Alertmanager with functional options

main.go

package main

import "alertmanager"

func main() {
  dur, _ := time.ParseDuration("1m")
  // without a proxy:
  alertmanager.NewAlertmanager("prod", "https://alertmanager", dur)
  // or
  alertmanager.NewAlertmanager("prod", "https://alertmanager", dur, alertmanager.WithProxy(false))
  
  // with a proxy:
  alertmanager.NewAlertmanager("local", "http://localhost:3411", dur, alertmanager.WithProxy(true))
}

upstream.go

package alertmanager

type Alertmanager struct {}
type Option function(am *Alertmanager) {}

var (
	upstreams = map[string]*Alertmanager{}
)

// NewAlertmanager creates a new Alertmanager instance, unsee clients will talk
// to directly to it without unsee proxying any request
func NewAlertmanager(name, uri string, timeout time.Duration, opts ...Option) error {
	if _, found := upstreams[name]; found {
		return fmt.Errorf("Alertmanager upstream '%s' already exist", name)
	}

	for _, am := range upstreams {
		if am.URI == uri {
			return fmt.Errorf("Alertmanager upstream '%s' already collects from '%s'", am.Name, am.URI)
		}
	}

	am := &Alertmanager{
		URI:           uri,
		Timeout:       timeout,
		Name:          name,
		ProxyRequests: false,
		lock:          sync.RWMutex{},
		alertGroups:   []models.AlertGroup{},
		silences:      map[string]models.Silence{},
		colors:        models.LabelsColorMap{},
		autocomplete:  []models.Autocomplete{},
		metrics: alertmanagerMetrics{
			errors: map[string]float64{
				labelValueErrorsAlerts:   0,
				labelValueErrorsSilences: 0,
			},
		},
	}
	
	for _, opt := range opts {
		opt(am)
	}
	
	upstreams[name] = am
	
	return nil
}

func WithProxy(proxied bool) Option {
	return func(am *Alertmanager) {
		am.ProxyRequests := proxied
	}
}