metadata: split context to incoming and outgoing

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

client/noop.go

@@ -187,7 +187,7 @@ func (n *noopClient) Publish(ctx context.Context, p Message, opts ...PublishOpti
 
 	options := NewPublishOptions(opts...)
 
-	md, ok := metadata.FromContext(ctx)
+	md, ok := metadata.FromOutgoingContext(ctx)
 	if !ok {
 		md = metadata.New(0)
 	}

go.mod

@@ -7,15 +7,15 @@ require (
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible
 	github.com/ef-ds/deque v1.0.4
 	github.com/golang/protobuf v1.4.3
-	github.com/google/uuid v1.1.5
+	github.com/google/uuid v1.2.0
 	github.com/imdario/mergo v0.3.11
 	github.com/kr/text v0.2.0 // indirect
-	github.com/miekg/dns v1.1.35
+	github.com/miekg/dns v1.1.38
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/oxtoacart/bpool v0.0.0-20190530202638-03653db5a59c
 	github.com/stretchr/testify v1.7.0
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad // indirect
-	golang.org/x/net v0.0.0-20201224014010-6772e930b67b
+	golang.org/x/net v0.0.0-20210119194325-5f4716e94777
 	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e // indirect
 	google.golang.org/protobuf v1.25.0
 	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect

go.sum

@@ -31,16 +31,16 @@ github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMyw
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.0 h1:/QaMHBdZ26BB3SSst0Iwl10Epc+xhTquomWX0oZEB6w=
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/uuid v1.1.5 h1:kxhtnfFVi+rYdOALN0B3k9UT86zVJKfBimRaciULW4I=
+github.com/google/uuid v1.2.0 h1:qJYtXnJRWmpe7m/3XlyhrsLrEURqHRM2kxzoxXqyUDs=
-github.com/google/uuid v1.1.5/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/imdario/mergo v0.3.11 h1:3tnifQM4i+fbajXKBHXWEH+KvNHqojZ778UH75j3bGA=
 github.com/imdario/mergo v0.3.11/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/miekg/dns v1.1.35 h1:oTfOaDH+mZkdcgdIjH6yBajRGtIwcwcaR+rt23ZSrJs=
+github.com/miekg/dns v1.1.38 h1:MtIY+fmHUVVgv1AXzmKMWcwdCYxTRPG1EDjpqF4RCEw=
-github.com/miekg/dns v1.1.35/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
+github.com/miekg/dns v1.1.38/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/oxtoacart/bpool v0.0.0-20190530202638-03653db5a59c h1:rp5dCmg/yLR3mgFuSOe4oEnDDmGLROTvMragMUXpTQw=
@@ -52,7 +52,6 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/unistack-org/micro v1.18.0 h1:EbFiII0bKV0Xcua7o6J30MFmm4/g0Hv3ECOKzsUBihU=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad h1:DN0cp81fZ3njFcrLCytUHRSUkqBjfTo4Tx9RJTWs0EY=
@@ -69,8 +68,8 @@ golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20201224014010-6772e930b67b h1:iFwSg7t5GZmB/Q5TjiEAsdoLDrdJRC1RiF2WhuV29Qw=
+golang.org/x/net v0.0.0-20210119194325-5f4716e94777 h1:003p0dJM77cxMSyCPFphvZf/Y5/NXf5fzg6ufd1/Oew=
-golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20210119194325-5f4716e94777/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

metadata/context.go

@@ -5,35 +5,64 @@ import (
 	"context"
 )
 
+type mdIncomingKey struct{}
+type mdOutgoingKey struct{}
+type mdKey struct{}
+
+// FromIncomingContext returns metadata from incoming ctx
+// returned metadata shoud not be modified or race condition happens
+func FromIncomingContext(ctx context.Context) (Metadata, bool) {
+	if ctx == nil {
+		return nil, false
+	}
+	md, ok := ctx.Value(mdIncomingKey{}).(Metadata)
+	return md, ok
+}
+
+// FromOutgoingContext returns metadata from outgoing ctx
+// returned metadata shoud not be modified or race condition happens
+func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
+	if ctx == nil {
+		return nil, false
+	}
+	md, ok := ctx.Value(mdOutgoingKey{}).(Metadata)
+	return md, ok
+}
+
 // FromContext returns metadata from the given context
+// returned metadata shoud not be modified or race condition happens
+//
+// Deprecated: use FromIncomingContext or FromOutgoingContext
 func FromContext(ctx context.Context) (Metadata, bool) {
 	if ctx == nil {
 		return nil, false
 	}
-	md, ok := ctx.Value(metadataKey{}).(Metadata)
+	md, ok := ctx.Value(mdKey{}).(Metadata)
-	if !ok {
+	return md, ok
-		return nil, ok
-	}
-	nmd := Copy(md)
-	return nmd, ok
 }
 
 // NewContext creates a new context with the given metadata
+//
+// Deprecated: use NewIncomingContext or NewOutgoingContext
 func NewContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	return context.WithValue(ctx, metadataKey{}, Copy(md))
+	return context.WithValue(ctx, mdKey{}, md)
 }
 
-// MergeContext merges metadata to existing metadata, overwriting if specified
+// NewIncomingContext creates a new context with incoming metadata attached
-func MergeContext(ctx context.Context, pmd Metadata, overwrite bool) context.Context {
+func NewIncomingContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	md, ok := FromContext(ctx)
+	return context.WithValue(ctx, mdIncomingKey{}, md)
-	if !ok {
+}
-		return context.WithValue(ctx, metadataKey{}, Copy(pmd))
+
-	}
+// NewOutgoingContext creates a new context with outcoming metadata attached
-	return context.WithValue(ctx, metadataKey{}, Merge(md, pmd, overwrite))
+func NewOutgoingContext(ctx context.Context, md Metadata) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, mdOutgoingKey{}, md)
 }

metadata/metadata.go

@@ -2,7 +2,6 @@
 package metadata
 
 import (
-	"context"
 	"net/textproto"
 	"sort"
 )
@@ -12,16 +11,14 @@ var (
 	HeaderPrefix = "Micro-"
 )
 
-type metadataKey struct{}
-
 // Metadata is our way of representing request headers internally.
 // They're used at the RPC level and translate back and forth
 // from Transport headers.
 type Metadata map[string]string
 
 var (
-	// DefaultMetadataSize used when need to init new Metadata
+	// defaultMetadataSize used when need to init new Metadata
-	DefaultMetadataSize = 6
+	defaultMetadataSize = 2
 )
 
 type Iterator struct {
@@ -72,12 +69,9 @@ func (md Metadata) Set(key, val string) {
 // Del is used to remove value from metadata
 func (md Metadata) Del(key string) {
 	// fast path
-	if _, ok := md[key]; ok {
 	delete(md, key)
-	} else {
 	// slow path
 	delete(md, textproto.CanonicalMIMEHeaderKey(key))
-	}
 }
 
 // Copy makes a copy of the metadata
@@ -89,39 +83,10 @@ func Copy(md Metadata) Metadata {
 	return nmd
 }
 
-// Del deletes key from metadata
-func Del(ctx context.Context, key string) context.Context {
-	md, ok := FromContext(ctx)
-	if !ok {
-		md = New(0)
-	}
-	md.Del(key)
-	return context.WithValue(ctx, metadataKey{}, md)
-}
-
-// Set add key with val to metadata
-func Set(ctx context.Context, key, val string) context.Context {
-	md, ok := FromContext(ctx)
-	if !ok {
-		md = New(0)
-	}
-	md.Set(key, val)
-	return context.WithValue(ctx, metadataKey{}, md)
-}
-
-// Get returns a single value from metadata in the context
-func Get(ctx context.Context, key string) (string, bool) {
-	md, ok := FromContext(ctx)
-	if !ok {
-		return "", ok
-	}
-	return md.Get(key)
-}
-
 // New return new sized metadata
 func New(size int) Metadata {
 	if size == 0 {
-		size = DefaultMetadataSize
+		size = defaultMetadataSize
 	}
 	return make(Metadata, size)
 }

metadata/metadata_test.go

@@ -2,8 +2,6 @@ package metadata
 
 import (
 	"context"
-	"fmt"
-	"reflect"
 	"testing"
 )
 
@@ -32,26 +30,27 @@ func TestIterator(t *testing.T) {
 	var k, v string
 
 	for iter.Next(&k, &v) {
-		fmt.Printf("k: %s, v: %s\n", k, v)
+		//fmt.Printf("k: %s, v: %s\n", k, v)
 	}
 }
 
 func TestMedataCanonicalKey(t *testing.T) {
-	ctx := Set(context.TODO(), "x-request-id", "12345")
+	md := New(1)
-	v, ok := Get(ctx, "x-request-id")
+	md.Set("x-request-id", "12345")
+	v, ok := md.Get("x-request-id")
 	if !ok {
 		t.Fatalf("failed to get x-request-id")
 	} else if v != "12345" {
 		t.Fatalf("invalid metadata value: %s != %s", "12345", v)
 	}
 
-	v, ok = Get(ctx, "X-Request-Id")
+	v, ok = md.Get("X-Request-Id")
 	if !ok {
 		t.Fatalf("failed to get x-request-id")
 	} else if v != "12345" {
 		t.Fatalf("invalid metadata value: %s != %s", "12345", v)
 	}
-	v, ok = Get(ctx, "X-Request-ID")
+	v, ok = md.Get("X-Request-ID")
 	if !ok {
 		t.Fatalf("failed to get x-request-id")
 	} else if v != "12345" {
@@ -61,9 +60,11 @@ func TestMedataCanonicalKey(t *testing.T) {
 }
 
 func TestMetadataSet(t *testing.T) {
-	ctx := Set(context.TODO(), "Key", "val")
+	md := New(1)
 
-	val, ok := Get(ctx, "Key")
+	md.Set("Key", "val")
+
+	val, ok := md.Get("Key")
 	if !ok {
 		t.Fatal("key Key not found")
 	}
@@ -78,15 +79,8 @@ func TestMetadataDelete(t *testing.T) {
 		"Baz": "empty",
 	}
 
-	ctx := NewContext(context.TODO(), md)
+	md.Del("Baz")
-	ctx = Del(ctx, "Baz")
+	_, ok := md.Get("Baz")
-
-	emd, ok := FromContext(ctx)
-	if !ok {
-		t.Fatal("key Key not found")
-	}
-
-	_, ok = emd["Baz"]
 	if ok {
 		t.Fatal("key Baz not deleted")
 	}
@@ -137,42 +131,3 @@ func TestMetadataContext(t *testing.T) {
 		t.Errorf("Expected metadata length 1 got %d", i)
 	}
 }
-
-func TestMergeContext(t *testing.T) {
-	type args struct {
-		existing  Metadata
-		append    Metadata
-		overwrite bool
-	}
-	tests := []struct {
-		name string
-		args args
-		want Metadata
-	}{
-		{
-			name: "matching key, overwrite false",
-			args: args{
-				existing:  Metadata{"Foo": "bar", "Sumo": "demo"},
-				append:    Metadata{"Sumo": "demo2"},
-				overwrite: false,
-			},
-			want: Metadata{"Foo": "bar", "Sumo": "demo"},
-		},
-		{
-			name: "matching key, overwrite true",
-			args: args{
-				existing:  Metadata{"Foo": "bar", "Sumo": "demo"},
-				append:    Metadata{"Sumo": "demo2"},
-				overwrite: true,
-			},
-			want: Metadata{"Foo": "bar", "Sumo": "demo2"},
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if got, _ := FromContext(MergeContext(NewContext(context.TODO(), tt.args.existing), tt.args.append, tt.args.overwrite)); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("MergeContext() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}

tracer/context.go

@@ -14,11 +14,12 @@ const (
 
 // FromContext returns a span from context
 func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFound bool) {
-	if ctx == nil {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
 		return "", "", false
 	}
-	traceID, traceOk := metadata.Get(ctx, traceIDKey)
+	traceID, traceOk := md.Get(traceIDKey)
-	microID, microOk := metadata.Get(ctx, "Micro-Id")
+	microID, microOk := md.Get("Micro-Id")
 	if !traceOk && !microOk {
 		isFound = false
 		return
@@ -26,17 +27,17 @@ func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFo
 	if !traceOk {
 		traceID = microID
 	}
-	parentSpanID, ok := metadata.Get(ctx, spanIDKey)
+	parentSpanID, ok = md.Get(spanIDKey)
 	return traceID, parentSpanID, ok
 }
 
 // NewContext saves the trace and span ids in the context
 func NewContext(ctx context.Context, traceID, parentSpanID string) context.Context {
-	if ctx == nil {
+	md, ok := metadata.FromContext(ctx)
-		ctx = context.Background()
+	if !ok {
+		md = metadata.New(2)
 	}
-	md := metadata.New(2)
 	md.Set(traceIDKey, traceID)
 	md.Set(spanIDKey, parentSpanID)
-	return metadata.MergeContext(ctx, md, true)
+	return metadata.NewContext(ctx, md)
 }

util/ctx/ctx.go

@@ -10,10 +10,9 @@ import (
 
 func FromRequest(r *http.Request) context.Context {
 	ctx := r.Context()
-	md, ok := metadata.FromContext(ctx)
+	md, ok := metadata.FromIncomingContext(ctx)
 	if !ok {
-		// create needed map with specific len
+		md = metadata.New(len(r.Header) + 2)
-		md = make(metadata.Metadata, len(r.Header)+2)
 	}
 	for key, val := range r.Header {
 		md.Set(key, strings.Join(val, ","))
@@ -22,5 +21,5 @@ func FromRequest(r *http.Request) context.Context {
 	md["Host"] = r.Host
 	// pass http method
 	md["Method"] = r.Method
-	return metadata.NewContext(ctx, md)
+	return metadata.NewIncomingContext(ctx, md)
 }

util/ctx/ctx_test.go

@@ -28,7 +28,7 @@ func TestRequestToContext(t *testing.T) {
 
 	for _, d := range testData {
 		ctx := FromRequest(d.request)
-		md, ok := metadata.FromContext(ctx)
+		md, ok := metadata.FromIncomingContext(ctx)
 		if !ok {
 			t.Fatalf("Expected metadata for request %+v", d.request)
 		}