From EC2 to Alex Tolley

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Lenard Hoover
6 years ago
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1 From EC2 to Alex Tolley alexandertolley@gmail.com June 2nd, 2009

2 Why Port to AppEngine? 1. Closer to "Big Switch" idea plug and play.

3 Why Port to AppEngine? 2. Cheaper vs EC2 costs Basic EC2 instance: ~ $60/month AppEngineJava: low usage is FREE

4 Why Port to AppEngine? 3. Simpler development cycle Just upload code and go!

5 Why Port to AppEngine? Amazon feels like this...

6 Why Port to AppEngine? Google is like this... Toaster with wall socket

7 The Application Description Web page text and image annotation for research and scholarshoip. Client UI HTML & Javascript coded with GWT (Google Web Toolkit) Server Java Servlets Amazon SimpleDB for database Amazon S3 for metadata and content storage

8 AppEngine Limitations 30 second timeout No long running apps, e.g. genetic algorithm, no streaming. No threads Servlet cannot spawn threads (impacts SimpleDB) No file system writes All writes must be to persistance storage, including log files No sockets Impacts on libraries more details:

9 AppEngine Limitations AppEngineJava!= Java

10 Components GWT (Google Web Toolkit) - Eclipse plugin Works out of the box......but project structure differences are enough to drive you a little crazy

11 Standard GWT project layout

12 Standard GWT project layout Which means the relative path to the image is direct, e.g: DOM.setStyleAttribute(widget.getElement(), "backgroundimage", "url(image/myimage.jpg)");

13 AppEngine project layout

14 AppEngine project layout Which means the relative path to the image starts from a higher directory e.g: DOM.setStyleAttribute(widget.getElement(), "backgroundimage", "url(../image/myimage.jpg)"); Therefore you will likely have to ensure that all resource strings, in code and CSS files are modified for this new structure.

15 AppEngine project layout src/com/cloud/demo/my_appengine_project.gwt.xml

16 AppEngine project layout WEB-INF/web.xml Configuration hell. Can be very tiresome to ensure all the parts are correct. It may be easier to import the code into a new base project to save the effort.

17 AppEngine project layout war/my_appengine_project.html Configuration hell. Can be very tiresome to ensure all the parts are correct. It may be easier to import the code into a new base project to save the effort.

18 Checking 3rd Party Libraries

19 Checking 3rd Party Libraries

20 Checking 3rd Party Libraries

21 Checking 3rd Party Libraries

22 The libraries Jet S3 library Works fine, no illegal code.

23 The libraries Jet S3 library Works fine, no illegal code....except you don't need it now!

24 SimpleDB => HardDB Java Library for Amazon SimpleDB - Full featured library, if somewhat over engineered. - Creates all request strings - Uses Apache commons libraries. - developer: Elena@AWS [Used by my application] 'Simple' SimpleDB code in single Java file/class (240 lines) - Very simple - Assumes user creates request strings. - developer: ian schumacher

25 SimpleDB = HardDB 1. Java Library for Amazon SimpleDB - Full featured library, if somewhat over engineered. - Creates all request strings - Uses Apache commons libraries. - Elena@AWS [Used by my application] 2. 'Simple' SimpleDB code in single Java file/class (240 lines) - Very simple - Assumes user creates request strings. - ianschumacher Both fail illegal code test. option 1 fails as Apache libraries uses socket connections that are called in code. option 2 can be fixed with modification of base64 encoding

26 SimpleDB = HardDB The SimpleDB library option was abandoned as there was no reasonable hope of rebuilding and modifying the Apache libraries to work. In addition, my project used the older SimpleDB API which required threading for performance. The 'simple' SimpleDB code was not used because it would require creating a new library around that core. There are no other library solutions that can be used out of the box with AppEngineJava

27 SimpleDB = HardDB Decision was made to go with Google DataStore

28 Google DataStore A repository that stores data objects and that can be queried like a database. A PersistanceManager handles the CRUD operations. Very easy to implement.

29 Google DataStore Limitations: Similar to SimpleDB Query options are even more limited than SimpleDB, but sufficient. ( e.g. no logical NOT)

30 Summary: Check that your application can live with the AppEngine sandbox and timeout limitations AppEngineJava!= Java. AppEngineJava has language restrictions Try to use OSS and import libraries Create the GWT as a fresh project and import the old project, possibly renaming the entrypoint class. Amazon S3 is fine - but do you need it? Amazon SimpleDB - needs a AppEngineJava friendly library - seriously consider DataStore instead in this case.

Rich Web Applications in Server-side Java without. Plug-ins or JavaScript

Rich Web Applications in Server-side Java without twitter: #vaadin @joonaslehtinen Plug-ins or JavaScript Joonas Lehtinen, PhD Vaadin Ltd - CEO joonas@vaadin.com ? Vaadin is a UI framework for desktop-like