CLOUD DEVELOPMENT
Running a Web service on Google App Engine
William Brogden, Contributor
07.21.2009
Rating: --- (out of 5)
|
App Engine is Google's service for building Web applications in the cloud. The initial version only supported Python, but Java servlet support has recently entered early release. Developers can experiment with a quota of free resources, so naturally I was interested. I downloaded the software development kit (SDK) Version 1.2.1 and got the Google plug-in for Eclipse 3.4.2. Documentation for the Java version has not quite caught up with the quality of the Python documentation, but you'll find what you need with a little digging.
App Engine Java servlet environment
The runtime environment for the App Engine is Java 6 with the standard libraries. The structure of a Java servlet in the App Engine environment follows normal Java practice for Servlet API 2.5 with certain restrictions. All of the static resources normally served directly by the servlet container -- such as HTML files, CSS files and images -- are placed according to convention under the root directory of the application. For example, you might have a logo image addressed as "/graphics/mylogo.gif."
Resources that are private to the application and are only read, never written, such as jar libraries, class files and configuration files, are stored under the usual "/WEB-INF" directory. For obvious security reasons, Google can't let an application wander unrestrained through the file system, so if your application reads and writes files, you will have to make some major adjustments to use the persistent data-storage methods that App Engine supports. Furthermore, your servlet must complete a response within 30 seconds and may not start any new processes.
Scaling to an increased user-request load is handled automatically by creating new instances of an application and removing them when the load decreases. The App Engine environment ensures that all instances will have access to correctly updated common resources. Here are some of the Google specific tools your application can mak...
To continue reading for free, register below or login
To read more you must become a member of SearchCloudComputing.com
|
|
Rate this Tip
|
To rate tips, you must be a member of SearchCloudComputing.com.
Register now
to start rating these tips. Log in if you are already a member.
|
DISCLAIMER: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.
|
|
|
|
|
|
|
