docker image not working or running properly - api

Question

This is part of a major issue i've been fighting to get resolve in a span of 2 or even 3 weeks, first of all, i'm not a docker expert, in fact, i don't even know a thing about docker, all i know is that i need to use it in order to make a connection between an api in localhost and my app in react native, the thing is, i manage to make it work on another two projects i created to test docker, but not in the one i actually need to. This is a dockerfile for an api in .net core 2.2
my dockerfile is a combination of the code i found in stackoverflow and the example in docker documentation to create a docker in .net core, this specific file worked for me on another two api, one as a blank project, and the other one with a class library.
The code below shows the dockerfile, when i run the command line and create the image, it shows no errors, but i know there is something wrong, because when i run docker image ls, the docker image is around 200-300mb size, which seems way too small, and when i run that image with docker run... and check the list of docker containers runnning, it shows nothing
FROM mcr.microsoft.com/dotnet/core/sdk:2.2 AS build-env
WORKDIR /app
# Copy csproj and restore as distinct layers
WORKDIR /src
COPY ISARRHH.sln ./
COPY ISARRHH.BusinessGraph/*.csproj ./ISARRHH.BusinessGraph/
COPY ISARRHH.APIWeb/*.csproj ./ISARRHH.APIWeb/
RUN dotnet restore
# Copy everything else and build
COPY . ./
WORKDIR /src/ISARRHH.BusinessGraph
RUN dotnet publish -c Release -o /app
WORKDIR /src/ISARRHH.APIWeb
RUN dotnet publish -c Release -o /app
# Build runtime image
FROM mcr.microsoft.com/dotnet/core/aspnet:2.2
WORKDIR /app
COPY --from=build-env /app .
ENTRYPOINT ["dotnet", "isarrhh.dll"]
#######################################################
I want this bloody docker to work, this was the plan b on one of the modules i'm working on, and is giving me a headache, i managed to make it work on another project, i want it to work on this api which works with office 365 and sharepoint
EDIT: this is the project structure
ISARRHH (Solution)
|
|--ISARRHH.APIWeb (API)
| |_Dependencies
| |_Controllers
| |_Models
| |_Properties
| |_appsettings.json
| |_appsettings.Development.json
| |_Authentication.cs
| |_Configuration.cs
| |_Program.cs
| |_ProtectedApiCallHelper.cs
| |_PublicAppUsingUsernamePassword.cs
| |_SiteInformation.cs
| |_Startup.cs
| |_SiteInformation.cs
|
|--ISARRHH.BusinessGraph (Class Library)
| |_Dependencies
| |_UserGraph.cs
|
|--Solution Items
|_Dockerfile
|_.dockerignore
EDIT2: More information
REPOSITORY TAG IMAGE ID CREATED SIZE
isarrhh latest 67fc0628c921 13 minutes ago 268MB
according to this, the image was created succesfully apparently, but when i run it with
docker run -d -p 3001:80 ...
then i check with
docker container ls
i see no container running, also, when i check with the command you provided here
docker logs -t isachile
i get this:
MacBook: ISARRHH$ docker logs -t isachile
2019-07-31T18:49:22.553317346Z Did you mean to run dotnet SDK commands? Please install dotnet SDK from:
2019-07-31T18:49:22.553390430Z https://go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409
EDIT 3: SOLVED IT -- SORT OF...
i manage to run my docker by manually copy and pasting ever file on a different project, each file individually copy and paste in this second project, and each time creating the docker image, yes, a seriously horrible and tedious process, but it worked, although, we're not considering this solution anymore, since the process is too slow for our scrum project, we need to connect react native to our localhost api, i still need an answer for this

Answer 1

So there's two things here, and neither necessarily indicates a problem with Docker or your Dockerfile.
Size is only 200-300MB
That's about right. You haven't indicated whether you're using Windows or Linux containers, but in either case, most of the weight comes simply from the .NET Core runtime. The whole point of containers is that the host OS is shared (unlike a VM where every VM gets its own separate OS installation). The only things coming from the base OS image are user-specific files and directories. The main system components are proxied to the host operating system. Long and short, I don't know what you're expecting here in terms of size, but honestly 200-300MB is a bit on the large size for an image. It's possible in many cases to package ASP.NET Core app images down to as little as 25MB-30MB, though if you include the full runtime, it's generally going to be closer to your 200-300MB.
The container isn't running.
All the means is that it exited. When the container is run, the entrypoint line will be called, which just starts up the ASP.NET Core app running in Kestrel. That of course runs Program.Main, since it's just a console app, after all. That in turn builds the web host and calls Run, which listens for TCP socket connections, keeping the app running, which therefore keeps the container running.
If the container isn't running, then the app exited. That could happen for different reasons, but the most likely cause is that a runtime exception was thrown during the web host build phase (i.e. something in Program or Startup is throwing an exception). Try running something like:
docker logs -t {container name}
And you'll probably see a stacktrace and exception there. Fix the issue accordingly.