* Added client pid to each gRPC requests to YDB over header x-ydb-client-pid

Author: asmyasnikov

CHANGELOG.md

@@ -1,3 +1,4 @@
+* Added client pid to each gRPC requests to YDB over header `x-ydb-client-pid`
 * Added `ydb.WithApplicationName` option
 * Added `Dict` support for `ydb.ParamsBuilder()`
 

internal/meta/context.go

@@ -25,7 +25,13 @@ func traceID(ctx context.Context) (string, bool) {
 
 // WithApplicationName returns a copy of parent context with custom user-agent info
 func WithApplicationName(ctx context.Context, applicationName string) context.Context {
-	return metadata.AppendToOutgoingContext(ctx, HeaderApplicationName, applicationName)
+	md, has := metadata.FromOutgoingContext(ctx)
+	if !has {
+		md = metadata.MD{}
+	}
+	md.Set(HeaderApplicationName, applicationName)
+
+	return metadata.NewOutgoingContext(ctx, md)
 }
 
 // WithRequestType returns a copy of parent context with custom request type

internal/meta/context_test.go

@@ -21,6 +21,18 @@ func TestContext(t *testing.T) {
 			header: HeaderApplicationName,
 			values: []string{"test"},
 		},
+		{
+			name: "WithApplicationName",
+			ctx: WithApplicationName(
+				WithApplicationName(
+					context.Background(),
+					"test1",
+				),
+				"test2",
+			),
+			header: HeaderApplicationName,
+			values: []string{"test2"},
+		},
 		{
 			name:   "WithTraceID",
 			ctx:    WithTraceID(context.Background(), "my-trace-id"),

internal/meta/headers.go

@@ -9,6 +9,7 @@ const (
 	HeaderTraceID            = "x-ydb-trace-id"
 	HeaderApplicationName    = "x-ydb-application-name"
 	HeaderClientCapabilities = "x-ydb-client-capabilities"
+	HeaderClientPid          = "x-ydb-client-pid"
 
 	// outgoing hints
 	HintSessionBalancer = "session-balancer"

internal/meta/meta.go

@@ -3,6 +3,8 @@ package meta
 import (
 	"context"
 	"fmt"
+	"os"
+	"strconv"
 
 	"google.golang.org/grpc/metadata"
 
@@ -20,6 +22,7 @@ func New(
 	opts ...Option,
 ) *Meta {
 	m := &Meta{
+		pid:         strconv.Itoa(os.Getpid()),
 		trace:       trace,
 		credentials: credentials,
 		database:    database,
@@ -67,6 +70,7 @@ func ForbidOption(feature string) Option {
 }
 
 type Meta struct {
+	pid             string
 	trace           *trace.Driver
 	credentials     credentials.Credentials
 	database        string
@@ -81,6 +85,8 @@ func (m *Meta) meta(ctx context.Context) (_ metadata.MD, err error) {
 		md = metadata.MD{}
 	}
 
+	md.Set(HeaderClientPid, m.pid)
+
 	if len(md.Get(HeaderDatabase)) == 0 {
 		md.Set(HeaderDatabase, m.database)
 	}

internal/meta/test/meta_test.go

@@ -41,6 +41,8 @@ func TestMetaRequiredHeaders(t *testing.T) {
 	require.Equal(t, []string{"database"}, md.Get(internal.HeaderDatabase))
 	require.Equal(t, []string{"requestType"}, md.Get(internal.HeaderRequestType))
 	require.Equal(t, []string{"token"}, md.Get(internal.HeaderTicket))
+	require.NotEmpty(t, md.Get(internal.HeaderClientPid))
+	require.NotEmpty(t, md.Get(internal.HeaderClientPid)[0])
 	require.Equal(t, []string{"test app"}, md.Get(internal.HeaderApplicationName))
 	require.Equal(t, []string{"traceID"}, md.Get(internal.HeaderTraceID))
 	require.Equal(t, []string{