Cloud computing opens new perspectives in data management, application development, and internetworking technologies. Google, Amazon, and Salesforce are leading companies in cloud computing.
Cloud developers provide three major cloud system types: software as a service (SaaS), infrastructure as a service (IaaS), and platform as a service (PaaS). With SaaS, the consumer pays for a subscription to some software, and all or part of the consumer’s data and managing code reside on remote servers. Both horizontal and vertical market software are leased through service level agreements (SLAs). Some typical examples of horizontal SaaS are subscription management software, mail servers, search engines, and office suites, and some examples of vertical SaaS are more specialized, such as accounting software, management information systems, and customer relations management systems. Google Docs is a popular SaaS example. Consumers access Google Docs via a thin client--that is, a Web browser.
IaaS delivers on-demand virtual machines that provide scalability to the running software. IaaS involves the physical storage space and processing capabilities that enable the use of SaaS and PaaS, if so desired (or these services can be used autonomously by the customer). Hardware, servers, and networking components are typical examples of IaaS. Amazon’s Elastic Compute Cloud (EC2) implements this type of service.
Finally, with PaaS, the software developers build code that is executed on a PaaS provider’s platform--instead of the platform owned by an enterprise. PaaS is a development platform hosted in the cloud and accessed via a network. The functionality that PaaS offers involves at least the following: developer studios that include all necessary tools to build a Web application, seamless deployment to the hosted runtime environment, and management and monitoring tools. PaaS offers the potential for general developers to build Web applications without having any tools installed in their own space. Google App Engine (GAE), a characteristic example of PaaS, allows developers to have an immediate available platform for hosting their Web applications. In particular, the service allows developers to use Google’s powerful services, such as BigTable and authentication services.
This book is precisely about how to build applications coded in Java that will run over Google’s flagship PaaS product. Its authors are two experienced software engineers who have been active members of the cloud computing ecosystem for the last five years. The book is one of few in the literature that provides concrete examples of how to build and deploy applications in the cloud.
The book consists of nine chapters. The authors explain, from the ground up, how to build and deploy various Web applications running over the App Engine. The first four chapters present the basic features of the App Engine and alternative libraries that run on the App Engine, and then conclude with the creation of a primitive project. The remaining five chapters show, using extensive code examples, how to authenticate users, how to use the App Engine’s data store, and how to administer the application (versioning and log file analysis).
Potential readers need to have a good knowledge of the Java programming language and sufficient familiarity with integrated development environments (IDEs), since installation and the use of Eclipse (and the Google plug-in for Eclipse) are required. The target audience includes software development professionals and, to some extent, members of academia--graduate students, instructors, and researchers--who wish to explore the benefits and vulnerabilities of cloud computing, particularly the virtues and drawbacks of PaaS.
