custom application metrics

3 files changed, 109 insertions, 14 deletions

diff --git a/service/metrics/config.go b/service/metrics/config.go
index b93d8f50..b9b21ea9 100644
--- a/service/metrics/config.go
+++ b/service/metrics/config.go
@@ -11,11 +11,11 @@ type Config struct {
 	Address string
 
 	// Collect define application specific metrics.
-	Collect map[string]Metric
+	Collect map[string]Collector
 }
 
-// Metric describes single application specific metric.
-type Metric struct {
+// Collector describes single application specific metric.
+type Collector struct {
 	// Namespace of the metric.
 	Namespace string
 
@@ -41,11 +41,13 @@ func (c *Config) Hydrate(cfg service.Config) error {
 }
 
 // register application specific metrics.
-func (c *Config) registerMetrics() error {
+func (c *Config) initCollectors() (map[string]prometheus.Collector, error) {
 	if c.Collect == nil {
-		return nil
+		return nil, nil
 	}
 
+	collectors := make(map[string]prometheus.Collector)
+
 	for name, m := range c.Collect {
 		var collector prometheus.Collector
 		switch m.Type {
@@ -103,13 +105,15 @@ func (c *Config) registerMetrics() error {
 				collector = prometheus.NewSummary(opts)
 			}
 		default:
-			return fmt.Errorf("invalid metric type %s", m.Type)
+			return nil, fmt.Errorf("invalid metric type `%s` for `%s`", m.Type, name)
 		}
 
 		if err := prometheus.Register(collector); err != nil {
-			return err
+			return nil, err
 		}
+
+		collectors[name] = collector
 	}
 
-	return nil
+	return collectors, nil
 }
diff --git a/service/metrics/rpc.go b/service/metrics/rpc.go
new file mode 100644
index 00000000..5d1b8102
--- /dev/null
+++ b/service/metrics/rpc.go
@@ -0,0 +1,72 @@
+package metrics
+
+import (
+	"fmt"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type rpcServer struct{ svc *Service }
+
+type Metric struct {
+	// Collector name.
+	Name string
+
+	// Collector value.
+	Value float64
+
+	// Labels associated with metric. Only for vector metrics.
+	Labels []string
+}
+
+// Add new metric to the designated collector.
+func (rpc *rpcServer) Add(m *Metric, ok *bool) error {
+	c := rpc.svc.Collector(m.Name)
+	if c == nil {
+		return fmt.Errorf("undefined collector `%s`", m.Name)
+	}
+
+	switch c.(type) {
+	case prometheus.Gauge:
+		c.(prometheus.Gauge).Add(m.Value)
+
+	case *prometheus.GaugeVec:
+		if len(m.Labels) == 0 {
+			return fmt.Errorf("required labels for collector `%s`", m.Name)
+		}
+
+		c.(*prometheus.GaugeVec).WithLabelValues(m.Labels...).Add(m.Value)
+
+	case prometheus.Counter:
+		c.(prometheus.Counter).Add(m.Value)
+
+	case *prometheus.CounterVec:
+		if len(m.Labels) == 0 {
+			return fmt.Errorf("required labels for collector `%s`", m.Name)
+		}
+
+		c.(*prometheus.CounterVec).WithLabelValues(m.Labels...).Add(m.Value)
+
+	case prometheus.Summary:
+		c.(prometheus.Counter).Add(m.Value)
+
+	case *prometheus.SummaryVec:
+		if len(m.Labels) == 0 {
+			return fmt.Errorf("required labels for collector `%s`", m.Name)
+		}
+
+		c.(*prometheus.SummaryVec).WithLabelValues(m.Labels...).Observe(m.Value)
+
+	case prometheus.Histogram:
+		c.(prometheus.Histogram).Observe(m.Value)
+
+	case *prometheus.HistogramVec:
+		if len(m.Labels) == 0 {
+			return fmt.Errorf("required labels for collector `%s`", m.Name)
+		}
+
+		c.(*prometheus.HistogramVec).WithLabelValues(m.Labels...).Observe(m.Value)
+	}
+
+	*ok = true
+	return nil
+}
diff --git a/service/metrics/service.go b/service/metrics/service.go
index 2823b1a4..c7cfa376 100644
--- a/service/metrics/service.go
+++ b/service/metrics/service.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/spiral/roadrunner/service/rpc"
 	"net/http"
 	"sync"
 )
@@ -13,14 +14,22 @@ const ID = "metrics"
 
 // Service to manage application metrics using Prometheus.
 type Service struct {
-	cfg  *Config
-	mu   sync.Mutex
-	http *http.Server
+	cfg        *Config
+	mu         sync.Mutex
+	http       *http.Server
+	collectors map[string]prometheus.Collector
 }
 
 // Init service.
-func (s *Service) Init(cfg *Config) (bool, error) {
+func (s *Service) Init(cfg *Config, r *rpc.Service) (bool, error) {
 	s.cfg = cfg
+
+	if r != nil {
+		if err := r.Register(ID, &rpcServer{s}); err != nil {
+			return false, err
+		}
+	}
+
 	return true, nil
 }
 
@@ -42,9 +51,9 @@ func (s *Service) MustRegister(c prometheus.Collector) {
 }
 
 // Serve prometheus metrics service.
-func (s *Service) Serve() error {
+func (s *Service) Serve() (err error) {
 	// register application specific metrics
-	if err := s.cfg.registerMetrics(); err != nil {
+	if s.collectors, err = s.cfg.initCollectors(); err != nil {
 		return err
 	}
 
@@ -65,3 +74,13 @@ func (s *Service) Stop() {
 		go s.http.Shutdown(context.Background())
 	}
 }
+
+// Collector returns application specific collector by name or nil if collector not found.
+func (s *Service) Collector(name string) prometheus.Collector {
+	collector, ok := s.collectors[name]
+	if !ok {
+		return nil
+	}
+
+	return collector
+}