Kubernetes之YAML语法

我会带着你远行 2022-11-18 13:58 246阅读 0赞

> **YAML 是一种非常简洁/强大/专门用来写配置文件的语言！**

`YAML` 全称是 **”YAML Ain’t a Markup Language”** 的递归缩写，该语言的设计参考了 `JSON` / `XML` 和 `SDL` 等语言,强调以数据为中心，简洁易读，编写简单。

![Kubernetes的YAML语法][Kubernetes_YAML]

**Kubernetes的YAML语法**

--------------------

## 1. YAML 语法特性 ##

> **学过编程的人理解起来应该非常容易**

![多种数据格式化结构方式][f782e05de367207de5cd59ec6ba978f8.png]

**多种数据格式化结构方式**

*  **\[1\] 语法特点**
    
     *  大小写敏感
     *  通过缩进表示层级关系
     *  禁止使用`tab`缩进，只能使用空格键
     *  缩进的空格数目不重要，只要相同层级左对齐
     *  使用`#`表示注释

yaml

# yaml
    languages:
        - Ruby
        - Perl
        - Python
    websites:
        YAML: yaml.org
        Ruby: ruby-lang.org
        Python: python.org
        Perl: use.perl.org
    
    # Json
    {
        languages: [
            'Ruby',
            'Perl',
            'Python'
        ],
        websites: {
            YAML: 'yaml.org',
            Ruby: 'ruby-lang.org',
            Python: 'python.org',
            Perl: 'use.perl.org'
        }
    }

*  **\[2\] 数据结构**
    
     *  **对象:** 键值对的字典
     *  **数组:** 一组按次序排列的列表
     *  **纯量:** 单个的且不可再分的值

yaml

# 纯量
    hello
    
    # 数组
    - Cat
    - Dog
    - Goldfish
    
    # 对象
    animal: pets

*  **\[3\] 引号区别**
    
     *  **单引号(`''`):** 特殊字符作为普通字符串处理
     *  **双引号(`""`):** 特殊字符作为本身想表示的意思

yaml

# 单引号
    name: 'Hi,\nTom'
    
    # 双引号
    name: "Hi,\nTom"

*  **\[4\] 内置类型列表**

yaml

# YAML允许使用个感叹号(!)强制转换数据类型
    # 单叹号通常是自定义类型，双叹号是内置类型
    money: !!str
    123
    
    date: !Boolean
    true

<table> 
 <thead> 
  <tr> 
   <th>对应编号</th> 
   <th>内置类型</th> 
   <th>解释说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td><strong><code>!!int</code></strong></td> 
   <td>整数类型</td> 
  </tr> 
  <tr> 
   <td>2</td> 
   <td><strong><code>!!float</code></strong></td> 
   <td>浮点类型</td> 
  </tr> 
  <tr> 
   <td>3</td> 
   <td><strong><code>!!bool</code></strong></td> 
   <td>布尔类型</td> 
  </tr> 
  <tr> 
   <td>4</td> 
   <td><strong><code>!!str</code></strong></td> 
   <td>字符串类型</td> 
  </tr> 
  <tr> 
   <td>5</td> 
   <td><strong><code>!!null</code></strong></td> 
   <td>空值</td> 
  </tr> 
  <tr> 
   <td>6</td> 
   <td><strong><code>!!set</code></strong></td> 
   <td>集合</td> 
  </tr> 
  <tr> 
   <td>7</td> 
   <td><strong><code>!!seq</code></strong></td> 
   <td>列表</td> 
  </tr> 
  <tr> 
   <td>8</td> 
   <td><strong><code>!!map</code></strong></td> 
   <td>键值表</td> 
  </tr> 
  <tr> 
   <td>9</td> 
   <td><strong><code>!!binary</code></strong></td> 
   <td>字符串类型</td> 
  </tr> 
  <tr> 
   <td>10</td> 
   <td><strong><code>!!timestamp</code></strong></td> 
   <td>日期时间类型</td> 
  </tr> 
  <tr> 
   <td>11</td> 
   <td><strong><code>!!omap</code></strong>/<strong><code>!!pairs</code></strong></td> 
   <td>键值列表</td> 
  </tr> 
 </tbody> 
</table>

--------------------

## 2. YAML 中的纯量 ##

> **纯量是最基本的且不可再分的值**

*  **\[1\] 字符串**

yaml

# 不适用引号
    name: Tom
    
    # 使用单引号
    name: 'Tom'
    
    # 使用双引号
    name: "Tom"

*  **\[2\] 布尔值**

yaml

debug: true
    debug: false

*  **\[3\] 数字**

yaml

12       # 十进制整数
    014      # 八进制整数
    0xC      ＃十六进制整数
    13.4     ＃浮点数
    1.2e+34  ＃指数
    .inf     ＃无穷大

*  **\[4\] Null**

yaml

date: ~
    date: null

*  **\[5\] 时间**

yaml

# 使用iso-8601标准表示日期
    date: 2018-01-01t16:59:43.10-05:00

--------------------

## 3. YAML 特殊类型 ##

> **日常使用中基本不会用到的类型**

*  **\[1\] 文本块**

yaml

# 注意“|”与文本之间须另起一行
    # 使用|标注的文本内容缩进表示的块，可以保留块中已有的回车换行
    value: |
      hello
      world!
    
    # 输出结果
    # hello 换行 world！

yaml

# +表示保留文字块末尾的换行
    # -表示删除字符串末尾的换行
    value: |
    hello
    
    value: |-
    hello
    
    value: |+
    hello
    
    # 输出结果
    # hello\n hello hello\n\n

yaml

# 注意“>”与文本之间的空格
    # 使用>标注的文本内容缩进表示的块，将块中回车替换为空格最终连接成一行
    value: > hello
    world!
    
    # 输出结果
    # hello 空格 world！

*  **\[2\] 锚点与引用**

yaml

# 复制代码注意*引用部分不能追加内容
    # 使用&定义数据锚点，即要复制的数据
    # 使用*引用锚点数据，即数据的复制目的地
    name: &a yaml
    book: *a
    books:
       - java
       - *a
       - python
    
    # 输出结果
    book： yaml
    books：[java, yaml, python]

--------------------

## 4. YAML 实例说明 ##

> **光说不练假把式 => [JS-Yaml 官网实例地址][JS-Yaml]**

![Kubernetes的YAML语法][Kubernetes_YAML 1]

**Kubernetes的YAML语法**

yaml

---
    # Collection Types #############################################################
    ################################################################################
    
    # http://yaml.org/type/map.html -----------------------------------------------#
    
    map:
      # Unordered set of key: value pairs.
      Block style: !!map
        Clark: Evans
        Ingy: döt Net
        Oren: Ben-Kiki
      Flow style: !!map { Clark: Evans, Ingy: döt Net, Oren: Ben-Kiki }
    
    # http://yaml.org/type/omap.html ----------------------------------------------#
    
    omap:
      # Explicitly typed ordered map (dictionary).
      Bestiary: !!omap
        - aardvark: African pig-like ant eater. Ugly.
        - anteater: South-American ant eater. Two species.
        - anaconda: South-American constrictor snake. Scaly.
        # Etc.
      # Flow style
      Numbers: !!omap [one: 1, two: 2, three: 3]
    
    # http://yaml.org/type/pairs.html ---------------------------------------------#
    
    pairs:
      # Explicitly typed pairs.
      Block tasks: !!pairs
        - meeting: with team.
        - meeting: with boss.
        - break: lunch.
        - meeting: with client.
      Flow tasks: !!pairs [meeting: with team, meeting: with boss]
    
    # http://yaml.org/type/set.html -----------------------------------------------#
    
    set:
      # Explicitly typed set.
      baseball players: !!set
        ? Mark McGwire
        ? Sammy Sosa
        ? Ken Griffey
      # Flow style
      baseball teams: !!set { Boston Red Sox, Detroit Tigers, New York Yankees }
    
    # http://yaml.org/type/seq.html -----------------------------------------------#
    
    seq:
      # Ordered sequence of nodes
      Block style: !!seq
        - Mercury # Rotates - no light/dark sides.
        - Venus # Deadliest. Aptly named.
        - Earth # Mostly dirt.
        - Mars # Seems empty.
        - Jupiter # The king.
        - Saturn # Pretty.
        - Uranus # Where the sun hardly shines.
        - Neptune # Boring. No rings.
        - Pluto # You call this a planet?
      Flow style: !!seq [
          Mercury,
          Venus,
          Earth,
          Mars, # Rocks
          Jupiter,
          Saturn,
          Uranus,
          Neptune, # Gas
          Pluto,
        ] # Overrated
    
    # Scalar Types #################################################################
    ################################################################################
    
    # http://yaml.org/type/bool.html ----------------------------------------------#
    
    bool:
      - true
      - True
      - TRUE
      - false
      - False
      - FALSE
    
    # http://yaml.org/type/float.html ---------------------------------------------#
    
    float:
      canonical: 6.8523015e+5
      exponentioal: 685.230_15e+03
      fixed: 685_230.15
      sexagesimal: 190:20:30.15
      negative infinity: -.inf
      not a number: .NaN
    
    # http://yaml.org/type/int.html -----------------------------------------------#
    
    int:
      canonical: 685230
      decimal: +685_230
      octal: 02472256
      hexadecimal: 0x_0A_74_AE
      binary: 0b1010_0111_0100_1010_1110
      sexagesimal: 190:20:30
    
    # http://yaml.org/type/merge.html ---------------------------------------------#
    
    merge:
      - &CENTER { x: 1, y: 2 }
      - &LEFT { x: 0, y: 2 }
      - &BIG { r: 10 }
      - &SMALL { r: 1 }
    
      # All the following maps are equal:
    
      - # Explicit keys
        x: 1
        y: 2
        r: 10
        label: nothing
    
      - # Merge one map
        <<: *CENTER
        r: 10
        label: center
    
      - # Merge multiple maps
        <<: [*CENTER, *BIG]
        label: center/big
    
      - # Override
        <<: [*BIG, *LEFT, *SMALL]
        x: 1
        label: big/left/small
    
    # http://yaml.org/type/null.html ----------------------------------------------#
    
    null:
      # This mapping has four keys,
      # one has a value.
      empty:
      canonical: ~
      english: null
      ~: null key
      # This sequence has five
      # entries, two have values.
      sparse:
        - ~
        - 2nd entry
        -
        - 4th entry
        - Null
    
    # http://yaml.org/type/str.html -----------------------------------------------#
    
    string: abcd
    
    # http://yaml.org/type/timestamp.html -----------------------------------------#
    
    timestamp:
      canonical: 2001-12-15T02:59:43.1Z
      valid iso8601: 2001-12-14t21:59:43.10-05:00
      space separated: 2001-12-14 21:59:43.10 -5
      no time zone (Z): 2001-12-15 2:59:43.10
      date (00:00:00Z): 2002-12-14
    
    # JavaScript Specific Types ####################################################
    ################################################################################
    
    # https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/RegExp
    
    regexp:
      simple: !!js/regexp foobar
      modifiers: !!js/regexp /foobar/mi
    
    # https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/undefined
    
    undefined: !!js/undefined ~
    
    # https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function
    
    function: !!js/function >
      function foobar() {
        return 'Wow! JS-YAML Rocks!';
      }
    
    # Custom types #################################################################
    ################################################################################
    
    # JS-YAML allows you to specify a custom YAML types for your structures.
    # This is a simple example of custom constructor defined in `js/demo.js` for
    # custom `!sexy` type:
    #
    # var SexyYamlType = new jsyaml.Type('!sexy', {
    #   kind: 'sequence',
    #   construct: function (data) {
    #     return data.map(function (string) { return 'sexy ' + string; });
    #   }
    # });
    #
    # var SEXY_SCHEMA = jsyaml.Schema.create([ SexyYamlType ]);
    #
    # result = jsyaml.load(yourData, { schema: SEXY_SCHEMA });
    
    foobar: !sexy
      - bunny
      - chocolate

[Kubernetes_YAML]: /images/20221022/21eb3ae451634c3a909e103eace5ecc3.png
[f782e05de367207de5cd59ec6ba978f8.png]: /images/20221022/f66bc6f95d674859a5cb0e599a393fd3.png
[JS-Yaml]: https://nodeca.github.io/js-yaml
[Kubernetes_YAML 1]: /images/20221022/dfe22fde9118409ea65a050e30dd195c.png