Generate deterministic examples (#3521)

* Generate deterministic examples

The random generated is seeded with the API name.

* Leverage built-in sync map for readability

* Fix race condition in test

Author: raphael

codegen/generator/transport.go

@@ -10,8 +10,7 @@ import (
 )
 
 // Transport iterates through the roots and returns the files needed to render
-// the transport code. It returns an error if the roots slice does not include
-// at least one transport design.
+// the transport code.
 func Transport(genpkg string, roots []eval.Root) ([]*codegen.File, error) {
 	var files []*codegen.File
 	for _, root := range roots {

expr/example.go

@@ -4,10 +4,9 @@ import (
 	"fmt"
 	"math"
 	"regexp"
+	"regexp/syntax"
+	"strings"
 	"time"
-
-	regen "github.com/AnatolyRugalev/goregen"
-	googleuuid "github.com/google/uuid"
 )
 
 const (
@@ -209,23 +208,17 @@ func byFormat(a *AttributeExpr, r *ExampleGenerator) any {
 		FormatIP:       r.IPv4Address().String(),
 		FormatURI:      r.URL(),
 		FormatMAC: func() string {
-			res, err := regen.Generate(`([0-9A-F]{2}-){5}[0-9A-F]{2}`)
+			res, err := syntax.Parse(`([0-9A-F]{2}-){5}[0-9A-F]{2}`, 0)
 			if err != nil {
 				return "12-34-56-78-9A-BC"
 			}
-			return res
+			return patgen(res, r)
 		}(),
 		FormatCIDR:    "192.168.100.14/24",
 		FormatRegexp:  r.Characters(3) + ".*",
 		FormatRFC1123: time.Unix(int64(r.Int())%1454957045, 0).UTC().Format(time.RFC1123), // to obtain a "fixed" rand
-		FormatUUID: func() string {
-			uuid, err := googleuuid.NewUUID()
-			if err != nil {
-				return "12345678-1234-1234-9232-123456789ABC"
-			}
-			return uuid.String()
-		}(),
-		FormatJSON: `{"name":"example","email":"[email protected]"}`,
+		FormatUUID:    r.UUID(),
+		FormatJSON:    `{"name":"example","email":"[email protected]"}`,
 	}[format]; ok {
 		return res
 	}
@@ -240,11 +233,67 @@ func byPattern(a *AttributeExpr, r *ExampleGenerator) any {
 		return false
 	}
 	pattern := a.Validation.Pattern
-	gen, err := regen.NewGenerator(pattern, &regen.GeneratorArgs{MaxUnboundedRepeatCount: 6})
+	re, err := syntax.Parse(pattern, syntax.Perl)
 	if err != nil {
 		return r.Name()
 	}
-	return gen.Generate()
+	return patgen(re.Simplify(), r)
+}
+
+func patgen(re *syntax.Regexp, r *ExampleGenerator) string {
+	switch re.Op {
+	case syntax.OpAlternate:
+		i := r.Int() % len(re.Sub)
+		return patgen(re.Sub[i], r)
+	case syntax.OpCapture:
+		return patgen(re.Sub[0], r)
+	case syntax.OpConcat:
+		var res strings.Builder
+		for _, sub := range re.Sub {
+			res.WriteString(patgen(sub, r))
+		}
+		return res.String()
+	case syntax.OpLiteral:
+		return string(re.Rune)
+	case syntax.OpStar:
+		var res strings.Builder
+		count := r.Int() % 3
+		for i := 0; i < count; i++ {
+			res.WriteString(patgen(re.Sub[0], r))
+		}
+		return res.String()
+	case syntax.OpPlus:
+		var res strings.Builder
+		count := r.Int()%2 + 1
+		for i := 0; i < count; i++ {
+			res.WriteString(patgen(re.Sub[0], r))
+		}
+		return res.String()
+	case syntax.OpQuest:
+		if r.Int()%2 == 0 {
+			return patgen(re.Sub[0], r)
+		}
+		return ""
+	case syntax.OpRepeat:
+		var res strings.Builder
+		for i := 0; i < re.Min; i++ {
+			res.WriteString(patgen(re.Sub[0], r))
+		}
+		return res.String()
+	case syntax.OpCharClass:
+		var chars []rune
+		for i := 0; i < len(re.Rune); i += 2 {
+			start, end := re.Rune[i], re.Rune[i+1]
+			for j := start; j <= end; j++ {
+				chars = append(chars, j)
+			}
+		}
+		return string(chars[r.Int()%len(chars)])
+	case syntax.OpAnyChar, syntax.OpAnyCharNotNL:
+		return r.Characters(1)
+	default:
+		return ""
+	}
 }
 
 func byMinMax(a *AttributeExpr, r *ExampleGenerator) any {

expr/example_test.go

@@ -18,7 +18,7 @@ func TestByPattern(t *testing.T) {
 		ExpectedMaxLen int
 	}{
 		{"not-a-regexp", "foo", 3},
-		{"max-len", "foo.*", 9},
+		{"max-len", "foo[a-z]+", 9},
 		{"max-len-2", "^/api/example/[0-9]+$", 19},
 	}
 	r := expr.NewRandom("test")

expr/random.go

@@ -3,6 +3,7 @@ package expr
 import (
 	"crypto/md5"
 	"encoding/binary"
+	"fmt"
 	"math/rand"
 	"net"
 	"strings"
@@ -53,6 +54,8 @@ type Randomizer interface {
 	URL() string
 	// Characters generates a n-character string example
 	Characters(n int) string
+	// UUID generates a random v4 UUID
+	UUID() string
 }
 
 // NewRandom returns a random value generator seeded from the given string
@@ -165,6 +168,13 @@ func (r *FakerRandomizer) URL() string {
 func (r *FakerRandomizer) Characters(n int) string {
 	return r.faker.Characters(n)
 }
+func (r *FakerRandomizer) UUID() string {
+	uuid := make([]byte, 16)
+	r.rand.Read(uuid)
+	uuid[6] = (uuid[6] & 0x0f) | 0x40
+	uuid[8] = (uuid[8] & 0x3f) | 0x80
+	return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[0:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:])
+}
 func (r *FakerRandomizer) Name() string {
 	return r.faker.Name()
 }
@@ -197,3 +207,4 @@ func (DeterministicRandomizer) IPv4Address() net.IP     { return net.IPv4zero }
 func (DeterministicRandomizer) IPv6Address() net.IP     { return net.IPv6zero }
 func (DeterministicRandomizer) URL() string             { return "https://example.com/foo" }
 func (DeterministicRandomizer) Characters(n int) string { return strings.Repeat("a", n) }
+func (DeterministicRandomizer) UUID() string            { return "550e8400-e29b-41d4-a716-446655440000" }

expr/types.go

@@ -3,6 +3,7 @@ package expr
 import (
 	"fmt"
 	"reflect"
+	"sort"
 
 	"goa.design/goa/v3/eval"
 )
@@ -591,8 +592,15 @@ func (m *Map) Example(r *ExampleGenerator) any {
 // which cannot be handled by json.Marshal.
 func (m *Map) MakeMap(raw map[any]any) any {
 	ma := reflect.MakeMap(toReflectType(m))
-	for key, value := range raw {
-		ma.SetMapIndex(reflect.ValueOf(key), reflect.ValueOf(value))
+	keys := make([]any, 0, len(raw))
+	for key := range raw {
+		keys = append(keys, key)
+	}
+	sort.Slice(keys, func(i, j int) bool {
+		return reflect.ValueOf(keys[i]).String() < reflect.ValueOf(keys[j]).String()
+	})
+	for _, key := range keys {
+		ma.SetMapIndex(reflect.ValueOf(key), reflect.ValueOf(raw[key]))
 	}
 	return ma.Interface()
 }

go.mod

@@ -3,7 +3,6 @@ module goa.design/goa/v3
 go 1.20
 
 require (
-	github.com/AnatolyRugalev/goregen v0.1.0
 	github.com/dimfeld/httppath v0.0.0-20170720192232-ee938bf73598
 	github.com/getkin/kin-openapi v0.124.0
 	github.com/go-chi/chi/v5 v5.0.12
@@ -15,7 +14,7 @@ require (
 	github.com/stretchr/testify v1.9.0
 	golang.org/x/text v0.15.0
 	golang.org/x/tools v0.21.0
-	google.golang.org/grpc v1.63.2
+	google.golang.org/grpc v1.64.0
 	google.golang.org/protobuf v1.34.1
 	gopkg.in/yaml.v3 v3.0.1
 )
@@ -35,5 +34,5 @@ require (
 	golang.org/x/net v0.25.0 // indirect
 	golang.org/x/sync v0.7.0 // indirect
 	golang.org/x/sys v0.20.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20240401170217-c3f982113cda // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240515191416-fc5f0ca64291 // indirect
 )

go.sum

@@ -1,5 +1,3 @@
-github.com/AnatolyRugalev/goregen v0.1.0 h1:xrdXkLaskMnbxW0x4FWNj2yoednv0X2bcTBWpuJGYfE=
-github.com/AnatolyRugalev/goregen v0.1.0/go.mod h1:sVlY1tjcirqLBRZnCcIq1+7/Lwmqz5g7IK8AStjOVzI=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -62,10 +60,10 @@ golang.org/x/text v0.15.0 h1:h1V/4gjBv8v9cjcR6+AR5+/cIYK5N/WAgiv4xlsEtAk=
 golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/tools v0.21.0 h1:qc0xYgIbsSDt9EyWz05J5wfa7LOVW0YTLOXrqdLAWIw=
 golang.org/x/tools v0.21.0/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240401170217-c3f982113cda h1:LI5DOvAxUPMv/50agcLLoo+AdWc1irS9Rzz4vPuD1V4=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240401170217-c3f982113cda/go.mod h1:WtryC6hu0hhx87FDGxWCDptyssuo68sk10vYjF+T9fY=
-google.golang.org/grpc v1.63.2 h1:MUeiw1B2maTVZthpU5xvASfTh3LDbxHd6IJ6QQVU+xM=
-google.golang.org/grpc v1.63.2/go.mod h1:WAX/8DgncnokcFUldAxq7GeB5DXHDbMF+lLvDomNkRA=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240515191416-fc5f0ca64291 h1:AgADTJarZTBqgjiUzRgfaBchgYB3/WFTC80GPwsMcRI=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240515191416-fc5f0ca64291/go.mod h1:EfXuqaE1J41VCDicxHzUDm+8rk+7ZdXzHV0IhO/I6s0=
+google.golang.org/grpc v1.64.0 h1:KH3VH9y/MgNQg1dE7b3XfVK0GsPSIzJwdF617gUSbvY=
+google.golang.org/grpc v1.64.0/go.mod h1:oxjF8E3FBnjp+/gVFYdWacaLDx9na1aqy9oovLpxQYg=
 google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=
 google.golang.org/protobuf v1.34.1/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

grpc/middleware/canceler.go

@@ -39,44 +39,27 @@ import (
 //	...
 func StreamCanceler(ctx context.Context) grpc.StreamServerInterceptor {
 	var (
-		cancels   = map[*context.CancelFunc]struct{}{}
-		cancelMu  = new(sync.Mutex)
+		cancels   sync.Map
 		canceling uint32
 	)
 
 	go func() {
 		<-ctx.Done()
 		atomic.StoreUint32(&canceling, 1)
-		cancelMu.Lock()
-		defer cancelMu.Unlock()
-		for cancel := range cancels {
+		cancels.Range(func(key any, value any) bool {
+			cancel := key.(*context.CancelFunc)
 			(*cancel)()
-		}
+			return true
+		})
 	}()
 	return grpc.StreamServerInterceptor(func(srv any, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
 		if atomic.LoadUint32(&canceling) == 1 {
 			return status.Error(codes.Unavailable, "server is stopping")
 		}
-		var (
-			cctx   = ss.Context()
-			cancel context.CancelFunc
-		)
-		cctx, cancel = context.WithCancel(cctx)
-
-		// add the cancel function
-		cancelMu.Lock()
-		cancels[&cancel] = struct{}{}
-		cancelMu.Unlock()
-
-		// invoke rpc
+		cctx, cancel := context.WithCancel(ss.Context())
+		cancels.Store(&cancel, struct{}{})
 		err := handler(srv, NewWrappedServerStream(cctx, ss))
-
-		// remove the cancel function
-		cancelMu.Lock()
-		delete(cancels, &cancel)
-		cancelMu.Unlock()
-
-		// cleanup the WithCancel
+		cancels.Delete(&cancel)
 		cancel()
 
 		return err

grpc/middleware/canceler_test.go

@@ -52,7 +52,9 @@ func TestStreamCanceler(t *testing.T) {
 			}()
 
 			if err := grpcm.StreamCanceler(ctx)(nil, c.stream, stream, c.handler); err != nil {
-				t.Errorf("StreamCanceler error: %v", err)
+				if err.Error() != "server is stopping" {
+					t.Errorf("StreamCanceler error: %v", err)
+				}
 			}
 		})
 	}