1 files changed, 119 insertions, 0 deletions
diff --git a/service/metrics/config.go b/service/metrics/config.go
new file mode 100644
index 00000000..b9b21ea9
--- /dev/null
+++ b/service/metrics/config.go
@@ -0,0 +1,119 @@
+package metrics
+
+import (
+	"fmt"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/spiral/roadrunner/service"
+)
+
+type Config struct {
+	// Address to listen
+	Address string
+
+	// Collect define application specific metrics.
+	Collect map[string]Collector
+}
+
+// Collector describes single application specific metric.
+type Collector struct {
+	// Namespace of the metric.
+	Namespace string
+
+	// Subsystem of the metric.
+	Subsystem string
+
+	// Collector type (histogram, gauge, counter, summary).
+	Type string
+
+	// Help of collector.
+	Help string
+
+	// Labels for vectorized metrics.
+	Labels []string
+
+	// Buckets for histogram metric.
+	Buckets []float64
+}
+
+// Hydrate configuration.
+func (c *Config) Hydrate(cfg service.Config) error {
+	return cfg.Unmarshal(c)
+}
+
+// register application specific metrics.
+func (c *Config) initCollectors() (map[string]prometheus.Collector, error) {
+	if c.Collect == nil {
+		return nil, nil
+	}
+
+	collectors := make(map[string]prometheus.Collector)
+
+	for name, m := range c.Collect {
+		var collector prometheus.Collector
+		switch m.Type {
+		case "histogram":
+			opts := prometheus.HistogramOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+				Buckets:   m.Buckets,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewHistogramVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewHistogram(opts)
+			}
+		case "gauge":
+			opts := prometheus.GaugeOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewGaugeVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewGauge(opts)
+			}
+		case "counter":
+			opts := prometheus.CounterOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewCounterVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewCounter(opts)
+			}
+		case "summary":
+			opts := prometheus.SummaryOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewSummaryVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewSummary(opts)
+			}
+		default:
+			return nil, fmt.Errorf("invalid metric type `%s` for `%s`", m.Type, name)
+		}
+
+		if err := prometheus.Register(collector); err != nil {
+			return nil, err
+		}
+
+		collectors[name] = collector
+	}
+
+	return collectors, nil
+}