docker（9）Dockerfile制作镜像

前言

如果我们已经安装了一个python3的环境，如果另一台机器也需要安装同样的环境又要敲一遍，很麻烦，这里可以配置Dockerfile文件，让其自动安装，类似shell脚本

Dockerfile编写

在当前目录新建一个文件夹docker-run， cd进入到文件夹，touch新建一个Dockerfile，然后vi打开文件，开始编辑

[root@jkc ~]# mkdir docker-run
[root@jkc ~]# cd docker-run/
[root@jkc docker-run]# touch Dockerfile
[root@jkc docker-run]# vi Dockerfile

编辑内容如下：

# 1.基于python3.6.8镜像
FROM python:3.6.8

# 2.镜像维护者的姓名和邮箱地址
MAINTAINER jkc  <1044500650@qq.com>

# 3.更新pip
RUN pip install --upgrade pip --index-url https://pypi.douban.com/simple 

# 4.指定当前工作目i录
WORKDIR /code

# 5.将当年目录文件夹下的所有文件拷贝到code目录
COPY . .

# 6.安装第三方包
RUN pip install -r requirements.txt --index-url https://pypi.douban.com/simple

# 7.传递参数
ENTRYPOINT ["pytest"]

# 8.默认显示帮助信息
CMD ["--help"]

Dockerfile配置详细解释

• FROM：先拉取python3.6.8作为基础镜像，然后在上面修改
• MAINTAINER：填写镜像维护者的姓名和邮箱地址
• RUN：更新pip到最新版本
• WORKDIR：用来指定当前工作目录（或者称为当前目录），容器启动时执行的命令会在该目录下执行，比如接下来要执行pytest test_1.py就会在指定的目录下执行
• COPY：COPY ，拷贝文件到目标路径，上述是拷贝上下文目录中的文件到当前目录(就是指WORKDIR指定的目录)
• RUN：安装requirements.txt文件
• ENTRYPOINT：默认命令行参数pytest
• CMD：与ENTRYPOINT连用，作为ENTRYPOINT的参数，这里默认命令就是pytest --help，如果你想默认执行命令是pytest -s，那么就把CMD改成CMD["-s"]就可以了
  
  此时我们当前目录下还没有requirements.txt文件，接下来创建文件，并写入需要安装的第三方包

[root@jkc docker-run]# ls
Dockerfile  requirements.txt
[root@jkc docker-run]# cat requirements.txt
pytest==3.6.3
requests==2.20.1

build构建镜像文件

docker build 命令用于使用 Dockerfile 创建镜像。OPTIONS说明：

-f :指定要使用的Dockerfile路径；

--pull :尝试去更新镜像的新版本；

--quiet, -q :安静模式，成功后只输出镜像 ID；

--tag, -t: 镜像的名字及标签，通常 name:tag 或者 name 格式；可以在一次构建中为一个镜像设置多个标签。

-t参数设置镜像名称jkc_pytest和tag标签名称v1，注意最后面有个点. 这个点代表上下文目录的路径，就是当前路径，我这里是/root/docker_run

docker build -t jkc_pytest:v1 .

[root@jkc docker-run]# docker build -t jkc_pytest:v1 .
Sending build context to Docker daemon  7.168kB
Step 1/8 : FROM python:3.6.8
 ---> 48c06762acf0
Step 2/8 : MAINTAINER jkc  <1044500650@qq.com>
 ---> Running in 986c40cdf6d9
Removing intermediate container 986c40cdf6d9
 ---> 157699a7ac69
Step 3/8 : RUN pip install --upgrade pip --index-url https://pypi.douban.com/simple
 ---> Running in 1420e29b1810
Looking in indexes: https://pypi.douban.com/simple
Collecting pip
  Downloading https://pypi.doubanio.com/packages/de/47/58b9f3e6f611dfd17fb8bd9ed3e6f93b7ee662fb85bdfee3565e8979ddf7/pip-21.0-py3-none-any.whl (1.5MB)
Installing collected packages: pip
  Found existing installation: pip 19.1.1
    Uninstalling pip-19.1.1:
      Successfully uninstalled pip-19.1.1
Successfully installed pip-21.0
Removing intermediate container 1420e29b1810
 ---> f77fce861c3d
Step 4/8 : WORKDIR /code
 ---> Running in 0a1229af5f02
Removing intermediate container 0a1229af5f02
 ---> 2201ff40156b
Step 5/8 : COPY . .
 ---> 89fd63a6e517
Step 6/8 : RUN pip install -r requirements.txt --index-url https://pypi.douban.com/simple
 ---> Running in 778b4c1a69e9
Looking in indexes: https://pypi.douban.com/simple
Collecting pytest==3.6.3
  Downloading https://pypi.doubanio.com/packages/77/64/3a76f6fbb0f392d60c5960f2b2fbad8c2b802dada87ca6d1b99c0083a929/pytest-3.6.3-py2.py3-none-any.whl (195 kB)
Collecting requests==2.20.1
  Downloading https://pypi.doubanio.com/packages/ff/17/5cbb026005115301a8fb2f9b0e3e8d32313142fe8b617070e7baad20554f/requests-2.20.1-py2.py3-none-any.whl (57 kB)
Collecting atomicwrites>=1.0
  Downloading https://pypi.doubanio.com/packages/2c/a0/da5f49008ec6e9a658dbf5d7310a4debd397bce0b4db03cf8a410066bb87/atomicwrites-1.4.0-py2.py3-none-any.whl (6.8 kB)
Requirement already satisfied: setuptools in /usr/local/lib/python3.6/site-packages (from pytest==3.6.3->-r requirements.txt (line 1)) (41.0.1)
Collecting pluggy<0.7,>=0.5
  Downloading https://pypi.doubanio.com/packages/ba/65/ded3bc40bbf8d887f262f150fbe1ae6637765b5c9534bd55690ed2c0b0f7/pluggy-0.6.0-py3-none-any.whl (13 kB)
Collecting six>=1.10.0
  Downloading https://pypi.doubanio.com/packages/ee/ff/48bde5c0f013094d729fe4b0316ba2a24774b3ff1c52d924a8a4cb04078a/six-1.15.0-py2.py3-none-any.whl (10 kB)
Collecting attrs>=17.4.0
  Downloading https://pypi.doubanio.com/packages/c3/aa/cb45262569fcc047bf070b5de61813724d6726db83259222cd7b4c79821a/attrs-20.3.0-py2.py3-none-any.whl (49 kB)
Collecting py>=1.5.0
  Downloading https://pypi.doubanio.com/packages/67/32/6fe01cfc3d1a27c92fdbcdfc3f67856da8cbadf0dd9f2e18055202b2dc62/py-1.10.0-py2.py3-none-any.whl (97 kB)
Collecting more-itertools>=4.0.0
  Downloading https://pypi.doubanio.com/packages/66/58/63146600d8c35188f2c4de3f1e2fe77a54e9c9ac99ac3b652f09e042f637/more_itertools-8.6.0-py3-none-any.whl (45 kB)
Collecting idna<2.8,>=2.5
  Downloading https://pypi.doubanio.com/packages/4b/2a/0276479a4b3caeb8a8c1af2f8e4355746a97fab05a372e4a2c6a6b876165/idna-2.7-py2.py3-none-any.whl (58 kB)
Collecting certifi>=2017.4.17
  Downloading https://pypi.doubanio.com/packages/5e/a0/5f06e1e1d463903cf0c0eebeb751791119ed7a4b3737fdc9a77f1cdfb51f/certifi-2020.12.5-py2.py3-none-any.whl (147 kB)
Collecting chardet<3.1.0,>=3.0.2
  Downloading https://pypi.doubanio.com/packages/bc/a9/01ffebfb562e4274b6487b4bb1ddec7ca55ec7510b22e4c51f14098443b8/chardet-3.0.4-py2.py3-none-any.whl (133 kB)
Collecting urllib3<1.25,>=1.21.1
  Downloading https://pypi.doubanio.com/packages/01/11/525b02e4acc0c747de8b6ccdab376331597c569c42ea66ab0a1dbd36eca2/urllib3-1.24.3-py2.py3-none-any.whl (118 kB)
Installing collected packages: urllib3, six, py, pluggy, more-itertools, idna, chardet, certifi, attrs, atomicwrites, requests, pytest
Successfully installed atomicwrites-1.4.0 attrs-20.3.0 certifi-2020.12.5 chardet-3.0.4 idna-2.7 more-itertools-8.6.0 pluggy-0.6.0 py-1.10.0 pytest-3.6.3 requests-2.20.1 six-1.15.0 urllib3-1.24.3
Removing intermediate container 778b4c1a69e9
 ---> 8dbb604ee32b
Step 7/8 : ENTRYPOINT ["pytest"]
 ---> Running in 9f8af21deb12
Removing intermediate container 9f8af21deb12
 ---> bc1569590d44
Step 8/8 : CMD ["--help"]
 ---> Running in f4a600409184
Removing intermediate container f4a600409184
 ---> f7033ca36724
Successfully built f7033ca36724
Successfully tagged jkc_pytest:v1
[root@jkc docker-run]#

运行过程中可以看到按步骤运行，如：Step 1/8

运行完成后，可以通过docker images查看生成的镜像

[root@jkc docker-run]# docker images
REPOSITORY                  TAG                 IMAGE ID            CREATED             SIZE
jkc_pytest                  v1                  f7033ca36724        8 minutes ago       944MB

run运行容器

在当前目录新建一个test_1.py文件，写入pytest测试脚本

import pytest

def test_one():
    print("正在执行----test_one")
    x = "this"
    assert 'h' in x

def test_two():
    print("正在执行----test_two")
    x = "hello"
    assert x

def test_three():
    print("正在执行----test_three")
    a = "hello"
    b = "hello world"
    assert a in b

if __name__ == "__main__":
    pytest.main(["-s", "test_h.py"])

使用docker run运行容器

• -it -t让docker分配一个伪终端并绑定到容器的标准输入上, -i则让容器的标准输入保持打开.
• --rm 容器退出时，自动清除容器。 --rm选项不能与-d同时使用
• -v 将容器的工作目录/code挂载到宿主机的$PWD，也就是当前目录
• jkc_pytest:v1 容器名称和tag名称
• test_1.py 后面跟着需要执行的脚本名称

[root@jkc docker-run]# docker run -it --rm -v "$PWD":/code jkc_pytest:v1 test_1.py  -s
====================================================== test session starts ======================================================
platform linux -- Python 3.6.8, pytest-3.6.3, py-1.10.0, pluggy-0.6.0
rootdir: /code, inifile:
collected 3 items                                                                                                               

test_1.py 正在执行----test_one
.正在执行----test_two
.正在执行----test_three
.

=================================================== 3 passed in 0.04 seconds ====================================================
[root@jkc docker-run]#