execute functions in specific order - go

Question

I have the following function
func (c *Connection) ConnectVpn() error {
cmd := exec.Command(c.Command, c.Args...)
var password bytes.Buffer
password.WriteString(os.Getenv("PASSWORD"))
cmd.Stdin = &password
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Start()
if err != nil {
return err
}
return err
}
This function call the openconnect binary and connects in a private vpn to be able to reach a specific server (it works fine).
The problem is that when I call cmd.Start() it creates a thread and allows me to execute the another function named checkCertificate() but then this function is called before the vpn connects so it fails.
When I try to let the VPN connects and use cmd.RUN() this process do not run on background so the process never finish and it never tells to cmd.Wait() it finished because it shouldn't finish.
days, err := domain.CheckCertificate()
if err != nil {
log.Fatalln(err)
}
I have tried to use channels to try to sync the results between them but when I do this the checkCertificate() function keeps being executed before the VPN executes and I can't reach the server I need.
Any idea in how I could let the ConnectVPN() function be running on foreground and even so send some signal to my other function to say vpn is connected now, please run?
I have tried to send the openconnect to background with cmd.Process.Signal(syscall.SIGTSTP) but when I bring it back it breaks the main function.

Answer 1

I have implemented the function to check if this is connected as was suggested before.
Now it only triggers the other functions if this VPN is connected.
package main
import (
"fmt"
"gitlabCertCheck/request"
"gitlabCertCheck/teams"
"gitlabCertCheck/vpn"
"net/http"
"os"
"strconv"
)
func checker() {
client := http.Client{}
_, err := client.Get(os.Getenv("HTTPS_HOST"))
if err != nil {
checker()
}
return
}
func main() {
args := []string{"--user", os.Getenv("USERNAME"), "--authgroup", "default", "--background",os.Getenv("VPN_SERVER")}
conn := vpn.NewConnection("openconnect", args)
err := conn.ConnectVpn()
if err != nil {
fmt.Println(err)
os.Exit(1)
}
checker()
client := request.Request{}
domain := client.NewRequest(os.Getenv("HOST"), os.Getenv("PORT"))
days, err := domain.CheckCertificate()
if err != nil {
fmt.Println(err)
}
card := teams.Card{}
card.CustomCard.Title = "Certificate Alert"
card.CustomCard.Text = "Certificate will expire in " + strconv.Itoa(days) + " days"
card.NewCard(card.CustomCard)
err = card.SendMessageCard(os.Getenv("TEAMS_WEBHOOK"))
if err != nil {
fmt.Println(err)
}
}
Thank you everyone