package main import ( "errors" "os" "time" "git.iamthefij.com/iamthefij/slog" "gopkg.in/yaml.v2" ) var errInvalidConfig = errors.New("Invalid configuration") // Config type is contains all provided user configuration type Config struct { CheckInterval time.Duration `yaml:"check_interval"` DefaultAlertAfter int16 `yaml:"default_alert_after"` DefaultAlertEvery *int16 `yaml:"default_alert_every"` DefaultAlertDown []string `yaml:"default_alert_down"` DefaultAlertUp []string `yaml:"default_alert_up"` Monitors []*Monitor Alerts map[string]*Alert } // CommandOrShell type wraps a string or list of strings // for executing a command directly or in a shell type CommandOrShell struct { ShellCommand string Command []string } // Empty checks if the Command has a value func (cos CommandOrShell) Empty() bool { return (cos.ShellCommand == "" && cos.Command == nil) } // UnmarshalYAML allows unmarshalling either a string or slice of strings // and parsing them as either a command or a shell command. func (cos *CommandOrShell) UnmarshalYAML(unmarshal func(interface{}) error) error { var cmd []string err := unmarshal(&cmd) // Error indicates this is shell command if err != nil { var shellCmd string err := unmarshal(&shellCmd) if err != nil { return err } cos.ShellCommand = shellCmd } else { cos.Command = cmd } return nil } // IsValid checks config validity and returns true if valid func (config Config) IsValid() (isValid bool) { isValid = true // Validate alerts if config.Alerts == nil || len(config.Alerts) == 0 { // This should never happen because there is a default alert named 'log' for now slog.Errorf("Invalid alert configuration: Must provide at least one alert") isValid = false } for _, alert := range config.Alerts { if !alert.IsValid() { slog.Errorf("Invalid alert configuration: %+v", alert.Name) isValid = false } else { slog.Debugf("Loaded alert %s", alert.Name) } } // Validate monitors if config.Monitors == nil || len(config.Monitors) == 0 { slog.Errorf("Invalid monitor configuration: Must provide at least one monitor") isValid = false } for _, monitor := range config.Monitors { if !monitor.IsValid() { slog.Errorf("Invalid monitor configuration: %s", monitor.Name) isValid = false } // Check that all Monitor alerts actually exist for _, isUp := range []bool{true, false} { for _, alertName := range monitor.GetAlertNames(isUp) { if _, ok := config.Alerts[alertName]; !ok { slog.Errorf( "Invalid monitor configuration: %s. Unknown alert %s", monitor.Name, alertName, ) isValid = false } } } } return isValid } // Init performs extra initialization on top of loading the config from file func (config *Config) Init() (err error) { for _, monitor := range config.Monitors { if monitor.AlertAfter == 0 && config.DefaultAlertAfter > 0 { monitor.AlertAfter = config.DefaultAlertAfter } if monitor.AlertEvery == nil && config.DefaultAlertEvery != nil { monitor.AlertEvery = config.DefaultAlertEvery } if len(monitor.AlertDown) == 0 && len(config.DefaultAlertDown) > 0 { monitor.AlertDown = config.DefaultAlertDown } if len(monitor.AlertUp) == 0 && len(config.DefaultAlertUp) > 0 { monitor.AlertUp = config.DefaultAlertUp } } for name, alert := range config.Alerts { alert.Name = name if err = alert.BuildTemplates(); err != nil { return } } return } // LoadConfig will read config from the given path and parse it func LoadConfig(filePath string) (config Config, err error) { data, err := os.ReadFile(filePath) if err != nil { return } err = yaml.Unmarshal(data, &config) if err != nil { return } slog.Debugf("Config values:\n%v\n", config) // Finish initializing configuration if err = config.Init(); err != nil { return } if !config.IsValid() { err = errInvalidConfig return } return config, err }