Merge pull request #103514 from soltysh/format_string

Hide long and multiline strings when printing

staging/src/k8s.io/cli-runtime/pkg/printers/tableprinter.go

@@ -32,6 +32,8 @@ import (
 	"k8s.io/apimachinery/pkg/watch"
 )
 
+const maxStringLength = 100
+
 var _ ResourcePrinter = &HumanReadablePrinter{}
 
 type printHandler struct {
@@ -208,7 +210,28 @@ func printTable(table *metav1.Table, output io.Writer, options PrintOptions) err
 				fmt.Fprint(output, "\t")
 			}
 			if cell != nil {
-				fmt.Fprint(output, cell)
+				switch val := cell.(type) {
+				case string:
+					print := val
+					more := 0
+					// cut to maxStringLength
+					if len(val) > maxStringLength {
+						more = len(print) - maxStringLength
+						print = print[:maxStringLength]
+					}
+					// and also check for newlines
+					newline := strings.Index(print, "\n")
+					if newline >= 0 {
+						more = more + len(print) - newline
+						print = print[:newline]
+					}
+					fmt.Fprint(output, print)
+					if more > 0 {
+						fmt.Fprintf(output, " + %d more...", more)
+					}
+				default:
+					fmt.Fprint(output, val)
+				}
 			}
 		}
 		fmt.Fprintln(output)

staging/src/k8s.io/cli-runtime/pkg/printers/tableprinter_test.go

@@ -722,3 +722,70 @@ func TestUnknownTypePrinting(t *testing.T) {
 		t.Errorf("An error was expected from printing unknown type")
 	}
 }
+
+func TestStringPrinting(t *testing.T) {
+	tests := []struct {
+		columns  []metav1.TableColumnDefinition
+		rows     []metav1.TableRow
+		expected string
+	}{
+		// multiline string
+		{
+			columns: []metav1.TableColumnDefinition{
+				{Name: "Name", Type: "string"},
+				{Name: "Age", Type: "string"},
+				{Name: "Description", Type: "string"},
+			},
+			rows: []metav1.TableRow{
+				{Cells: []interface{}{"test1", "20h", "This is first line\nThis is second line\nThis is third line\nand another one\n"}},
+			},
+			expected: `NAME    AGE   DESCRIPTION
+test1   20h   This is first line + 56 more...
+`,
+		},
+		// lengthy string
+		{
+			columns: []metav1.TableColumnDefinition{
+				{Name: "Name", Type: "string"},
+				{Name: "Age", Type: "string"},
+				{Name: "Description", Type: "string"},
+			},
+			rows: []metav1.TableRow{
+				{Cells: []interface{}{"test1", "20h", "This is first line which is long and goes for on and on and on an on and on and on and on and on and on and on and on and on and on and on"}},
+			},
+			expected: `NAME    AGE   DESCRIPTION
+test1   20h   This is first line which is long and goes for on and on and on an on and on and on and on and on and + 38 more...
+`,
+		},
+		// lengthy string + newline
+		{
+			columns: []metav1.TableColumnDefinition{
+				{Name: "Name", Type: "string"},
+				{Name: "Age", Type: "string"},
+				{Name: "Description", Type: "string"},
+			},
+			rows: []metav1.TableRow{
+				{Cells: []interface{}{"test1", "20h", "This is first\n line which is long and goes for on and on and on an on and on and on and on and on and on and on and on and on and on and on"}},
+			},
+			expected: `NAME    AGE   DESCRIPTION
+test1   20h   This is first + 126 more...
+`,
+		},
+	}
+
+	for _, test := range tests {
+		// Create the table from the columns and rows.
+		table := &metav1.Table{
+			ColumnDefinitions: test.columns,
+			Rows:              test.rows,
+		}
+		// Print the table
+		out := bytes.NewBuffer([]byte{})
+		printer := NewTablePrinter(PrintOptions{})
+		printer.PrintObj(table, out)
+
+		if test.expected != out.String() {
+			t.Errorf("Table printing error: expected \n(%s), got \n(%s)", test.expected, out.String())
+		}
+	}
+}