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

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.

CodePudding user response：

By default, the EXPOSE instruction does not expose the container’s ports to be accessible from the host. In other words, it only makes the stated ports available for inter-container interaction. For example, let’s say you have a Node.js application and a Redis server deployed on the same Docker network. To ensure the Node.js application communicates with the Redis server, the Redis container should expose a port. If you check the Dockerfile of the official Redis image, a line is included that says EXPOSE 6379. This is what allows the two containers to talk with one another. Therefore, when your Node.js application connects to the 6379 port of the Redis container, the EXPOSE directive is what ensures the inter-container communication takes place.

you can't publish a port to your host via Dockerfile. you should do that via the docker-compose.yml file or via the command line. after your image gets built with the Dockerfile then you can use the command below to publish port 5000 of your container to port 5000 of your host.

docker run -it image:tag -p 5000:5000

CodePudding user response：

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