I currently designing a solution for communication between a Charge Point for Electrical Vehicles and the backoffice. the ChargePoint are connected to the Network of the Telephone company and the backoffice is hosted on Azure. The Chargepoint don't have a public IP-address. In order to send messagese from the backoffice to the ChargePoint we want to implement Azure Service Bus (ASB) Relay. The ChargePoint OS is embeded Linux and Azure is Microsoft. The ASB Relay only works with WCF bindings. I found out that mono supports WCF but cann't find if it supports httpRelayBinding?
what kind of communication are you looking for between the device and service? If you need Relay like two-way or one-way synchronous RPC communication then you could use a simple http client to call into the service, a sample for this is here: http://code.msdn.microsoft.com/windowsazure/Relayed-Messaging-Bindings-a6477ba0
Also if you are looking for different patterns of communication such a brokered messaging where you can send/receive messages w/ data then you can consider using Service Bus Queues and Topics. I recently covered some of these usage scenarios in my session at TechEd: http://channel9.msdn.com/Events/TechEd/NorthAmerica/2013/WAD-B336
Related
I have a virtual machine on Azure which will listen to messages over the servicebus of Azure. And another developer needs to connect to this servicebus to send messages to my service. To do so, we need to come up with some protocol for this communication system. And I was thinking about using WSDL to make the server something webservice-like, but instead of listening to the standard HTTP ports it would connect to the service bus and within it a topic with subscription, or whatever. I'm still not sure what would be best.
So, is it possible? Has anyone done something similar before? Are there some examples?
Service Bus provides both Brokered and Relayed messaging models. With using Topics/Queues you are essentially sending and receiving message to/from the broker. So you can use APIs/protocols that the broker supports. As an example you can use the NetMessagingBinding from your service/client to send and receive messages through the queue. There is no contract here other than what you put in the BrokeredMessage body and properties values. The application on either end can decode/decipher that info as needed.
In the case of Relayed messaging however you are making a end-to-end connection between the client and the service with Service Bus serving as the proxy in-between for auth, location-transparency and even load-balancing. So here you can use from a variety of RelayBindings such as NetTcpRelayBinding or webHttpRelayBinding but then both the client and the service need to be available at the same time. Here you need the service and clients to be using the same contract.
I have a question that is confusing me what are the differences between the types of service bus, the brokered messaging and the relayed messaging? I am not looking for it from the development perspective but I want to understand more the concept and the differences between them.
Thank you.
Service Bus Relay and Service Bus Brokered Messaging are both mechanisms for developing distributed and hybrid applications. However, they target different development and access patterns.
Service Bus (SB) Relay provides a simple & secure way to do service remoting, i.e., it enables you to securely expose a service hosted on a private cloud to external clients. As is the case with service remoting scenarios, clients explicitly invoke the methods exposed by the "Relayed" service. The primary advantage of SB Relay is that the service can be exposed without requiring any changes to your Firewall settings or any intrusive changes to your corporate network infrastructure.
SB Brokered Messaging on the other hand provides a durable messaging platform with components such as Queues, Topics and Subscriptions. These can be used to implement complex patterns such as publish-subscribe and temporal decoupling between different parts of your application. Since the brokered messaging infrastructure can reliably store the messages, the senders and the receivers do not have to be online at the same time, or do not have to process the messages at the same pace.
Relayed messaging is thus appropriate for scenarios where you have a service that you want to expose to external clients. Clients interact with the "Relayed" service in the same manner that they would if they were on the local network, except that they access it via the SB Relay endpoint. Since this is a service remoting scenario, response is immediate subject to network latency. However, if for whatever reason the service is unavailable at that moment, the client's request will always fail.
In the case of brokered messaging, since the send & receive operations are decoupled, the sender can continue to send messages that are reliably stored on the service regardless of whether the receiver is online or not. However, the tradeoff for this resiliency is that the request will be processed subject to receiver's ability to retrieve and process the message.
I think the main difference is the synchronous vs asynchronous nature of connectivity.
Where relay is mostly a firewall friendly way to expose web services to the public world (even behind firewalls, NAT devices, etc), messaging is more of a way to exchange in an asynchronous way messages over queues and topics. (look at it as the next version MSMQ with cloud support :))
Everything depends on the scenario, but if you are looking for
- Routing (pub/sub)
- Loose coupling sender & receiver
- Load leveling
Then you should definitely go for messaging.
If you want to make your service easily reachable for the outside world, relay service is your friend.
From Azure's site:
Relay
The Service Bus Relay service enables you to build hybrid applications
that run in both a Windows Azure datacenter and your own on-premises
enterprise environment. The Service Bus relay facilitates this by
enabling you to securely expose Windows Communication Foundation (WCF)
services that reside within a corporate enterprise network to the
public cloud, without having to open up a firewall connection or
requiring intrusive changes to a corporate network infrastructure.
Relay also handle load balancing for you (you can have multiple applications listen at the same endpoint for the majority of the bindings).
Brokered Messaging
The second messaging solution, new in the latest release of the
Service Bus, enables “brokered” messaging capabilities. These can be
thought of as asynchronous, or decoupled messaging features that
support publish-subscribe, temporal decoupling, and load balancing
scenarios using the Service Bus messaging infrastructure. Decoupled
communication has many advantages; for example, clients and servers
can connect as needed and perform their operations in an asynchronous
fashion.
Brokered messaging includes Queues and Topics / Subscriptions that allow you to send / receive messages asynchronously.
The main difference is that for relay, you have applications listening at an endpoint. When you send a message, the application processes that message when it is received. For brokered messaging, the message is stored when it is received by the client and can be processed at any time.
I am working on a Windows Phone 8 app which is connected to Azure Service Bus Relay. Since i cant add Microsoft.ServiceBus.dll to the WP8 project, I had to go with BasicHttpBinding which works fine.
Now I want to use the service bus relay with topics in WP8. Is this even possible? I cant use NamespaceManager which is discussed here: http://www.windowsazure.com/en-us/develop/net/how-to-guides/service-bus-topics/ , because its not supported by WP8.
My question is simply, is this possible to do? And what approach should i choose?
We do not have any libraries that target Windows Phone at this point but are working on producing these. You can make direct http calls to the REST APIs and send/receive messages etc. Samples for these are available:
http://code.msdn.microsoft.com/windowsazure/Brokered-Messaging-569cff88
https://github.com/WindowsAzure/azure-sdk-for-java/tree/master/microsoft-azure-api/src/main/java/com/microsoft/windowsazure/services/ServiceBus
http://msdn.microsoft.com/en-us/library/hh780762.aspx
Zeezer,
"Now I want to use the service bus relay with topics in WP8"
Not sure if you are conflating two separate issues...
We do not have an SDK for Service Bus Relay for the Windows Phone. However, if your service is using any of the *HttpRelayBinding's, you can use a regular HTTP client from the Windows Phone app to communicate with the Relay endpoint for your service. You will need to include the ACS token for authenticating to Service Bus Relay in a custom HTTP header called ServiceBusAuthorization.
I’m designing a backend that allows users to establish a TCP socket with it and send/receive stuff along this socket (using a pseudo-protocol I’ve made up) in real-time.
It has to be scalable – i.e. architected on a cloud host. Currently I’m evaluating Windows Azure.
To achieve scalability the application will run on several Web Role Instances. Meaning the users’ TCP sockets will be split across several instances (via a load balancer).
This backend is an event-driven application – when a user sends something to it the message should be passed on to all other connected users.
This means there must be a reliable way to send messages from one Web Role Instance to all other Web Role Instances. As far as I understand, this is what inter-role communication refers to.
Using Service Bus, is it possible for all Web Role Instances to subscribe to a Topic and publish messages to it? Thus implementing the event-driven requirements of my distributed application?
(If not then I’ve misunderstood what this article is about: http://windowsazurecat.com/2011/08/how-to-simplify-scale-inter-role-communication-using-windows-azure-service-bus/)
I wanted to find this out before delving too deep into learning C#, .NET and Windows Azure development.
Thank you for your help.
Yes, using the service bus, all the web roles could send messages to a single topic and each role could have unique individual subscriptions to that topic, such that they all receive the messages sent.
Clemens Vaster has implemented an extension to SignalR using the service bus. It is possible that SignalR + the Service Bus may meet the needs of your project, including the TCP socket implementation.
http://vasters.com/clemensv/2012/02/13/SignalR+Powered+By+Service+Bus.aspx
What is the diffence between appfabric service bus and WCF?
Is service bus is an alternate for wcf on azure?
Does service bus provide all the functionality as wcf?
when to use service bus and when to use wcf in azure application?
Please help me....
Thanks in advance
The service bus doesn't provide services themselves - instead if provides connectivity to services - e.g. routing, scalability, security, etc.
So you will normally write your services in WCF, and can then optionally provide connectivity to those services using the bus.
This article provides a good intro to the service bus - http://msdn.microsoft.com/en-us/magazine/dd569756.aspx
You don't need to move away from WCF. However, imagine your application, sitting in Windows Azure, trying to access a WCF service in your data center (or hosted somewhere). And imagine that the data center has a firewall that blocks incoming connections. Service bus offers a way for you to make service calls to that service endpoint. Essentially, the two sides each connect to an AppFabric Service Bus endpoint. At that point, they have a connection where WCF calls can be made.
The bindings are similar to what you use today. If you're using netTcpBinding, for instance, you'd now use netTcpRelayBinding, as the calls are relayed through the service bus.
The Windows Azure Platform Training Kit has a very good introductory lab to walk you through the basics of Service Bus.
ServiceBus is a way to communicate asynchronously. Asynchronous communication implies it is good for multi-machine programming due to fault tolerance and it does not block.
WCF is a programming stack used to interface with various mediums (ie. Pipes, TCP, HTTP, ServiceBus).
They serve orthogonal purposes. You can use WCF without ServiceBus and ServiceBus without WCF.