Dynamic service name with ocelot and consul - consul

Question

I am using Ocelot and API gateway with Consul and the service discovery.
I am registering services in the Consul with dynamic names like : service.name.1234 and service.name.5678
This services are statful and not meant to be scaled at all
Since i am working with Ocelot i would like to be able to route a request to the desired service but since the names are dynamic i would need to use the query string parameter as the service name
Example : http://myapp.com/service/1234
Should be redirected to the container with the name service.name.1234
Is there any way to achive this using both products? or maybe other product?
Thank you

Answer 1

I have been searching for myself for the same solution but found only one comment on GitHub and it helped me a lot
So, you need to create custom middleware that will rewrite Ocelot`s DownstreamRoute:
public static async Task InvokeAsync(HttpContext httpContext, Func<Task> next)
{
var downstreamRoute = httpContext.Items.DownstreamRoute();
var yourServiceName = //get query string parameter from httpContext;
//rewrite any parameter that you want
httpContext.Items.UpsertDownstreamRoute(
new DownstreamRoute(
downstreamRoute.Key,
downstreamRoute.UpstreamPathTemplate,
downstreamRoute.UpstreamHeadersFindAndReplace,
downstreamRoute.DownstreamHeadersFindAndReplace,
downstreamRoute.DownstreamAddresses,
tenantServiceName,
...
));
}
And after that call it in Startup.cs:
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
// some other code
var configuration = new OcelotPipelineConfiguration
{
PreQueryStringBuilderMiddleware = async (ctx, next) =>
{
await RouteContextRetrieverMiddleware.InvokeAsync(ctx, next);
await next.Invoke();
}
};
app.UseOcelot(configuration).GetAwaiter().GetResult();
}