👮 CUE-Lang

 1# Install GO
 2GO_VERSION="1.21.0"
 3wget https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz
 4sudo tar -C /usr/local -xzf go${GO_VERSION}.linux-amd64.tar.gz
 5export PATH=$PATH:/usr/local/go/bin
 6
 7go install cuelang.org/go/cmd/cue@latest
 8sudo cp -pr ./go /usr/local/.
 9
10# or use Container
11printf "\e[1;34m[INFO]\e[m Install CUElang:\n";    
12podman pull docker.io/cuelang/cue:latest

 1# import a file 
 2cue import imageset-config.yaml 
 3
 4# Validate 
 5cue vet imageset-config.cue imageset-config.yaml
 6
 7
 8* Some basics example
 9
10```go
11// This is a comment
12_greeting: "Welcome" // Hidden fields start with "_"
13#project:  "CUE"     // Definitions start with "#"
14
15message: "\(_greeting) to \(#project)!" // Regular fields are exported
16
17#Person: {
18  age: number            // Mandatory condition and must be a number
19  hobbies?: [...string]  // non mandatory but if present must be a list of string
20}
21
22// Constrain which call #Person and check if age
23#Adult: #Person & {
24  age: >=18
25}
26
27// =~ match a regular expression
28#Phone: string & =~ "[0-9]+"
29
30// Mapping
31instanceType: {
32    web: "small"
33    app: "medium"
34    db:  "large"
35}
36
37server1: {
38    role:     "app"
39    instance: instanceType[role]
40}
41
42// server1.instance: "medium"

1# executable have extension name "_tool.cue"
2
3# usage
4cue cmd prompter

 1package foo
 2
 3import (
 4	"tool/cli"
 5	"tool/exec"
 6	"tool/file"
 7)
 8
 9// moved to the data.cue file to show how we can reference "pure" Cue files
10city: "Amsterdam"
11
12// A command named "prompter"
13command: prompter: {
14
15	// save transcript to this file
16	var: {
17		file: *"out.txt" | string @tag(file)
18	} // you can use "-t flag=filename.txt" to change the output file, see "cue help injection" for more details
19
20	// prompt the user for some input
21	ask: cli.Ask & {
22		prompt:   "What is your name?"
23		response: string
24	}
25
26	// run an external command, starts after ask
27	echo: exec.Run & {
28		// note the reference to ask and city here
29		cmd: ["echo", "Hello", ask.response + "!", "Have you been to", city + "?"]
30		stdout: string // capture stdout, don't print to the terminal
31	}
32
33	// append to a file, starts after echo
34	append: file.Append & {
35		filename: var.file
36		contents: echo.stdout // because we reference the echo task
37	}
38
39	// also starts after echo, and concurrently with append
40	print: cli.Print & {
41		text: echo.stdout // write the output to the terminal since we captured it previously
42	}
43}