contrib: Adding WithCustomTag to various integrations

contrib/confluentinc/confluent-kafka-go/kafka/kafka.go

@@ -98,6 +98,13 @@ func (c *Consumer) startSpan(msg *kafka.Message) ddtrace.Span {
 		tracer.Tag("offset", msg.TopicPartition.Offset),
 		tracer.Measured(),
 	}
+
+	if c.cfg.tagFns != nil {
+		for key, tagFn := range c.cfg.tagFns {
+			opts = append(opts, tracer.Tag(key, tagFn(msg)))
+		}
+	}
+
 	if !math.IsNaN(c.cfg.analyticsRate) {
 		opts = append(opts, tracer.Tag(ext.EventSampleRate, c.cfg.analyticsRate))
 	}

contrib/confluentinc/confluent-kafka-go/kafka/kafka_test.go

@@ -277,3 +277,49 @@ func TestDeprecatedContext(t *testing.T) {
 	<-c.Events()
 
 }
+
+func TestCustomTags(t *testing.T) {
+	mt := mocktracer.Start()
+	defer mt.Stop()
+
+	c, err := NewConsumer(&kafka.ConfigMap{
+		"go.events.channel.enable": true, // required for the events channel to be turned on
+		"group.id":                 testGroupID,
+		"socket.timeout.ms":        10,
+		"session.timeout.ms":       10,
+		"enable.auto.offset.store": false,
+	}, WithCustomTag("foo", func(msg *kafka.Message) interface{} {
+		return "bar"
+	}), WithCustomTag("key", func(msg *kafka.Message) interface{} {
+		return msg.Key
+	}))
+	assert.NoError(t, err)
+
+	err = c.Subscribe(testTopic, nil)
+	assert.NoError(t, err)
+
+	go func() {
+		c.Consumer.Events() <- &kafka.Message{
+			TopicPartition: kafka.TopicPartition{
+				Topic:     &testTopic,
+				Partition: 1,
+				Offset:    1,
+			},
+			Key:   []byte("key1"),
+			Value: []byte("value1"),
+		}
+	}()
+
+	_ = (<-c.Events()).(*kafka.Message)
+
+	c.Close()
+	// wait for the events channel to be closed
+	<-c.Events()
+
+	spans := mt.FinishedSpans()
+	assert.Len(t, spans, 1)
+	s := spans[0]
+
+	assert.Equal(t, "bar", s.Tag("foo"))
+	assert.Equal(t, []byte("key1"), s.Tag("key"))
+}

contrib/confluentinc/confluent-kafka-go/kafka/option.go

@@ -11,13 +11,16 @@ import (
 
 	"gopkg.in/DataDog/dd-trace-go.v1/internal"
 	"gopkg.in/DataDog/dd-trace-go.v1/internal/globalconfig"
+
+	"github.com/confluentinc/confluent-kafka-go/kafka"
 )
 
 type config struct {
 	ctx                 context.Context
 	consumerServiceName string
 	producerServiceName string
 	analyticsRate       float64
+	tagFns              map[string]func(msg *kafka.Message) interface{}
 }
 
 // An Option customizes the config.
@@ -82,3 +85,14 @@ func WithAnalyticsRate(rate float64) Option {
 		}
 	}
 }
+
+// WithCustomTag will cause the given tagFn to be evaluated after executing
+// a query and attach the result to the span tagged by the key.
+func WithCustomTag(tag string, tagFn func(msg *kafka.Message) interface{}) Option {
+	return func(cfg *config) {
+		if cfg.tagFns == nil {
+			cfg.tagFns = make(map[string]func(msg *kafka.Message) interface{})
+		}
+		cfg.tagFns[tag] = tagFn
+	}
+}

contrib/database/sql/conn.go

@@ -216,6 +216,13 @@ func (tp *traceParams) tryTrace(ctx context.Context, qtype queryType, query stri
 		tracer.SpanType(ext.SpanTypeSQL),
 		tracer.StartTime(startTime),
 	)
+
+	if tp.cfg.tags != nil {
+		for key, tag := range tp.cfg.tags {
+			opts = append(opts, tracer.Tag(key, tag))
+		}
+	}
+
 	if !math.IsNaN(tp.cfg.analyticsRate) {
 		opts = append(opts, tracer.Tag(ext.EventSampleRate, tp.cfg.analyticsRate))
 	}

contrib/database/sql/conn_test.go

@@ -168,3 +168,94 @@ func TestWithChildSpansOnly(t *testing.T) {
 		})
 	}
 }
+
+func TestWithCustomTag(t *testing.T) {
+	type sqlRegister struct {
+		name   string
+		dsn    string
+		driver driver.Driver
+	}
+	type want struct {
+		opName     string
+		customTags map[string]interface{}
+	}
+	testcases := []struct {
+		name        string
+		sqlRegister sqlRegister
+		want        want
+		options     []Option
+	}{
+		{
+			name: "mysql",
+			sqlRegister: sqlRegister{
+				name:   "mysql",
+				dsn:    "test:test@tcp(127.0.0.1:3306)/test",
+				driver: &mysql.MySQLDriver{},
+			},
+			want: want{
+				opName: "mysql.query",
+				customTags: map[string]interface{}{
+					"foo": "bar",
+					"baz": 123,
+				},
+			},
+			options: []Option{
+				WithCustomTag("foo", "bar"),
+				WithCustomTag("baz", 123),
+			},
+		},
+		{
+			name: "postgres",
+			sqlRegister: sqlRegister{
+				name:   "postgres",
+				dsn:    "postgres://postgres:postgres@127.0.0.1:5432/postgres?sslmode=disable",
+				driver: &pq.Driver{},
+			},
+			want: want{
+				opName: "postgres.query",
+				customTags: map[string]interface{}{
+					"foo": "bar",
+					"baz": 123,
+				},
+			},
+			options: []Option{
+				WithCustomTag("foo", "bar"),
+				WithCustomTag("baz", 123),
+			},
+		},
+	}
+	mt := mocktracer.Start()
+	defer mt.Stop()
+	for _, tt := range testcases {
+		t.Run(tt.name, func(t *testing.T) {
+			Register(tt.sqlRegister.name, tt.sqlRegister.driver, tt.options...)
+			defer unregister(tt.sqlRegister.name)
+			db, err := Open(tt.sqlRegister.name, tt.sqlRegister.dsn, tt.options...)
+			if err != nil {
+				log.Fatal(err)
+			}
+			defer db.Close()
+			mt.Reset()
+
+			rows, err := db.QueryContext(context.Background(), "SELECT 1")
+			assert.NoError(t, err)
+			rows.Close()
+
+			spans := mt.FinishedSpans()
+			assert.Len(t, spans, 2)
+
+			connectSpan := spans[0]
+			assert.Equal(t, tt.want.opName, connectSpan.OperationName())
+			assert.Equal(t, "Connect", connectSpan.Tag("sql.query_type"))
+			for k, v := range tt.want.customTags {
+				assert.Equal(t, v, connectSpan.Tag(k), "Value mismatch on tag %s", k)
+			}
+
+			span := spans[1]
+			assert.Equal(t, tt.want.opName, span.OperationName())
+			for k, v := range tt.want.customTags {
+				assert.Equal(t, v, span.Tag(k), "Value mismatch on tag %s", k)
+			}
+		})
+	}
+}

contrib/database/sql/option.go

@@ -18,6 +18,7 @@ type config struct {
 	analyticsRate        float64
 	dsn                  string
 	childSpansOnly       bool
+	tags                 map[string]interface{}
 	commentInjectionMode tracer.SQLCommentInjectionMode
 }
 
@@ -88,6 +89,16 @@ func WithChildSpansOnly() Option {
 	}
 }
 
+// WithCustomTag will attach the value to the span tagged by the key.
+func WithCustomTag(key string, value interface{}) Option {
+	return func(cfg *config) {
+		if cfg.tags == nil {
+			cfg.tags = make(map[string]interface{})
+		}
+		cfg.tags[key] = value
+	}
+}
+
 // WithSQLCommentInjection enables injection of tags as sql comments on traced queries.
 // This includes dynamic values like span id, trace id and sampling priority which can make queries
 // unique for some cache implementations. Use WithStaticTagsCommentInjection if this is a concern.

contrib/google.golang.org/grpc/client.go

@@ -39,7 +39,7 @@ func (cs *clientStream) RecvMsg(m interface{}) (err error) {
 			cs.method,
 			"grpc.message",
 			cs.cfg.clientServiceName(),
-			tracer.AnalyticsRate(cs.cfg.analyticsRate),
+			addCustomTags(cs.cfg, tracer.AnalyticsRate(cs.cfg.analyticsRate))...,
 		)
 		if p, ok := peer.FromContext(cs.Context()); ok {
 			setSpanTargetFromPeer(span, *p)
@@ -57,7 +57,7 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 			cs.method,
 			"grpc.message",
 			cs.cfg.clientServiceName(),
-			tracer.AnalyticsRate(cs.cfg.analyticsRate),
+			addCustomTags(cs.cfg, tracer.AnalyticsRate(cs.cfg.analyticsRate))...,
 		)
 		if p, ok := peer.FromContext(cs.Context()); ok {
 			setSpanTargetFromPeer(span, *p)
@@ -170,7 +170,7 @@ func doClientRequest(
 		method,
 		"grpc.client",
 		cfg.clientServiceName(),
-		tracer.AnalyticsRate(cfg.analyticsRate),
+		addCustomTags(cfg, tracer.AnalyticsRate(cfg.analyticsRate))...,
 	)
 	if methodKind != "" {
 		span.SetTag(tagMethodKind, methodKind)

contrib/google.golang.org/grpc/grpc.go

@@ -22,6 +22,24 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+func addCustomTags(cfg *config, opts ...tracer.StartSpanOption) []tracer.StartSpanOption {
+	if cfg == nil || len(cfg.tags) == 0 {
+		return opts
+	}
+
+	ret := make([]tracer.StartSpanOption, len(cfg.tags)+len(opts))
+	i := 0
+	for _, opt := range opts {
+		ret[i] = opt
+		i++
+	}
+	for key, tag := range cfg.tags {
+		ret[i] = tracer.Tag(key, tag)
+		i++
+	}
+	return ret
+}
+
 func startSpanFromContext(
 	ctx context.Context, method, operation, service string, opts ...tracer.StartSpanOption,
 ) (ddtrace.Span, context.Context) {
@@ -31,6 +49,7 @@ func startSpanFromContext(
 		tracer.Tag(tagMethodName, method),
 		tracer.SpanType(ext.AppTypeRPC),
 	)
+
 	md, _ := metadata.FromIncomingContext(ctx) // nil is ok
 	if sctx, err := tracer.Extract(grpcutil.MDCarrier(md)); err == nil {
 		opts = append(opts, tracer.ChildOf(sctx))

contrib/google.golang.org/grpc/grpc_test.go

@@ -797,6 +797,42 @@ func TestIgnoredMetadata(t *testing.T) {
 	}
 }
 
+func TestCustomTag(t *testing.T) {
+	mt := mocktracer.Start()
+	defer mt.Stop()
+	for _, c := range []struct {
+		key   string
+		value interface{}
+	}{
+		{key: "foo", value: "bar"},
+		{key: "val", value: 123},
+	} {
+		rig, err := newRig(true, WithCustomTag(c.key, c.value))
+		if err != nil {
+			t.Fatalf("error setting up rig: %s", err)
+		}
+		ctx := context.Background()
+		span, ctx := tracer.StartSpanFromContext(ctx, "x", tracer.ServiceName("y"), tracer.ResourceName("z"))
+		rig.client.Ping(ctx, &FixtureRequest{Name: "pass"})
+		span.Finish()
+
+		spans := mt.FinishedSpans()
+
+		var serverSpan mocktracer.Span
+		for _, s := range spans {
+			switch s.OperationName() {
+			case "grpc.server":
+				serverSpan = s
+			}
+		}
+
+		assert.NotNil(t, serverSpan)
+		assert.Equal(t, c.value, serverSpan.Tag(c.key))
+		rig.Close()
+		mt.Reset()
+	}
+}
+
 func BenchmarkUnaryServerInterceptor(b *testing.B) {
 	// need to use the real tracer to get representative measurments
 	tracer.Start(tracer.WithLogger(log.DiscardLogger{}),

contrib/google.golang.org/grpc/option.go

@@ -29,6 +29,7 @@ type config struct {
 	withMetadataTags    bool
 	ignoredMetadata     map[string]struct{}
 	withRequestTags     bool
+	tags                map[string]interface{}
 }
 
 func (cfg *config) serverServiceName() string {
@@ -171,3 +172,13 @@ func WithRequestTags() Option {
 		cfg.withRequestTags = true
 	}
 }
+
+// WithCustomTag will attach the value to the span tagged by the key.
+func WithCustomTag(key string, value interface{}) Option {
+	return func(cfg *config) {
+		if cfg.tags == nil {
+			cfg.tags = make(map[string]interface{})
+		}
+		cfg.tags[key] = value
+	}
+}