How to use chromedp to do a bunch of screenshot tasks on Mac

chromedp_init.go

var (
	CHROME_EXEC_PATH  = "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"
	USER_DATA_DIR     = fmt.Sprintf("/Users/%s/Library/Application Support/Google/Chrome/", GetCurrentUserName())
	PROFILE_DIRECTORY = "Default"
)

func GetCurrentUserName() string {
	currentUser, _ := user.Current()
	username := currentUser.Username
	return username
}

func main() {

	opts := append(
		chromedp.DefaultExecAllocatorOptions[:0], // No default options to provent chrome account login problems.
		chromedp.ExecPath(CHROME_EXEC_PATH),
		chromedp.DisableGPU,
		chromedp.UserDataDir(USER_DATA_DIR),
		chromedp.Flag("profile-directory", PROFILE_DIRECTORY),
		chromedp.Flag("headless", false),
		chromedp.Flag("flag-switches-begin", true),
		chromedp.Flag("flag-switches-end", true),
		chromedp.Flag("enable-automation", false),
		chromedp.Flag("disable-blink-features", "AutomationControlled"),
		chromedp.Flag("new-window", true),
	)
	c, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
	defer cancel()

	// create a new browser
	chromeCtx, cancel := chromedp.NewContext(
		c,
	)
	defer cancel()

	// Execute an empty task to user
	chromedp.Run(chromeCtx, make([]chromedp.Action, 0, 1)...) 

}

full_code.go

// It is a Google Analytics Marketing Website which tracks a series of metrics as shown below.
// Getting
package main

import (
	"context"
	"fmt"
	"io/ioutil"
	"log"
	"os/user"
	"time"

	"github.com/chromedp/chromedp"
)

var (
	CHROME_EXEC_PATH  = "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"
	USER_DATA_DIR     = fmt.Sprintf("/Users/%s/Library/Application Support/Google/Chrome/", GetCurrentUserName())
	PROFILE_DIRECTORY = "Default"
)

func GetCurrentUserName() string {
	currentUser, _ := user.Current()
	username := currentUser.Username
	return username
}

func main() {
	opts := append(
		chromedp.DefaultExecAllocatorOptions[:0], // No default options to provent chrome account login problems.
		chromedp.ExecPath(CHROME_EXEC_PATH),
		chromedp.DisableGPU,
		chromedp.UserDataDir(USER_DATA_DIR),
		chromedp.Flag("profile-directory", PROFILE_DIRECTORY),
		chromedp.Flag("headless", false),
		chromedp.Flag("flag-switches-begin", true),
		chromedp.Flag("flag-switches-end", true),
				chromedp.Flag("enable-automation", false),
		chromedp.Flag("disable-blink-features", "AutomationControlled"),
		chromedp.Flag("new-window", true),
	)
	c, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
	defer cancel()

	// create a new browser
	chromeCtx, cancel := chromedp.NewContext(
		c,
	)
	defer cancel()

	// Execute an empty task to user
	chromedp.Run(chromeCtx, make([]chromedp.Action, 0, 1)...)

	// the screenshot calling part is easy to understand.
	var targets []Target = []Target{
		{"https://datastudio.google.com/u/0/reporting/0B_U5RNpwhcE6SF85TENURnc4UjA/preview", "datastudio", 966, 1308},
	}

	for _, target := range targets {
		var buf []byte
		// start the browser
		if err := chromedp.Run(chromeCtx,
			Screenshot(target, 100, &buf)); err != nil {
			log.Fatal(err)
		}

		// capture
		file := fmt.Sprintf("report-%s.png", target.Name)
		if err := ioutil.WriteFile(file, buf, 0o644); err != nil {
			log.Fatal(err)
		}
	}

	log.Printf("Successfully wrote Screenshot.png")
}

// Second, The main screenshot function definition is below.
// - Navigate to the target web page.
// - Emulate the viewport size according to the target parameters.
// - Sleep for 10 seconds.
// - Capture the screenshot.
//
func Screenshot(target Target, quality int, res *[]byte) chromedp.Tasks {
	return chromedp.Tasks{
		chromedp.Navigate(target.Url),
		chromedp.EmulateViewport(int64(target.ViewX), int64(target.ViewY)),
		chromedp.Sleep(10 * time.Second),
		chromedp.FullScreenshot(res, quality),
	}
}

// target web page and it's viewport size
type Target struct {
	Url   string `json:"url"`
	Name  string `json:"name"`
	ViewX int    `json:"viewX"`
	ViewY int    `json:"viewY"`
}

screenshot_calling.go

	var targets []Target = []Target{
		{"https://datastudio.google.com/u/0/reporting/0B_U5RNpwhcE6SF85TENURnc4UjA/preview", "datastudio", 966, 1308},
	}

	for _, target := range targets {
		var buf []byte
		// start the browser
		if err := chromedp.Run(chromeCtx,
			Screenshot(target, 100, &buf)); err != nil {
			log.Fatal(err)
		}

		// capture
		file := fmt.Sprintf("report-%s.png", target.Name)
		if err := ioutil.WriteFile(file, buf, 0o644); err != nil {
			log.Fatal(err)
		}
	}

screenshot_chromedp.go

package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/user"
	"time"

	"github.com/chromedp/chromedp"
)

var (
	CHROME_EXEC_PATH = "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"
	USER_DATA_DIR    = fmt.Sprintf("/Users/%s/Library/Application Support/Google/Chrome/", GetCurrentUserName())
)

func GetCurrentUserName() string {
	currentUser, _ := user.Current()
	username := currentUser.Username
	return username
}

type Target struct {
	Url   string `json:"url"`
	Name  string `json:"name"`
	ViewX int    `json:"viewX"`
	ViewY int    `json:"viewY"`
}

var (
	urlsFile = flag.String("inputfile", "urls.json", "a file containing urls to screenshot")
	profile  = flag.String("profile", "Default", "choose which profile to use, enter chrome://version/ to see your profile")
	sleep    = flag.Int("sleep", 5, "sleep seconds between each screenshot")
)

func main() {
	flag.Parse()

	// check file existing
	content, err := ioutil.ReadFile(*urlsFile)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("Current user is :", GetCurrentUserName())
	fmt.Println("Current profile directory is:", *profile)

	opts := append(
		chromedp.DefaultExecAllocatorOptions[:0], // No default options to provent chrome account login problems.
		chromedp.ExecPath(CHROME_EXEC_PATH),
		chromedp.DisableGPU,
		chromedp.UserDataDir(USER_DATA_DIR),
		chromedp.Flag("profile-directory", *profile),
		chromedp.Flag("headless", false),
		chromedp.Flag("flag-switches-begin", true),
		chromedp.Flag("flag-switches-end", true),
		chromedp.Flag("enable-automation", false),
		chromedp.Flag("disable-blink-features", "AutomationControlled"),
		chromedp.Flag("new-window", true),
	)
	c, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
	defer cancel()

	// create context
	chromeCtx, cancel := chromedp.NewContext(
		c,
	)
	defer cancel()

	// Execute an empty task to user
	chromedp.Run(chromeCtx, make([]chromedp.Action, 0, 1)...)

	// parse content into json array
	fmt.Println("Starting to screenshot")
	var targets []Target
	err = json.Unmarshal(content, &targets)
	if err != nil {
		log.Fatal(err)
	}

	currentDate := time.Now().Format("2006-01-02")
	fmt.Println("YYYY-MM-DD : ", currentDate)

	// make folder if not exist
	os.Mkdir(currentDate, 0755)

	for _, target := range targets {
		func(name string, url string) {
			var buf []byte
			// capture entire browser viewport, returning png with quality=90
			if err := chromedp.Run(chromeCtx,
				fullScreenshot(target, 100, &buf)); err != nil {
				log.Fatal(err)
			}
			// capture
			file := fmt.Sprintf("%s/report-%s.png", currentDate, name)
			if err := ioutil.WriteFile(file, buf, 0o644); err != nil {
				log.Fatal(err)
			}
			log.Printf("%s saved", file)
		}(target.Name, target.Url)

	}

	log.Printf("Successfully wrote fullScreenshot.png")
}

func fullScreenshot(target Target, quality int, res *[]byte) chromedp.Tasks {
	return chromedp.Tasks{
		chromedp.Navigate(target.Url),
		chromedp.Click(`span.mat-mdc-button-touch-target`, chromedp.NodeVisible),
		chromedp.EmulateViewport(int64(target.ViewX), int64(target.ViewY)),
		chromedp.WaitVisible(`.tableBody`),
		chromedp.WaitVisible(`.valueLabel`),
		chromedp.WaitReady(`.tableBody`),
		chromedp.WaitReady(`.valueLabel`),
		chromedp.Sleep(time.Duration(*sleep) * time.Second),
		// chromedp.EvaluateAsDevTools(js, nil),
		chromedp.FullScreenshot(res, quality),
	}
}

screenshot_func.go

type Target struct {
	Url   string `json:"url"`
	Name  string `json:"name"`
	ViewX int    `json:"viewX"`
	ViewY int    `json:"viewY"`
}


func Screenshot(target Target, quality int, res *[]byte) chromedp.Tasks {
	return chromedp.Tasks{
		chromedp.Navigate(target.Url),
		chromedp.EmulateViewport(int64(target.ViewX), int64(target.ViewY)),
		chromedp.Sleep(10 * time.Second),
		chromedp.FullScreenshot(res, quality),
	}
}

urls.json

[
    {
        "url": "https://datastudio.google.com/u/1/reporting/c11a5b80-55d1-40aa-9666-9fe0e81cc902/page/u86rB?params=%7B%22df173%22:%22include%25EE%2580%25800%25EE%2580%2580IN%25EE%2580%2580IOS%22%7D",
        "name": "dof2-ios",
        "viewX":1300,
        "viewY":1470
    },
    {
        "url": "https://datastudio.google.com/u/1/reporting/c11a5b80-55d1-40aa-9666-9fe0e81cc902/page/u86rB?params=%7B%22df173%22:%22include%25EE%2580%25800%25EE%2580%2580IN%25EE%2580%2580ANDROID%22%7D",
        "name": "dof2-android",
        "viewX":1300,
        "viewY":1470
    },
    {
        "url": "https://datastudio.google.com/u/1/reporting/9bd45efe-57ac-4a81-8f1a-c2aafd76c6b2/page/NRKVB",
        "name":"Downloader",
        "viewX":1300,
        "viewY":1477
    }
]