makes jaeger tracing configurable

pkg/tracing/tracing.go

@@ -0,0 +1,77 @@
+package tracing
+
+import (
+	"io"
+	"io/ioutil"
+
+	"github.com/grafana/grafana/pkg/log"
+	"github.com/grafana/grafana/pkg/setting"
+
+	opentracing "github.com/opentracing/opentracing-go"
+	jaeger "github.com/uber/jaeger-client-go"
+	jaegercfg "github.com/uber/jaeger-client-go/config"
+	jaegerlog "github.com/uber/jaeger-client-go/log"
+	ini "gopkg.in/ini.v1"
+)
+
+var (
+	logger log.Logger = log.New("tracing")
+)
+
+type TracingSettings struct {
+	Enabled bool
+	Address string
+}
+
+func Init(file *ini.File) (io.Closer, error) {
+	settings := parseSettings(file)
+	return internalInit(settings)
+}
+
+func parseSettings(file *ini.File) *TracingSettings {
+	settings := &TracingSettings{}
+
+	var section, err = setting.Cfg.GetSection("tracing.jaeger")
+	if err != nil {
+		return settings
+	}
+
+	settings.Address = section.Key("address").MustString("")
+	if settings.Address != "" {
+		settings.Enabled = true
+	}
+
+	return settings
+}
+
+func internalInit(settings *TracingSettings) (io.Closer, error) {
+	if !settings.Enabled {
+		return ioutil.NopCloser(nil), nil
+	}
+
+	cfg := jaegercfg.Configuration{
+		Disabled: !settings.Enabled,
+		Sampler: &jaegercfg.SamplerConfig{
+			Type:  jaeger.SamplerTypeConst,
+			Param: 1,
+		},
+		Reporter: &jaegercfg.ReporterConfig{
+			LogSpans:           false,
+			LocalAgentHostPort: settings.Address,
+		},
+	}
+
+	jLogger := jaegerlog.StdLogger
+
+	tracer, closer, err := cfg.New(
+		"grafana",
+		jaegercfg.Logger(jLogger),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	logger.Info("Initialized jaeger tracer", "address", settings.Address)
+	opentracing.InitGlobalTracer(tracer)
+	return closer, nil
+}