refactor: drop gocsv to stdlib encoding/csv

Author: SoulPancake

cmd/tuple/read.go

@@ -48,18 +48,50 @@ 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
 }
 
-func (r readResponse) toCsvDTO() ([]readResponseCSVDTO, error) {
-	readResponseDTO := make([]readResponseCSVDTO, 0, len(r.simple))
+type readResponseCSVDTOList []readResponseCSVDTO
+
+var readResponseCSVHeaders = []string{
+	"user_type",
+	"user_id",
+	"user_relation",
+	"relation",
+	"object_type",
+	"object_id",
+	"condition_name",
+	"condition_context",
+}
+
+func (l readResponseCSVDTOList) MarshalCSV() ([]string, [][]string, error) {
+	records := make([][]string, 0, len(l))
+
+	for _, dto := range l {
+		records = append(records, []string{
+			dto.UserType,
+			dto.UserID,
+			dto.UserRelation,
+			dto.Relation,
+			dto.ObjectType,
+			dto.ObjectID,
+			dto.ConditionName,
+			dto.ConditionContext,
+		})
+	}
+
+	return readResponseCSVHeaders, records, nil
+}
+
+func (r readResponse) toCsvDTO() (readResponseCSVDTOList, error) {
+	readResponseDTO := make(readResponseCSVDTOList, 0, len(r.simple))
 
 	for _, readRes := range r.simple {
 		// Handle Condition

cmd/tuple/read_test.go

@@ -438,7 +438,7 @@ func TestReadResponseCSVDTOParser(t *testing.T) {
 
 	testCases := []struct {
 		readRes  readResponse
-		expected []readResponseCSVDTO
+		expected readResponseCSVDTOList
 	}{
 		{
 			readRes: readResponse{
@@ -460,7 +460,7 @@ func TestReadResponseCSVDTOParser(t *testing.T) {
 					},
 				},
 			},
-			expected: []readResponseCSVDTO{
+			expected: readResponseCSVDTOList{
 				{
 					UserType:         "user",
 					UserID:           "anne",

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/hashicorp/go-multierror v1.1.1
 	github.com/mattn/go-isatty v0.0.22
 	github.com/muesli/mango-cobra v1.3.0

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 +18,13 @@ limitations under the License.
 package output
 
 import (
+	"bytes"
+	"encoding/csv"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 
-	"github.com/gocarina/gocsv"
 	"gopkg.in/yaml.v3"
 
 	"github.com/mattn/go-isatty"
@@ -74,7 +76,7 @@ func (prt *csvPrinter) DisplayColor(data any) error {
 }
 
 func (prt *csvPrinter) DisplayNoColor(data any) error {
-	b, err := gocsv.MarshalBytes(data)
+	b, err := marshalCSV(data)
 	if err != nil {
 		return fmt.Errorf("unable to marshal CSV with error: %w", err)
 	}
@@ -84,6 +86,43 @@ func (prt *csvPrinter) DisplayNoColor(data any) error {
 	return nil
 }
 
+var errNotCSVMarshaler = errors.New("type does not implement output.CSVMarshaler")
+
+// CSVMarshaler is implemented by types that can render themselves as CSV:
+// a header row followed by one record per element.
+type CSVMarshaler interface {
+	MarshalCSV() (headers []string, records [][]string, err error)
+}
+
+func marshalCSV(data any) ([]byte, error) {
+	marshaler, ok := data.(CSVMarshaler)
+	if !ok {
+		return nil, fmt.Errorf("cannot marshal %T to csv: %w", data, errNotCSVMarshaler)
+	}
+
+	headers, records, err := marshaler.MarshalCSV()
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal csv: %w", err)
+	}
+
+	buffer := &bytes.Buffer{}
+	writer := csv.NewWriter(buffer)
+
+	if err := writer.Write(headers); err != nil {
+		return nil, fmt.Errorf("failed to write csv header: %w", err)
+	}
+
+	if err := writer.WriteAll(records); err != nil {
+		return nil, fmt.Errorf("failed to write csv records: %w", err)
+	}
+
+	if err := writer.Error(); err != nil {
+		return nil, fmt.Errorf("failed to flush csv: %w", err)
+	}
+
+	return buffer.Bytes(), nil
+}
+
 func (prt *yamlPrinter) DisplayColor(data any) error {
 	return prt.DisplayNoColor(data)
 }

internal/output/marshal_test.go

@@ -0,0 +1,89 @@
+package output
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type fakeCSVMarshaler struct {
+	headers []string
+	records [][]string
+	err     error
+}
+
+func (f fakeCSVMarshaler) MarshalCSV() ([]string, [][]string, error) {
+	return f.headers, f.records, f.err
+}
+
+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()
+
+			got, err := marshalCSV(fakeCSVMarshaler{headers: headers, records: test.records})
+			require.NoError(t, err)
+			assert.Equal(t, test.expected, string(got))
+		})
+	}
+}
+
+func TestMarshalCSVNotAMarshaler(t *testing.T) {
+	t.Parallel()
+
+	_, err := marshalCSV([]string{"a", "b"})
+	assert.ErrorIs(t, err, errNotCSVMarshaler)
+}
+
+func TestMarshalCSVMarshalerError(t *testing.T) {
+	t.Parallel()
+
+	sentinel := errors.New("boom")
+
+	_, err := marshalCSV(fakeCSVMarshaler{err: sentinel})
+	assert.ErrorIs(t, err, sentinel)
+}