[LS-60884] remove uses of rand.Seed (#71)

## What is the current behavior?
`rand.Seed` is deprecated, and this deprecated method being in use is
preventing the linter from allowing changes to this repo


## What is the new behavior?
All uses of `rand.Seed(someseed)` are removed. This is replaced with
`rand.New(rand.NewSource(someseed))` which is the preferred way to
handle this according to doc strings. Instead of using the global `rand`
in random generation, the preferred method seems to be to pass down the
generator created by `rand.New` so this also passed down generators into
any method that uses them

There is a question here of where we should pass generators as function
args and where we should just put the generator as a field in the
structs, but a bunch of these structs have json annotations that suggest
they are read from files and i do not really know how to make sure
`rand` gets populated in the case where some of these structs are
constructed from json

---------

Co-authored-by: jason.crouse <[email protected]>

.gitignore

@@ -1,3 +1,4 @@
 build
 vendor/
 dist/
+.idea/

generatorreceiver/generator_receiver.go

@@ -61,10 +61,6 @@ func (g generatorReceiver) Start(ctx context.Context, host component.Host) error
 	// rand is used to generate seeds the underlying *rand.Rand
 	generatorRand := rand.New(rand.NewSource(g.randomSeed))
 
-	// Metrics generator uses the global rand.Rand
-	// TODO: LS-60180 - rand.Seed is deprecated, use rand.NewSource
-	rand.Seed(generatorRand.Int63())
-
 	if g.server != nil {
 		err := g.server.Start(ctx, host)
 		if err != nil {
@@ -79,7 +75,7 @@ func (g generatorReceiver) Start(ctx context.Context, host component.Host) error
 				continue
 			}
 			k.Cfg = topoFile.Config
-			k.CreatePods(s.ServiceName)
+			k.CreatePods(s.ServiceName, generatorRand)
 		}
 	}
 
@@ -88,7 +84,7 @@ func (g generatorReceiver) Start(ctx context.Context, host component.Host) error
 
 			// Service defined metrics
 			for _, m := range s.Metrics {
-				metricTicker := g.startMetricGenerator(ctx, s.ServiceName, m)
+				metricTicker := g.startMetricGenerator(ctx, s.ServiceName, m, generatorRand)
 				g.tickers = append(g.tickers, metricTicker)
 			}
 
@@ -104,7 +100,7 @@ func (g generatorReceiver) Start(ctx context.Context, host component.Host) error
 					// keep the same flags as the resources.
 					k8sMetrics[i].EmbeddedFlags = resource.EmbeddedFlags
 
-					metricTicker := g.startMetricGenerator(ctx, s.ServiceName, k8sMetrics[i])
+					metricTicker := g.startMetricGenerator(ctx, s.ServiceName, k8sMetrics[i], generatorRand)
 					g.tickers = append(g.tickers, metricTicker)
 				}
 			}
@@ -150,14 +146,19 @@ func (g generatorReceiver) Start(ctx context.Context, host component.Host) error
 	return nil
 }
 
-func (g *generatorReceiver) startMetricGenerator(ctx context.Context, serviceName string, m topology.Metric) *time.Ticker {
+func (g *generatorReceiver) startMetricGenerator(
+	ctx context.Context,
+	serviceName string,
+	m topology.Metric,
+	random *rand.Rand,
+) *time.Ticker {
 	// TODO: do we actually need to generate every second?
 	metricTicker := time.NewTicker(topology.DefaultMetricTickerPeriod)
 	go func() {
 		g.logger.Info("generating metrics", zap.String("service", serviceName), zap.String("name", m.Name), zap.String("flag_set", m.EmbeddedFlags.FlagSet), zap.String("flag_unset", m.EmbeddedFlags.FlagUnset))
 		metricGen := generator.NewMetricGenerator(g.randomSeed)
 		for range metricTicker.C {
-			m.Pod.RestartIfNeeded(m.EmbeddedFlags, g.logger)
+			m.Pod.RestartIfNeeded(m.EmbeddedFlags, g.logger, random)
 
 			if metrics, report := metricGen.Generate(&m, serviceName); report {
 				err := g.metricConsumer.ConsumeMetrics(ctx, metrics)

generatorreceiver/internal/generator/trace_generator.go

@@ -77,7 +77,7 @@ func (g *TraceGenerator) createSpanForServiceRouteCall(traces *ptrace.Traces, se
 
 	resourceAttributeSet := serviceTier.GetResourceAttributeSet(traceId)
 	attrs := resource.Attributes()
-	resourceAttributeSet.GetAttributes().InsertTags(&attrs)
+	resourceAttributeSet.GetAttributes(g.random).InsertTags(&attrs, g.random)
 
 	rspan.ScopeSpans()
 	ils := rspan.ScopeSpans().AppendEmpty()
@@ -94,7 +94,7 @@ func (g *TraceGenerator) createSpanForServiceRouteCall(traces *ptrace.Traces, se
 
 	ts := serviceTier.GetTagSet(routeName, traceId) // ts is single TagSet consisting of tags from the service AND route
 	attr := span.Attributes()
-	ts.Tags.InsertTags(&attr) // add service and route tags to span attributes
+	ts.Tags.InsertTags(&attr, g.random) // add service and route tags to span attributes
 
 	for _, tg := range ts.TagGenerators {
 		tg.Init(g.random)
@@ -106,9 +106,9 @@ func (g *TraceGenerator) createSpanForServiceRouteCall(traces *ptrace.Traces, se
 	// TODO: this is still a bit weird - we're calling each downstream route
 	// after a sample of the current route's latency, which doesn't really
 	// make sense - but maybe it's realistic enough?
-	endTime := startTimeNanos + route.SampleLatency(traceId)
+	endTime := startTimeNanos + route.SampleLatency(traceId, g.random)
 	for _, c := range route.DownstreamCalls {
-		var childStartTimeNanos = startTimeNanos + route.SampleLatency(traceId)
+		var childStartTimeNanos = startTimeNanos + route.SampleLatency(traceId, g.random)
 
 		childSpan := g.createSpanForServiceRouteCall(traces, c.Service, c.Route, childStartTimeNanos, traceId, newSpanId)
 		val, ok := childSpan.Attributes().Get("error")

generatorreceiver/internal/generator/trace_generator_test.go

@@ -109,7 +109,7 @@ func TestTraceGenerator_createSpanForServiceRouteCall2(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			traces := ptrace.NewTraces()
-			g := NewTraceGenerator(testTopology, rand.New(rand.NewSource(rand.Int63())), tt.args.serviceName, tt.args.routeName)
+			g := NewTraceGenerator(testTopology, rand.New(rand.NewSource(123)), tt.args.serviceName, tt.args.routeName)
 			genTraceID := g.genTraceId()
 			rootSpan := g.createSpanForServiceRouteCall(&traces, g.service, g.route, tt.args.startTimeNanos, genTraceID, pcommon.NewSpanIDEmpty())
 			convertedSpanStartTime := pcommon.NewTimestampFromTime(time.Unix(0, tt.args.startTimeNanos))

generatorreceiver/internal/topology/kubernetes.go

@@ -75,20 +75,20 @@ type ResourceUsage struct {
 	Jitter float64 `json:"jitter" yaml:"jitter"`
 }
 
-func (k *Kubernetes) CreatePods(serviceName string) {
+func (k *Kubernetes) CreatePods(serviceName string, random *rand.Rand) {
 	k.mutex.Lock()
 	defer k.mutex.Unlock()
-	k.ReplicaSetName = serviceName + "-" + generateK8sName(10)
+	k.ReplicaSetName = serviceName + "-" + generateK8sName(10, random)
 	k.Namespace = serviceName
 	k.Service = serviceName
 	k.pods = make([]*Pod, k.GetPodCount())
 	for i := 0; i < len(k.pods); i++ {
 		k.pods[i] = &Pod{
 			StartTime:       time.Now(),
-			PodName:         k.ReplicaSetName + "-" + generateK8sName(5),
+			PodName:         k.ReplicaSetName + "-" + generateK8sName(5, random),
 			Container:       serviceName,
 			Kubernetes:      k,
-			RestartDuration: k.RestartDurationWithJitter(),
+			RestartDuration: k.RestartDurationWithJitter(random),
 		}
 	}
 }
@@ -103,7 +103,7 @@ func (k *Kubernetes) GetPodCount() int {
 	}
 }
 
-func (p *Pod) RestartIfNeeded(flags flags.EmbeddedFlags, logger *zap.Logger) bool {
+func (p *Pod) RestartIfNeeded(flags flags.EmbeddedFlags, logger *zap.Logger, random *rand.Rand) bool {
 	if p == nil || p.Kubernetes.Restart.Every == 0 {
 		return false
 	}
@@ -115,35 +115,35 @@ func (p *Pod) RestartIfNeeded(flags flags.EmbeddedFlags, logger *zap.Logger) boo
 	if flagTime.After(p.StartTime) {
 		// consider that the pod started at the time that a flag was enabled/disabled.
 		// TODO: restart with some jitter
-		p.restart(logger)
+		p.restart(logger, random)
 		return true
 	} else if time.Since(p.StartTime) >= p.RestartDuration {
 		// TODO: restart with some jitter
-		p.restart(logger)
+		p.restart(logger, random)
 		return true
 	}
 	return false
 
 }
 
-func (p *Pod) restart(logger *zap.Logger) {
+func (p *Pod) restart(logger *zap.Logger, random *rand.Rand) {
 	// this is locked by RestartIfNeeded
 	p.StartTime = time.Now()
-	p.RestartDuration = p.Kubernetes.RestartDurationWithJitter()
-	p.PodName = p.Kubernetes.ReplicaSetName + "-" + generateK8sName(5)
+	p.RestartDuration = p.Kubernetes.RestartDurationWithJitter(random)
+	p.PodName = p.Kubernetes.ReplicaSetName + "-" + generateK8sName(5, random)
 	logger.Info("pod restarted", zap.String("service", p.Kubernetes.Service), zap.String("pod", p.PodName))
 }
 
-func (k *Kubernetes) randomPod() *Pod {
-	return k.pods[rand.Intn(len(k.pods))]
+func (k *Kubernetes) randomPod(random *rand.Rand) *Pod {
+	return k.pods[random.Intn(len(k.pods))]
 }
 
 // only called from tag generator!
-func (k *Kubernetes) GetRandomK8sTags() map[string]string {
+func (k *Kubernetes) GetRandomK8sTags(random *rand.Rand) map[string]string {
 	k.mutex.Lock()
 	defer k.mutex.Unlock()
 
-	pod := k.randomPod()
+	pod := k.randomPod(random)
 	// ref: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/resource/semantic_conventions/k8s.md
 	return k.GetK8sTags(pod)
 }
@@ -187,8 +187,8 @@ func (p *Pod) ReplaceTags(tags map[string]string) map[string]string {
 	return replaced
 }
 
-func (k *Kubernetes) RestartDurationWithJitter() time.Duration {
-	return k.Restart.Every + time.Duration(float64(k.Restart.Jitter)*(rand.Float64()-0.5))
+func (k *Kubernetes) RestartDurationWithJitter(random *rand.Rand) time.Duration {
+	return k.Restart.Every + time.Duration(float64(k.Restart.Jitter)*(random.Float64()-0.5))
 }
 
 func (k *Kubernetes) GenerateMetrics() []Metric {
@@ -664,12 +664,12 @@ func (k *Kubernetes) GenerateMetrics() []Metric {
 	return metrics
 }
 
-func generateK8sName(n int) string {
+func generateK8sName(nameLength int, random *rand.Rand) string {
 	var letters = []rune("bcdfghjklmnpqrstvwxz2456789")
 
-	b := make([]rune, n)
+	b := make([]rune, nameLength)
 	for i := range b {
-		b[i] = letters[rand.Intn(len(letters))]
+		b[i] = letters[random.Intn(len(letters))]
 	}
 	return string(b)
 }

generatorreceiver/internal/topology/kubernetes_test.go

@@ -2,6 +2,7 @@ package topology
 
 import (
 	"github.com/stretchr/testify/require"
+	"math/rand"
 	"testing"
 	"time"
 )
@@ -59,13 +60,14 @@ func TestMultiPod(t *testing.T) {
 		},
 		PodCount: nPods,
 	}
-	k.CreatePods("some")
+	random := rand.New(rand.NewSource(123))
+	k.CreatePods("some", random)
 
 	// we should see more than one pod name in the tags
 	// (odds of this test failing randomly are 1 in 7**100 =~ 3 in 10^85
 	names := make(map[string]bool)
 	for i := 0; i < 100; i++ {
-		tags := k.GetRandomK8sTags()
+		tags := k.GetRandomK8sTags(random)
 		names[tags["k8s.pod.name"]] = true
 	}
 	require.Greater(t, len(names), 1, "multiple pod names should be generated")
@@ -90,7 +92,7 @@ func TestMultiPod(t *testing.T) {
 			},
 		},
 	}
-	k.CreatePods("some")
+	k.CreatePods("some", random)
 	require.Equal(t, 2, k.GetPodCount(), "pod count defaults to config value")
 	k = &Kubernetes{
 		ClusterName: "some-cluster",
@@ -99,6 +101,6 @@ func TestMultiPod(t *testing.T) {
 			Jitter: minute,
 		},
 	}
-	k.CreatePods("some")
+	k.CreatePods("some", random)
 	require.Equal(t, 1, k.GetPodCount(), "pod count defaults to 1 if no config value")
 }

generatorreceiver/internal/topology/latency_percentiles.go

@@ -28,7 +28,7 @@ type LatencyPercentiles struct {
 	flags.EmbeddedFlags `json:",inline" yaml:",inline"`
 }
 
-func (l *LatencyPercentiles) Sample() int64 {
+func (l *LatencyPercentiles) Sample(random *rand.Rand) int64 {
 	if l == nil {
 		// This results from having a list where
 		// items are !ShouldGenerate() which leaves
@@ -38,9 +38,9 @@ func (l *LatencyPercentiles) Sample() int64 {
 	uniform := func(timeA, timeB time.Duration) int64 {
 		minimum := float64(timeA.Nanoseconds())
 		maximum := float64(timeB.Nanoseconds())
-		return int64(minimum + (maximum-minimum)*rand.Float64())
+		return int64(minimum + (maximum-minimum)*random.Float64())
 	}
-	genNumber := rand.Float64()
+	genNumber := random.Float64()
 	switch {
 	case genNumber < 0.5:
 		return uniform(l.durations.p0, l.durations.p50)
@@ -90,7 +90,7 @@ func (l *LatencyPercentiles) loadDurations() error {
 
 type LatencyConfigs []*LatencyPercentiles
 
-func (lcfg *LatencyConfigs) Sample(traceID pcommon.TraceID) int64 {
+func (lcfg *LatencyConfigs) Sample(traceID pcommon.TraceID, random *rand.Rand) int64 {
 	var defaultCfg *LatencyPercentiles
 	var enabled []*LatencyPercentiles
 	for _, cfg := range *lcfg {
@@ -104,8 +104,8 @@ func (lcfg *LatencyConfigs) Sample(traceID pcommon.TraceID) int64 {
 		picked := pickBasedOnWeight(enabled, traceID)
 
 		if picked != nil {
-			return picked.Sample()
+			return picked.Sample(random)
 		}
 	}
-	return defaultCfg.Sample()
+	return defaultCfg.Sample(random)
 }

generatorreceiver/internal/topology/latency_percentiles_test.go

@@ -1,6 +1,7 @@
 package topology
 
 import (
+	"math/rand"
 	"testing"
 	"time"
 
@@ -52,7 +53,7 @@ func TestLatencyPercentiles_WorksWithoutWeights(t *testing.T) {
 		err := cfg.loadDurations()
 		require.NoError(t, err)
 	}
-
-	latency := cfgs.Sample(pcommon.NewTraceIDEmpty())
+	random := rand.New(rand.NewSource(123))
+	latency := cfgs.Sample(pcommon.NewTraceIDEmpty(), random)
 	require.Equal(t, 100*time.Millisecond, time.Duration(latency))
 }

generatorreceiver/internal/topology/metric.go

@@ -62,24 +62,23 @@ type Metric struct {
 	Shape               Shape             `json:"shape" yaml:"shape"`
 	ShapeInterface      ShapeInterface    `json:"-" yaml:"-"`
 	Tags                map[string]string `json:"tags" yaml:"tags"`
-	TagGenerator       TagGenerator    `json:"tagGenerator,omitempty" yaml:"tagGenerator,omitempty"`
+	TagGenerator        TagGenerator      `json:"tagGenerator,omitempty" yaml:"tagGenerator,omitempty"`
 	Jitter              float64           `json:"jitter" yaml:"jitter"`
 	flags.EmbeddedFlags `json:",inline" yaml:",inline"`
 	Pod                 *Pod
-	Random *rand.Rand
+	Random              *rand.Rand
 }
 
 func (m *Metric) GetTags() map[string]string {
 	if m.Pod != nil {
 		return m.Pod.ReplaceTags(m.Tags)
 	}
 
-
 	tags := make(map[string]string)
-	for k,v := range m.Tags {
+	for k, v := range m.Tags {
 		tags[k] = v
 	}
-	for k,v := range m.TagGenerator.GetRefreshedTags() {
+	for k, v := range m.TagGenerator.GetRefreshedTags() {
 		tags[k] = v
 	}
 
@@ -159,7 +158,7 @@ func (m *Metric) GetValue() float64 {
 	v := m.Min + (m.Max-m.Min)*factor
 
 	// jitter deviation is calculated in percentage that ranges from [-m.Jitter/2, m.Jitter/2)%
-	j := 1 + rand.Float64()*m.Jitter - m.Jitter/2
+	j := 1 + m.Random.Float64()*m.Jitter - m.Jitter/2
 
 	v = v * j
 

generatorreceiver/internal/topology/resource_attribute_set.go

@@ -2,6 +2,7 @@ package topology
 
 import (
 	"github.com/lightstep/telemetry-generator/generatorreceiver/internal/flags"
+	"math/rand"
 )
 
 type ResourceAttributeSet struct {
@@ -11,13 +12,13 @@ type ResourceAttributeSet struct {
 	flags.EmbeddedFlags `json:",inline" yaml:",inline"`
 }
 
-func (r *ResourceAttributeSet) GetAttributes() *TagMap {
+func (r *ResourceAttributeSet) GetAttributes(random *rand.Rand) *TagMap {
 	tm := make(TagMap)
 	for k, v := range r.ResourceAttributes {
 		tm[k] = v
 	}
 	if k8s := r.Kubernetes; k8s != nil {
-		for k, v := range k8s.GetRandomK8sTags() {
+		for k, v := range k8s.GetRandomK8sTags(random) {
 			tm[k] = v
 		}
 	}

generatorreceiver/internal/topology/resource_attribute_set_test.go

@@ -68,15 +68,16 @@ func TestResourceAttributeSet_GetAttributes(t *testing.T) {
 			}
 
 			if k := resourceAttrSet.Kubernetes; k != nil {
-				rand.Seed(123)
-				k.CreatePods(tt.service)
+				random := rand.New(rand.NewSource(123))
+				k.CreatePods(tt.service, random)
 
 				// k8s.pod.name structure was copied from CreatePods()
-				rand.Seed(123)
-				tt.expected["k8s.pod.name"] = tt.service + "-" + generateK8sName(10) + "-" + generateK8sName(5)
+				random = rand.New(rand.NewSource(123))
+				tt.expected["k8s.pod.name"] = tt.service + "-" + generateK8sName(10, random) + "-" + generateK8sName(5, random)
 			}
 
-			require.Equal(t, tt.expected, *resourceAttrSet.GetAttributes())
+			random := rand.New(rand.NewSource(123))
+			require.Equal(t, tt.expected, *resourceAttrSet.GetAttributes(random))
 		})
 	}
 }