Kubernetes YAML 编写 讲解
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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。
YAML 语法特性
学过编程的人理解起来应该非常容易
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
# yamllanguages: - Ruby - Perl - Pythonwebsites: 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' }}
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
# 纯量hello # 数组- Cat- Dog- Goldfish # 对象animal: pets
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
# 单引号name: 'Hi,\nTom' # 双引号name: "Hi,\nTom"
内置类型列表
# 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: !!str123 date: !Booleantrue
YAML 中的纯量
纯量是最基本的且不可再分的值
字符串
# 不适用引号name: Tom # 使用单引号name: 'Tom' # 使用双引号name: "Tom"
布尔值
debug: truedebug: false
数字
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
Null
date: ~date: null
时间
# 使用iso-8601标准表示日期date: 2018-01-01t16:59:43.10-05:00
YAML 特殊类型
日常使用中基本不会用到的类型
文本块
# 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！！
# +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
# 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: > helloworld! # 输出结果# hello 空格 world！
锚点与引用
# 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 yamlbook: *abooks: - java - *a - python # 输出结果book： yamlbooks：[java, yaml, python]
YAML 实例说明
光说不练假把式 => JS-Yaml 官网实例地址 https://nodeca.github.io/js-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
