feat: Add custom summary error type (#3459)

Add custom error type to to decode and encode `Errors` field

Added some extra checks to handle existing BSR summary types with `Error` fields

internal/bsr/types.go

@@ -5,10 +5,49 @@ package bsr
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"time"
 )
 
+type SummaryError struct {
+	Message string `json:"message"`
+}
+
+func (e *SummaryError) Error() string {
+	return e.Message
+}
+
+func (e *SummaryError) MarshalJSON() ([]byte, error) {
+	return json.Marshal(e.Message)
+}
+
+func (e *SummaryError) UnmarshalJSON(data []byte) error {
+	var rawMessage json.RawMessage
+	var message string
+
+	err := json.Unmarshal(data, &rawMessage)
+	if err != nil {
+		return err
+	}
+
+	switch {
+	case len(rawMessage) > 0 && string(rawMessage) == `"{}"`:
+		e.Message = ""
+	case len(rawMessage) > 0 && string(rawMessage) == `"null"`:
+		e.Message = ""
+	case len(rawMessage) <= 0:
+		e.Message = ""
+	default:
+		if err := json.Unmarshal(data, &message); err != nil {
+			return err
+		}
+		e.Message = message
+	}
+
+	return nil
+}
+
 // BaseSummary contains the common fields of all summary types.
 type BaseSummary struct {
 	Id        string
@@ -49,7 +88,7 @@ type BaseSessionSummary struct {
 	ConnectionCount uint64
 	StartTime       time.Time
 	EndTime         time.Time
-	Errors          string
+	Errors          SummaryError
 }
 
 // SessionSummary contains statistics for a session container
@@ -89,12 +128,12 @@ func (b *BaseSessionSummary) GetConnectionCount() uint64 {
 
 // GetErrors returns errors.
 func (b *BaseSessionSummary) GetErrors() error {
-	return errors.New(b.Errors)
+	return errors.New(b.Errors.Message)
 }
 
 // SetErrors sets errors.
 func (b *BaseSessionSummary) SetErrors(e error) {
-	b.Errors = e.Error()
+	b.Errors = SummaryError{Message: e.Error()}
 }
 
 // BaseChannelSummary encapsulates data for a channel, including its id, channel type,
@@ -170,7 +209,7 @@ type BaseConnectionSummary struct {
 	EndTime      time.Time
 	BytesUp      uint64
 	BytesDown    uint64
-	Errors       string
+	Errors       SummaryError
 }
 
 // ConnectionSummary contains statistics for a connection container
@@ -224,10 +263,10 @@ func (b *BaseConnectionSummary) GetBytesDown() uint64 {
 
 // GetErrors returns errors.
 func (b *BaseConnectionSummary) GetErrors() error {
-	return errors.New(b.Errors)
+	return &b.Errors
 }
 
 // SetErrors sets errors.
 func (b *BaseConnectionSummary) SetErrors(e error) {
-	b.Errors = e.Error()
+	b.Errors = SummaryError{Message: e.Error()}
 }

internal/bsr/types_test.go

@@ -0,0 +1,106 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package bsr_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/hashicorp/boundary/internal/bsr"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSummaryError_MarshalJSON(t *testing.T) {
+	cases := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{
+			name: "error string",
+			in:   "error",
+			want: "\"error\"",
+		},
+		{
+			name: "empty string",
+			in:   "",
+			want: "\"\"",
+		},
+		{
+			name: "empty object",
+			in:   `{}`,
+			want: "\"{}\"",
+		},
+		{
+			name: "empty object",
+			in:   `null`,
+			want: "\"null\"",
+		},
+		{
+			name: "key value object",
+			in:   `{"message": "failed to load"}`,
+			want: "\"{\\\"message\\\": \\\"failed to load\\\"}\"",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			summaryErr := bsr.SummaryError{Message: tc.in}
+
+			got, err := summaryErr.MarshalJSON()
+			require.NoError(t, err)
+
+			assert.Equal(t, tc.want, string(got))
+		})
+	}
+}
+
+func TestSummaryError_UnmarshalJSON(t *testing.T) {
+	cases := []struct {
+		name string
+		in   any
+		want string
+	}{
+		{
+			name: "error string",
+			in:   "error",
+			want: "error",
+		},
+		{
+			name: "empty string",
+			in:   "",
+			want: "",
+		},
+		{
+			name: "empty object",
+			in:   `{}`,
+			want: "",
+		},
+		{
+			name: "empty object",
+			in:   `null`,
+			want: "",
+		},
+		{
+			name: "key value object",
+			in:   `{"message": "failed to load"}`,
+			want: "{\"message\": \"failed to load\"}",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			var summaryErr bsr.SummaryError
+
+			input, err := json.Marshal(tc.in)
+			require.NoError(t, err)
+
+			err = summaryErr.UnmarshalJSON(input)
+			require.NoError(t, err)
+
+			assert.Equal(t, tc.want, summaryErr.Message)
+		})
+	}
+}