COPY failed: file not found in build context or excluded by .dockerignore: stat solution/yourProject.csproj: file does not exist

前言

最近透過 Visual Studio 2019 來建置 docker image 是沒問題的，但是如果透過 Command 來下 docker build 就會發生以下的錯誤，

COPY failed: file not found in build context or excluded by .dockerignore: stat solution/yourProject.csproj: file does not exist

於是直接在專案的目錄下，直接開啟 Command 然後下，

docker build -t rmimage -f Dockerfile .

的確就會出現 COPY Failed 的錯誤，

研究

Dockerfile 如下，

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

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

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

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

依錯誤來看，應該是Visual Studio 建立方案時，方案與專案目錄的關係，所以 ….

解法1

即然是 Folder 的關系，所以就往上一層就可以了，所以 Command 就依 How Visual Studio builds containerized apps 改成往上一層即可(從 1個點 改成 2 個點 )

docker build -t rmimage -f Dockerfile .. 

解法 2

後來又查到 Getting “Program does not contain a static ‘Main’ method suitable for an entry point” when building using docker, why?
所以就將 Dockerfile 從專案的目錄移到方案的目錄，再下 docker build 就 OK 了哦!

當然，如果覺得這樣麻煩，可以在建立方案時，勾選將解決方案與專案置於相同目錄中的選項也可以哦!

參考資料

Getting “Program does not contain a static ‘Main’ method suitable for an entry point” when building using docker, why?
How Visual Studio builds containerized apps