bot initiated message

chatbot.go

package main

import (
	"context"
	"io/ioutil"
	"log"
	"net/http"
	"os"

	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	chat "google.golang.org/api/chat/v1"
)

func main() {
	// serviceAccountKeyPath is the path to a JSON file.
	serviceAccountKeyPath := os.Getenv("SERVICE_ACCOUNT_KEY_PATH")
	if serviceAccountKeyPath == "" {
		log.Fatal("missing required SERVICE_ACCOUNT_KEY_PATH")
	}

	// Parent can be found via the URL (e.g., https://chat.google.com/dm/{ID})
	parent := os.Getenv("CHAT_SPACE")
	if parent == "" {
		log.Fatal("missing required CHAT_SPACE")
	}

	msgText := os.Getenv("MESSAGE_TEXT")
	if msgText == "" {
		msgText = "hello world"
	}

	service, err := chat.New(getOauthClient(serviceAccountKeyPath))
	if err != nil {
		log.Fatalf("failed to create service client: %s", err)
	}

	msgService := chat.NewSpacesMessagesService(service)
	call := msgService.Create("spaces/"+parent, &chat.Message{
		Text: msgText,
	})
	msg, err := call.Do()
	if err != nil {
		log.Fatalf("failed to create message: %s", err)
	}
	log.Printf("msg: %+v", msg)
}

func getOauthClient(serviceAccountKeyPath string) *http.Client {
	ctx := context.Background()
	data, err := ioutil.ReadFile(serviceAccountKeyPath)
	if err != nil {
		log.Fatal(err)
	}
	creds, err := google.CredentialsFromJSON(ctx, data, "https://www.googleapis.com/auth/chat.bot")
	if err != nil {
		log.Fatal(err)
	}

	return oauth2.NewClient(ctx, creds.TokenSource)
}