Add dynamic addresses in gateway NserviceBus

Question

I am working on sending message to distributed systems. Hence I prefer to use Gateway. The problem is I am getting Sitekeys,addresses and channelType information dynamically. Nservicebus checks sitekeys and corresponding address in app.config. But there is nothing in my app.config. I wanted to modify app.config dynamically from code. Is this correct approach? Or there is any way to do this.

Below is the code.

App.config

<GatewayConfig>
    <Sites>
      <Site Key="RemoteSite" Address="http://localhost:25899/RemoteSite/" ChannelType="Http" />
    </Sites>
    <Channels>
      <Channel Address="http://localhost:25899/Headquarters/" ChannelType="Http" />
    </Channels>
  </GatewayConfig>

Code

          string[] siteKeys =
            {
                "RemoteSite"
            };
            PriceUpdated priceUpdated = new PriceUpdated
            {
                ProductId = 2,
                NewPrice = 100.0,
                ValidFrom = DateTime.Today,
            };
            bus.SendToSites(siteKeys, priceUpdated);

Answer 1

You can do this dynamically during startup by creating a GatewayConfig object by inheriting from IProvideConfiguration<GatewayConfig> as shown in the following example.

If there are new entries the bus instance needs to be rebuild.

public class GatewayConfigConfigurationProvider : IProvideConfiguration<GatewayConfig>
{

    public GatewayConfig GetConfiguration()
    {
        return new GatewayConfig
        {
            Channels =
            {
                new ChannelConfig
                {
                    Address = "http://localhost:25899/Headquarters/",
                    ChannelType = "Http"
                }
            },
            Sites =
            {
                new SiteConfig
                {
                    Address = "http://localhost:25899/RemoteSite/",
                    ChannelType = "Http",
                    Key = "RemoteSite"
                }
            }
        };
    }
}

This example is based on the following sample from the documentation website:

• http://docs.particular.net/nservicebus/gateway/
• http://docs.particular.net/samples/gateway/

Answer 2

Unfortunately you cannot change app.config settings at runtime. I believe the reason is that nservicebus would need to do some initialization with the remote site before the endpoint starts.