toshi0607 / CUE-sandbox

CUE-sandbox

Introduction

JSON

$ cue export json.cue
{
    "one": 1,
    "two": 2,
    "two-and-a-half": 2.5,
    "list": [
        1,
        2,
        3
    ]
}

Duplicate Fields

$ cue eval dup.cue
a: 4
s: {
    b: 2
    c: 2
}
l: [1, 2]

Constraints

$ cue eval check.cue
schema: {
    name:  string
    age:   int
    human: true
}
viola: {
    name:  "Viola"
    age:   38
    human: true
}

JSON Superset

$ cue export json.cue
{
    "one": 1,
    "two": 2,
    "two-and-a-half": 2.5,
    "list": [
        1,
        2,
        3
    ]
}

Definitions

cue export schema.cue
{
    "lossy": {
        "address": "1.2.3.4",
        "port": 8888,
        "protocol": "udp"
    }
}

Validation

$ cue vet schema.cue data.yaml
languages.1.name: invalid value "dutch" (out of bound =~"^\\p{Lu}"):
    ./schema.cue:3:8
    ./data.yaml:5:12

Order is irrelevant

$ cue eval -i order.cue
a: {
    x: 1
    y: 2
}
b: {
    x: 1
    y: 2
}

Folding of Single-Field Structs

$ cue export fold.cue
{
    "outer": {
        "middle1": {
            "inner": 3
        },
        "middle2": {
            "inner": 7
        }
    }
}

Type Hierarchy

cue eval types.cue
point: {
    x: number
    y: number
}
xaxis: {
    x: number
    y: 0
}
yaxis: {
    x: 0
    y: number
}
origin: {
    x: 0
    y: 0
}

Bottom / Error

$ cue eval -i bottom.cue
a: _|_ // a: conflicting values 5 and 4
l: [1, _|_, // l.1: conflicting values 3 and 2
]
list: [0, 1, 2]
val: _|_ // val: index out of range [3] with length 3

$ cue eval bottom.cue
a: conflicting values 5 and 4:
    ./bottom.cue:1:4
    ./bottom.cue:2:4
l.1: conflicting values 3 and 2:
    ./bottom.cue:4:9
    ./bottom.cue:5:9
val: index out of range [3] with length 3:
    ./bottom.cue:8:11

$ cue vet bottom.cue
a: conflicting values 5 and 4:
    ./bottom.cue:1:4
    ./bottom.cue:2:4
l.1: conflicting values 3 and 2:
    ./bottom.cue:4:9
    ./bottom.cue:5:9
val: index out of range [3] with length 3:
    ./bottom.cue:8:11

Numbers

$ cue eval -i numbers.cue
a: 4
b: 4.0
c: _|_ // c: conflicting values int and 4.0 (mismatched types int and float)
d: 4
e: [1_234, 5M, 1.5Gi, 0x1000_0000]

String Literals

$ cue export stringlit.cue
{
    "a": "😎",
    "b": "Hello\nWorld!"
}

"Raw" Strings

msg1: #"The sequence "\U0001F604" renders as \#U0001F604."#

msg2: ##"""
    A regular expression can conveniently be written as:

        #"\d{3}"#

    This construct works for bytes, strings and their
    multi-line variants.
    """##

Bytes

$ cue export bytes.cue
{
    "a": "A2FiYw=="
}

$ echo "A2FiYw==" | base64 -d
abc%

Closed structs

cue eval -i structs.cue
a: {
    field: int
}
b: {
    field: int
    feild: _|_ // b.feild: field not allowed
}

Definitions (type)

$ cue eval -ic defs.cue
msg: "Hello world!"
a: {
    field: 3
}
err: {
    field: int
    feild: _|_ // err.feild: field not allowed
}

Structs

$ cue eval -c structs.cue
b: {
    foo: 3
}

Disjunctions

$ cue eval disjunctions.cue
#Conn: {
    address:  string
    port:     int
    protocol: "tcp" | "udp"
}
lossy: {
    address:  "1.2.3.4"
    port:     8888
    protocol: "udp"
}

Default Values

$ cue eval defaults.cue
replicas: 1
protocol: "tcp" | "udp"

Disjunctions of Structs

$ cue eval sumstruct.cue 
floor: {
    level:   0 | 1
    hasExit: true
} | {
    level:   -1 | 2 | 3
    hasExit: false
}

Bounds

$ cue eval -ic bounds.cue
a:  3.5
b:  _|_ // b: conflicting values int and 3.5 (mismatched types int and float)
c:  3
d:  "ma"
e:  _|_ // e: invalid value "mu" (out of bound <"mo")
r1: >=5 & <8

Predefined Bounds

$ cue eval -ic bound.cue
a: _|_ // a: invalid value -1 (out of bound >=0)
b: 128
c: 2000000000

Lists

$ cue eval -i lists.cue
IP: [uint8, uint8, uint8, uint8]
PrivateIP: [10, uint8, uint8, uint8] | [192, 168, uint8, uint8] | [172, uint & >=16 & <=32, uint8, uint8]
myIP: [10, 2, 3, 4]
yourIP: _|_ // yourIP: 3 errors in empty disjunction: (and 3 more errors)

Templates

$ cue eval templates.cue
job: {
    list: {
        name:     "list"
        replicas: 1
        command:  "ls"
    }
    nginx: {
        name:     "nginx"
        command:  "nginx"
        replicas: 2
    }
}

References and Scopes

$ cue eval scopes.cue
v: 1
a: {
    v: 2
    c: 1
    b: 2
}
b: 1

Accessing Fields

$ cue eval selectors.cue
a: {
    b:     2
    "c-e": 5
}
v: 2
w: 5

Aliases

$ cue eval alias.cue
a: {
    d: 3
}
b: {
    a: {
        c: 3
    }
}

Emit Values

$ cue export emit.cue
"Hello world!"

Reference Cycles

$ cue eval -i -c cycle.cue
x: 200
y: 100
a: b + 100
b: a - 100

Cycles in Fields

$ cue eval cycleref.cue
labels: {
    app:  "foo"
    name: "bar"
}
selectors: {
    name: "bar"
    app:  "foo"
}

Hidden Fields

$ cue export hidden.cue
{
    "_foo": 2,
    "foo": 4
}

Operators

$ cue eval -i op.cue
a: 1.5
b: 1
c: "blahblahblah"
d: [1, 2, 3, 1, 2, 3, 1, 2, 3]
e: true

Interpolation

$ cue eval interpolation.cue
"You are 14 dollars over budget!"
#cost:   102
#budget: 88

$ cue export interpolation.cue
"You are 14 dollars over budget!"

Interpolation of Field Names

$ cue eval genfield.cue
sandwich.butterAndCheese: reference "hasCheese" not found:
    ./genfield.cue:5:35

# comment out butterAndCheese: hasButter && hasCheese
$ cue eval genfield.cue
sandwich: {
    type:      "Cheese"
    hasCheese: true
    hasButter: true
}

List Comprehensions

$ cue export listcomp.cue
[
    4,
    16,
    36,
    64
]

Field Comprehensions

$ cue eval -c fieldcomp.cue
barcelona: {
    pos:     1
    name:    "Barcelona"
    nameLen: 9
}
shanghai: {
    pos:     2
    name:    "Shanghai"
    nameLen: 8
}
munich: {
    pos:     3
    name:    "Munich"
    nameLen: 6
}

Conditional Fields

$ cue eval conditional.cue
justification: string
price:         200

$ cue export conditional.cue
justification: incomplete value string:
    ./conditional.cue:5:20

# add justification: "sorry"
$ cue export conditional.cue
{
    "price": 200,
    "justification": "sorry"
}

Regular expressions

$ cue eval -i regexp.cue
a: true
b: true
c: =~"^[a-z]{3}$"
d: "foo"
e: _|_ // e: invalid value "foo bar" (out of bound =~"^[a-z]{3}$")

Null Coalescing

$ cue eval coalesce.cue
list: ["Cat", "Mouse", "Dog"]
a: "Cat"
b: "None"
n: [null]
v: "default"

Packages

$ cue eval a.cue b.cue
foo: 100
bar: 200

Imports

$ cue eval imports.cue
data: "{\"a\":2.6457513110645907}"

Kuberentes

$ cd kubernetes/original
$ cue mod init
$ go mod init example.com
go: creating new go.mod: module example.com
go: to add module requirements and sums:
        go mod tidy

$ cd services
$ cue import ./...
path, list, or files flag needed to handle multiple objects in file ./services/frontend/bartender/kube.yaml
$ cue import ./... -p kube
path, list, or files flag needed to handle multiple objects in file ./services/frontend/bartender/kube.yaml

$ cue import ./... -p kube -l 'strings.ToCamel(kind)' -l metadata.name -f
$ $ tree . | head
.
├── frontend
│   ├── bartender
│   │   ├── kube.cue
│   │   └── kube.yaml
│   ├── breaddispatcher
│   │   ├── kube.cue
│   │   └── kube.yaml
│   ├── host
│   │   ├── kube.cue

$ cat mon/prometheus/configmap.cue | head
package kube

configMap: prometheus: {
        apiVersion: "v1"
        kind:       "ConfigMap"
        metadata: name: "prometheus"
        data: {
                "alert.rules": """
                        groups:
                        - name: rules.yaml

$ cue import ./... -p kube -l 'strings.ToCamel(kind)' -l metadata.name -f -R
$ cat mon/prometheus/configmap.cue | head
package kube

import yaml656e63 "encoding/yaml"

configMap: prometheus: {
        apiVersion: "v1"
        kind:       "ConfigMap"
        metadata: name: "prometheus"
        data: {
                "alert.rules": yaml656e63.Marshal(_cue_alert_rules)

$ cue eval ./mon/prometheus -e configMap.prometheus | head
apiVersion: "v1"
kind:       "ConfigMap"
metadata: {
    name: "prometheus"
}
data: {
    "alert.rules": """
        groups:
          - name: rules.yaml
            rules: