Docker构建自定义镜像

留言

在在Gitlab Pipeline中集成进ut覆盖率和测试报告中提到存在可改进之处，即单次CI耗时过长。


耗时主要在下载diff_cover(需要下载pip)，以及Golang(用的是docker image)以及gocover-cobertura和gotestsum

考虑将这些工具打包在一起，构建成一个新的镜像，CI阶段就可以大幅度降低耗时


Dockerfile如下：

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FROM  golang:latest

RUN echo '这是一个爽哥构建的一个工具'
RUN apt-get update && apt install python3-pip -y && pip3 install diff_cover  && go env -w GOPROXY="https://goproxy.cn,direct" && go get github.com/boumenot/gocover-cobertura@v1.2.0 && go get gotest.tools/gotestsum@v1.7.0

因为Docker是分层下载，每一个RUN就是单独一层。所以尽可能如上这样写，而不要写多个RUN

执行docker build -t ci_tool:v1 .

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[+] Building 547.2s (4/7)                                                                                                                                              
[+] Building 547.6s (4/7)                                                                                                                                              
[+] Building 548.0s (4/7)                                                                                                                                              
[+] Building 635.7s (7/8)                                                                                                                                              
[+] Building 635.9s (7/8)                                                                                                                                              
[+] Building 636.0s (7/8)                                                                                                                                              
[+] Building 636.2s (7/8)                                                                                                                                              
[+] Building 636.3s (7/8)                                                                                                                                              
[+] Building 685.9s (7/8)                                                                                                                                                         
 => => extracting sha256:94a23d3cb5be24659b25f17537307e7f568d665244f6a383c1c6e51e31080749                                                                                    1.5s
 => => sha256:499ac46314c257f999ffe452e3a4ac1c8bc46c373f461074d4737870caca50bd 102.65MB / 102.65MB                                                                         144.3s
[+] Building 687.3s (7/8)                                                                                                                                                                                                               
[+] Building 694.8s (9/9) FINISHED                                                                                                                                                                                                      
 => [internal] load build definition from Dockerfile                                                                                                                                                                               0.0s
 => => transferring dockerfile: 342B                                                                                                                                                                                               0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                  0.0s
 => => transferring context: 2B                                                                                                                                                                                                    0.0s
 => [internal] load metadata for docker.io/library/golang:latest                                                                                                                                                                   5.4s
 => [auth] library/golang:pull token for registry-1.docker.io                                                                                                                                                                      0.0s
 => [1/3] FROM docker.io/library/golang:latest@sha256:0fa6504d3f1613f554c42131b8bf2dd1b2346fb69c2fc24a312e7cba6c87a71e                                                                                                           627.8s
 => => resolve docker.io/library/golang:latest@sha256:0fa6504d3f1613f554c42131b8bf2dd1b2346fb69c2fc24a312e7cba6c87a71e                                                                                                             0.0s
 => => sha256:ac9d381bd1e98fa8759f80ff42db63c8fce4ac9407b2e7c8e0f031ed9f96432b 5.14MB / 5.14MB                                                                                                                                    11.6s
 => => sha256:aa9c5b49b9db3dd2553e8ae6c2081b77274ec0a8b1f9903b0e5ac83900642098 10.66MB / 10.66MB                                                                                                                                  26.6s 
 => => sha256:0fa6504d3f1613f554c42131b8bf2dd1b2346fb69c2fc24a312e7cba6c87a71e 2.35kB / 2.35kB                                                                                                                                     0.0s         0.4s
 => => sha256:89b5d1fa04af24c4cae53f775b9382755b2ba1082bda77b9f8febaa8676b54cb 1.80kB / 1.80kB                                                                                                                                     0.0s
 => => sha256:cac175c1423a6f67bcf70033345b7dc7d733176ab28932904a3e457acc6f5c56 7.08kB / 7.08kB                                                                                                                                     0.0s
 => => sha256:94a23d3cb5be24659b25f17537307e7f568d665244f6a383c1c6e51e31080749 53.60MB / 53.60MB                                                                                                                                  84.6s
 => => sha256:841dd868500b6685b6cda93c97ea76e817b427d7a10bf73e9d03356fac199ffd 54.67MB / 54.67MB                                                                                                                                 618.3s         0.4s
 => => sha256:627b3401fb617535edd16e96bd5941ecea7fe10ce6087bd47707602cfc396c2b 81.01MB / 81.01MB                                                                                                                                 157.3s
 => => extracting sha256:94a23d3cb5be24659b25f17537307e7f568d665244f6a383c1c6e51e31080749                                                                                                                                          1.5s
 => => sha256:499ac46314c257f999ffe452e3a4ac1c8bc46c373f461074d4737870caca50bd 102.65MB / 102.65MB                                                                                                                               144.3s
 => => extracting sha256:ac9d381bd1e98fa8759f80ff42db63c8fce4ac9407b2e7c8e0f031ed9f96432b                                                                                                                                          0.1s
 => => extracting sha256:aa9c5b49b9db3dd2553e8ae6c2081b77274ec0a8b1f9903b0e5ac83900642098                                                                                                                                          0.2s
 => => sha256:63c2674d92dba6ae349f7ae5d7460b37a9dc8744644dedd1f83d0ed1dbd7c806 124B / 124B                                                                                                                                       145.7s
 => => extracting sha256:841dd868500b6685b6cda93c97ea76e817b427d7a10bf73e9d03356fac199ffd                                                                                                                                          1.7s
 => => extracting sha256:627b3401fb617535edd16e96bd5941ecea7fe10ce6087bd47707602cfc396c2b                                                                                                                                          2.2s
 => => extracting sha256:499ac46314c257f999ffe452e3a4ac1c8bc46c373f461074d4737870caca50bd                                                                                                                                          3.0s
 => => extracting sha256:63c2674d92dba6ae349f7ae5d7460b37a9dc8744644dedd1f83d0ed1dbd7c806                                                                                                                                          0.0s
 => [auth] library/golang:pull token for registry-1.docker.io                                                                                                                                                                      0.0s
 => [2/3] RUN echo '这是一个爽哥构建的一个工具'                                                                                                                                                                                                 0.4s
 => [3/3] RUN apt-get update && apt install python3-pip -y && pip3 install diff_cover  && go env -w GOPROXY="https://goproxy.cn,direct" && go get github.com/boumenot/gocover-cobertura@v1.2.0 && go get gotest.tools/gotestsum@  59.3s
 => exporting to image                                                                                                                                                                                                             1.6s
 => => exporting layers                                                                                                                                                                                                            1.6s
 => => writing image sha256:28a8ad1ca810ef0c17b80390c809d7fe3fc327e6dc8c4a8a994df1d9b69d057f                                                                                                                                       0.0s
 => => naming to docker.io/library/ci_tool:v1                                                                                                                                                                                      0.0s

Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them

启动，而后执行docker exec -it 容器id /bin/sh 进入容器，

可见符合预期~


将其push到dockerhub时报错，denied: requested access to the resource is denied

这是因为构建时要在前面加上自己的dockerhub的username


执行docker build -t cuishuang/ci_tool:v1 . 重新构建并push

之后在hub.docker.com/就能够看到


发现上面的Dockerfile漏了go get github.com/axw/gocov/…和go get github.com/AlekSi/gocov-xml这两步，在Dockerfile加上，

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FROM  golang:latest

RUN echo '这是一个爽哥构建的一个工具'
RUN apt-get update && apt install python3-pip -y && pip3 install diff_cover  && go env -w GOPROXY="https://goproxy.cn,direct" && go get github.com/boumenot/gocover-cobertura@v1.2.0 && go get gotest.tools/gotestsum@v1.7.0 && go get github.com/axw/gocov/... && go get github.com/AlekSi/gocov-xml

并docker build -t cuishuang/ci_tool:v2 . 重新构建，而后push到dockerhub


而后便可改造之前项目的.gitlab-ci.yml

并进行提交


发现Pipeline-Unittest阶段失败

具体原因为：

failed to pull image "cuishuang/ci_tool:latest" with specified policies [always]: Error response from daemon: manifest for cuishuang/ci_tool:latest not found: manifest unknown: manifest unknown (manager.go:203:19s)


将image: cuishuang/ci_tool:latest改为image: cuishuang/ci_tool:v2并提交。

发现可以pull到该镜像，但执行一些命令时失败：


在实际跑gitlab-runner的ubuntu机器上(amd架构)，启动上面构建的镜像：

docker run --name shuang_tool -d cuishuang/ci_tool:v2

而后进入，发现镜像启动失败


在本机(Mac M1,arm架构)启动，却没有该问题。

参考这篇，应该是arm和amd架构导致的问题


在ubuntu机器上新建Dockerfile， docker build -t cuishuang/ci_tool:v3 .进行构建

而后push到dockerhub。


但在ubuntu上apt-get update命令总失败

尝试看下docker能不能像go build一样可以交叉编译

跨平台构建 Docker 镜像新姿势，x86、arm 一把梭

继续解决apt-get update命令失败的问题，换一下源就可以了

docker ubuntu 换源

如果更换后出现类似The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32 这样的错误，可通过sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys xxxxxx 解决

一番尝试后，发现apt-get update及之后pip3 install diff_cover有各种各样的坑…。

(可以将相关的去掉然后构建，进入容器中去执行，发现报的这些依赖问题依然不好解决)

为绕过这些坑，聚焦主线，将之前的使用到diff-cover工具的部分去掉

(另外为了方便找到失败的原因，可将之前写在一个RUN里的多条命令拆开，一个命令一个RUN，这样容易获悉是哪一条命令执行出错)


同时将在ubuntu上构建出的镜像上传到docker hub


将改动提交，而后进入pipeline流程，可以看到shuang-unit-test阶段的job执行成功



这样就把CI的shuang-unit-test阶段用到的各种工具放在了一起，只需要拉取这个镜像即可~

(pull这个镜像比那各种现场apt update，go get要快太多了…)

docker镜像采用分层机制，在默认的官方golang镜像基础上，添加新的工具~

而官方的golang镜像默认是基于ubuntu系统，体积较大，拉取时间较长


构建后的镜像达到了1.05GB，压缩后也近400MB

一般都用基于精简款linux的alpine的来构建，可参考这篇

基于alpine构建体积更小的Docker镜

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