I am struggling to access my ASP.NET Core 8.0 web app (Swagger UI) from outside my container.
Without Docker, it is accessible at the following URL: http://localhost:90/swagger/index.html
I can start the app by executing an .exe file which results in the following output:
info: Microsoft.Hosting.Lifetime[14]
Now listening on: http://localhost:90
info: Microsoft.Hosting.Lifetime[0]
Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
Hosting environment: Production
info: Microsoft.Hosting.Lifetime[0]
Content root path: C:\Users\Username\Documents\Git\WetterApi\WetterApi
The file structure of my already compiled app looks like following:
Dockerfile:
FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS runtime
COPY . .
EXPOSE 90
ENV ASPNETCORE_ENVIRONMENT=Development
ENV DOTNET_RUNNING_IN_CONTAINER=true
ENTRYPOINT ["dotnet","/WetterApi.dll", "--server.urls","<http://+:90>"]
Building Image:
docker build -t wetter_api_test .
Starting:
docker run --rm -it -p 80:90 wetter_api_test
Port 80 as I want to have it available at http://localhost:80/swagger/index.html outside of the container
Output:
warn: Microsoft.AspNetCore.Server.Kestrel[0]
Overriding address(es) 'http://*:8080'. Binding to endpoints defined via IConfiguration and/or UseKestrel() instead.
info: Microsoft.Hosting.Lifetime[14]
Now listening on: http://localhost:90
info: Microsoft.Hosting.Lifetime[0]
Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
Content root path: /
Curl on the Container Web App:
curl http://localhost:80/swagger/index.html
curl : The underlying connection was closed: The connection was closed unexpectedly.
Does anyone see what exactly I am overlooking or what I do not understand here?
I am thankful for any hint or solution.
Added the following lines to the Dockerfile:
ENV DOTNET_URLS=http://+:90
ENV ASPNETCORE_URLS=http://+:90
ENV ASPNETCORE_HTTP_PORTS=90
But still, my app is not accessible from outside the container.
Removed Port Configs in my Dockerfile:
FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS runtime
COPY . .
ENV ASPNETCORE_ENVIRONMENT=Development
ENV DOTNET_RUNNING_IN_CONTAINER=true
ENTRYPOINT ["dotnet","/WetterApi.dll"]
Running the container with:
docker run --rm -it -p 80:8080 wetter_api_test
Result:
curl http://localhost:80/swagger/index.html
curl : The underlying connection was closed: The
connection was closed unexpectedly.
When checking the Port Mapping via docker ps everything seems fine to me:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2d179c430f50 wetter_api_test "dotnet /WetterApi.d…" About a minute ago Up About a minute 0.0.0.0:80->8080/tcp gracious_satoshi
I suspect there's an issue with your application.
To try to replicate your issue, I made the following Dockerfile based on yours. I've added a build step that creates a template webapi application and then uses your Dockerfile as the runtime step.
FROM mcr.microsoft.com/dotnet/sdk:8.0 as builder
WORKDIR /src
RUN dotnet new webapi -n WetterApi -o . && \
dotnet publish -o app
FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS runtime
COPY --from=builder /src/app/* .
ENV ASPNETCORE_ENVIRONMENT=Development
ENV DOTNET_RUNNING_IN_CONTAINER=true
ENTRYPOINT ["dotnet","/WetterApi.dll"]
When I build, run and test it with
docker build -t test .
docker run -d -p 80:8080 test
curl http://localhost:80/swagger/index.html
it works as expected.
So I don't think there's anything wrong with your Dockerfile or the way you run it.