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Java Web Programming on Google Cloud Platform [1/3] : Google App Engine


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Java Web Programming on Google App Engine, July 2012

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Java Web Programming on Google Cloud Platform [1/3] : Google App Engine

  1. 1. Google App EngineAssoc.Prof. Dr.Thanachart Numnonda Asst.Prof. Thanisa Kruawaisayawan July 2012
  2. 2. AgendaWhat is Cloud Computing?What is Google App Engine?Google App Engine for JavaGoogle App Engine Development cycle
  3. 3. What is Cloud Computing?
  4. 4. Cloud computing : Definition (Wikipedia) Cloud Computing is Internet-based computing,whereby shared resources, software, and information are provided to computers and other devices on demand, like the electricity grid.
  5. 5. Cloud computing characteristicsMassive, abstracted infrastructureDynamic allocation, scaling, movement of applicationsPay per useNo long-term commitmentsOS, application architecture independentNo hardware or software to install
  6. 6. Grid to Cloud Evolution
  7. 7. Web 2.0 & Cloud ComputingWeb 2,0 concentrate on the private user and clouds are decscendents of data centers which services the enterpriseWeb 2.0 promote SaaSWeb 2.0 needs massive scaling technologiesUser centric Web 2.0 companies (Twitter, Slideshare) are relying on Cloud Services
  8. 8. ISP to Cloud Evolution
  9. 9. Software as a Service (SaaS)SaaS is at the highest layer and features a complete application offered as a service, on-demand,via multitenancy — meaning a single instance of the software runs on the provider’s infrastructure and serves multiple client organizations.
  10. 10. Platform as a Service (PaaS)The middle layer, or PaaS, is the encapsulation of a development environment abstraction and the packaging of a payload of servicesPaaS offerings can provide for every phase of software development and testing, or they can be specialized around a particular area, such as content management
  11. 11. Infrastructure as a Service (IaaS)IaaS is at the lowest layer and is a means of delivering basic storage and compute capabilities as standardized services over the network.Servers, storage systems, switches,routers, and other systems are pooled (through virtualization technology, for example) to handle specific types of workloads — from batch processing to server/storage augmentation during peak loads.
  12. 12. Deployment ModelPublic Cloud: provider refers to the cloud platform that targets any types of customers.Private Cloud: infrastructure that’s hosted internally, targeting specific customers or sometimes exclusively within an organization.Hybrid Cloud: the combination of public and private clouds, or sometimes on-premise services.
  13. 13. IaaS & PaaS: Developers PerspectivesIaaS normally provides up to O/S level as your choice; for example Amazon Web Services (AWS) offers several types of Operating Systems such as Windows Server, Linux SUSE, and Linux Red Hat. Developer need to install own middleware, database, etc.PaaS, given that the database server, VM, and web server VM are readily provisioned,
  14. 14. Setting Up App in IaaSSource:
  15. 15. Setting Up App in PaaSSource:
  16. 16. PaaS for JavaAmazon Elastic BeanstalkCloudBeesCloud FoundryGoogle App EngineHeroku for JavaRed Hat OpenShift
  17. 17. PaaS for Java: Comparison
  18. 18. PaaS for Java: ComparisonSource:
  19. 19. What is Google App Engine?
  20. 20. Google App Engine : Definition (Wikipedia)It is a platform for hosting web applications in Google- managed data centers. It is cloud computing technology which virtualizes applications across multiple servers and data centers.
  21. 21. Google App EngineRunning your web application in Google infrastructureSupport different runtime environments Java (JRE 6 with limitation, Servlet 2.5, JDO, JPA) Python (2.5.2)Apps run in sandbox.Automatic scaling and load balancingNo server restart, no network issues
  22. 22. Hosting Java web apps traditionallyNot so popular except enterpriseHigh rates as compared to PHP hostingShared Tomcat instance among usersRestrictions on any time deployments due to shared serverDedicated hosts works fine but they are costly
  23. 23. You end up with all this
  24. 24. Google Datacenters at Dallas, Oregon
  25. 25. GAE Architecture
  26. 26. GAE Physical Deployment Diagram
  27. 27. Architecture : Application Server
  28. 28. Distributed web hosting platform
  29. 29. Distributed Datastore
  30. 30. Distributed memcache
  31. 31. Specialized services
  32. 32. Google Apps + your apps
  33. 33. Google App Engine for Java
  34. 34. GAE/JWas released on April 08 with Python support. Java included on August 09
  35. 35. App Engine for Java : One YearSource: What’s Hot in Java for App Engine Google Con 2010
  36. 36. GAE Java Runtime EnvironmentJava 6 VMServlet 2.5 ContainerHTTP Session support (need to enable explicitly)JDO/JPA for Datastore APIJSR 107 for Memcache APIjavax.mail for Mail API for URLFetch API
  37. 37. Java Standards on GAE
  38. 38. Services by App EngineMemcache API – high performance in-memory key-value cacheDatastore – database storage and operationsURLFetch – invoking external URLsMail – sending mail from your applicationTask Queues – for invoking background processesImages – for image manipulationCron Jobs – scheduled tasks on defined timeUser Accounts – using Google accounts for authentication
  39. 39. LimitationsProgramming Model : Application runs in sandbox and can not Write to file system Make arbitrary network connections Use multiple threads/processes Perform long-lasting processing Permissions Know about other instances/applicationsQuotas (Requests, In/Out bandwidth, CPU time, API calls)
  40. 40. GAE Datastore
  41. 41. GAE DatastoreStoring data and manipulationBased on BigtableBigtable is proprietary and hidden from the app developersNot a relational database (No SQL)GQL (Google Query Language) to queryStores data as entitiesDistribution, replication, load balancing behind the sceneNeed to use JDO/JPA
  42. 42. User Service : Google AccountsGoogle Accounts are encouraged as the preferred authentication mechanism for App Engine – It assumes that all users have a Google Account – Google authentication for private domains isn’t available yetAccess to Google account data -> email, idThe Development Server simulates Google AccountsAccess constraints based on roles
  43. 43. User API : Exampleimport*; import*;UserService userService == UserServiceFactory.getUserService(); UserService userService UserServiceFactory.getUserService();User user == userService.getCurrentUser(); User user userService.getCurrentUser();String navBar; String navBar;if (user == null) {{ if (user == null) navBar == "<p>Welcome! <a href="" ++ userService.createLoginURL("/") navBar "<p>Welcome! <a href="" userService.createLoginURL("/") +"">Sign in or register</a> to customize.</p>"; +"">Sign in or register</a> to customize.</p>";}} else {{ else navBar == "<p>Welcome, "" ++ user.getEmail() ++ "! You can <a href="" navBar "<p>Welcome, user.getEmail() "! You can <a href="" +userService.createLogoutURL("/") +"">sign out</a>.</p>"; +userService.createLogoutURL("/") +"">sign out</a>.</p>";}}
  44. 44. URLFetch APIInvoking external URLs from your application over HTTP and HTTPsimport*; import*;import*; import*;URL url == new URL("htp://..."); URL url new URL("htp://...");InputStream inp == new InputStreamReader(url.openStream()); InputStream inp new InputStreamReader(url.openStream());BufferedReader reader == new BufferedReader(inp); BufferedReader reader new BufferedReader(inp);String line; String line;while ((line == reader.readLine()) != null) {{ while ((line reader.readLine()) != null) //do something //do something}}reader.close(); reader.close();
  45. 45. Mail APISend emails on the behalf of app administrator to the Google account use.You can not receive emailsimport javax.mail.*; import javax.mail.*;Session session == Session.getDefaultInstance(new Properties(), null); Session session Session.getDefaultInstance(new Properties(), null);InternetAddress admins == new InternetAddress("admins"); InternetAddress admins new InternetAddress("admins");Message msg == new MimeMessage(session); Message msg new MimeMessage(session);msg.setFrom(admins); msg.setFrom(admins);msg.addRecipient(Message.RecipientType.TO, admins); msg.addRecipient(Message.RecipientType.TO, admins);msg.setSubject("subject"); msg.setSubject("subject");msg.setText("text"); msg.setText("text");Transport.send(msg); Transport.send(msg);
  46. 46. Memcache ServiceDistributed in memory cache, better than DataStoreKey-value pair mappingConfigurable expiration time butUnreliable might be vanished at any timeSupported Interfaces : – JACHE (JSR 107: JCACHE – Java Temporary Caching API) – The Low-Level Memcache API
  47. 47. Memcache API : Exampleimport static java.util.Collections.emptyMap; import static java.util.Collections.emptyMap;import javax.cache.*; import javax.cache.*;CacheFactory cacheFactory == CacheManager.getInstance().getCacheFactory(); CacheFactory cacheFactory CacheManager.getInstance().getCacheFactory();Cache cache == cacheFactory.createCache(emptyMap()); Cache cache cacheFactory.createCache(emptyMap());cache.put(key, value); cache.put(key, value);cache.get(key); cache.get(key);
  48. 48. Task Queues APIPerform background processes by inserting tasks into queues.Instructions need to be mention in file queue.xml, in the WEB-INF/ dirimport; import;import; import;import; import;// ... // ...TaskOptions taskOptions == TaskOptions taskOptionsTaskOptions.Builder.url("/send_invitation_task") TaskOptions.Builder.url("/send_invitation_task") .param("address", "") .param("address", "") .param("firstname", "Juliet"); .param("firstname", "Juliet");Queue queue == QueueFactory.getDefaultQueue(); Queue queue QueueFactory.getDefaultQueue();queue.add(taskOptions); queue.add(taskOptions);
  49. 49. Cron JobsUp to 20 scheduled tasks per appCron jobs (scheduled tasks) supported in cron.xml in WEB-INF dirSchedule instructions contain Englis-like format<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?><cronentries> <cronentries><cron> <cron><url>/listbooks</url> <url>/listbooks</url><description>Repopulate the cache every day at <description>Repopulate the cache every day at5am</description> 5am</description><schedule>every day 05:00</schedule> <schedule>every day 05:00</schedule></cron> </cron></cronentries> </cronentries>
  50. 50. Images APIManipulation of imagesTransformation of imagesChanging image formats
  51. 51. GAE Development Cycle
  52. 52. GAE Development Cycle
  53. 53. Getting StartedThe application owner must have a Google Account to get the tools regardless of language.Use Java 6 for development.Eclipse and Netbeans have official plugins.Both SDKs ship with a Development Web Server that runs locally and provides a sandbox almost identical to the real run-time.
  54. 54. Software Development KitApp Engine SDK – Includes web server (Jetty) – Emulates all the GAE servicesSDK includes an upload tool to deploy app to GAECommand line tools included.
  55. 55. Google Plugin for Eclipse
  56. 56. Development EnvironmentDevelopment ServerApplication lifecycle managementEclipse/NetBeans plugins / Firefox plugin (GWT).
  57. 57. Google Plugin for Eclipse
  58. 58. Development Server http://localhost:8888
  59. 59. Development Server Admin Console http://localhost:8888/_ah/admin
  60. 60. Deployment EnvironmentApplication is deployed as .war which contains.Deployment is integrated in IDEDeploy multiple version of the application at the same timeYour app lives at – <app_id> or – Custom domain with Google Apps
  61. 61. Running your app on Googlehttp://<version>.<appid>
  62. 62. Managing ApplicationsAdministration ConsoleApplication DashboardMultiple application versionsAnalyzing log files (including admin)Analyzing resource usag
  63. 63. GAE Dashboard
  64. 64. ResourcesGoogle App Engine at a glance, Stefan ChristophDeveloping Java Based Web Applications inGoogle App Engine, Tahir Akram, Dec. 2009Google App Engine, Patrick Chanezon, Mar 2010
  65. 65. Thank you