package main import ( "errors" "flag" "fmt" "time" "git.iamthefij.com/iamthefij/slog" ) var ( // ExportMetrics will track whether or not we want to export metrics to prometheus ExportMetrics = false // MetricsPort is the port to expose metrics on MetricsPort = 8080 // Metrics contains all active metrics Metrics = NewMetrics() // PyCompat enables support for legacy Python templates PyCompat = false // version of minitor being run version = "dev" errUnknownAlert = errors.New("unknown alert") ) func sendAlerts(config *Config, monitor *Monitor, alertNotice *AlertNotice) error { slog.Debugf("Received an alert notice from %s", alertNotice.MonitorName) alertNames := monitor.GetAlertNames(alertNotice.IsUp) if alertNames == nil { // This should only happen for a recovery alert. AlertDown is validated not empty slog.Warningf( "Received alert, but no alert mechanisms exist. MonitorName=%s IsUp=%t", alertNotice.MonitorName, alertNotice.IsUp, ) return nil } for _, alertName := range alertNames { if alert, ok := config.Alerts[alertName]; ok { output, err := alert.Send(*alertNotice) if err != nil { slog.Errorf( "Alert '%s' failed. result=%v: output=%s", alert.Name, err, output, ) return err } // Count alert metrics Metrics.CountAlert(monitor.Name, alert.Name) } else { // This case should never actually happen since we validate against it slog.Errorf("Unknown alert for monitor %s: %s", alertNotice.MonitorName, alertName) return fmt.Errorf("unknown alert for monitor %s: %s: %w", alertNotice.MonitorName, alertName, errUnknownAlert) } } return nil } func checkMonitors(config *Config) error { // TODO: Run this in goroutines and capture exceptions for _, monitor := range config.Monitors { if monitor.ShouldCheck() { success, alertNotice := monitor.Check() hasAlert := alertNotice != nil // Track status metrics Metrics.SetMonitorStatus(monitor.Name, monitor.IsUp()) Metrics.CountCheck(monitor.Name, success, monitor.LastCheckMilliseconds(), hasAlert) if alertNotice != nil { err := sendAlerts(config, monitor, alertNotice) // If there was an error in sending an alert, exit early and bubble it up if err != nil { return err } } } } return nil } func main() { showVersion := flag.Bool("version", false, "Display the version of minitor and exit") configPath := flag.String("config", "config.yml", "Alternate configuration path (default: config.yml)") flag.BoolVar(&slog.DebugLevel, "debug", false, "Enables debug logs (default: false)") flag.BoolVar(&ExportMetrics, "metrics", false, "Enables prometheus metrics exporting (default: false)") flag.BoolVar(&PyCompat, "py-compat", false, "Enables support for legacy Python Minitor config. Will eventually be removed. (default: false)") flag.IntVar(&MetricsPort, "metrics-port", MetricsPort, "The port that Prometheus metrics should be exported on, if enabled. (default: 8080)") flag.Parse() // Print version if flag is provided if *showVersion { fmt.Println("Minitor version:", version) return } // Load configuration config, err := LoadConfig(*configPath) slog.OnErrFatalf(err, "Error loading config: %v", err) // Serve metrics exporter, if specified if ExportMetrics { slog.Infof("Exporting metrics to Prometheus on port %d", MetricsPort) go ServeMetrics() } // Start main loop for { err = checkMonitors(&config) slog.OnErrPanicf(err, "Error checking monitors") time.Sleep(config.CheckInterval.Value()) } }