Golang

In this section

• 🐍 Cobra

  A Command Builder for Go

  Usefull

  • 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
  7# Install Cobra - CLI builder
  8go install github.com/spf13/cobra-cli@latest
  9sudo cp -pr ./go /usr/local/.
  

  • Init

  1mkdir -p ${project} && cd ${project}
  2go mod init ${project}
  3cobra-cli init
  4go build
  5go install
  6cobra-cli add timezone
  

• 👮 CUE-lang

  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