towerops-agent/ssh.go

98 lines
2.8 KiB
Go

package main
import (
"context"
"fmt"
"log/slog"
"net"
"strconv"
"strings"
"time"
"github.com/towerops-app/towerops-agent/pb"
"golang.org/x/crypto/ssh"
)
var sshBackup = executeMikrotikBackup
var sshDial = ssh.Dial
var doPing = pingDevice
// executeMikrotikBackup connects via SSH and runs /export compact.
func executeMikrotikBackup(ip string, port uint16, username, password string) (string, error) {
// SECURITY: TOFU (Trust-On-First-Use) host key verification.
// On first connection the key is stored; subsequent connections reject mismatches.
config := &ssh.ClientConfig{
User: username,
Auth: []ssh.AuthMethod{ssh.Password(password)},
HostKeyCallback: sshHostKeyCallback(),
Timeout: 30 * time.Second,
}
addr := net.JoinHostPort(ip, strconv.Itoa(int(port)))
conn, err := sshDial("tcp", addr, config)
if err != nil {
return "", fmt.Errorf("ssh dial %s: %w", addr, err)
}
defer func() { _ = conn.Close() }()
session, err := conn.NewSession()
if err != nil {
return "", fmt.Errorf("ssh session: %w", err)
}
defer func() { _ = session.Close() }()
output, err := session.CombinedOutput("/export compact")
if err != nil {
if trimmed := strings.TrimSpace(string(output)); trimmed != "" {
return "", fmt.Errorf("ssh command: %w: %s", err, trimmed)
}
return "", fmt.Errorf("ssh command: %w", err)
}
return string(output), nil
}
// executePingJob pings a device and sends a monitoring check result.
func executePingJob(ctx context.Context, job *pb.AgentJob, resultCh chan<- *pb.MonitoringCheck) {
dev := job.SnmpDevice
if dev == nil {
slog.Error("job missing device info for ping", "job_id", job.JobId)
sendMonitoringCheckWithTimeout(ctx, resultCh, &pb.MonitoringCheck{
DeviceId: job.DeviceId,
Status: "failure",
Timestamp: time.Now().Unix(),
}, job.JobId)
return
}
timestamp := time.Now().Unix()
responseTime, err := doPing(dev.Ip, 5000)
if err != nil {
slog.Warn("device down", "device", job.DeviceId, "error", err)
sendMonitoringCheckWithTimeout(ctx, resultCh, &pb.MonitoringCheck{
DeviceId: job.DeviceId,
Status: "failure",
Timestamp: timestamp,
}, job.JobId)
return
}
slog.Debug("device up", "device", job.DeviceId, "response_time_ms", responseTime)
sendMonitoringCheckWithTimeout(ctx, resultCh, &pb.MonitoringCheck{
DeviceId: job.DeviceId,
Status: "success",
ResponseTimeMs: responseTime,
Timestamp: timestamp,
}, job.JobId)
}
func sendMonitoringCheckWithTimeout(ctx context.Context, resultCh chan<- *pb.MonitoringCheck, result *pb.MonitoringCheck, jobID string) {
sendCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
defer cancel()
select {
case resultCh <- result:
case <-sendCtx.Done():
slog.Error("monitoring check result send timeout - agent overloaded", "job_id", jobID)
}
}