通过dockerfile制作镜像

时间:2020-04-22 Tynam.Yang 人气:1

　　Dockerfile是一个用于构建Docker镜像的文本文件，其中包含了创建Docker镜像的全部指令。就是将我们安装环境的每个步骤使用指令的形式存放在一个文件中，最后生成一个需要的环境。
　　Docker使用Dockerfile构建镜像步骤：

创建dockerfile文件
通过build命令生成image镜像文件
运行容器
上传仓库

创建dockerfile文件

1、创建dockerfile

新建一个文件夹，api-demo

然后进入api-demo，创建dockerfile

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox
$ mkdir api—-demo
$ cd api—-demo/
$ touch Dockerfile
$ vi Dockerfile

编写Dockerfile文件如下：

# 基于基础镜像
FROM python:3.6

# 设置code文件夹是工作目录
WORKDIR /code

# 将代码添加到code文件夹下
COPY test_api.py  /code/

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

# pip安装依赖包
RUN pip install -U pytest
RUN pip install -U requests

# 执行命令
CMD ["python", "test_api.py"]

2、dockerfile常用指令　　

Dockerfile 语法：

Dockerfile语法由两部分构成，注释和命令+参数

示例：

# 基于基础镜像
FROM python:3.6

常用指令如下

ADD

ADD命令有两个参数，源和目标。它的基本作用是从源系统的文件系统上复制文件到目标容器的文件系统。如果源是一个URL，那该URL的内容将被下载并复制到容器中。

# Usage: ADD [source directory or URL] [destination directory]
ADD /my_app_folder /my_app_folder

COPY

用于将文件作为一个新的层添加到镜像中。通常使用 COPY 指令将应用代码赋值到镜像中。

COPY test_api.py  /code/

CMD

和RUN命令相似，CMD可以用于执行特定的命令。和RUN不同的是，这些命令不是在镜像构建的过程中执行的，而是在用镜像构建容器后被调用。

CMD ["python", "test_api.py"]

ENTRYPOINT

配置容器启动后执行的命令，并且不可被 docker run 提供的参数覆盖。

每个 Dockerfile 中只能有一个 ENTRYPOINT，当指定多个时，只有最后一个起效。

ENTRYPOINT 帮助你配置一个容器使之可执行化，如果你结合CMD命令和ENTRYPOINT命令，你可以从CMD命令中移除“application”而仅仅保留参数，参数将传递给ENTRYPOINT命令。

# Usage: ENTRYPOINT application "argument", "argument", ..
# Remember: arguments are optional. They can be provided by CMD
# or during the creation of a container.
ENTRYPOINT echo
# Usage example with CMD:
# Arguments set with CMD can be overridden during *run*
CMD "Hello docker!"
ENTRYPOINT echo

ENV

ENV命令用于设置环境变量。这些变量以”key=value”的形式存在，并可以在容器内被脚本或者程序调用。这个机制给在容器中运行应用带来了极大的便利。

# Usage: ENV key value
ENV SERVER_WORKS 4

EXPOSE

EXPOSE用来指定端口，使容器内的应用可以通过端口和外界交互。

# Usage: EXPOSE [port]
EXPOSE 8080

FROM

FROM命令可能是最重要的Dockerfile命令。改命令定义了使用哪个基础镜像启动构建流程。基础镜像可以为任意镜像。如果基础镜像没有被发现，Docker将试图从Docker image index来查找该镜像。FROM命令必须是Dockerfile的首个命令。

# Usage: FROM [image name]
FROM ubuntu

MAINTAINER

我建议这个命令放在Dockerfile的起始部分，虽然理论上它可以放置于Dockerfile的任意位置。这个命令用于声明作者，并应该放在FROM的后面。

# Usage: MAINTAINER [name]
MAINTAINER authors_name

RUN

RUN命令是Dockerfile执行命令的核心部分。它接受命令作为参数并用于创建镜像。不像CMD命令，RUN命令用于创建镜像（在之前commit的层之上形成新的层）。

# pip安装依赖包
RUN pip install -U pytest

USER

USER命令用于设置运行容器的UID。

# Usage: USER [UID]
USER 751

VOLUME

VOLUME命令用于让你的容器访问宿主机上的目录。

# Usage: VOLUME ["https://img.qb5200.com/download-x/dir_1", "https://img.qb5200.com/download-x/dir_2" ..]
VOLUME ["/my_files"]

WORKDIR

WORKDIR命令用于设置CMD指明的命令的运行目录。

# Usage: WORKDIR /path
WORKDIR ~/

　3、创建python文件

创建python文件 test_api.py，在这做一个简单的接口测试，一个成功的测试用例和一个失败的测试用例，代码如下：

# coding=utf-8
import requests
import pytest


def test_1():
    search_url = 'https://baidu.com/'

    respose = requests.get(url=search_url)

    assert 200 == respose.status_code


def test_2():
    search_url = 'https://baidu.com/'

    respose = requests.get(url=search_url)

    assert 400 == respose.status_code


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

通过build构建镜像文件

使用docker build 命令创建镜像。

使用命令：（注意命令最后面的点）

docker build -t tynam/api-demo:v1.1 .

OPTIONS说明：

- --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。例如 tynam/api-demo:v1.1

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox/api—-demo
$ docker build -t tynam/api-demo:v1.1 .
Sending build context to Docker daemon  3.072kB
Step 1/7 : FROM python:3.6
---> 0db2e2bbf438
Step 2/7 : WORKDIR /code
---> Using cache
---> 688dd9856f6e
Step 3/7 : COPY test_api.py  /code/
---> 87e29f28e665
Step 4/7 : RUN pip install --upgrade pip --index-url http://pypi.douban.com/simple
---> Running in 14f5c424c164
Looking in indexes: http://pypi.douban.com/simple
Requirement already up-to-date: pip in /usr/local/lib/python3.6/site-packages (20.0.2)
Removing intermediate container 14f5c424c164
---> fbdb47946e97
Step 5/7 : RUN pip install -U pytest
---> Running in 6ffb142f983d
Collecting pytest
  Downloading pytest-5.4.1-py3-none-any.whl (246 kB)
Collecting wcwidth
  Downloading wcwidth-0.1.9-py2.py3-none-any.whl (19 kB)
Collecting importlib-metadata>=0.12; python_version < "3.8"
  Downloading importlib_metadata-1.6.0-py2.py3-none-any.whl (30 kB)
Collecting attrs>=17.4.0
  Downloading attrs-19.3.0-py2.py3-none-any.whl (39 kB)
Collecting more-itertools>=4.0.0
  Downloading more_itertools-8.2.0-py3-none-any.whl (43 kB)
Collecting pluggy<1.0,>=0.12
  Downloading pluggy-0.13.1-py2.py3-none-any.whl (18 kB)
Collecting packaging
  Downloading packaging-20.3-py2.py3-none-any.whl (37 kB)
Collecting py>=1.5.0
  Downloading py-1.8.1-py2.py3-none-any.whl (83 kB)
Collecting zipp>=0.5
  Downloading zipp-3.1.0-py3-none-any.whl (4.9 kB)
Collecting pyparsing>=2.0.2
  Downloading pyparsing-2.4.7-py2.py3-none-any.whl (67 kB)
Collecting six
  Downloading six-1.14.0-py2.py3-none-any.whl (10 kB)
Installing collected packages: wcwidth, zipp, importlib-metadata, attrs, more-itertools, pluggy, pyparsing, six, packaging, py, pytest
Successfully installed attrs-19.3.0 importlib-metadata-1.6.0 more-itertools-8.2.0 packaging-20.3 pluggy-0.13.1 py-1.8.1 pyparsing-2.4.7 pytest-5.4.1 six-1.14.0 wcwidth-0.1.9 zipp-3.1.0
Removing intermediate container 6ffb142f983d
---> 0fe23e1c2a89
Step 6/7 : RUN pip install -U requests
---> Running in 21163a3acd67
Collecting requests
  Downloading requests-2.23.0-py2.py3-none-any.whl (58 kB)
Collecting certifi>=2017.4.17
  Downloading certifi-2020.4.5.1-py2.py3-none-any.whl (157 kB)
Collecting chardet<4,>=3.0.2
  Downloading chardet-3.0.4-py2.py3-none-any.whl (133 kB)
Collecting idna<3,>=2.5
  Downloading idna-2.9-py2.py3-none-any.whl (58 kB)
Collecting urllib3!=1.25.0,!=1.25.1,<1.26,>=1.21.1
  Downloading urllib3-1.25.9-py2.py3-none-any.whl (126 kB)
Installing collected packages: certifi, chardet, idna, urllib3, requests
Successfully installed certifi-2020.4.5.1 chardet-3.0.4 idna-2.9 requests-2.23.0 urllib3-1.25.9
Removing intermediate container 21163a3acd67
---> 8a8ae3f778a5
Step 7/7 : CMD ["python", "test_api.py"]
---> Running in f7310b052d08
Removing intermediate container f7310b052d08
---> 308b0f67af64
Successfully built 308b0f67af64
Successfully tagged tynam/api-demo:v1.1
SECURITY WARNING: You are building a Docker image from Windows against a non-Windows Docker host. All files and directories added to build context will have '-rwxr-xr-x' permissions. It is recommended to double check and reset permissions for sensitive files and directories.

　　在运行过程中，可以看到运行步骤，及运行的指令。例如第五步：Step 5/7 : RUN pip install -U pytest

镜像创建完成后可以使用命令查看创建的镜像：

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox/api—-demo
$ docker images
REPOSITORY                  TAG                IMAGE ID            CREATED            SIZE
tynam/api-demo              v1.1                308b0f67af64        12 minutes ago      927MB

运行容器

镜像创建完成后开始运行，使用命令;

docker run -it tynam/api-demo:v1.1

运行结果如下：

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox/api—-demo
$ docker run -it tynam/api-demo:v1.1
================================================= test session starts ==================================================
platform linux -- Python 3.6.10, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
rootdir: /code
collected 2 items

test_api.py .F

======================================================= FAILURES =======================================================
________________________________________________________ test_2 ________________________________________________________

    def test_2():
        search_url = 'https://baidu.com/'

        respose = requests.get(url=search_url)

>      assert 400 == respose.status_code
E      assert 400 == 200
E        +  where 200 = <Response [200]>.status_code

test_api.py:19: AssertionError
=============================================== short test summary info ================================================
FAILED test_api.py::test_2 - assert 400 == 200
============================================= 1 failed, 1 passed in 0.61s ==============================================

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox/api—-demo

上传仓库

docker拥有自己的镜像仓库，官方仓库网站是 https://hub.docker.com/

镜像上传仓库的流程为：登录>>tag操作>>push

1、创建账号

进入docker hub https://hub.docker.com/ 注册账号，然后创建自己的仓库

例如笔者创建的仓库名为 api

2、本地登录docker

使用命令登录自己的docker

docker login

示例：

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox
$ docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username (tynam): tynam
Password:
Login Succeeded

3、修改镜像名

修改镜像名和仓库名一致，镜像名称必须和 hub 中的仓库名称一致，否则将会抛出错误, 使用命令:

docker tag IMAGEID(镜像id) REPOSITORY:TAG（仓库：标签）

示例：

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox/api—-demo
$ docker tag 308b0f67af64 tynam/api:v1.1

修改后查看镜像

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox/api—-demo
$ docker images
REPOSITORY                  TAG                IMAGE ID            CREATED            SIZE
tynam/api-demo              v1.1                308b0f67af64        16 minutes ago      927MB
tynam/api                    v1.1                308b0f67af64        16 minutes ago      927MB

4、上传镜像

docker push [REPOSITORY]:[TAG]

示例：

TynamYang@XA-LSR-Tynam MINGW64 https://img.qb5200.com/download-x/dhttps://img.qb5200.com/download-x/docker/Docker Toolbox
$ docker push tynam/api:v1.1
The push refers to repository [docker.io/tynam/api]
de38accaade6: Pushed
52574f25c16c: Pushed
c2e450965650: Pushed
86dd60275049: Pushed
58f7d369eb64: Pushed
7e8b1f6898b0: Mounted from tynam/test
e91ff66f967f: Mounted from tynam/test
e05388744d34: Mounted from tynam/test
d4aeb4b1e8cc: Mounted from tynam/test
46829331b1e4: Mounted from tynam/test
d35c5bda4793: Mounted from tynam/test
a3c1026c6bcc: Mounted from tynam/test
f1d420c2af1a: Mounted from tynam/test
461719022993: Mounted from tynam/test
v1.1: digest: sha256:c821d6afcfb43cc03b47bf3e0241d04472f4ecc83455dd5b6a3acc6a1b5b3276 size: 3265

上传完成后进入自己的仓库可以查看上传结果

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