common.go

/*
Copyright 2023 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package utils

import (
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"os"
	"strings"
	"time"
)

var DEBUG bool

func init() {
	DEBUG = false
	debugENV := os.Getenv("MAGE_DEBUG")
	if debugENV == "true" {
		DEBUG = true
	}
}

// CheckArgs should be used to ensure the right command line arguments are
// passed before executing an example.
func CheckArgs(arg ...string) {
	if len(os.Args) < len(arg)+1 {
		ErrorF("Usage: %s %s", os.Args[0], strings.Join(arg, " "))
		os.Exit(1)
	}
}

// CheckIfError should be used to naively panics if an error is not nil.
func CheckIfError(err error, format string, args ...interface{}) {
	if err == nil {
		return
	}

	fmt.Printf("\x1b[31;1m%s ERROR %s %s\x1b[0m\n", timeStamp(), fmt.Sprintf(format, args...), err)
	os.Exit(1)
}

// Info should be used to describe the example commands that are about to run.
func Info(format string, args ...interface{}) {
	fmt.Printf("\x1b[34;1m%s INFO: %s\x1b[0m\n", timeStamp(), fmt.Sprintf(format, args...))
}

func timeStamp() string {
	t := time.Now()
	return t.Format(time.RFC3339)
}

// Warning should be used to display a warning
func Warning(format string, args ...interface{}) {
	fmt.Printf("\x1b[36;1m%s WARNING: %s\x1b[0m\n", timeStamp(), fmt.Sprintf(format, args...))
}

// Info should be used to describe the example commands that are about to run.
func Debug(format string, args ...interface{}) {
	if DEBUG {
		fmt.Printf("\x1b[34;1m%s DEBUG: %s\x1b[0m\n", timeStamp(), fmt.Sprintf(format, args...))
	}
}

// Info should be used to describe the example commands that are about to run.
func ErrorF(format string, args ...interface{}) {
	fmt.Printf("\x1b[31;1m%s ERROR: %s\x1b[0m\n", timeStamp(), fmt.Sprintf(format, args...))
}

func DownloadFile(url string) (string, error) {
	client := &http.Client{
		Transport: &http.Transport{
			DialContext: (&net.Dialer{
				Timeout:   5 * time.Second,
				KeepAlive: 5 * time.Second,
			}).DialContext,
			TLSHandshakeTimeout:   5 * time.Second,
			ResponseHeaderTimeout: 5 * time.Second,
			ExpectContinueTimeout: 1 * time.Second,
			MaxIdleConnsPerHost:   -1,
		},
	}
	resp, err := client.Get(url)
	if err != nil {
		return "", nil
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", errors.New(fmt.Sprintf("could not retrieve file, response from server %d for file %s", resp.StatusCode, url))
	}
	bodyBytes, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", nil
	}
	return string(bodyBytes), nil
}