tsh request search, add support for --format flag

lib/asciitable/example_test.go

@@ -34,3 +34,28 @@ func ExampleMakeTable() {
 	// Write the table to stdout.
 	fmt.Println(t.AsBuffer().String())
 }
+
+func ExampleMakeColumnsAndRows() {
+	type dbResourceRow struct {
+		DatabaseName string `asciitable:"DB Name"` // This column will appear in the table under a custom name.
+		Skip         string `asciitable:"-"`       // This column will be skipped entirely.
+		ResourceID   string // It will derive the name "Resource ID"
+	}
+
+	rows := []dbResourceRow{
+		{DatabaseName: "orders", Skip: "ignored", ResourceID: "db-1"},
+		{DatabaseName: "users", Skip: "ignored", ResourceID: "db-2"},
+	}
+
+	// Build table columns + rows.
+	cols, data, err := MakeColumnsAndRows(rows, nil)
+	if err != nil {
+		panic(err)
+	}
+
+	// Create asciitable table.
+	table := MakeTable(cols, data...)
+
+	// Write the table to stdout.
+	fmt.Println(table.AsBuffer().String())
+}

lib/asciitable/struct.go

@@ -0,0 +1,93 @@
+/*
+ * Teleport
+ * Copyright (C) 2025  Gravitational, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package asciitable
+
+import (
+	"fmt"
+	"reflect"
+	"regexp"
+	"slices"
+
+	"github.com/gravitational/trace"
+)
+
+const asciitableTag = "asciitable"
+
+// Regular expression to convert from "DatabaseRoles" to "Database Roles" etc.
+var headerSplitRe = regexp.MustCompile(`([a-z])([A-Z])`)
+
+// MakeColumnsAndRows converts a slice of structs into column headers and
+// row data suitable for use with asciitable.MakeTable.
+// T must be a struct type. If T is not a struct, the function returns an error.
+//
+// Column headers are determined by the `asciitable` struct tag. If the tag is
+// empty, the header is derived from the field name (e.g., "DatabaseRoles"
+// becomes "Database Roles").
+//
+// includeColumns optionally restricts which columns are returned. Each value
+// must match the final header name (tag value is used if present, otherwise the
+// derived name). If includeColumns is empty or nil, all fields are included.
+func MakeColumnsAndRows[T any](rows []T, includeColumns []string) ([]string, [][]string, error) {
+	t := reflect.TypeOf((*T)(nil)).Elem()
+	if t.Kind() != reflect.Struct {
+		return nil, nil, trace.Errorf("only slices of struct are supported: got slice of %s", t.Kind())
+	}
+
+	type fieldInfo struct {
+		index int
+		name  string
+	}
+
+	var fields []fieldInfo
+	var columns []string
+
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+
+		header := f.Tag.Get(asciitableTag)
+		if header == "-" {
+			continue
+		}
+		if header == "" {
+			header = headerSplitRe.ReplaceAllString(f.Name, "${1} ${2}")
+		}
+
+		if len(includeColumns) > 0 && !slices.Contains(includeColumns, header) {
+			continue
+		}
+
+		fields = append(fields, fieldInfo{
+			index: i,
+			name:  header,
+		})
+		columns = append(columns, header)
+	}
+
+	outRows := make([][]string, 0, len(rows))
+	for _, row := range rows {
+		v := reflect.ValueOf(row)
+		rowValues := make([]string, 0, len(fields))
+		for _, fi := range fields {
+			rowValues = append(rowValues, fmt.Sprintf("%v", v.Field(fi.index)))
+		}
+		outRows = append(outRows, rowValues)
+	}
+
+	return columns, outRows, nil
+}

lib/asciitable/struct_test.go

@@ -0,0 +1,178 @@
+/*
+ * Teleport
+ * Copyright (C) 2025  Gravitational, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package asciitable
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/gravitational/trace"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMakeColumnsAndRows(t *testing.T) {
+	type row struct {
+		Name       string
+		ResourceID string
+	}
+
+	rows := []row{
+		{Name: "n1", ResourceID: "id1"},
+		{Name: "n2", ResourceID: "id2"},
+	}
+
+	cols, data, err := MakeColumnsAndRows(rows, nil)
+	require.NoError(t, err)
+
+	require.Equal(t, []string{"Name", "Resource ID"}, cols)
+	require.Equal(t, [][]string{
+		{"n1", "id1"},
+		{"n2", "id2"},
+	}, data)
+}
+
+func TestMakeColumnsAndRowsWithTagsAndSkip(t *testing.T) {
+	type row struct {
+		Name       string `asciitable:"Custom Name"`
+		Skip       string `asciitable:"-"`
+		ResourceID string `asciitable:"Resource ID"`
+	}
+
+	rows := []row{
+		{Name: "n1", Skip: "skip1", ResourceID: "id1"},
+		{Name: "n2", Skip: "skip2", ResourceID: "id2"},
+	}
+
+	cols, data, err := MakeColumnsAndRows(rows, nil)
+	require.NoError(t, err)
+
+	require.Equal(t, []string{"Custom Name", "Resource ID"}, cols)
+	require.Equal(t, [][]string{
+		{"n1", "id1"},
+		{"n2", "id2"},
+	}, data)
+}
+
+func TestMakeColumnsAndRowsIncludeColumns(t *testing.T) {
+	type row struct {
+		Name       string
+		Hostname   string
+		Labels     string
+		ResourceID string
+	}
+
+	rows := []row{
+		{Name: "n1", Hostname: "h1", Labels: "a=1", ResourceID: "id1"},
+		{Name: "n2", Hostname: "h2", Labels: "b=2", ResourceID: "id2"},
+	}
+
+	cols, data, err := MakeColumnsAndRows(rows, []string{"Name", "Labels"})
+	require.NoError(t, err)
+
+	require.Equal(t, []string{"Name", "Labels"}, cols)
+	require.Equal(t, [][]string{
+		{"n1", "a=1"},
+		{"n2", "b=2"},
+	}, data)
+}
+
+func TestMakeColumnsAndRowsIncludeColumnsWithTags(t *testing.T) {
+	type row struct {
+		Name       string `asciitable:"Custom Name"`
+		ResourceID string `asciitable:"Resource ID"`
+	}
+
+	rows := []row{
+		{Name: "n1", ResourceID: "id1"},
+		{Name: "n2", ResourceID: "id2"},
+	}
+
+	cols, data, err := MakeColumnsAndRows(rows, []string{"Custom Name"})
+	require.NoError(t, err)
+
+	require.Equal(t, []string{"Custom Name"}, cols)
+	require.Equal(t, [][]string{
+		{"n1"},
+		{"n2"},
+	}, data)
+}
+
+func TestMakeColumnsAndRowsCamelCaseLongName(t *testing.T) {
+	type row struct {
+		VeryLongFieldName string
+	}
+
+	rows := []row{
+		{VeryLongFieldName: "value1"},
+	}
+
+	cols, data, err := MakeColumnsAndRows(rows, nil)
+	require.NoError(t, err)
+
+	require.Len(t, cols, 1)
+	require.Equal(t, "Very Long Field Name", cols[0])
+	require.Equal(t, [][]string{{"value1"}}, data)
+}
+
+func TestMakeColumnsAndRowsEmptySlice(t *testing.T) {
+	type row struct {
+		Name       string
+		ResourceID string
+	}
+
+	var rows []row
+
+	cols, data, err := MakeColumnsAndRows(rows, nil)
+	require.NoError(t, err)
+
+	require.Equal(t, []string{"Name", "Resource ID"}, cols)
+	require.Empty(t, data)
+}
+
+func TestMakeColumnsAndRowsNonStructType(t *testing.T) {
+	rows := []int{1, 2, 3}
+
+	cols, data, err := MakeColumnsAndRows(rows, nil)
+	require.Error(t, err)
+	require.Nil(t, cols)
+	require.Nil(t, data)
+
+	var traceErr trace.Error
+	ok := errors.As(err, &traceErr)
+	require.True(t, ok)
+
+	require.Contains(t, err.Error(), "only slices of struct are supported")
+}
+
+func TestMakeColumnsAndRowsIncludeColumnsUnknown(t *testing.T) {
+	type row struct {
+		Name string
+	}
+
+	rows := []row{
+		{Name: "n1"},
+	}
+
+	cols, data, err := MakeColumnsAndRows(rows, []string{"Unknown"})
+	require.NoError(t, err)
+
+	require.Empty(t, cols)
+	require.Equal(t, [][]string{{}}, data)
+	require.Len(t, data, 1)
+}

lib/utils/jsontools.go

@@ -117,8 +117,7 @@ func FastMarshalIndent(v any, prefix, indent string) ([]byte, error) {
 // WriteJSONArray marshals values as a JSON array.
 func WriteJSONArray[T any](w io.Writer, values []T) error {
 	if len(values) == 0 {
-		_, err := w.Write([]byte("[]"))
-		return err
+		values = []T{}
 	}
 	return WriteJSON(w, values)
 }
@@ -163,6 +162,14 @@ func StreamJSONArray[T any](items stream.Stream[T], out io.Writer, indent bool)
 	return trace.NewAggregate(items.Done(), stream.Flush())
 }
 
+// WriteYAMLArray marshals values as a YAML array.
+func WriteYAMLArray[T any](w io.Writer, values []T) error {
+	if len(values) == 0 {
+		values = []T{}
+	}
+	return writeYAML(w, values)
+}
+
 const yamlDocDelimiter = "---"
 
 // WriteYAML detects whether value is a list

tool/tctl/common/workload_identity_test.go

@@ -211,7 +211,7 @@ func TestWorkloadIdentityRevocation(t *testing.T) {
 			},
 		)
 		require.NoError(t, err)
-		require.Equal(t, "[]", buf.String())
+		require.Equal(t, "[]\n", buf.String())
 	})
 
 	t.Run("workload-identity revocations add", func(t *testing.T) {
@@ -307,6 +307,6 @@ func TestWorkloadIdentityRevocation(t *testing.T) {
 			},
 		)
 		require.NoError(t, err)
-		require.Equal(t, "[]", buf.String())
+		require.Equal(t, "[]\n", buf.String())
 	})
 }