Various smaller improvements (#37)

* Eliminate use of math/rand outside of pkg/random

All random calls are protected by mutex

* Migrate to math/rand/v2

* Move rand.Rand and it's mutex into a single struct

* Remove dependency github.com/pkg/errors

* Use gotestsum to run tests

* Make target to format code

Author: stoewer

.github/workflows/lint-test.yml

@@ -15,6 +15,9 @@ jobs:
           go-version: ^1.22
           cache: true
 
+      - name: Format
+        run: make check-fmt
+
       - name: Lint
         uses: golangci/[email protected]
         with:

Makefile

@@ -3,7 +3,7 @@ IMAGE      ?= ghcr.io/grafana/xk6-client-tracing
 IMAGE_TAG  ?= latest
 
 GO_MODULE      := $(shell head -n1 go.mod | cut -d' ' -f2)
-GO_TEST_OPTS   := -race -count=1 -cover
+GO_TEST_OPTS   := -race -count=1 -cover -v
 GO_LINT_OPTS   := --config ./golangci.yml
 XK6_BUILD_OPTS := --output ./$(BINARY)
 
@@ -13,12 +13,19 @@ build:
 
 .PHONY: test
 test:
-	go test $(GO_TEST_OPTS) ./...
+	go tool gotestsum --format=testname -- $(GO_TEST_OPTS) ./...
 
 .PHONY: lint
 lint:
 	golangci-lint run $(GO_LINT_OPTS) ./...
 
+.PHONY: fmt
+fmt:
+	go tool goimports -w ./
+
+check-fmt: fmt
+	@git diff --exit-code
+
 .PHONY: docker
 docker:
 	docker build . -t $(IMAGE):$(IMAGE_TAG)

go.mod

@@ -4,9 +4,13 @@ go 1.23.0
 
 toolchain go1.24.0
 
+tool (
+	golang.org/x/tools/cmd/goimports
+	gotest.tools/gotestsum
+)
+
 require (
 	github.com/grafana/sobek v0.0.0-20250219104821-ed22af7a8d6c
-	github.com/pkg/errors v0.9.1
 	github.com/stretchr/testify v1.10.0
 	go.k6.io/k6 v0.57.0
 	go.opentelemetry.io/collector/component v0.120.0
@@ -25,9 +29,11 @@ require (
 )
 
 require (
+	github.com/bitfield/gotestdox v0.2.2 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/dlclark/regexp2 v1.11.5 // indirect
+	github.com/dnephin/pflag v1.0.7 // indirect
 	github.com/evanw/esbuild v0.25.0 // indirect
 	github.com/fatih/color v1.18.0 // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
@@ -38,6 +44,7 @@ require (
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/pprof v0.0.0-20250302191652-9094ed2288e7 // indirect
+	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.1 // indirect
 	github.com/hashicorp/go-version v1.7.0 // indirect
@@ -90,14 +97,19 @@ require (
 	go.opentelemetry.io/proto/otlp v1.5.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/crypto v0.35.0 // indirect
+	golang.org/x/mod v0.17.0 // indirect
 	golang.org/x/net v0.35.0 // indirect
+	golang.org/x/sync v0.11.0 // indirect
 	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/term v0.29.0 // indirect
 	golang.org/x/text v0.22.0 // indirect
 	golang.org/x/time v0.10.0 // indirect
+	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20250303144028-a0af3efb3deb // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250303144028-a0af3efb3deb // indirect
 	google.golang.org/grpc v1.70.0 // indirect
 	google.golang.org/protobuf v1.36.5 // indirect
 	gopkg.in/guregu/null.v3 v3.5.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
+	gotest.tools/gotestsum v1.12.0 // indirect
 )

go.sum

@@ -2,9 +2,9 @@ package random
 
 import (
 	crand "crypto/rand"
+	"encoding/binary"
 	"fmt"
-	"math/big"
-	"math/rand"
+	"math/rand/v2"
 	"net/http"
 	"sync"
 	"time"
@@ -25,25 +25,38 @@ var (
 		"order", "payment", "customer", "product", "stock", "inventory",
 		"shipping", "billing", "checkout", "cart", "search", "analytics"}
 
-	rnd     *rand.Rand
-	randMtx = sync.Mutex{}
+	// rnd contains rand.Rand instance protected by a mutex
+	rnd = struct {
+		sync.Mutex
+		*rand.Rand
+	}{}
 )
 
 func init() {
-	seed, _ := crand.Int(crand.Reader, big.NewInt(int64(^uint64(0)>>1)))
-	rnd = rand.New(rand.NewSource(seed.Int64()))
+	var seed [32]byte
+	_, err := crand.Read(seed[:])
+	if err != nil {
+		panic(err)
+	}
+	rnd.Rand = rand.New(rand.NewChaCha8(seed))
 }
 
 func Float32() float32 {
-	randMtx.Lock()
-	defer randMtx.Unlock()
+	rnd.Lock()
+	defer rnd.Unlock()
 	return rnd.Float32()
 }
 
+func IntN(n int) int {
+	rnd.Lock()
+	defer rnd.Unlock()
+	return rnd.IntN(n)
+}
+
 func SelectElement[T any](elements []T) T {
-	randMtx.Lock()
-	defer randMtx.Unlock()
-	return elements[rnd.Intn(len(elements))]
+	rnd.Lock()
+	defer rnd.Unlock()
+	return elements[rnd.IntN(len(elements))]
 }
 
 func String(n int) string {
@@ -59,23 +72,23 @@ func K6String(n int) string {
 }
 
 func IntBetween(min, max int) int {
-	randMtx.Lock()
-	defer randMtx.Unlock()
-	n := rnd.Intn(max - min)
+	rnd.Lock()
+	defer rnd.Unlock()
+	n := rnd.IntN(max - min)
 	return min + n
 }
 
 func Duration(min, max time.Duration) time.Duration {
-	randMtx.Lock()
-	defer randMtx.Unlock()
-	n := rnd.Int63n(int64(max) - int64(min))
+	rnd.Lock()
+	defer rnd.Unlock()
+	n := rnd.Int64N(int64(max) - int64(min))
 	return min + time.Duration(n)
 }
 
 func IPAddr() string {
-	randMtx.Lock()
-	defer randMtx.Unlock()
-	return fmt.Sprintf("192.168.%d.%d", rnd.Intn(255), rnd.Intn(255))
+	rnd.Lock()
+	defer rnd.Unlock()
+	return fmt.Sprintf("192.168.%d.%d", rnd.IntN(255), rnd.IntN(255))
 }
 
 func Port() int {
@@ -127,20 +140,21 @@ func OperationForResource(resource string) string {
 }
 
 func TraceID() pcommon.TraceID {
-	randMtx.Lock()
-	defer randMtx.Unlock()
+	rnd.Lock()
+	defer rnd.Unlock()
 
 	var b [16]byte
-	_, _ = rnd.Read(b[:]) // always returns nil error
+	binary.BigEndian.PutUint64(b[:8], rnd.Uint64())
+	binary.BigEndian.PutUint64(b[8:], rnd.Uint64())
 	return b
 }
 
 func SpanID() pcommon.SpanID {
-	randMtx.Lock()
-	defer randMtx.Unlock()
+	rnd.Lock()
+	defer rnd.Unlock()
 
 	var b [8]byte
-	_, _ = rnd.Read(b[:]) // always returns nil error
+	binary.BigEndian.PutUint64(b[:], rnd.Uint64())
 	return b
 }
 

pkg/random/random.go

@@ -3,7 +3,6 @@ package tracegen
 import (
 	"encoding/hex"
 	"fmt"
-	"math/rand"
 	"strconv"
 	"time"
 	"unsafe"
@@ -99,7 +98,7 @@ func (g *ParameterizedGenerator) Traces() ptrace.Traces {
 
 func (g *ParameterizedGenerator) generateSpan(t *TraceParams, dest ptrace.Span) {
 	endTime := time.Now().Round(time.Second)
-	startTime := endTime.Add(-time.Duration(rand.Intn(500)+10) * time.Millisecond)
+	startTime := endTime.Add(-time.Duration(random.IntN(500)+10) * time.Millisecond)
 
 	var traceID pcommon.TraceID
 	b, _ := hex.DecodeString(t.ID)
@@ -151,8 +150,8 @@ func (g *ParameterizedGenerator) generateSpan(t *TraceParams, dest ptrace.Span)
 			break
 		}
 
-		rKey := random.K6String(rand.Intn(15))
-		rVal := random.K6String(rand.Intn(15))
+		rKey := random.K6String(random.IntN(15) + 1)
+		rVal := random.K6String(random.IntN(15) + 1)
 		attrs.PutStr(rKey, rVal)
 
 		size += int64(unsafe.Sizeof(rKey)) + int64(unsafe.Sizeof(rVal))

pkg/tracegen/parameterized.go

@@ -1,6 +1,7 @@
 package tracegen
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -10,7 +11,6 @@ import (
 
 	"github.com/grafana/xk6-client-tracing/pkg/random"
 	"github.com/grafana/xk6-client-tracing/pkg/util"
-	"github.com/pkg/errors"
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/collector/pdata/ptrace"
 )
@@ -147,7 +147,7 @@ func NewTemplatedGenerator(template *TraceTemplate) (*TemplatedGenerator, error)
 	gen := &TemplatedGenerator{}
 	err := gen.initialize(template)
 	if err != nil {
-		return nil, errors.Wrap(err, "fail to create new templated generator")
+		return nil, fmt.Errorf("fail to create new templated generator: %w", err)
 	}
 	return gen, nil
 }
@@ -609,7 +609,7 @@ func initializeSpanKind(parent *internalSpanTemplate, tmpl, child *SpanTemplate)
 	if k, found := tmpl.Attributes["span.kind"]; found {
 		kindStr, ok := k.(string)
 		if !ok {
-			return ptrace.SpanKindUnspecified, errors.Errorf("attribute %s expected to be a string, but was %T", "span.kind", k)
+			return ptrace.SpanKindUnspecified, fmt.Errorf("attribute span.kind expected to be a string, but was %T", k)
 		}
 		kind = spanKindFromString(kindStr)
 	} else {

pkg/tracegen/templated.go

@@ -3,11 +3,11 @@ package clienttracing
 import (
 	"context"
 	"encoding/base64"
+	"fmt"
 	"os"
 	"sync"
 
 	"github.com/grafana/sobek"
-	"github.com/pkg/errors"
 	"go.k6.io/k6/js/common"
 	"go.k6.io/k6/js/modules"
 	"go.opentelemetry.io/collector/component"
@@ -85,13 +85,13 @@ func (ct *TracingModule) newClient(g sobek.ConstructorCall, rt *sobek.Runtime) *
 	var cfg ClientConfig
 	err := rt.ExportTo(g.Argument(0), &cfg)
 	if err != nil {
-		common.Throw(rt, errors.Wrap(err, "unable to create client: constructor expects first argument to be ClientConfig"))
+		common.Throw(rt, fmt.Errorf("unable to create client: constructor expects first argument to be ClientConfig: %w", err))
 	}
 
 	if ct.client == nil {
 		ct.client, err = NewClient(&cfg, ct.vu)
 		if err != nil {
-			common.Throw(rt, errors.Wrap(err, "unable to create client"))
+			common.Throw(rt, fmt.Errorf("unable to create client: %w", err))
 		}
 	}
 
@@ -107,7 +107,7 @@ func (ct *TracingModule) newParameterizedGenerator(g sobek.ConstructorCall, rt *
 		var param []*tracegen.TraceParams
 		err := rt.ExportTo(paramVal, &param)
 		if err != nil {
-			common.Throw(rt, errors.Wrap(err, "the ParameterizedGenerator constructor expects first argument to be []TraceParams"))
+			common.Throw(rt, fmt.Errorf("the ParameterizedGenerator constructor expects first argument to be []TraceParams: %w", err))
 		}
 
 		generator = tracegen.NewParameterizedGenerator(param)
@@ -126,12 +126,12 @@ func (ct *TracingModule) newTemplatedGenerator(g sobek.ConstructorCall, rt *sobe
 		var tmpl tracegen.TraceTemplate
 		err := rt.ExportTo(tmplVal, &tmpl)
 		if err != nil {
-			common.Throw(rt, errors.Wrap(err, "the TemplatedGenerator constructor expects first argument to be TraceTemplate"))
+			common.Throw(rt, fmt.Errorf("the TemplatedGenerator constructor expects first argument to be TraceTemplate: %w", err))
 		}
 
 		generator, err = tracegen.NewTemplatedGenerator(&tmpl)
 		if err != nil {
-			common.Throw(rt, errors.Wrap(err, "unable to generate TemplatedGenerator"))
+			common.Throw(rt, fmt.Errorf("unable to generate TemplatedGenerator: %w", err))
 		}
 
 		ct.templatedGenerators[tmplObj] = generator
@@ -208,7 +208,7 @@ func NewClient(cfg *ClientConfig, vu modules.VU) (*Client, error) {
 			}, cfg.Headers),
 		}
 	default:
-		return nil, errors.Errorf("failed to init exporter: unknown exporter type %s", cfg.Exporter)
+		return nil, fmt.Errorf("failed to init exporter: unknown exporter type %s", cfg.Exporter)
 	}
 
 	exporter, err := factory.CreateTraces(
@@ -224,12 +224,12 @@ func NewClient(cfg *ClientConfig, vu modules.VU) (*Client, error) {
 		exporterCfg,
 	)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed create exporter")
+		return nil, fmt.Errorf("failed create exporter: %w", err)
 	}
 
 	err = exporter.Start(vu.Context(), componenttest.NewNopHost())
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to start exporter")
+		return nil, fmt.Errorf("failed to start exporter: %w", err)
 	}
 
 	return &Client{