cmd/query: init tracer config from env

Signed-off-by: Alexander Saltykov <alexander-s@yandex-team.ru>

cmd/query/app/tracing.go

@@ -0,0 +1,25 @@
+package app
+
+import (
+	"os"
+
+	jaegerClientConfig "github.com/uber/jaeger-client-go/config"
+)
+
+func TracerConfig() (*jaegerClientConfig.Configuration, error) {
+	cfg, err := jaegerClientConfig.FromEnv()
+	if err != nil {
+		return nil, err
+	}
+	// backwards compatibility
+	if e := os.Getenv("JAEGER_RPC_METRICS"); e == "" {
+		cfg.RPCMetrics = true
+	}
+	if e := os.Getenv("JAEGER_SAMPLER_TYPE"); e == "" {
+		cfg.Sampler.Type = "probabilistic"
+	}
+	if e := os.Getenv("JAEGER_SAMPLER_PARAM"); e == "" {
+		cfg.Sampler.Param = 1.0
+	}
+	return cfg, nil
+}

cmd/query/main.go

@@ -64,22 +64,18 @@ func main() {
 			baseFactory := svc.MetricsFactory.Namespace(metrics.NSOptions{Name: "jaeger"})
 			metricsFactory := baseFactory.Namespace(metrics.NSOptions{Name: "query"})
 
-			tracer, closer, err := jaegerClientConfig.Configuration{
-				ServiceName: "jaeger-query",
-				Sampler: &jaegerClientConfig.SamplerConfig{
-					Type:  "probabilistic",
-					Param: 1.0,
-				},
-				RPCMetrics: true,
-			}.NewTracer(
+			cfg, err := app.TracerConfig()
+			if err != nil {
+				logger.Fatal("Failed to read tracer config from env", zap.Error(err))
+			}
+			closer, err := cfg.InitGlobalTracer("jaeger-query",
 				jaegerClientConfig.Metrics(svc.MetricsFactory),
 				jaegerClientConfig.Logger(jaegerClientZapLog.NewLogger(logger)),
 			)
 			if err != nil {
 				logger.Fatal("Failed to initialize tracer", zap.Error(err))
 			}
 			defer closer.Close()
-			opentracing.SetGlobalTracer(tracer)
 			queryOpts := new(app.QueryOptions).InitFromViper(v)
 			// TODO: Need to figure out set enable/disable propagation on storage plugins.
 			v.Set(spanstore.StoragePropagationKey, queryOpts.BearerTokenPropagation)
@@ -102,7 +98,7 @@ func main() {
 				dependencyReader,
 				*queryServiceOptions)
 
-			server := app.NewServer(svc, queryService, queryOpts, tracer)
+			server := app.NewServer(svc, queryService, queryOpts, opentracing.GlobalTracer())
 
 			if err := server.Start(); err != nil {
 				logger.Fatal("Could not start servers", zap.Error(err))