Docker: Cannot launch .Net Core 3.1 Web Api on browser after docker run

Question

I'm new to Docker and, as a start, I'm trying to accomplish a basic task, dockerize a .Net Core 3.1 Web Api and run it from the command line (not From Visual Studio where it actually works).

I create my project image using the following Dockerfile and with the next command:

docker build -t concepttest_crud1 .

Dockerfile (created by Visual Studio):

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443

FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS build
WORKDIR /src
COPY ["Gfi_ConceptTest_CRUD1/Gfi_ConceptTest_CRUD1.csproj", "Gfi_ConceptTest_CRUD1/"]
RUN dotnet restore "Gfi_ConceptTest_CRUD1/Gfi_ConceptTest_CRUD1.csproj"
COPY . .
WORKDIR "/src/Gfi_ConceptTest_CRUD1"
RUN dotnet build "Gfi_ConceptTest_CRUD1.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "Gfi_ConceptTest_CRUD1.csproj" -c Release -o /app/publish

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "Gfi_ConceptTest_CRUD1.dll"]

4) I run my image with the following command:

docker run -d -p 8080:44390 --name crud1 concepttest_crud1

where 44390 is the port I have my api configured on in Visual Studio.

When debugging I use to access the api through:

https://localhost:44390/api/Authors

5) I'm trying to test my dockerized api in Chrome with the next url:

https://localhost:8080/api/Authors

to no avail. No matter with url I try, my api won't start when the docker run command executes with no errors.

docker ps output:

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                     NAMES
8df6c92c6678        concepttest_crud1   "dotnet Gfi_ConceptT…"   22 minutes ago      Up 22 minutes       0.0.0.0:8080->44390/tcp   crud1

docker images output:

REPOSITORY                             TAG                 IMAGE ID            CREATED             SIZE
concepttest_crud1                      latest              878e4c4845f6        About an hour ago   228MB
<none>                                 <none>              36a29990113c        About an hour ago   1GB

In the Docker images output I don't know why I see two images (a second with no name) when I expect only one.

I've also tried http://192.168.99.100:8080/api/Authors but it is not working either.

Edit 1: Adding docker inspect.

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            "ConsoleSize": [
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]

Edit 2: Added curl.

docker exec -it 0f0bf4b4de30 /bin/bash . root@4237f947b2b0:/app# curl https://localhost:8080/api/Authors

.: .: Is a directory

Edit 3: New curl

docker exec -it 0f0bf4b4de30 /bin/bash . root@4237f947b2b0:/app# curl https://localhost/api/Authors
.: .: Is a directory

https://localhost:44390 is your api configured on in Visual Studio (local machine). https://localhost:8080 is your docker container which point to 44390 inside docker. But in Dockerfile there is Expose 443 (uncoment first) and you should point 8080 to 443 (-p 8080:443) to access your api inside container — d0niek
– d0niek, Commented Dec 23, 2019 at 12:12
Thank you very much for your quick response @d0niek. As you suggested I re-run image with docker run -dt -p 8080:443 --name crud1 crud1 but localhost:8080/api/Authors still cannot be accessed. Any more suggestions? — Diego Perez
– Diego Perez, Commented Dec 23, 2019 at 12:24
have you uncoment Expose 443 in your Dockerfile and rebuild image? — d0niek
– d0niek, Commented Dec 23, 2019 at 12:25
Yes, in fact they were both already uncommented, but the comment marks shown here were a mistake when pasting to StackOverflow. — Diego Perez
– Diego Perez, Commented Dec 23, 2019 at 12:27

Diego Perez · Accepted Answer · 2020-01-09 12:07:00Z

6

In my case it was due to having SSL enabled inthe project, but after removing everything related to https it started working as expected.

Having SSL enabled implies installing a SSL certificate inside the docker container and enabling it, things I wasn't able to do as I don't have a certificate and I'm just learning docker.

Steps I've done:

In Startup.cs I've disabled https redirection

//app.UseHttpsRedirection();

And in project properties under "Debug" section I unchecked "Enable SSL".

Then I was able to run the container as expected.

answered Jan 9, 2020 at 12:07

Diego Perez

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