Added integration support for DataDog APM Tracing

vendor/gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer/option.go

@@ -0,0 +1,163 @@
+package tracer
+
+import (
+	"os"
+	"path/filepath"
+	"time"
+
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/ext"
+)
+
+// config holds the tracer configuration.
+type config struct {
+	// debug, when true, writes details to logs.
+	debug bool
+
+	// serviceName specifies the name of this application.
+	serviceName string
+
+	// sampler specifies the sampler that will be used for sampling traces.
+	sampler Sampler
+
+	// agentAddr specifies the hostname and  of the agent where the traces
+	// are sent to.
+	agentAddr string
+
+	// globalTags holds a set of tags that will be automatically applied to
+	// all spans.
+	globalTags map[string]interface{}
+
+	// transport specifies the Transport interface which will be used to send data to the agent.
+	transport transport
+
+	// propagator propagates span context cross-process
+	propagator Propagator
+}
+
+// StartOption represents a function that can be provided as a parameter to Start.
+type StartOption func(*config)
+
+// defaults sets the default values for a config.
+func defaults(c *config) {
+	c.serviceName = filepath.Base(os.Args[0])
+	c.sampler = NewAllSampler()
+	c.agentAddr = defaultAddress
+}
+
+// WithDebugMode enables debug mode on the tracer, resulting in more verbose logging.
+func WithDebugMode(enabled bool) StartOption {
+	return func(c *config) {
+		c.debug = enabled
+	}
+}
+
+// WithPropagator sets an alternative propagator to be used by the tracer.
+func WithPropagator(p Propagator) StartOption {
+	return func(c *config) {
+		c.propagator = p
+	}
+}
+
+// WithServiceName sets the default service name to be used with the tracer.
+func WithServiceName(name string) StartOption {
+	return func(c *config) {
+		c.serviceName = name
+	}
+}
+
+// WithAgentAddr sets the address where the agent is located. The default is
+// localhost:8126. It should contain both host and port.
+func WithAgentAddr(addr string) StartOption {
+	return func(c *config) {
+		c.agentAddr = addr
+	}
+}
+
+// WithGlobalTag sets a key/value pair which will be set as a tag on all spans
+// created by tracer. This option may be used multiple times.
+func WithGlobalTag(k string, v interface{}) StartOption {
+	return func(c *config) {
+		if c.globalTags == nil {
+			c.globalTags = make(map[string]interface{})
+		}
+		c.globalTags[k] = v
+	}
+}
+
+// WithSampler sets the given sampler to be used with the tracer. By default
+// an all-permissive sampler is used.
+func WithSampler(s Sampler) StartOption {
+	return func(c *config) {
+		c.sampler = s
+	}
+}
+
+// StartSpanOption is a configuration option for StartSpan. It is aliased in order
+// to help godoc group all the functions returning it together. It is considered
+// more correct to refer to it as the type as the origin, ddtrace.StartSpanOption.
+type StartSpanOption = ddtrace.StartSpanOption
+
+// Tag sets the given key/value pair as a tag on the started Span.
+func Tag(k string, v interface{}) StartSpanOption {
+	return func(cfg *ddtrace.StartSpanConfig) {
+		if cfg.Tags == nil {
+			cfg.Tags = map[string]interface{}{}
+		}
+		cfg.Tags[k] = v
+	}
+}
+
+// ServiceName sets the given service name on the started span. For example "http.server".
+func ServiceName(name string) StartSpanOption {
+	return Tag(ext.ServiceName, name)
+}
+
+// ResourceName sets the given resource name on the started span. A resource could
+// be an SQL query, a URL, an RPC method or something else.
+func ResourceName(name string) StartSpanOption {
+	return Tag(ext.ResourceName, name)
+}
+
+// SpanType sets the given span type on the started span. Some examples in the case of
+// the Datadog APM product could be "web", "db" or "cache".
+func SpanType(name string) StartSpanOption {
+	return Tag(ext.SpanType, name)
+}
+
+// ChildOf tells StartSpan to use the given span context as a parent for the
+// created span.
+func ChildOf(ctx ddtrace.SpanContext) StartSpanOption {
+	return func(cfg *ddtrace.StartSpanConfig) {
+		cfg.Parent = ctx
+	}
+}
+
+// StartTime sets a custom time as the start time for the created span. By
+// default a span is started using the creation time.
+func StartTime(t time.Time) StartSpanOption {
+	return func(cfg *ddtrace.StartSpanConfig) {
+		cfg.StartTime = t
+	}
+}
+
+// FinishOption is a configuration option for FinishSpan. It is aliased in order
+// to help godoc group all the functions returning it together. It is considered
+// more correct to refer to it as the type as the origin, ddtrace.FinishOption.
+type FinishOption = ddtrace.FinishOption
+
+// FinishTime sets the given time as the finishing time for the span. By default,
+// the current time is used.
+func FinishTime(t time.Time) FinishOption {
+	return func(cfg *ddtrace.FinishConfig) {
+		cfg.FinishTime = t
+	}
+}
+
+// WithError adds the given error to the span before marking it as finished. If it is
+// nil it will be disregarded.
+func WithError(err error) FinishOption {
+	return func(cfg *ddtrace.FinishConfig) {
+		cfg.Error = err
+	}
+}