Dockerfile优化推荐功能

背景信息

使用企业版构建服务，容器镜像服务可以在镜像构建前自动对构建的Dockerfile进行优化推荐。优化推荐功能会根据语法规则以及最优实践规则进行分析，最后输出分析结果。关于语法规则的更多内容，请参见官方语法规则。

分析结果分为Error和Warning两种等级：

• Error：Dockerfile中存在语法错误或容器镜像服务不支持的构建参数，此类问题将导致镜像构建出错，需要进行改正。

• Warning：Dockerfile中存在潜在问题，可能导致构建产生非预期的结果或者镜像存在冗余数据。

分析结果格式

语法检测结果

[Error] <Error message> at line <line number>: <Specific instruction content>
[Warning] <Warning message> at line <line number>: <Specific instruction content>
[Error] [Rule <Rule id>] <Error message> at line <line number>: <Specific instruction content>
[Warning] [Rule <Rule id>] <Warning message> at line <line number>: <Specific instruction content>

示例1

存在语法错误的Dockerfile。

# FROM指令使用了不支持的架构的基础镜像，并且没有指定多阶段构建的名称
FROM --platform=windows alpine as
# RUN指令使用了不支持的运行参数
RUN --security=insecure cat /proc/self/status | grep CapEff
# ADD指令缺少目的路径
ADD https://mirrors.edge.kernel.org/pub/linux/kernel/Historic/linux-0.01.tar.gz
# COPY指令不支持拷贝远程文件
COPY https://mirrors.edge.kernel.org/pub/linux/kernel/Historic/linux-0.01.tar.gz linux-0.01.tag.gz
# COPY/ADD拷贝的源文件路径在构建路径下不存在
COPY  <不存在的路径> /somedir/
# 错误的指令名称
CPY /foo /bar

语法检测结果输出。

[parse stage begin.]
[Error] Unsupported target architecture at line 2: windows.
[Error] Lack of stage name at line 2.
[Error] Unsupported security mode at line 4: insecure.
[Error] Lack of dest at line 6.
[Error] COPY does not support remote links. Please use the ADD instruction at line 8: https://mirrors.edge.kernel.org/pub/linux/kernel/Historic/linux-0.01.tar.gz.
[Error] Source path is not exist at line 10: <不存在的路径>.
[Error] Unknown instruction at line 12: CPY.
[Warning] No tag specified at line 2: from ["--platform=windows"] "alpine" "as".
[parse successfully, takes 0s.]

示例2

违背了最优实践规则的Dockerfile。

# 未指定镜像版本
FROM alpine AS a
# 安装软件包后未清除缓存
RUN apk add gcc
# 未指定镜像版本，使用了已有的阶段名
from ubuntu as a
# 安装软件包后未清除缓存，未使用--no-install-recommends避免下载不必要的软件包
RUN apt-get install -y gcc

语法检测结果输出。

[parse stage begin.]
[Warning] [Rule1003]When installing software with apt-get, it is recommended to include the --no-install-recommends parameter at line 8: RUN apt-get install -y gcc .
[Warning] No tag specified at line 2: FROM alpine AS a .
[Warning] No tag specified at line 6: from ubuntu as a .
[Warning] [Rule1001]Using a base image with a specific tag instead of the latest image.
[Error] Duplicate stage names with line 2: a at line 6: from ubuntu as a .
[Error] [Rule1014]Do not use duplicate stage names.
[parse successfully, takes 0s.]

检测规则

最优实践规则

FROM alpine:3.17 as complie
COPY <source code> code/
RUN make
FROM alpine:3.17
COPY --from=compile /code/bin bin/