[cmd/telemetrygen] Improvements and fixes to telemetrygen traces (ope…

…n-telemetry#21629)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
- Adds new option to disable the batchspanprocessor for testing large
trace sizes (enabled by default)
- Adds new option to configure size in MB of each trace generated for
load testing
- Fixes issue where large trace payloads (>2000) wouldn't generate the
correct number of traces, needed to add delay after each trace is
generated

---------

Co-authored-by: Pablo Baeyens <pbaeyens31+github@gmail.com>

.chloggen/telemetrygen-traces-batch-size-options.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: telemetrygen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Adds batch option to configure whether to batch traces, and size option to configure minimum size in MB of each trace for load testing.
+
+# One or more tracking issues related to the change
+issues: [9597]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

cmd/telemetrygen/internal/traces/config.go

@@ -15,6 +15,8 @@ type Config struct {
 	NumTraces        int
 	PropagateContext bool
 	ServiceName      string
+	Batch            bool
+	LoadSize         int
 }
 
 // Flags registers config flags.
@@ -23,4 +25,6 @@ func (c *Config) Flags(fs *pflag.FlagSet) {
 	fs.IntVar(&c.NumTraces, "traces", 1, "Number of traces to generate in each worker (ignored if duration is provided)")
 	fs.BoolVar(&c.PropagateContext, "marshal", false, "Whether to marshal trace context via HTTP headers")
 	fs.StringVar(&c.ServiceName, "service", "telemetrygen", "Service name to use")
+	fs.BoolVar(&c.Batch, "batch", true, "Whether to batch traces")
+	fs.IntVar(&c.LoadSize, "size", 0, "Desired minimum size in MB of string data for each trace generated. This can be used to test traces with large payloads, i.e. when testing the OTLP receiver endpoint max receive size.")
 }

cmd/telemetrygen/internal/traces/traces.go

@@ -72,13 +72,16 @@ func Start(cfg *Config) error {
 		}
 	}()
 
-	ssp := sdktrace.NewBatchSpanProcessor(exp, sdktrace.WithBatchTimeout(time.Second))
-	defer func() {
-		logger.Info("stop the batch span processor")
-		if tempError := ssp.Shutdown(context.Background()); tempError != nil {
-			logger.Error("failed to stop the batch span processor", zap.Error(err))
-		}
-	}()
+	var ssp sdktrace.SpanProcessor
+	if cfg.Batch {
+		ssp = sdktrace.NewBatchSpanProcessor(exp, sdktrace.WithBatchTimeout(time.Second))
+		defer func() {
+			logger.Info("stop the batch span processor")
+			if tempError := ssp.Shutdown(context.Background()); tempError != nil {
+				logger.Error("failed to stop the batch span processor", zap.Error(err))
+			}
+		}()
+	}
 
 	var attributes []attribute.KeyValue
 	// may be overridden by `-otlp-attributes service.name="foo"`
@@ -89,7 +92,9 @@ func Start(cfg *Config) error {
 		sdktrace.WithResource(resource.NewWithAttributes(semconv.SchemaURL, attributes...)),
 	)
 
-	tracerProvider.RegisterSpanProcessor(ssp)
+	if cfg.Batch {
+		tracerProvider.RegisterSpanProcessor(ssp)
+	}
 	otel.SetTracerProvider(tracerProvider)
 
 	if err = Run(cfg, logger); err != nil {
@@ -131,6 +136,7 @@ func Run(c *Config, logger *zap.Logger) error {
 			running:          running,
 			wg:               &wg,
 			logger:           logger.With(zap.Int("worker", i)),
+			loadSize:         c.LoadSize,
 		}
 
 		go w.simulateTraces()

cmd/telemetrygen/internal/traces/worker.go

@@ -5,11 +5,13 @@ package traces // import "github.com/open-telemetry/opentelemetry-collector-cont
 
 import (
 	"context"
+	"fmt"
 	"sync"
 	"sync/atomic"
 	"time"
 
 	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/propagation"
 	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
 	"go.opentelemetry.io/otel/trace"
@@ -25,12 +27,15 @@ type worker struct {
 	limitPerSecond   rate.Limit      // how many spans per second to generate
 	wg               *sync.WaitGroup // notify when done
 	logger           *zap.Logger
+	loadSize         int
 }
 
 const (
 	fakeIP string = "1.2.3.4"
 
 	fakeSpanDuration = 123 * time.Microsecond
+
+	charactersPerMB = 1024 * 1024 // One character takes up one byte of space, so this number comes from the number of bytes in a megabyte
 )
 
 func (w worker) simulateTraces() {
@@ -44,6 +49,9 @@ func (w worker) simulateTraces() {
 		),
 			trace.WithSpanKind(trace.SpanKindClient),
 		)
+		for j := 0; j < w.loadSize; j++ {
+			sp.SetAttributes(attribute.String(fmt.Sprintf("load-%v", j), string(make([]byte, charactersPerMB))))
+		}
 
 		childCtx := ctx
 		if w.propagateContext {