[usage] Fix report to JSON conversion

components/usage/pkg/contentservice/usage_report_test.go

@@ -0,0 +1,63 @@
+// Copyright (c) 2022 Gitpod GmbH. All rights reserved.
+// Licensed under the GNU Affero General Public License (AGPL).
+// See License-AGPL.txt in the project root for license information.
+
+package contentservice
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"github.com/gitpod-io/gitpod/usage/pkg/db"
+	"github.com/gitpod-io/gitpod/usage/pkg/db/dbtest"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+	"testing"
+	"time"
+)
+
+func TestUsageReport_ToJSON(t *testing.T) {
+	report := UsageReport{
+		GenerationTime: time.Now().UTC(),
+		From:           time.Now().UTC(),
+		To:             time.Now().UTC(),
+		RawSessions: []db.WorkspaceInstanceForUsage{
+			{
+				ID:          uuid.New(),
+				WorkspaceID: dbtest.GenerateWorkspaceID(),
+				OwnerID:     uuid.New(),
+				ProjectID: sql.NullString{
+					String: "project-id",
+					Valid:  true,
+				},
+				WorkspaceClass:     "workspace-class",
+				Type:               "regular",
+				UsageAttributionID: db.NewTeamAttributionID(uuid.New().String()),
+				CreationTime:       db.NewVarcharTime(time.Now()),
+				StartedTime:        db.NewVarcharTime(time.Now()),
+				StoppingTime:       db.NewVarcharTime(time.Now()),
+				StoppedTime:        db.NewVarcharTime(time.Now()),
+			},
+		},
+		InvalidSessions: []InvalidSession{
+			{
+				Reason:  "some-reason",
+				Session: db.WorkspaceInstanceForUsage{},
+			},
+		},
+		UsageRecords: []db.WorkspaceInstanceUsage{
+			dbtest.NewWorkspaceInstanceUsage(t, db.WorkspaceInstanceUsage{}),
+		},
+	}
+
+	b, err := json.Marshal(report)
+	require.NoError(t, err)
+
+	var actual UsageReport
+	err = json.Unmarshal(b, &actual)
+	require.NoError(t, err)
+
+	fmt.Println(report, actual)
+	require.EqualValues(t, report, actual)
+
+}

components/usage/pkg/db/types.go

@@ -13,7 +13,7 @@ import (
 
 func NewVarcharTime(t time.Time) VarcharTime {
 	return VarcharTime{
-		t:     t,
+		t:     t.UTC(),
 		valid: true,
 	}
 }
@@ -92,12 +92,35 @@ func (n VarcharTime) String() string {
 	return ""
 }
 
-func (u VarcharTime) MarshalJSON() ([]byte, error) {
-	if !u.IsSet() {
-		return []byte(""), nil
+var null = "null"
+
+func (n VarcharTime) MarshalJSON() ([]byte, error) {
+	if !n.IsSet() {
+		return []byte(null), nil
+	}
+
+	return n.Time().UTC().MarshalJSON()
+}
+
+func (n *VarcharTime) UnmarshalJSON(data []byte) error {
+	if string(data) == null {
+		n.valid = false
+		return nil
 	}
 
-	return u.Time().MarshalJSON()
+	t := time.Time{}
+	if err := t.UnmarshalJSON(data); err != nil {
+		return fmt.Errorf("failed to unmarshal VarcharTime %s: %w", string(data), err)
+	}
+
+	if t.IsZero() {
+		return nil
+	}
+
+	n.valid = true
+	n.t = t.UTC()
+
+	return nil
 }
 
 const ISO8601Format = "2006-01-02T15:04:05.000Z"