metrics.go

package muninplugin

import (
	"fmt"
	"reflect"
	"strings"
)

// Metrics is a map that stores the name of a Metric as its key, and
// a pointer to a Metric as its value.
type Metrics map[string]*Metric

// NewMetrics returns a non-nil Metrics
func newMetrics() Metrics {
	return make(Metrics)
}

// Values returns the output for use by a regular Munin data
// collection run.
func (ms Metrics) Values() string {
	var result []string
	for k, v := range ms {
		switch sw := v.Value.(type) {
		case float32, float64:
			result = append(result, fmt.Sprintf("%s.value %.2f\n", k, sw))
		case int8, uint8, int32, uint32, int64, uint64, int, uint:
			result = append(result, fmt.Sprintf("%s.value %d\n", k, sw))
		default:
			result = append(result, fmt.Sprintf("%s.value U\n", k))
		}
	}
	return strings.Join(result, "")
}

// Config returns the output for use by an initial Munin run
// to collect configuration data used by subsequent value runs.
func (ms Metrics) Config() string {
	var result []string
	for k, v := range ms {
		// The load label is the string used as a key in the Metrics map.
		result = append(result, fmt.Sprintf("%s.label %s\n", k, k))

		val := reflect.ValueOf(*v)
		for i := 0; i < val.NumField(); i++ {
			value := val.Field(i)
			kind := value.Kind()
			fieldType := val.Type().Field(i)
			tags := fieldType.Tag
			muninTag := tags.Get("munin")
			if muninTag != "" {
				switch kind {
				case reflect.String:
					if value.String() != "" {
						result = append(result,
							fmt.Sprintf("%s%s %s\n", k, muninTag, value.String()))
					}
				case reflect.Bool:
					result = append(result, fmt.Sprintf("%s%s %s\n", k, muninTag, toYN(value.Bool())))
				case reflect.Interface:
					switch value.Interface().(type) {
					case int, int8, int32, int64:
						result = append(result,
							fmt.Sprintf("%s%s %d\n", k, muninTag, value.Interface()))
					case float32, float64:
						result = append(result,
							fmt.Sprintf("%s%s %.2f\n", k, muninTag, value.Interface()))
					}
				}
			}
		}
	}
	return strings.Join(result, "")
}