grpc: Add external dependencies to context from grpc metadata

Author: monstermunchkin

grpc/middleware.go

@@ -7,6 +7,7 @@ import (
 	"encoding/gob"
 	"strings"
 
+	"github.com/pace/bricks/http/middleware"
 	"github.com/pace/bricks/pkg/tracking/utm"
 	"google.golang.org/grpc/metadata"
 )
@@ -36,3 +37,22 @@ func EncodeContextWithUTMData(parentCtx context.Context) context.Context {
 	}
 	return metadata.AppendToOutgoingContext(parentCtx, utmMetadataKey, w.String())
 }
+
+// AddExternalDependencyMetadataToContext adds external dependencies to the context if they are present in the metadata.
+func AddExternalDependencyMetadataToContext(ctx context.Context, md metadata.MD) context.Context {
+	// If there are no external dependencies in the metadata, we can return the context as is.
+	externalDependencies := md.Get(MetadataKeyExternalDependencies)
+	if len(externalDependencies) == 0 {
+		return ctx
+	}
+
+	// If there are external dependencies in the metadata, we need to parse them and add them to the context.
+	edc := middleware.ExternalDependencyContextFromContext(ctx)
+	if edc == nil {
+		edc = &middleware.ExternalDependencyContext{}
+	}
+
+	edc.Parse(externalDependencies[0])
+
+	return middleware.ContextWithExternalDependency(ctx, edc)
+}

grpc/middleware_test.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"testing"
 
+	"github.com/pace/bricks/http/middleware"
 	"github.com/pace/bricks/pkg/tracking/utm"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc/metadata"
@@ -31,3 +32,29 @@ func TestEncodeContextWithUTMData(t *testing.T) {
 	require.True(t, exists)
 	require.Equal(t, data, utmData)
 }
+
+func TestAddExternalDependencyMetadataToContext(t *testing.T) {
+	md := metadata.New(map[string]string{
+		MetadataKeyExternalDependencies: "dep1:1,dep2:2,dep3:3",
+	})
+	ctx := context.Background()
+	ctx = AddExternalDependencyMetadataToContext(ctx, md)
+	edc := middleware.ExternalDependencyContextFromContext(ctx)
+	require.NotNil(t, edc)
+	require.Equal(t, "dep1:1,dep2:2,dep3:3", edc.String())
+
+	ctx = AddExternalDependencyMetadataToContext(ctx, metadata.New(map[string]string{
+		MetadataKeyExternalDependencies: "dep4:4,dep5:5,dep6:6",
+	}))
+	edc = middleware.ExternalDependencyContextFromContext(ctx)
+	require.NotNil(t, edc)
+	require.Equal(t, "dep1:1,dep2:2,dep3:3,dep4:4,dep5:5,dep6:6", edc.String())
+}
+
+func TestAddExternalDependencyMetadataToContext_NoDependencies(t *testing.T) {
+	md := metadata.New(map[string]string{})
+	ctx := context.Background()
+	ctx = AddExternalDependencyMetadataToContext(ctx, md)
+	edc := middleware.ExternalDependencyContextFromContext(ctx)
+	require.Nil(t, edc)
+}