安装

系统：centos

安装golang

yum install golang -y

安装cue
Go设置 go get 为国内源 - ChnMig - 博客园 (cnblogs.com)

cue/install.md at master · cue-lang/cue (github.com)

# cue  切换国内源
export GOPROXY=https://goproxy.cn,direct
# 安装cue
go install cuelang.org/go/cmd/cue@latest
# 将cue添加到环境变量
export PATH=/root/go/bin:$PATH

使用参考手册

• CUE (cuelang.org)
• Cue Lang介绍 - 简书 (jianshu.com)
• CUE是何方神圣?_russellgao的博客-CSDN博客
• Introduction | CUE (cuelang.org)
• (38条消息) CUE是何方神圣?_russellgao的博客-CSDN博客

常用命令

1 导出为具体格式的文件

• 转化成： json cue export json.cue --out json
• 转化成： yaml cue export json.cue --out yaml
• 转化成 text ：cue export json.cue --out text
• 输出到文件： cue export json.cue --out json --outfile json.cue.json

示例：定义模板、数据文件，使用cue输出yaml文件

--schema.cue-- 
#Language: {
        tag:  string
        name: =~"^\\p{Lu}" // Must start with an uppercase letter.
}
languages: [...#Language]

--data.yaml--
languages:
  - tag: en
    name: English
  - tag: nl
    name: Dutch
  - tag: no
    name: Norwegian

# 校验成功的输出
[root@VM-12-11-centos ~]# cue export schema.cue data.yaml --out yaml
languages:
  - tag: en
    name: English
  - tag: nl
    name: Dutch
  - tag: no
    name: Norwegian
# 校验失败输出
[root@VM-12-11-centos ~]# cue export schema.cue data.yaml --out yaml
languages.1.name: invalid value "dutch" (out of bound =~"^\\p{Lu}"):
    ./schema.cue:3:8
    ./data.yaml:5:12

2 模板数据校验

基础练习

cue/doc/tutorial/basics at master · cue-lang/cue (github.com)

1. json

cue export json.cue
cmp stdout expect-stdout-cue
-- json.cue --
one: 1
two: 2

// A field using quotes.
"two-and-a-half": 2.5

list: [
    1,
    2,
    3,
]

-- expect-stdout-cue --
{
    "list": [
        1,
        2,
        3
    ],
    "one": 1,
    "two": 2,
    "two-and-a-half": 2.5
}

2. cue

cue eval dup.cue
cmp stdout expect-stdout-cue
-- dup.cue --
a: 4
a: 4

s: { b: 2 }
s: { c: 2 }

l: [ 1, 2 ]
l: [ 1, 2 ]

-- expect-stdout-cue --
a: 4
s: {
    b: 2
    c: 2
}
l: [1, 2]

3. depulate

cue eval dup.cue
cmp stdout expect-stdout-cue

-- dup.cue --
a: 4
a: 4

s: { b: 2 }
s: { c: 2 }

l: [ 1, 2 ]
l: [ 1, 2 ]

-- expect-stdout-cue --
a: 4
s: {
    b: 2
    c: 2
}
l: [1, 2]

4. constraint

cue eval check.cue
cmp stdout expect-stdout-cue
-- check.cue --
schema: {
    name:  string
    age:   int
    human: true // always true
}

viola: schema
viola: {
    name: "Viola"
    age:  38
}

-- expect-stdout-cue --
schema: {
    name:  string
    age:   int
    human: true
}
viola: {
    name:  "Viola"
    age:   38
    human: true
}

5. schema

cue export schema.cue
cmp stdout expect-stdout-cue

-- frontmatter.toml --
title = "Definitions"
description = ""

-- text.md --
In CUE, schemas are typically written as Definitions.
A definition is a field which identifier starts with
`#` or `_#`.
This tells CUE that they are to be used for validation and should
not be output as data; it is okay for them to remain unspecified.

A definition also tells CUE the full set of allowed fields.
In other words, definitions define "closed" structs.
Including a `...` in struct keeps it open.

-- schema.cue --
#Conn: {
    address:  string
    port:     int
    protocol: string
    // ...    // uncomment this to allow any field
}

lossy: #Conn & {
    address:  "1.2.3.4"
    port:     8888
    protocol: "udp"
    // foo: 2 // uncomment this to get an error
}

-- expect-stdout-cue --
{
    "lossy": {
        "address": "1.2.3.4",
        "port": 8888,
        "protocol": "udp"
    }
}

6. validation

! cue vet schema.cue data.yaml
cmp stderr expect-stderr
cue eval schema.cue data.yaml

-- frontmatter.toml --
title = "Validation"
description = ""

-- text.md --
Constraints can be used to validate values of concrete instances.
They can be applied to CUE data, or directly to YAML or JSON.

-- schema.cue --
#Language: {
    tag:  string
    name: =~"^\\p{Lu}" // Must start with an uppercase letter.
}
languages: [...#Language]

-- data.yaml --
languages:
  - tag: en
    name: English
  - tag: nl
    name: dutch
  - tag: no
    name: Norwegian

-- expect-stderr --
languages.1.name: invalid value "dutch" (does not match =~"^\\p{Lu}"):
    ./schema.cue:3:8
    ./data.yaml:5:12