refactor: drop gocsv to stdlib encoding/csv

cmd/tuple/read.go

@@ -17,10 +17,12 @@ limitations under the License.
 package tuple
 
 import (
+	"bufio"
 	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"os"
 	"strings"
 
 	openfga "github.com/openfga/go-sdk"
@@ -48,14 +50,38 @@ type readResponse struct {
 }
 
 type readResponseCSVDTO struct {
-	UserType         string `csv:"user_type"`
-	UserID           string `csv:"user_id"`
-	UserRelation     string `csv:"user_relation,omitempty"`
-	Relation         string `csv:"relation"`
-	ObjectType       string `csv:"object_type"`
-	ObjectID         string `csv:"object_id"`
-	ConditionName    string `csv:"condition_name,omitempty"`
-	ConditionContext string `csv:"condition_context,omitempty"`
+	UserType         string
+	UserID           string
+	UserRelation     string
+	Relation         string
+	ObjectType       string
+	ObjectID         string
+	ConditionName    string
+	ConditionContext string
+}
+
+var readResponseCSVHeaders = []string{
+	"user_type",
+	"user_id",
+	"user_relation",
+	"relation",
+	"object_type",
+	"object_id",
+	"condition_name",
+	"condition_context",
+}
+
+func (dto readResponseCSVDTO) MarshalCSV() ([]string, error) {
+	return []string{
+		dto.UserType,
+		dto.UserID,
+		dto.UserRelation,
+		dto.Relation,
+		dto.ObjectType,
+		dto.ObjectID,
+		dto.ConditionName,
+		dto.ConditionContext,
+	}, nil
 }
 
 func (r readResponse) toCsvDTO() ([]readResponseCSVDTO, error) {
@@ -196,19 +222,27 @@ var readCmd = &cobra.Command{
 
 		simpleOutput, _ := cmd.Flags().GetBool("simple-output")
 		outputFormat, _ := cmd.Flags().GetString("output-format")
-		dataPrinter := output.NewUniPrinter(outputFormat)
 
 		if outputFormat == "csv" {
-			data, _ := response.toCsvDTO()
-
-			err := dataPrinter.Display(data)
+			records, err := response.toCsvDTO()
 			if err != nil {
+				return fmt.Errorf("failed to convert response to csv: %w", err)
+			}
+
+			writer := bufio.NewWriter(os.Stdout)
+			if err := output.MarshalCSV(records, writer, readResponseCSVHeaders...); err != nil {
+				return fmt.Errorf("failed to marshal csv: %w", err)
+			}
+
+			if err := writer.Flush(); err != nil {
 				return fmt.Errorf("failed to display csv: %w", err)
 			}
 
 			return nil
 		}
 
+		dataPrinter := output.NewUniPrinter(outputFormat)
+
 		var data any
 
 		data = *response.complete

cmd/tuple/read_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	openfga "github.com/openfga/go-sdk"
 	"github.com/openfga/go-sdk/client"
@@ -487,6 +488,43 @@ func TestReadResponseCSVDTOParser(t *testing.T) {
 	}
 }
 
+func TestReadResponseCSVDTOListMarshalCSV(t *testing.T) {
+	t.Parallel()
+
+	list := []readResponseCSVDTO{
+		{
+			UserType:         "user",
+			UserID:           "anne",
+			Relation:         "reader",
+			ObjectType:       "document",
+			ObjectID:         "secret.doc",
+			ConditionName:    "inOfficeIP",
+			ConditionContext: `{"ip_addr":"10.0.0.1"}`,
+		},
+		{
+			UserType:   "user",
+			UserID:     "john",
+			Relation:   "writer",
+			ObjectType: "document",
+			ObjectID:   "abc.doc",
+		},
+	}
+
+	rows := make([][]string, 0, len(list))
+
+	for _, record := range list {
+		row, err := record.MarshalCSV()
+		require.NoError(t, err)
+
+		rows = append(rows, row)
+	}
+
+	assert.Equal(t, [][]string{
+		{"user", "anne", "", "reader", "document", "secret.doc", "inOfficeIP", `{"ip_addr":"10.0.0.1"}`},
+		{"user", "john", "", "writer", "document", "abc.doc", "", ""},
+	}, rows)
+}
+
 func toPointer[T any](p T) *T {
 	return &p
 }

go.mod

@@ -5,7 +5,6 @@ go 1.25.7
 toolchain go1.26.4
 
 require (
-	github.com/gocarina/gocsv v0.0.0-20240520201108-78e41c74b4b1
 	github.com/mattn/go-isatty v0.0.22
 	github.com/muesli/mango-cobra v1.3.0
 	github.com/muesli/roff v0.1.0

go.sum

@@ -74,8 +74,6 @@ github.com/go-sql-driver/mysql v1.10.0/go.mod h1:M+cqaI7+xxXGG9swrdeUIoPG3Y3KCkF
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-viper/mapstructure/v2 v2.5.0 h1:vM5IJoUAy3d7zRSVtIwQgBj7BiWtMPfmPEgAXnvj1Ro=
 github.com/go-viper/mapstructure/v2 v2.5.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
-github.com/gocarina/gocsv v0.0.0-20240520201108-78e41c74b4b1 h1:FWNFq4fM1wPfcK40yHE5UO3RUdSNPaBC+j3PokzA6OQ=
-github.com/gocarina/gocsv v0.0.0-20240520201108-78e41c74b4b1/go.mod h1:5YoVOkjYAQumqlV356Hj3xeYh4BdZuLE0/nRkf2NKkI=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
 github.com/golang-jwt/jwt/v5 v5.3.1 h1:kYf81DTWFe7t+1VvL7eS+jKFVWaUnK9cB1qbwn63YCY=

internal/output/marshal.go

@@ -18,11 +18,12 @@ limitations under the License.
 package output
 
 import (
+	"encoding/csv"
 	"encoding/json"
 	"fmt"
+	"io"
 	"os"
 
-	"github.com/gocarina/gocsv"
 	"gopkg.in/yaml.v3"
 
 	"github.com/mattn/go-isatty"
@@ -38,9 +39,6 @@ type Printer interface {
 // jsonPrinter implements the Printer interface for JSON output.
 type jsonPrinter struct{}
 
-// csvPrinter implements the Printer interface for CSV output.
-type csvPrinter struct{}
-
 // yamlPrinter implements the Printer interface for YAML output.
 type yamlPrinter struct{}
 
@@ -69,17 +67,37 @@ func (prt *jsonPrinter) DisplayColor(data any) error {
 	return nil
 }
 
-func (prt *csvPrinter) DisplayColor(data any) error {
-	return prt.DisplayNoColor(data)
+// CSVMarshaler is implemented by a value that can encode itself as a CSV record.
+type CSVMarshaler interface {
+	MarshalCSV() ([]string, error)
 }
 
-func (prt *csvPrinter) DisplayNoColor(data any) error {
-	b, err := gocsv.MarshalBytes(data)
-	if err != nil {
-		return fmt.Errorf("unable to marshal CSV with error: %w", err)
+// MarshalCSV writes an optional header row followed by one record per element to w.
+func MarshalCSV[T CSVMarshaler](records []T, w io.Writer, header ...string) error {
+	writer := csv.NewWriter(w)
+
+	if len(header) > 0 {
+		if err := writer.Write(header); err != nil {
+			return fmt.Errorf("failed to write csv header: %w", err)
+		}
 	}
 
-	fmt.Println(string(b))
+	for _, record := range records {
+		row, err := record.MarshalCSV()
+		if err != nil {
+			return fmt.Errorf("failed to marshal csv record: %w", err)
+		}
+
+		if err := writer.Write(row); err != nil {
+			return fmt.Errorf("failed to write csv record: %w", err)
+		}
+	}
+
+	writer.Flush()
+
+	if err := writer.Error(); err != nil {
+		return fmt.Errorf("failed to flush csv: %w", err)
+	}
 
 	return nil
 }
@@ -115,8 +133,6 @@ func NewUniPrinter(outputFormat string) *UniPrinter {
 	switch outputFormat {
 	case "yaml":
 		uniPrinter.Printer = &yamlPrinter{}
-	case "csv":
-		uniPrinter.Printer = &csvPrinter{}
 	default:
 		uniPrinter.Printer = &jsonPrinter{}
 	}

internal/output/marshal_test.go

@@ -0,0 +1,105 @@
+package output
+
+import (
+	"bytes"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type fakeCSVRow struct {
+	fields []string
+	err    error
+}
+
+func (r fakeCSVRow) MarshalCSV() ([]string, error) {
+	return r.fields, r.err
+}
+
+func rows(values [][]string) []fakeCSVRow {
+	records := make([]fakeCSVRow, len(values))
+	for i, v := range values {
+		records[i] = fakeCSVRow{fields: v}
+	}
+
+	return records
+}
+
+func TestMarshalCSV(t *testing.T) {
+	t.Parallel()
+
+	headers := []string{"user_type", "user_id", "relation", "object_type", "object_id", "condition_context"}
+
+	tests := []struct {
+		name     string
+		records  [][]string
+		expected string
+	}{
+		{
+			name:     "no records writes only headers",
+			records:  nil,
+			expected: "user_type,user_id,relation,object_type,object_id,condition_context\n",
+		},
+		{
+			name: "single record",
+			records: [][]string{
+				{"user", "john", "writer", "document", "abc.doc", ""},
+			},
+			expected: "user_type,user_id,relation,object_type,object_id,condition_context\n" +
+				"user,john,writer,document,abc.doc,\n",
+		},
+		{
+			name: "multiple records",
+			records: [][]string{
+				{"user", "anne", "reader", "document", "x", ""},
+				{"group", "eng", "owner", "repo", "y", ""},
+			},
+			expected: "user_type,user_id,relation,object_type,object_id,condition_context\n" +
+				"user,anne,reader,document,x,\n" +
+				"group,eng,owner,repo,y,\n",
+		},
+		{
+			name: "values with commas, quotes and newlines are escaped",
+			records: [][]string{
+				{"user", "a,b", "say \"hi\"", "doc", "line\nbreak", `{"ip_addr":"10.0.0.1"}`},
+			},
+			expected: "user_type,user_id,relation,object_type,object_id,condition_context\n" +
+				"user,\"a,b\",\"say \"\"hi\"\"\",doc,\"line\nbreak\",\"{\"\"ip_addr\"\":\"\"10.0.0.1\"\"}\"\n",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			var buf bytes.Buffer
+
+			err := MarshalCSV(rows(test.records), &buf, headers...)
+			require.NoError(t, err)
+			assert.Equal(t, test.expected, buf.String())
+		})
+	}
+}
+
+func TestMarshalCSVNoHeader(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+
+	err := MarshalCSV(rows([][]string{{"user", "john"}}), &buf)
+	require.NoError(t, err)
+	assert.Equal(t, "user,john\n", buf.String())
+}
+
+func TestMarshalCSVRecordError(t *testing.T) {
+	t.Parallel()
+
+	sentinel := errors.New("boom")
+
+	var buf bytes.Buffer
+
+	err := MarshalCSV([]fakeCSVRow{{err: sentinel}}, &buf, "col")
+	assert.ErrorIs(t, err, sentinel)
+}