Porting Google App Engine Applications to IBM Middleware

Transcription

1 Porting Google App Engine Applications IBM Middleware Author: Animesh Singh, John Reif Abstract: Google App Engine is a cloud computing platform that hosts third party Web applications. Application authors write their application front ends in a high-level language like Python or Java. Applications can use other Google services like datasre and Google Accounts as their application back end. Authors upload the application front ends through the Admin console the Google App Engine. At IBM Cloud Labs we have produced interoperability code/documentation allow GAE application developers move easily IBM middleware. This document shows how port the three major Java-based Google App Engine APIs/functionalities the IBM middleware environment where application function can be expanded. The APIs discussed are datasre, Users, and URL fetch. Copyright IBM Corporation 2009

2 Introduction Google App Engine is a Google service that hosts third party Web applications. Application authors write their application front ends in a high-level language like Python or Java. Applications can use other Google services like datasre and Google Accounts as their application back end. Authors upload the application front ends through the Admin console the Google App Engine. Google App Engine is good for Web applications that are database-backed applications that look like Digg, Orkut, and Blogger. Google App Engine provides an environment run application front ends, a srage (datasre) back end, an authentication (Google Accounts) back end, an service, and a way fetch content from the Web. The Google App Engine environment limits what an application can do. Applications can read files in the application bundle, make Google App Engine API calls, and return an HTTP response the user. Applications cannot open network connections directly, write files a local disk, or run code not responding a user request. Since Google App Engine is an external hosted service, you sometimes need run your Java/J2EE code behind the corporate firewall, and all over XM enterprises choose IBM WebSphere do precisely this. Also there maybe other compelling technical and business reasons move between different environments. With this in mind, we are going discuss in this aritcle how IBM`s various middleware components can form a complete suite address all common application tasks. Just as important, we are going show how Java standards make it easy move your code from one environment the next At its most basic level WebSphere is a deployment environment for your Java code -- a regular J2EE servlet container -- and as it turns out, there are many such containers in the market. With day's Java runtime, App Engine is one example. WebSphere is another, as well as Tomcat, WebLogic and others Each of these deployment environments has its unique attributes. (WebSphere, for instance, offers complete set of J2EE features like Java Beans, JDBC, RMI and others.) Certain features and business rules will favor one environment over another, or require you move between them. But because all of these containers and databases can work with standard Java APIs and libraries, redeployment from App Engine WebSphere entails only a few config changes This document shows how port the three major Java-based Google App Engine APIs/functionalities the IBM middleware environment where application function can be expanded. If using IBM middleware implement these APIs, applicable IBM products would be used for each. For instance, a combination of IBM WebSphere Application Server v7.0 and IBM DB2 v9.1 database system would be used implement the datasre and a combination of IBM WebSphere Application Server v7.0 and IBM Tivoli Direcry Server v6.1 would be used implement the users API. The APIs discussed are: com.google.appengine.api.datasre com.google.appengine.api.users com.google.appengine.api.urlfetch Currently, only these APIs from Google App Engine are implemented/documented as part of this porting code. Future versions of this document and sample code may implement more APIs as they become available. Also please note that this is one of the ways imple nt/port the API functionalities, and a user can implement it differently. This article and associated code is meant provide guidance the users how they can port functionalities. Copyright IBM Corporation Porting Google App Engine Applications IBM Middleware

3 Building an app run on Google App Engine / IBM WebSphere Because the Google App Engine software development kit (SDK) is built on p of the Jetty server and follows the specification for a Java2 Enterprise Edition (J2EE) servlet, running a Google App Engine application on p of IBM WebSphere Application Server is straightforward. It is necessary, however, port the Google App Engine APIs support the basic application services of database access, authentication, and calls external URLs. Having mentioned that, whenever possible Google supports the Java standard, which provides the same functionality as their existing App Engine APIs. This section describes how port the Google APIs IBM mddleware, and if there is an alternative standard Java/J2EE implementation provided by Google for the functionality, we will use that. Porting datasre operations The datasre API is used persist Java objects the Google datasre. Alternatively Google also provides a Java data object (JDO) ( implementation that uses the DataNucleus project ( persist objects the datasre. Since JDO is a standard spec from Java, instead of implementing datasre API, we will be showing how datasre operations using JDO via datanucleus can be ported persist objects DB2. This assumes that the user has written a GAE application persist objects using JDO, and not proprietary Google datasre API. Follow these steps use DataNucleus write applications that can be ported from the Google datasre run on WebSphere talking IBM DB2 with minimal changes: 1. Configure DataNucleus in Eclipse using 2. Enable au enhancement enhance the classes. Identify the classes you are persisting the Google datasre, and refacr each change the primary key from String int. Google datasre takes Long, String, Key, String Encoded Key as the primary key for persistable classes, whereas DB2 takes int, Integer, long, Long through DataNucleus. 3. Change the datanucleus.properties file in your application point DB2. Here is a sample file: javax.jdo.persistencemanagerfacryclass=org.datanucleus.jdo.jdopersistenc emanagerfacry javax.jdo.option.connectiondrivername=com.ibm.db2.jcc.db2driver javax.jdo.option.connectionurl=jdbc:db2://9.x.x.x.:50000/paces javax.jdo.option.connectionusername=ldapdb2 javax.jdo.option.connectionpassword=time4fun datanucleus.validatetables=false datanucleus.validateconstraints=false datanucleus.nontransactionalread=true datanucleus.nontransactionalwrite=true So we have seen the with three minimal steps we can move an application which makes Google datasre calls IBM middleware persisting DB2 Porting user authentication operations In the context of the Google App engine, the users API is used authenticate application users against Google Accounts. In the context of IBM, we at IBM Cloud Labs have written code authenticate against IBM Tivoli Direcry Server Lightweight Direcry Access Procol (LDAP). The API code for interoperability ( InteropApis.jar ) is included with this bundle. Please note that you can implement in alternative ways also. Copyright IBM Corporation Porting Google App Engine Applications IBM Middleware

4 1. Place the InteropApis.jar in your lib direcry. 2. Import the LDIF file, userapi.ldif in your LDAP setup. dn: o=ibm,c=us objectclass: organization objectclass: p o: ibm dn: uid=guest1, o=ibm,c=us userpassword:: d2vsy29tzq== uid: guest1 objectclass: inetorgperson objectclass: p objectclass: person objectclass: organizationalperson sn: guest1 cn: guest1 dn: uid=ani@ibm.com, o=ibm,c=us mail: ani@ibm.com uid: ani@ibm.com userpassword:: dgltztrmdw4= Givenname: ANI objectclass: p objectclass: person objectclass: organizationalperson objectclass: inetorgperson title: ADMIN sn: ani@ibm.com cn: ani@ibm.com You can change dn, mail, uid, sn, and cn correspond another user, and extra users. The password shown encrypted in the above ldif file is time4fun. 3. In your application, make a direcry called resources under WebContent and add a properties file ldap.properties. A sample is provided below: LDAP_PROVIDER=com.sun.jndi.ldap.LdapCtxFacry LDAP_URL=ldap://9.x.x.x:389 LDAP_URL_CTX=com.sun.jndi.url BASE_SEARCH=o=ibm,c=us SECURITY_PROTOCOL=ssl LDAP_ROOT_USER=cn=root LDAP_ROOT_PWD=passw0rd 4. Change any package declaration import com.google.appengine.api.users.*; import com.ibm.appengine.api.users.*; and the line Copyright IBM Corporation Porting Google App Engine Applications IBM Middleware

5 UserService userservice = UserServiceFacry.getUserService(); UserService userservice = UserServiceFacry.getUserService(request); 5. Place the login.jsp and the error.jsp provided in the resources direcry. Using these steps you should be able port an application using Users API for authentication. Porting URL fetch operations The URL fetch API is used open connections external URLs. This API is written provide more security App engine operations. Although there are alternative ways achieve this on IBM platforms, we have implemented these APIs facilitate interoperability. 1. Change the following declaration in the URL Fetch API port it the IBM stack. import com.google.appengine.api.urlfetch.*; import com.ibm.appengine.api.urlfetch.*; and the line URLFetchService urlservice = URLFetchServiceFacry.getURLFetchService(); URLFetchService urlservice = URLFetchServiceFacry.getURLFetchService(request); App Engine also supports the standard java.net.url/httpurlconnection for URL fetch. Conclusion With these interoperability APIs and guidelines, you can port an application built for Google App Engine Java version an IBM middleware environment. We have implementation regarding all major APIs. As mentioned above, the InteropApis.jar is available in the bundle. For further information regarding this technical preview, send an singhan@us.ibm.com. References Google App Engine Web site: ( Sun JDO: ( DataNucleus: ( Copyright IBM Corporation Porting Google App Engine Applications IBM Middleware

6 Notices Trademarks The following are trademarks or registered trademarks the United States, other countries, or both: International Business Machines Corporation in DB2, IBM, Tivoli, WebSphere Java and all Java-based trademarks and logos are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. Special Notice The information contained in this document has not been submitted any formal IBM test and is distributed AS IS. The use of this information or the implementation of any of these techniques is a cusmer responsibility and depends on the cusmer s ability evaluate and integrate them in the cusmer s operational environment. While IBM may have reviewed each item for accuracy in a specific situation, there is no guarantee that the same or similar results will be obtained elsewhere. Anyone attempting adapt these techniques their own environments do so at their own risk. While IBM may have reviewed each item for accuracy in a specific situation, IBM offers no guarantee or warranty any user that the same or similar results will be obtained elsewhere. Any person attempting adapt the techniques contained in this document their own environment(s) does so at their own risk. Any performance data contained in this document were determined in various controlled laborary environments and are for reference purposes only. Cusmers should not adapt these performance numbers their own environments as system performance standards. The results that may be obtained in other operating environments may vary significantly. Users of this document should verify the applicable data for their specific environment. Copyright IBM Corporation Porting Google App Engine Applications IBM Middleware