Pinging from cmd-CodePudding

I have this app that needs to ping google.com to see if the network connection is alive.

The following works code fine and lists the directory content:

cmd = exec.Command("ls", "-lah")
var stdout, stderr bytes.Buffer
cmd.Stdout = &stdout
cmd.Stderr = &stderr
err = cmd.Run()
if err != nil {
    log.Fatalf("cmd.Run() failed with %s\n", err)
}
outStr, errStr := string(stdout.Bytes()), string(stderr.Bytes())
fmt.Printf("out:\n%s\nerr:\n%s\n", outStr, errStr)

When I change the args this hangs.

cmd = exec.Command("ping", "goole.com")

This causes an error: cmd.Run() failed with exit status 2

cmd = exec.Command("ping", "https://www.goole.com")

After i changed the args to:

cmd = exec.Command("ping -c 5", "goole.com")

I get

cmd.Run() failed with exec: "ping -c 5": executable file not found in $PATH

I'm using go mod for my dependencies. Any idea what I do wrong?

CodePudding user response：

The error is because you mention https. Try running as

cmd = exec.Command("ping", "www.google.com") or simply "google.com" should work too.

The reason the first one hangs is because you're calling ping without any other args which runs pings infinitely. So try calling it with args -c which mentions the count. This should work.

cmd := exec.Command("ping", "-c" , "3", "google.com")

Even better, make it faster with a smaller interval -i 0.1 or something that you see fit. But ensure you add the -c.

CodePudding user response：

The ping command runs indefinitely, which is why it appears to hang - ping never exits. You can force it to exit by limiting the number of ping attempts with the -c argument, e.g.

ping -c 5 goole.com will attempt 5 pings. This is the shell form. In your code, use:

cmd = exec.Command("ping", "-c1", "goole.com")

https://www.goole.com fails because ping expects a host name, not a URL.

CodePudding user response：

Why would you spawn a process to ping an IP address? Try go-ping, one of several packages that implement ICMP ping.