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《Terraform 101 从入门到实践》 Functions函数

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《Terraform 101 从入门到实践》 Functions函数

Terraform的函数

Terraform为了让大家在表达式上可以更加灵活方便地进行计算，提供了大量的内置函数（Function）。目前并不支持自定义函数，只能使用Terraform自带的。使用函数的格式也很简单，直接写函数名+参数即可。如下面的函数为取最大值：

> max(34, 45, 232, 25
232

这里把函数单独列成一章不是因为它很难理解，而因为它很常用，值得把这些函数梳理一下，以便查询使用吧。

数值计算函数

> abs(5
5
> abs(-3.1415926
3.1415926
> abs(0
0

返回大于等于该数值的最小整数：

> ceil(3
3
> ceil(3.1
4
> ceil(2.9
3

小于等于该数值的最大整数：

> floor(6
6
> floor(6.9
6
> floor(5.34
5

对数函数：

> log(16, 2
4
> log(9, 3
2.0000000000000004

指数函数：

> pow(6, 2
36
> pow(6, 1
6
> pow(6, 0
1

最大值、最小值：

> max(2, 98,  75, 4
98
> min(2, 98,  75, 4
2

字符串转换成整数，第二个参数为进制：

> parseint("16", 10
16
> parseint("16", 16
22
> parseint("FF", 16
255
> parseint("1010", 2
10

信号量函数：

> signum(6
1
> signum(-6
-1
> signum(0
0

字符串函数

删去换行，在从文件中读取文本时非常有用：

> chomp("www.pkslow.com"
"www.pkslow.com"
> chomp("www.pkslow.com\n"
"www.pkslow.com"
> chomp("www.pkslow.com\n\n"
"www.pkslow.com"
> chomp("www.pkslow.com\n\n\r"
"www.pkslow.com"
> chomp("www.pkslow.com\n\n\ra"
<<EOT
www.pkslow.com

a
EOT

格式化输出：

> format("Hi, %s!", "Larry"
"Hi, Larry!"

> format("My name is %s, I'm %d", "Larry", 18
"My name is Larry, I'm 18"

> format("The reuslt is %.2f", 3
"The reuslt is 3.00"

> format("The reuslt is %.2f", 3.1415
"The reuslt is 3.14"

> format("The reuslt is %8.2f", 3.1415
"The reuslt is     3.14"

遍历格式化列表：

> formatlist("My name is %s, I'm %d %s.", ["Larry", "Jeremy", "Tailor"], [18, 28, 33], "in 2022"
tolist([
  "My name is Larry, I'm 18 in 2022.",
  "My name is Jeremy, I'm 28 in 2022.",
  "My name is Tailor, I'm 33 in 2022.",
]

参数可以是List，还可以是单个变量。

> join(".", ["www", "pkslow", "com"]
"www.pkslow.com"
> join(", ", ["Larry", "Pkslow", "JJ"]
"Larry, Pkslow, JJ"

大小写字母转换：

> lower("Larry Nanhua DENG"
"larry nanhua deng"
> upper("Larry Nanhua DENG"
"LARRY NANHUA DENG"

首字母大写：

> title("larry"
"Larry"

替换：

> replace("www.larrydpk.com", "larrydpk", "pkslow"
"www.pkslow.com"
> replace("hello larry", "/la.*y/", "pkslow"
"hello pkslow"

分割：

> split(".", "www.pklow.com"
tolist([
  "www",
  "pklow",
  "com",
]

反转：

> strrev("pkslow"
"wolskp"

截取：

> substr("Larry Deng", 0, 5
"Larry"
> substr("Larry Deng", -4, -1
"Deng"

去除头尾某些特定字符，注意这里只要有对应字符就会删除：

> trim("?!what?!!!!!", "?!"
"what"
> trim("abaaaaabbLarry Dengaab", "ab"
"Larry Deng"

去除头尾特定字符串，注意与上面的区别：

> trimsuffix("?!what?!!!!!", "!!!"
"?!what?!!"
> trimprefix("?!what?!!!!!", "?!"
"what?!!!!!"

去除头尾的空格、换行等空串：

> trimspace(" Larry Deng \n\r"
"Larry Deng"

正则匹配，下面的例子是匹配第一个和匹配所有：

> regex("[a-z\\.]+", "2021www.pkslow.com2022larry deng 31415926"
"www.pkslow.com"
> regexall("[a-z\\.]+", "2021www.pkslow.com2022larry deng 31415926"
tolist([
  "www.pkslow.com",
  "larry",
  "deng",
]

更多正则匹配语法可参考：https://www.terraform.io/language/functions/regex

集合类函数

alltrue：判断列表是否全为真，空列表直接返回true。只能是bool类型或者对应的字符串。

> alltrue([true, "true"]
true
> alltrue([true, "true", false]
false
> alltrue([]
true
> alltrue([1]
╷
│ Error: Invalid function argument
│ 
│   on <console-input> line 1:
│   (source code not available
│ 
│ Invalid value for "list" parameter: element 0: bool required.

anytrue：判断列表是否有真，只要有一个为真就返回true。空列表为false。


> anytrue([true]
true
> anytrue([true, false]
true
> anytrue([false, false]
false
> anytrue([]
false



chunklist分片：根据分片数来对列表进行切分。


> chunklist(["www", "pkslow", "com", "Larry", "Deng"], 3
tolist([
  tolist([
    "www",
    "pkslow",
    "com",
  ],
  tolist([
    "Larry",
    "Deng",
  ],
]



coalesce返回第一个非空元素：


> coalesce("", "a", "b"
"a"
> coalesce("", "", "b"
"b"



coalescelist返回第一个非空列表：


> coalescelist([], ["pkslow"]
[
  "pkslow",
]



从字符串列表里把空的去掉：


> compact(["", "www", "", "pkslow", "com"]
tolist([
  "www",
  "pkslow",
  "com",
]



concat连接多个列表：


> concat([1, 2, 3], [4, 5, 6]
[
  1,
  2,
  3,
  4,
  5,
  6,
]



contains判断是否存在某个元素：


> contains(["www", "pkslow", "com"], "pkslow"
true
> contains(["www", "pkslow", "com"], "Larry"
false



distinct去除重复元素：


> distinct([1, 2, 2, 1, 3, 8, 1, 10]
tolist([
  1,
  2,
  3,
  8,
  10,
]



element获取列表的某个元素：


> element(["a", "b", "c"], 1
"b"
> element(["a", "b", "c"], 2
"c"
> element(["a", "b", "c"], 3
"a"
> element(["a", "b", "c"], 4
"b"



flatten把内嵌的列表都展开成一个列表：


> flatten([1, 2, 3, [1], [[6]]]
[
  1,
  2,
  3,
  1,
  6,
]



index获取列表中的元素的索引值：


> index(["www", "pkslow", "com"], "pkslow"
1



keys获取map的所有key值：


> keys({name="Larry", age=18, webSite="www.pkslow.com"}
[
  "age",
  "name",
  "webSite",
]



values获取map的value值：


> values({name="Larry", age=18, webSite="www.pkslow.com"}
[
  18,
  "Larry",
  "www.pkslow.com",
]



length获取字符串、列表、Map等的长度：


> length([]
0
> length(["pkslow"]
1
> length(["pkslow", "com"]
2
> length({pkslow = "com"}
1
> length("pkslow"
6



lookup(map, key, default根据key值在map中找到对应的value值，如果没有则返回默认值：


> lookup({name = "Larry", age = 18}, "age", 1
18
> lookup({name = "Larry", age = 18}, "myAge", 1
1



matchkeys(valueslist, keyslist, searchset对key值进行匹配。匹配到key值后，返回对应的Value值。


> matchkeys(["a", "b", "c", "d"], [1, 2, 3, 4], [2, 4]
tolist([
  "b",
  "d",
]



merge合并Map，key相同的会被最后的覆盖：


> merge({name = "Larry", webSite = "pkslow.com"}, {age = 18}
{
  "age" = 18
  "name" = "Larry"
  "webSite" = "pkslow.com"
}
> merge({name = "Larry", webSite = "pkslow.com"}, {age = 18}, {age = 13}
{
  "age" = 13
  "name" = "Larry"
  "webSite" = "pkslow.com"
}



one取集合的一个元素，如果为空则返回null；如果只有一个元素，则返回该元素；如果多个元素，则报错：


> one([]
null
> one(["pkslow"]
"pkslow"
> one(["pkslow", "com"]
╷
│ Error: Invalid function argument
│ 
│   on <console-input> line 1:
│   (source code not available
│ 
│ Invalid value for "list" parameter: must be a list, set, or tuple value with either zero or one elements.
╵



range生成顺序列表：


range(max
range(start, limit
range(start, limit, step

> range(3
tolist([
  0,
  1,
  2,
]
> range(1, 6
tolist([
  1,
  2,
  3,
  4,
  5,
]
> range(1, 6, 2
tolist([
  1,
  3,
  5,
]



reverse反转列表：


> reverse([1, 2, 3, 4]
[
  4,
  3,
  2,
  1,
]



setintersection对set求交集：


> setintersection([1, 2, 3], [2, 3, 4], [2, 3, 6]
toset([
  2,
  3,
]



setproduct列出所有组合可能：


> setproduct(["Larry", "Harry"], ["Deng", "Potter"]
tolist([
  [
    "Larry",
    "Deng",
  ],
  [
    "Larry",
    "Potter",
  ],
  [
    "Harry",
    "Deng",
  ],
  [
    "Harry",
    "Potter",
  ],
]



setsubtract：set的减法


> setsubtract([1, 2, 3], [3, 4]
toset([
  1,
  2,
]

# 求不同
> setunion(setsubtract(["a", "b", "c"], ["a", "c", "d"], setsubtract(["a", "c", "d"], ["a", "b", "c"]
[
  "b",
  "d",
]



setunion：set的加法


> setunion([1, 2, 3], [3, 4]
toset([
  1,
  2,
  3,
  4,
]



slice(list, startindex, endindex截取列表部分，包括startindex，但不包括endindex：


> slice(["a", "b", "c", "d", "e"], 1, 4
[
  "b",
  "c",
  "d",
]



sort对列表中的字符串进行排序，要注意如果输入的是数字，会先转化为字符串再排序：


> sort(["larry", "pkslow", "com", "deng"]
tolist([
  "com",
  "deng",
  "larry",
  "pkslow",
]
> sort([3, 6, 1, 9, 12, 79, 22]
tolist([
  "1",
  "12",
  "22",
  "3",
  "6",
  "79",
  "9",
]



sum求和：


> sum([3, 1.2, 9, 17.3, 2.2]
32.7



transpose对Map的key和value进行换位：


> transpose({"a" = ["1", "2"], "b" = ["2", "3"]}
tomap({
  "1" = tolist([
    "a",
  ]
  "2" = tolist([
    "a",
    "b",
  ]
  "3" = tolist([
    "b",
  ]
}



zipmap根据key和value的列表按一对一关系生成Map：


> zipmap(["age", "name"], [18, "Larry Deng"]
{
  "age" = 18
  "name" = "Larry Deng"
}



加密解密


Base64：


> base64encode("pkslow"
"cGtzbG93"
> base64decode("cGtzbG93"
"pkslow"
> textencodebase64("pkslow", "UTF-8"
"cGtzbG93"
> textdecodebase64("cGtzbG93", "UTF-8"
"pkslow"



csv文本解析：


> csvdecode("seq,name,age\n1,larry,18\n2,pkslow,3\n3,Jeremy,29"
tolist([
  {
    "age" = "18"
    "name" = "larry"
    "seq" = "1"
  },
  {
    "age" = "3"
    "name" = "pkslow"
    "seq" = "2"
  },
  {
    "age" = "29"
    "name" = "Jeremy"
    "seq" = "3"
  },
]



Json解析：


> jsonencode({"name"="Larry", "age"=18}
"{\"age\":18,\"name\":\"Larry\"}"
> jsondecode("{\"age\":18,\"name\":\"Larry\"}"
{
  "age" = 18
  "name" = "Larry"
}



URL：


> urlencode("Larry Deng/a/:/./@"
"Larry+Deng%2Fa%2F%3A%2F.%2F%40"



YAML：


> yamlencode({"a":"b", "c":"d"}
"a": "b"
"c": "d"

> yamlencode({"foo":[1, 2, 3], "bar": "baz"}
"bar": "baz"
"foo":
- 1
- 2
- 3

> yamlencode({"foo":[1, {"a":"b","c":"d"}, 3], "bar": "baz"}
"bar": "baz"
"foo":
- 1
- "a": "b"
  "c": "d"
- 3
> yamldecode("hello: world"
{
  "hello" = "world"
}

> yamldecode("true"
true

> yamldecode("{a: &foo [1, 2, 3], b: *foo}"
{
  "a" = [
    1,
    2,
    3,
  ]
  "b" = [
    1,
    2,
    3,
  ]
}



文件处理：


> abspath(path.root
"/Users/larry"



获取路径中的目录，或者是文件名：


> dirname("/home/larry/soft/terraform"
"/home/larry/soft"
> dirname("/home/larry/soft/terraform/"
"/home/larry/soft/terraform"
> basename("/home/larry/soft/terraform"
"terraform"
> basename("/home/larry/soft/terraform/"
"terraform"



判断文件是否存在，并获取文件内容：


> fileexists("/Users/larry/.bash_profile"
true
> file("/Users/larry/.bash_profile"
> filebase64("/Users/larry/.bash_profile"



根据模式匹配所有文件：


> fileset("/Users/larry", "*.bash*"
toset([
  ".bash_history",
  ".bash_profile",
  ".bash_profile.backup",
]



templatefile(path, vars模板化文件：指定文件和变量，把变量值替换掉模板中的变量。


时间函数


> formatdate("YYYY-MM-DD hh:mm:ss / D MMMM YYYY", timestamp(
"2022-03-05 08:25:48 / 5 March 2022"
> formatdate("EEEE, DD-MMM-YY hh:mm:ss ZZZ", "2018-01-02T23:12:01Z"
"Tuesday, 02-Jan-18 23:12:01 UTC"



时间加减：


> timeadd(timestamp(, "24h"
"2022-03-06T08:28:52Z"
> timeadd(timestamp(, "-24h20m"
"2022-03-04T08:19:08Z"



支持的单位有："ns", "us" (or "µs", "ms", "s", "m", and "h"。


其它


> md5("www.pkslow.com"
"97e164b60faf4d7875c2a8a5bc3f2245"



UUID：


> uuid(
"049bf418-15d1-e034-28db-92945067dcf6"



IP：


> cidrsubnet("172.16.0.0/12", 4, 2
"172.18.0.0/16"



更多请参考官网。
            
            

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                《Terraform 101 从入门到实践》 Functions函数
            

            

                
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