如何在Go语言中获取sshd服务状态？现有代码优化咨询

Let's break down how to fix this so you can get the exact service state regardless of whether sshd is running or stopped:

Key Issues with the Current Code #

• The systemctl check command doesn't exist in systemd — this is likely a typo. You'll want to use either systemctl is-active (for concise state output) or systemctl status (for detailed info).
• You're exiting immediately when the command returns an error, but systemd commands return non-zero exit codes for expected states like "inactive" or "failed" — these aren't errors you should abort on.

Optimization Steps #

• Use systemctl is-active for clean state output: This command returns a short, machine-readable state string (e.g., active, inactive, failed) and uses exit codes to indicate state:
  • Exit code 0: Service is active
  • Exit code 3: Service is inactive
  • Exit code 1: Service is in a failed state
• Don't exit on non-zero exit codes immediately: Instead, capture both the output and the error, then inspect the exit code and output to determine the actual state.
• Handle all possible states: Print the state clearly, and only exit if there's an unexpected error (like the systemctl command not being found, not just the service being stopped).

Updated Code Example #

package main

import (
	"errors"
	"fmt"
	"os"
	"os/exec"
	"strings"
)

func main() {
	// Use systemctl is-active for concise, machine-readable state
	cmd := exec.Command("systemctl", "is-active", "sshd")
	out, err := cmd.CombinedOutput()
	state := strings.TrimSpace(string(out))

	var exitErr *exec.ExitError
	if errors.As(err, &exitErr) {
		// Non-zero exit code is expected for inactive/failed states
		switch exitErr.ExitCode() {
		case 3:
			fmt.Printf("Status is: %s\n", state)
		case 1:
			fmt.Printf("Status is: %s (service has failed)\n", state)
		default:
			fmt.Printf("Unexpected error checking sshd state: %v\n", err)
			os.Exit(1)
		}
	} else if err != nil {
		// Handle actual errors (e.g., systemctl not found, permission issues)
		fmt.Printf("Failed to run systemctl command: %v\n", err)
		os.Exit(1)
	} else {
		// Exit code 0 means service is active
		fmt.Printf("Status is: %s\n", state)
	}

	// Continue execution regardless of service state (as requested)
	fmt.Println("Starting Role")
}

Explanation #

• We use systemctl is-active because it's designed for programmatic use — no need to parse long status outputs.
• We check if the error is an exec.ExitError (which wraps exit codes from the command) and handle expected exit codes (1 and 3) by printing the state instead of exiting.
• Only unexpected errors (like the systemctl command not existing) will trigger an exit.
• The service state is trimmed to remove any extra newlines or whitespace.

内容的提问来源于stack exchange，提问作者Adrian Cincu