than to protect shared resources from the application "not desirable". Each request has a maximum of 30 seconds to return a response to the client. Although this time seems good response for a web application, but the App Engine is optimized for the application response applications, less than a second. In addition, if an application uses more CPU, App Engine can slow it down, so that applications do not delay processor on a multi-server applications. A centralized CPU processing requirements may take a long time to complete, when App Engine scan, the CPU usage model and allocate accordingly.

Google App Engine provides two main execution environments for the application. That is the Java and Python, currently testing on the Go. The environment we choose will depend on the language and the related technology when we used to develop the application. The Java environment to execute the application was written for JVM6. Applications can be developed based on the Java programming language or a language most can compile and run on JVM: PHP example (using Quercus), Ruby (JRuby), Javascript (using Rhino), Scala, Groovy. App Engine also supports Google Web Toolkit (GWT). The Python environment to execute the applications are written based on the programming language Python 2.5 release. App Engine Python application called thanks to CGI. The application can use the most of the library of Python, Python's frameworks such as Django, web2py, Django. Both Java and Python environment are used same a model: a request to send to the application on the server, the application is activated (if necessary), the request processor calls and returns results for the client. Each environment using preprocessing (interpreter) for their own (JVM or Python).

Application deployment
  • To edit the information on the site users log into the admin page
  • To the user management page "administrate users" will allow to create new, edit the information anddelete user information.
 GAE gives us a crisp view of the cloud, about a model using the platform the provider, in which virtualization technology resources hardware, software, and systems the network, resources are dynamically allocated to ensure simplicity, flexibility, and scalability  high reliability is put on top. With GAE, customers can build and deploy web application onto the infrastructure of Giants Google - one of the most reputable airlines in the world.
 
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