I am trying to complete a Github action to build and deploy my .Net8 web API with Docker to Kubernetes. Here is the yml file I am currently using for the workflow:

name: Deploy to DigitalOcean Kubernetes

on:
  push:
    branches:
      - main 

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    env:
        NUGETUSERNAME: ${{ secrets.NUGETUSERNAME }}
        NUGETPASSWORD: ${{ secrets.NUGETPASSWORD }}
    steps:
    - name: Check out code
      uses: actions/checkout@v2

    - name: Log in to DigitalOcean Container Registry
      uses: docker/login-action@v1
      with:
        registry: registry.digitalocean.com
        username: _  # DigitalOcean requires username to be `_`
        password: ${{ secrets.DIGITALOCEAN_ACCESS_TOKEN }}
      
    - name: Replace Github Username In Nuget.Config
      run: sed -i 's/%NUGETUSERNAME%/${{ secrets.NUGETUSERNAME }}/g' x/x.Api/nuget.config
      
    - name: Replace Github Password In Nuget.Config
      run: sed -i 's/%NUGETPASSWORD%/${{ secrets.NUGETPASSWORD }}/g' x/x.Api/nuget.config

    - name: Build and push Docker image
      uses: docker/build-push-action@v2
      with:
        context: x/x.Api
        file: x/x.Api/Dockerfile
        push: true
        tags: registry.digitalocean.com/x-api/aggregator-api:latest  # Replace with your registry and image name

  deploy:
    needs: build-and-push
    runs-on: ubuntu-latest
    steps:
    - name: Install Kompose
      run: |
        curl -L https://github.com/kubernetes/kompose/releases/download/v1.26.0/kompose-linux-amd64 -o kompose
        chmod +x kompose
        sudo mv kompose /usr/local/bin/kompose

    - name: Convert Docker Compose to Kubernetes manifests
      run: kompose convert -f docker-compose.yml -o ./k8s/

    - name: Set up Kubectl
      uses: azure/setup-kubectl@v1

    - name: Configure Kubernetes context
      uses: azure/k8s-set-context@v1
      with:
        method: kubeconfig
        kubeconfig: ${{ secrets.KUBECONFIG }}

    - name: Deploy to Kubernetes
      run: |
        kubectl apply -f ./k8s/

    - name: Verify deployment
      run: kubectl rollout status deployment/x

Here is the Docker file of the API

FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
USER app
WORKDIR /app
EXPOSE 80
EXPOSE 443

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
ARG BUILD_CONFIGURATION=Release
WORKDIR /src
COPY ["x.Api.csproj", "x.Api/"]
COPY ./nuget.config ./
RUN dotnet restore "./x.Api/./x.Api.csproj" --configfile nuget.config 
COPY . .
WORKDIR "/src/x.Api"
RUN dotnet build "./x.csproj" -c $BUILD_CONFIGURATION -o /app/build

FROM build AS publish
ARG BUILD_CONFIGURATION=Release
RUN dotnet publish "./x.Api.csproj" -c $BUILD_CONFIGURATION -o /app/publish /p:UseAppHost=false

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

When the Github Action is run, it fails and I get the following (on dotnet build):

"Program does not contain a static 'Main' method suitable for an entry point"

I have updated the Docker file to use this line to be more specific:

RUN dotnet build "./x.Api.csproj" -v=q /property:StartupObject=x.Api.Program -c $BUILD_CONFIGURATION -o /app/build

It again fails with:

"Could not find 'x.Api.Program' specified for Main method" and "

This project builds fine locally using docker-compose.

Anyone know whats going on here?