[cmd/telemetrygen]: Allow float values for rate (#33984)

**Description:**
Fixes
#33982
Switch `--rate` flag in telemetrygen to support Float64 values

**Link to tracking Issue:**
#33982

**Testing:** Added unit tests for float value cases

**Documentation:** N/A

---------

Co-authored-by: Antoine Toulme <[email protected]>
Co-authored-by: Alex Boten <[email protected]>

.chloggen/telemetrygen-float-rate.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# 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: "telemetrygen `--rate` flag changed from Int64 to Float64"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33984]
+
+# (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:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

cmd/telemetrygen/internal/common/config.go

@@ -50,7 +50,7 @@ func (v *KeyValue) Type() string {
 
 type Config struct {
 	WorkerCount           int
-	Rate                  int64
+	Rate                  float64
 	TotalDuration         time.Duration
 	ReportingInterval     time.Duration
 	SkipSettingGRPCLogger bool
@@ -115,7 +115,7 @@ func (c *Config) GetTelemetryAttributes() []attribute.KeyValue {
 // CommonFlags registers common config flags.
 func (c *Config) CommonFlags(fs *pflag.FlagSet) {
 	fs.IntVar(&c.WorkerCount, "workers", 1, "Number of workers (goroutines) to run")
-	fs.Int64Var(&c.Rate, "rate", 0, "Approximately how many metrics per second each worker should generate. Zero means no throttling.")
+	fs.Float64Var(&c.Rate, "rate", 0, "Approximately how many metrics/spans/logs per second each worker should generate. Zero means no throttling.")
 	fs.DurationVar(&c.TotalDuration, "duration", 0, "For how long to run the test")
 	fs.DurationVar(&c.ReportingInterval, "interval", 1*time.Second, "Reporting interval")
 

cmd/telemetrygen/internal/logs/worker.go

@@ -77,13 +77,14 @@ func (w worker) simulateLogs(res *resource.Resource, exporter exporter, telemetr
 			lattrs.PutStr(string(attr.Key), telemetryAttributes[i].Value.AsString())
 		}
 
-		if err := exporter.export(logs); err != nil {
-			w.logger.Fatal("exporter failed", zap.Error(err))
-		}
 		if err := limiter.Wait(context.Background()); err != nil {
 			w.logger.Fatal("limiter wait failed, retry", zap.Error(err))
 		}
 
+		if err := exporter.export(logs); err != nil {
+			w.logger.Fatal("exporter failed", zap.Error(err))
+		}
+
 		i++
 		if w.numLogs != 0 && i >= int64(w.numLogs) {
 			break

cmd/telemetrygen/internal/metrics/worker.go

@@ -91,13 +91,14 @@ func (w worker) simulateMetrics(res *resource.Resource, exporterFunc func() (sdk
 			ScopeMetrics: []metricdata.ScopeMetrics{{Metrics: metrics}},
 		}
 
-		if err := exporter.Export(context.Background(), &rm); err != nil {
-			w.logger.Fatal("exporter failed", zap.Error(err))
-		}
 		if err := limiter.Wait(context.Background()); err != nil {
 			w.logger.Fatal("limiter wait failed, retry", zap.Error(err))
 		}
 
+		if err := exporter.Export(context.Background(), &rm); err != nil {
+			w.logger.Fatal("exporter failed", zap.Error(err))
+		}
+
 		i++
 		if w.numMetrics != 0 && i >= int64(w.numMetrics) {
 			break

cmd/telemetrygen/internal/traces/worker.go

@@ -50,6 +50,10 @@ func (w worker) simulateTraces(telemetryAttributes []attribute.KeyValue) {
 		spanStart := time.Now()
 		spanEnd := spanStart.Add(w.spanDuration)
 
+		if err := limiter.Wait(context.Background()); err != nil {
+			w.logger.Fatal("limiter waited failed, retry", zap.Error(err))
+		}
+
 		ctx, sp := tracer.Start(context.Background(), "lets-go", trace.WithAttributes(
 			semconv.NetPeerIPKey.String(fakeIP),
 			semconv.PeerServiceKey.String("telemetrygen-server"),
@@ -74,6 +78,10 @@ func (w worker) simulateTraces(telemetryAttributes []attribute.KeyValue) {
 		var endTimestamp trace.SpanEventOption
 
 		for j := 0; j < w.numChildSpans; j++ {
+			if err := limiter.Wait(context.Background()); err != nil {
+				w.logger.Fatal("limiter waited failed, retry", zap.Error(err))
+			}
+
 			_, child := tracer.Start(childCtx, "okey-dokey-"+strconv.Itoa(j), trace.WithAttributes(
 				semconv.NetPeerIPKey.String(fakeIP),
 				semconv.PeerServiceKey.String("telemetrygen-client"),
@@ -83,10 +91,6 @@ func (w worker) simulateTraces(telemetryAttributes []attribute.KeyValue) {
 			)
 			child.SetAttributes(telemetryAttributes...)
 
-			if err := limiter.Wait(context.Background()); err != nil {
-				w.logger.Fatal("limiter waited failed, retry", zap.Error(err))
-			}
-
 			endTimestamp = trace.WithTimestamp(spanEnd)
 			child.SetStatus(w.statusCode, "")
 			child.End(endTimestamp)