Move code to pkg

pkg/tracing/datadog/datadog.go

@@ -0,0 +1,50 @@
+package datadog
+
+import (
+	"io"
+	"strings"
+
+	"github.com/containous/traefik/pkg/log"
+	"github.com/opentracing/opentracing-go"
+	ddtracer "gopkg.in/DataDog/dd-trace-go.v1/ddtrace/opentracer"
+	datadog "gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+)
+
+// Name sets the name of this tracer
+const Name = "datadog"
+
+// Config provides configuration settings for a datadog tracer
+type Config struct {
+	LocalAgentHostPort string `description:"Set datadog-agent's host:port that the reporter will used. Defaults to localhost:8126" export:"false"`
+	GlobalTag          string `description:"Key:Value tag to be set on all the spans." export:"true"`
+	Debug              bool   `description:"Enable DataDog debug." export:"true"`
+	PrioritySampling   bool   `description:"Enable priority sampling. When using distributed tracing, this option must be enabled in order to get all the parts of a distributed trace sampled."`
+}
+
+// Setup sets up the tracer
+func (c *Config) Setup(serviceName string) (opentracing.Tracer, io.Closer, error) {
+	tag := strings.SplitN(c.GlobalTag, ":", 2)
+
+	value := ""
+	if len(tag) == 2 {
+		value = tag[1]
+	}
+
+	opts := []datadog.StartOption{
+		datadog.WithAgentAddr(c.LocalAgentHostPort),
+		datadog.WithServiceName(serviceName),
+		datadog.WithGlobalTag(tag[0], value),
+		datadog.WithDebugMode(c.Debug),
+	}
+	if c.PrioritySampling {
+		opts = append(opts, datadog.WithPrioritySampling())
+	}
+	tracer := ddtracer.New(opts...)
+
+	// Without this, child spans are getting the NOOP tracer
+	opentracing.SetGlobalTracer(tracer)
+
+	log.WithoutContext().Debug("DataDog tracer configured")
+
+	return tracer, nil, nil
+}