Problems with token issuer when running OpenIddict as a container - docker

Question

I'm trying to run OpenIddict in Docker together with an Api, the Api communicates with the OppenIddict application through a defined link in docker-compose (api -> login). I have a frontend application running outside of Docker accessing the Api and Login over localhost-addresses. Everything works fine until the point where the Api communicates with the Login application using the linked address (login), the problem then is that the issuer of the token doesn't match.
The issuer is in this case http://localhost:4000 and it's expecting http://login when OpenIddict is validating the token.
I've tried to change the issuer in Startup and the OpenIddictServerBuilder, the problem then is that it changes the base address used in the discovery document resulting in the frontend trying to connect to http://login.
One potential solution to this is to change the hosts file and set a network redirect (redirecting login to 127.0.1.1 and setting the network redirect to use localhost:4000), but this feels like a too complex solution.
I've had similar issues with IdentityServer4, but there you can change the issuer without affecting the base address.
Hope that I explain the issue well enough, any ideas is really appreciated!

Answer 1

Finally figured it out, you can specify a list of valid issuers during the configuration of the OpenIddict server in Startup. Here I can say that http://localhost:4000 is a valid issuer and therefore the token will be valid when the Api validates it even though it is communicating using a different address. I did it like this if it helps anyone in the future:
services.AddOpenIddict()
.AddCore()
.AddServer(builder =>
{
builder.Configure(options =>
{
options.TokenValidationParameters.ValidIssuers = new List<string>
{
"http://localhost:4000/",
};
});
});