1 files changed, 74 insertions, 0 deletions
diff --git a/core/setup/metrics.go b/core/setup/metrics.go
new file mode 100644
index 000000000..84fdadb29
--- /dev/null
+++ b/core/setup/metrics.go
@@ -0,0 +1,74 @@
+package setup
+
+import (
+	"sync"
+
+	"github.com/miekg/coredns/middleware"
+	"github.com/miekg/coredns/middleware/metrics"
+)
+
+const (
+	path = "/metrics"
+	addr = "localhost:9135" // 9153 is occupied by bind_exporter
+)
+
+var once sync.Once
+
+func Prometheus(c *Controller) (middleware.Middleware, error) {
+	met, err := parsePrometheus(c)
+	if err != nil {
+		return nil, err
+	}
+
+	once.Do(func() {
+		c.Startup = append(c.Startup, met.Start)
+	})
+
+	return func(next middleware.Handler) middleware.Handler {
+		met.Next = next
+		return met
+	}, nil
+}
+
+func parsePrometheus(c *Controller) (metrics.Metrics, error) {
+	var (
+		met metrics.Metrics
+		err error
+	)
+
+	for c.Next() {
+		if len(met.ZoneNames) > 0 {
+			return metrics.Metrics{}, c.Err("metrics: can only have one metrics module per server")
+		}
+		met = metrics.Metrics{ZoneNames: c.ServerBlockHosts}
+		for i, _ := range met.ZoneNames {
+			met.ZoneNames[i] = middleware.Host(met.ZoneNames[i]).Normalize()
+		}
+		args := c.RemainingArgs()
+
+		switch len(args) {
+		case 0:
+		case 1:
+			met.Addr = args[0]
+		default:
+			return metrics.Metrics{}, c.ArgErr()
+		}
+		for c.NextBlock() {
+			switch c.Val() {
+			case "address":
+				args = c.RemainingArgs()
+				if len(args) != 1 {
+					return metrics.Metrics{}, c.ArgErr()
+				}
+				met.Addr = args[0]
+			default:
+				return metrics.Metrics{}, c.Errf("metrics: unknown item: %s", c.Val())
+			}
+
+		}
+	}
+	if met.Addr == "" {
+		met.Addr = addr
+	}
+	return met, err
+}