CUE stands for Configure, Unify, Execute
Basics Installation 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 concepts top -> schema -> constraint -> data -> bottom
Command 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" Scripting 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} Sources Offical Documentation
