[SOLVED] Unable to reach my application from outside Docker container but everything works inside the container

Unable to reach my application from outside Docker container but everything works inside the container

I'm trying to run Rhino Compute in a docker container and facing a weird issue. I had built an image using the Dockerfile below and when I run it locally, there are no issues.

# escape=`

# see https://discourse.mcneel.com/t/docker-support/89322 for troubleshooting

# NOTE: use 'process' isolation to build image (otherwise rhino fails to install)

### builder image
FROM mcr.microsoft.com/dotnet/sdk:5.0 as builder

# copy everything, restore nuget packages and build app
COPY src/ ./src/
RUN dotnet publish -c Release -r win10-x64 --self-contained true src/compute.sln

### main image
# tag must match windows host for build (and run, if running with process isolation)
# e.g. 1903 for Windows 10 version 1903 host
FROM mcr.microsoft.com/windows:1809

#Copy the fonts and font install script
COPY fonts/* fonts/
COPY InstallFont.ps1 .

#Run font install scriptin powershell
RUN powershell -ExecutionPolicy Bypass -Command .\InstallFont.ps1

# install .net 4.8 if you're using the 1809 base image (see https://git.io/JUYio)
# comment this out for 1903 and newer
RUN curl -fSLo dotnet-framework-installer.exe https://download.visualstudio.microsoft.com/download/pr/7afca223-55d2-470a-8edc-6a1739ae3252/abd170b4b0ec15ad0222a809b761a036/ndp48-x86-x64-allos-enu.exe `
    && .\dotnet-framework-installer.exe /q `
    && del .\dotnet-framework-installer.exe `
    && powershell Remove-Item -Force -Recurse ${Env:TEMP}\*

# install rhino (with “-package -quiet” args)
# NOTE: edit this if you use a different version of rhino!
# the url below will always redirect to the latest rhino 7 (email required)
# https://www.rhino3d.com/download/rhino-for-windows/7/latest/direct?email=EMAIL
RUN curl -fSLo rhino_installer.exe https://www.rhino3d.com/download/rhino-for-windows/7/latest/direct?email=<myemail> `
    && .\rhino_installer.exe -package -quiet `
    && del .\rhino_installer.exe

# (optional) use the package manager to install plug-ins
# RUN ""C:\Program Files\Rhino 7\System\Yak.exe"" install jswan

# copy compute app to image
COPY --from=builder ["/src/dist", "/app"]
WORKDIR /app

# bind rhino.compute to port 5000

EXPOSE 5000

# uncomment to build core-hour billing credentials into image (not recommended)
# see https://developer.rhino3d.com/guides/compute/core-hour-billing/
#ENV RHINO_TOKEN=

CMD ["rhino.compute/rhino.compute.exe"]

Application code is here: https://github.com/mcneel/compute.rhino3d

As mentioned, everything works without any issues from inside the container when I curl against localhost:5000. But, I can't get any response when I try to curl from the host (after running docker run -p nodeport:containerport imagename). I'm not sure if it has something to do with firewall or anything in the Dockerfile is not configured properly.

Any help is appreciated.

Solution

I suspected the issue might be with "localhost", since it only responds to localhost from inside and it doesn't respond from anywhere else. We added .NET variable ASPNETCORE_URLS to our Dockerfile.

# bind rhino.compute to port 5000
ENV ASPNETCORE_URLS="http://*:5000"
EXPOSE 5000

This will ensure that the application is listening on interfaces, not only localhost and that resolved the issue