[CI Visibility] Add support for CI Visibility mode in ddtrace

ddtrace/tracer/civisibility_payload.go

@@ -0,0 +1,117 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2024 Datadog, Inc.
+
+package tracer
+
+import (
+	"bytes"
+	"sync/atomic"
+
+	"github.com/tinylib/msgp/msgp"
+	"gopkg.in/DataDog/dd-trace-go.v1/internal/globalconfig"
+	"gopkg.in/DataDog/dd-trace-go.v1/internal/version"
+)
+
+// ciVisibilityPayload represents a payload specifically designed for CI Visibility events.
+// It embeds the generic payload structure and adds methods to handle CI Visibility specific data.
+type ciVisibilityPayload struct {
+	*payload
+}
+
+// push adds a new CI Visibility event to the payload buffer.
+// It grows the buffer to accommodate the new event, encodes the event in MessagePack format, and updates the event count.
+//
+// Parameters:
+//
+//	event - The CI Visibility event to be added to the payload.
+//
+// Returns:
+//
+//	An error if encoding the event fails.
+func (p *ciVisibilityPayload) push(event *ciVisibilityEvent) error {
+	p.buf.Grow(event.Msgsize())
+	if err := msgp.Encode(&p.buf, event); err != nil {
+		return err
+	}
+	atomic.AddUint32(&p.count, 1)
+	p.updateHeader()
+	return nil
+}
+
+// newCiVisibilityPayload creates a new instance of civisibilitypayload.
+//
+// Returns:
+//
+//	A pointer to a newly initialized civisibilitypayload instance.
+func newCiVisibilityPayload() *ciVisibilityPayload {
+	return &ciVisibilityPayload{newPayload()}
+}
+
+// getBuffer retrieves the complete body of the CI Visibility payload, including metadata.
+// It reads the current payload buffer, adds metadata, and encodes the entire payload in MessagePack format.
+//
+// Parameters:
+//
+//	config - A pointer to the config structure containing environment settings.
+//
+// Returns:
+//
+//	A pointer to a bytes.Buffer containing the encoded CI Visibility payload.
+//	An error if reading from the buffer or encoding the payload fails.
+func (p *ciVisibilityPayload) getBuffer(config *config) (*bytes.Buffer, error) {
+
+	/*
+			The Payload format in the CI Visibility protocol is like this:
+			{
+			    "version": 1,
+			    "metadata": {
+			      "*": {
+			        "runtime-id": "...",
+			        "language": "...",
+			        "library_version": "...",
+			        "env": "..."
+			      }
+			    },
+			    "events": [
+			      // ...
+			    ]
+			}
+
+		The event format can be found in the `civisibility_tslv.go` file in the ciVisibilityEvent documentation
+	*/
+
+	// Create a buffer to read the current payload
+	payloadBuf := new(bytes.Buffer)
+	if _, err := payloadBuf.ReadFrom(p.payload); err != nil {
+		return nil, err
+	}
+
+	// Create the metadata map
+	allMetadata := map[string]string{
+		"language":        "go",
+		"runtime-id":      globalconfig.RuntimeID(),
+		"library_version": version.Tag,
+	}
+	if config.env != "" {
+		allMetadata["env"] = config.env
+	}
+
+	// Create the visibility payload
+	visibilityPayload := ciTestCyclePayload{
+		Version: 1,
+		Metadata: map[string]map[string]string{
+			"*": allMetadata,
+		},
+		Events: payloadBuf.Bytes(),
+	}
+
+	// Create a new buffer to encode the visibility payload in MessagePack format
+	encodedBuf := new(bytes.Buffer)
+	if err := msgp.Encode(encodedBuf, &visibilityPayload); err != nil {
+		return nil, err
+	}
+
+	return encodedBuf, nil
+}

ddtrace/tracer/civisibility_payload_test.go

@@ -0,0 +1,120 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2024 Datadog, Inc.
+
+package tracer
+
+import (
+	"bytes"
+	"io"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tinylib/msgp/msgp"
+)
+
+func newCiVisibilityEventsList(n int) []*ciVisibilityEvent {
+	list := make([]*ciVisibilityEvent, n)
+	for i := 0; i < n; i++ {
+		s := newBasicSpan("span.list." + strconv.Itoa(i%5+1))
+		s.Start = fixedTime
+		list[i] = getCiVisibilityEvent(s)
+	}
+
+	return list
+}
+
+// TestCiVisibilityPayloadIntegrity tests that whatever we push into the payload
+// allows us to read the same content as would have been encoded by
+// the codec.
+func TestCiVisibilityPayloadIntegrity(t *testing.T) {
+	want := new(bytes.Buffer)
+	for _, n := range []int{10, 1 << 10, 1 << 17} {
+		t.Run(strconv.Itoa(n), func(t *testing.T) {
+			assert := assert.New(t)
+			p := newCiVisibilityPayload()
+			var allEvents ciVisibilityEvents
+
+			for i := 0; i < n; i++ {
+				list := newCiVisibilityEventsList(i%5 + 1)
+				allEvents = append(allEvents, list...)
+				for _, event := range list {
+					p.push(event)
+				}
+			}
+
+			want.Reset()
+			err := msgp.Encode(want, allEvents)
+			assert.NoError(err)
+			assert.Equal(want.Len(), p.size())
+			assert.Equal(p.itemCount(), len(allEvents))
+
+			got, err := io.ReadAll(p)
+			assert.NoError(err)
+			assert.Equal(want.Bytes(), got)
+		})
+	}
+}
+
+// TestCiVisibilityPayloadDecode ensures that whatever we push into the payload can
+// be decoded by the codec.
+func TestCiVisibilityPayloadDecode(t *testing.T) {
+	assert := assert.New(t)
+	for _, n := range []int{10, 1 << 10} {
+		t.Run(strconv.Itoa(n), func(t *testing.T) {
+			p := newCiVisibilityPayload()
+			for i := 0; i < n; i++ {
+				list := newCiVisibilityEventsList(i%5 + 1)
+				for _, event := range list {
+					p.push(event)
+				}
+			}
+			var got ciVisibilityEvents
+			err := msgp.Decode(p, &got)
+			assert.NoError(err)
+		})
+	}
+}
+
+func BenchmarkCiVisibilityPayloadThroughput(b *testing.B) {
+	b.Run("10K", benchmarkCiVisibilityPayloadThroughput(1))
+	b.Run("100K", benchmarkCiVisibilityPayloadThroughput(10))
+	b.Run("1MB", benchmarkCiVisibilityPayloadThroughput(100))
+}
+
+// benchmarkCiVisibilityPayloadThroughput benchmarks the throughput of the payload by subsequently
+// pushing a list of civisibility events containing count spans of approximately 10KB in size each, until the
+// payload is filled.
+func benchmarkCiVisibilityPayloadThroughput(count int) func(*testing.B) {
+	return func(b *testing.B) {
+		p := newCiVisibilityPayload()
+		s := newBasicSpan("X")
+		s.Meta["key"] = strings.Repeat("X", 10*1024)
+		e := getCiVisibilityEvent(s)
+		events := make(ciVisibilityEvents, count)
+		for i := 0; i < count; i++ {
+			events[i] = e
+		}
+
+		b.ReportAllocs()
+		b.ResetTimer()
+		reset := func() {
+			p.header = make([]byte, 8)
+			p.off = 8
+			atomic.StoreUint32(&p.count, 0)
+			p.buf.Reset()
+		}
+		for i := 0; i < b.N; i++ {
+			reset()
+			for _, event := range events {
+				for p.size() < payloadMaxLimit {
+					p.push(event)
+				}
+			}
+		}
+	}
+}