优化 .net core 应用的 dockerfile

intro

在给 .net core 应用的写 dockerfile 的时候一直有个苦恼，就是如果有很多个项目，在 dockerfile 里写起来就会很繁琐，有很多项目文件要 copy，dockerfile 还不支持直接批量复制项目文件，今天要改的一个项目也是有好多个项目文件，不想再一个一个复制，于是 google 一下看有没有比较好的解决方案，找到一个折中的解决方案，分享一下

solution

1. 首先把所有的项目文件拷贝到 docker 镜像内 copy */*.csproj ./
2. 然后根据项目文件名称创建项目文件夹，并移动项目文件到对应的项目目录下

原来的 dockerfile

from mcr.microsoft.com/dotnet/core/sdk:3.0-alpine as build-env
workdir /src

# copy csproj and restore as distinct layers
copy activityreservation.common/*.csproj activityreservation.common/
copy activityreservation.models/*.csproj activityreservation.models/
copy activityreservation.dataaccess/*.csproj activityreservation.dataaccess/
copy activityreservation.business/*.csproj activityreservation.business/
copy activityreservation.helper/*.csproj activityreservation.helper/
copy activityreservation.wechatapi/*.csproj activityreservation.wechatapi/
copy activityreservation.adminlogic/*.csproj activityreservation.adminlogic/
copy activityreservation.api/*.csproj activityreservation.api/
copy activityreservation/activityreservation.csproj activityreservation/

# run dotnet restore activityreservation/activityreservation.csproj
## diff between netcore2.2 and netcore3.0
workdir /src/activityreservation
run dotnet restore

# copy everything and build
copy . .
run dotnet publish -c release -o out activityreservation/activityreservation.csproj

# build runtime image
from mcr.microsoft.com/dotnet/core/aspnet:3.0-alpine

label maintainer="weihanli"
workdir /app
copy --from=build-env /src/activityreservation/out .
expose 80
entrypoint ["dotnet", "activityreservation.dll"]

修改之后的 dockerfile

from mcr.microsoft.com/dotnet/core/sdk:3.0-alpine as build-env
workdir /src

# copy csproj and restore as distinct layers
# https://andrewlock.net/optimising-asp-net-core-apps-in-docker-avoiding-manually-copying-csproj-files-part-2/
copy */*.csproj ./
run for file in $(ls *.csproj); do mkdir -p ${file%.*}/ && mv $file ${file%.*}/; done

## diff between netcore2.2 and netcore3.0
workdir /src/activityreservation
run dotnet restore

# copy everything and build
copy . .
run dotnet publish -c release -o out activityreservation/activityreservation.csproj

# build runtime image
from mcr.microsoft.com/dotnet/core/aspnet:3.0-alpine

label maintainer="weihanli"
workdir /app
copy --from=build-env /src/activityreservation/out .
expose 80
entrypoint ["dotnet", "activityreservation.dll"]

是不是精简了许多，来看一下修改前后的对比，更明显的对比一下：

核心代码：

 # 拷贝所有的二级目录下的项目文件
copy */*.csproj ./
# 根据项目文件名称创建项目文件夹，并移动项目文件到对应的项目目录下
run for file in $(ls *.csproj); do mkdir -p ${file%.*}/ && mv $file ${file%.*}/; done 

more

注：上面的方法适用于项目文件目录名称和项目文件名称一致的情况，默认创建的项目应该都会符合这样的要求，如果你的项目文件是三级目录，如 src/*/*.csproj 的，需要自己根据项目情况调整 dockerfile

有没有学到呢~~

reference

• https://github.com/weihanli/activityreservation/blob/dev/dockerfile