I'm interested in openDayLight controller, and I am reading a lot of articles about it, but I have a question. In SAL we have plugin like OpenFlow, but I can define my own plugins like f.e. ping: https://wiki.opendaylight.org/view/Ping - to do so, I need to create like it states in the article: 4 bundles with OSGi framework and these 4 bundles are called modules, correct ? but plugin == service ? and f.e. ping plugin works in SAL next to f.e. openFlow ? I'm not sure if I understand correctly what is plugin,service,module,bundle.
When creating a plugin, you have to decide whether it is a Northbound or a Southbound plugin.
Southbound plugins deals directly with network devices. This is often done through some configuration protocol, like OpenFlow, SMTP and NETCONF.
Northbound plugins receive data from applications, processes them and may, ou may not, use an Southbound plugin to configure network devices. The Ping plugin, for example, is a Northbound plugin, like most of the ones you will probably implement.
However, your plugin may implement the device communication part, whitout the need of another specific southbound plugin. Service is the implementation part of yout plugin, which receives data from the northbound API, processes it and, if necessary, sends to the network devices through another southbound API or by some its own means.
The Nouthbound API is automatically created based on a YANG model, that's why ODL SAL is Model-Driven (MDSAL). After you create a model in a bundle, you implement the service in another bundle. All these bundles together are your plugin, or module.
Related
We have Android and iOS (Objective-C) mobile applications.
Our Business Intelligence team is interested in receiving the following parameters with each data event:
the app version
the user session id
We use gRPC for both the mobile-backend communication and also for communicating between the different microservices on the backend.
I am considering sending this information using open tracing spans that are started on the mobile app and pass the app version and session id trough the Baggage.
Can anyone advise if open tracing is suitable for this scenario or if there is a better alternative?
We are also considering using LinkerD on the backend
I'm not sure baggage is really what you want. OpenTracing also offers the possibility of adding tags to a span, which would probably be sufficient for your use-case.
A baggage item is sent downstream along with the span context, whereas a tag is "local" to a span. If you need access to the app version on a span downstream, then you indeed have to use a baggage item, but if all you need is to have the version information within the span, you should just tag it.
About OpenTracing being suitable or not: I'd say that's exactly the purpose of OpenTracing. Not only you'll potentially get "automatic" spans from the frameworks you are using (using the "framework integrations"), but also you can relate that to your business information. We have an example on Hawkular APM where we add both "operational" and "business" data to traces.
I'm in the process of exposing some of the data generated in one OSGi bundle with a REST interface so it can be consumed with typical http requests afterwards by anyone. To do this I'm using a combination of apache-cxf, JAX-RS and Jetty (for testing purposes mostly).
My whole application is distributed in two ways:
Core: Runs a set of minimal bundles as an OSGi framework.
Full: Core + plus a set of plugins to be used within Eclipse, in a graphical way, to put it that way.
While in the Core launch configuration I can make this work without any problems, have a look at the MANIFEST:
Require-Bundle: cxf-dosgi-ri-singlebundle-distribution;bundle-version="1.3.1",org.eclipse.core.runtime, org.eclipse.osgi.services;bundle-version="3.3.0", org.mortbay.jetty.server;bundle-version="6.1.23", org.mortbay.jetty.util;bundle-version="6.1.23"
When I try to launch the Full distribution, jetty server does not seem to start and thus, the RESTful service is not working properly. Full distribution comes with a lot more plugins, mostly related with wizards, perspectives and so on. Root of this problem is somehow related with the cxf-dosgi-ri-singlebundle-distribution bundle, and can be tackled by "forcing" auto-start of this bundle to true, instead of default (check image below):
While this is OK, my question is ...why is this happening? And second and most important, I distribute the Full distribution via an update site, so users can download it, open perspective and start using it, that said, will this affect the final distribution? Is there a way I can control this auto-start=true for the apache-cxf bundle in the update site?
Hope I can make myself clear...
Thanks!
I don't like answering my own questions, but since I'm getting no feedback and maybe someone else has the same problem...here it goes
I decided to change the whole design of my restful bundle, by not using apache-cxf, since it is really not needed. All I need to do what I want is the embedded Jetty server and javax for dealing with HttpRequests and HttpResponses. Thus, I get rid of dependecies with third party libraries, leveraging the launching problems at the same time.
Got the ideas from these official sites in Eclipe:
Embedding an HTTP server in Equinox
Writing a bundle-based server application
Besides, a more hands-on tutorials can be also found here:
OSGi as a Web Server application
Extending Eclipse: displaying HTML content from a bundled archive
Special thanks to both authors for the enlightenment :).
I have read through the chromiumembedded usage and looked at the cefclient application. Now i would like to provide my gwt application as an standalone application to my customers. Is it possible to package the gwt client code using chromiummebedded.
I am not sure how to make the RPC/RC calls to the server if its packaged in CEF.
I think you need to include an embedded webserver in your application, and serve the generated GWT application files from this.
Since the url for your server will be different, you could disable the same origin policy in ChromiumEmbedded to use normal RPC calls, but it might be better to use cross domain calls as describe in Googles tutorial
We're planning on creating a feedreader as a windows desktop- and iPad application. As we want to be able to show Websites AND to run (our own) JavaScript in this application, we thought about delivering the application as HTML/CSS/JavaScript, just wrapped by some .NET control or a Cocoa Touch webbrowser component. So the task at hand is to find out which framework to use to create the HTML/CSS/JS files to embed in the application.
For the development of the HTML/CSS/JavaScript we would be happy to use Vaadin, GWT, or some other framework, as we're a lot better with Java than with JS. We favor Vaadin after a short brainstorming, as the UI components are very nice, but I fear that most of the heavy lifting will be on the server and not in the client (and that wouldn't be too nice). We would also like GWT, but the Java-to-JS compiling takes a lot of time and an extra step, and slowed down development time in the past when using it.
The question is: which development framework would you choose (given you wanted to implement this project and you mostly did Java so far) and why? If there are better framework options (List of Rich Client Frameworks), please let me know.
Edit: The application will need to talk to our server from time to time (sync what has been read for example), but mainly should get the xml feeds itself. Therefore I hope that most of the generated code can be embedded in the application and there doesn't need to be heavy activity with our server.
Edit2: We (realistically even if you doubt) expect at least 10000 users.
Based on my experience with Vaadin, I'd go for that, but your requirements are somewhat favoring pure-GWT instead.
Vaadin needs the server and server connection. If building mostly offline desktop application, this can be solved with an embedded Jetty for example. (synchronize with an online service only when needed), but for iPad you would need to connect online right away to start the Vaadin application.
GWT runs completely at the client-side and you can build a JavaScript browser application that only connects when needed.
Because Vaadin is much quicker to develop, you could build a small Vaadin version first and see if that is actually problem on the iPad.
On the other hand, if you can assume going online right away, you can skip the local server installation altogether. Just run the application online and implement the desktop version using operating systems default browser control (i.e. the .NET control you suggested). Then Vaadin is easier.
Vaadin is just framework base on GWT but have two very important features:
don't need to run GWT compiler. It is pure java. Of course if not add addons because then gwt compiler must run.
you don't need to write communication code. So you don't need to solve DTO problems, non-serializable object mappings and dont need to write servlets.
I use Vaadin in my work for one year and we haven't performance problems yet (desktop like application with ~500 users). IMO very good solution is to use Vaadin just for UI, logic move to independent beans and connect this two elements using Spring or Guice.
In this case you should use MVP pattern and Domain Driven Development.
Bussines beans is domain objects and logic that use view interfaces to send responses.
Custom Vaadin components (could extends standard components) implements view interfaces.
That way is good when you decide to change UI engine if Vaadin is not for you. Just rewrite guice/spring mappings and write new implementations of view interfaces.
My 3 cents:
If you decide to use vaadin, You will benefit from already GOOD LOOKING components. Since you dont want to write (alot of) CSS , vaadin is already good looking out of the box. How ever, Vaadin is a SERVERSIDE framework. User interface interactions will hit the back end even if they dont involve getting any data (e.g moving from one tab to the other) .
If you decide to use GWT, you will have to atleast style the application (this is not hard) . There is also the problem of long compilation time (but you can test and debug on hosted mode which allows you to run the application without compiling , then you compile only when deploying). The main advantage of gwt is that you control what gets sent to the wire, For UI interactions that dont require getting data from the backend, it will work purely on the client side. You the developer will determine when to send a request to the back end. (Doing RPC requests in GWT is very easy)
Hope this will help you make the decision.
I have a server-code that's written in Python, and I have a client-code that's written with GWT. Now I want to run automation testing on the GWT against the data from the Python server.
From what I searched, people recommends using the Selenium, but I prefer to have a GWT-test that has more visibility into the client-code. That way I can verify the local database, and any data that are not exposed to the UI.
Also at this point I'm not too worried about the DOM aspect, layout, and the other UI stuff.
Is there anyway to make the GWTTest work with external server?
I've tried to search for the solution, or people with similar problem, but I couldn't find one. If this question has been asked previously, I apologize.
Thanks, KOkon.
You can use the GWTTest framework to incorporate testing some GWT components that call the server. But the tests won't be able to communicate directly with the server. If you need your tests to set up state on the server, I'm afraid you'll need to write special "for testing purposes only" RPC servers or servlets or similar to do it.
Having said that, I would (presumably like those who suggested Selenium) recommend three types of tests:
Unit tests for server components, and unit GWTTests for client components,
Integration tests for testing server code interaction with database, etc.
Selenium acceptance tests, which are "black box" - they don't have access to the innards of the GWT components.
What you could do is create a proxy servlet that gets started in the GWTTestCase embedded Jetty instance. That proxy could forward all calls to you real services in Python.