Add a printer that knows how to print user-defined columns

pkg/kubectl/custom_column_printer.go

+/*
+Copyright 2014 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubectl
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+	"text/tabwriter"
+
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/util/jsonpath"
+)
+
+const (
+	columnwidth       = 10
+	tabwidth          = 4
+	padding           = 3
+	padding_character = ' '
+	flags             = 0
+)
+
+// Column represents a user specified column
+type Column struct {
+	// The header to print above the column, general style is ALL_CAPS
+	Header string
+	// The pointer to the field in the object to print in JSONPath form
+	// e.g. {.ObjectMeta.Name}, see pkg/util/jsonpath for more details.
+	FieldSpec string
+}
+
+// CustomColumnPrinter is a printer that knows how to print arbitrary columns
+// of data from templates specified in the `Columns` array
+type CustomColumnsPrinter struct {
+	Columns []Column
+}
+
+func (s *CustomColumnsPrinter) PrintObj(obj runtime.Object, out io.Writer) error {
+	w := tabwriter.NewWriter(out, columnwidth, tabwidth, padding, padding_character, flags)
+	headers := make([]string, len(s.Columns))
+	for ix := range s.Columns {
+		headers[ix] = s.Columns[ix].Header
+	}
+	fmt.Fprintln(w, strings.Join(headers, "\t"))
+	parsers := make([]*jsonpath.JSONPath, len(s.Columns))
+	for ix := range s.Columns {
+		parsers[ix] = jsonpath.New(fmt.Sprintf("column%d", ix))
+		if err := parsers[ix].Parse(s.Columns[ix].FieldSpec); err != nil {
+			return err
+		}
+	}
+
+	if runtime.IsListType(obj) {
+		objs, err := runtime.ExtractList(obj)
+		if err != nil {
+			return err
+		}
+		for ix := range objs {
+			if err := s.printOneObject(objs[ix], parsers, w); err != nil {
+				return err
+			}
+		}
+	} else {
+		if err := s.printOneObject(obj, parsers, w); err != nil {
+			return err
+		}
+	}
+	return w.Flush()
+}
+
+func (s *CustomColumnsPrinter) printOneObject(obj runtime.Object, parsers []*jsonpath.JSONPath, out io.Writer) error {
+	columns := make([]string, len(parsers))
+	for ix := range parsers {
+		parser := parsers[ix]
+		values, err := parser.FindResults(reflect.ValueOf(obj).Elem().Interface())
+		if err != nil {
+			return err
+		}
+		if len(values) == 0 || len(values[0]) == 0 {
+			fmt.Fprintf(out, "<none>\t")
+		}
+		valueStrings := []string{}
+		for arrIx := range values {
+			for valIx := range values[arrIx] {
+				valueStrings = append(valueStrings, fmt.Sprintf("%v", values[arrIx][valIx].Interface()))
+			}
+		}
+		columns[ix] = strings.Join(valueStrings, ",")
+	}
+	fmt.Fprintln(out, strings.Join(columns, "\t"))
+	return nil
+}

pkg/kubectl/custom_column_printer_test.go

+/*
+Copyright 2014 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubectl
+
+import (
+	"bytes"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/api/v1"
+	"k8s.io/kubernetes/pkg/runtime"
+)
+
+func TestColumnPrint(t *testing.T) {
+	tests := []struct {
+		columns        []Column
+		obj            runtime.Object
+		expectedOutput string
+	}{
+		{
+			columns: []Column{
+				{
+					Header:    "NAME",
+					FieldSpec: "{.metadata.name}",
+				},
+			},
+			obj: &v1.Pod{ObjectMeta: v1.ObjectMeta{Name: "foo"}},
+			expectedOutput: `NAME
+foo
+`,
+		},
+		{
+			columns: []Column{
+				{
+					Header:    "NAME",
+					FieldSpec: "{.metadata.name}",
+				},
+			},
+			obj: &v1.PodList{
+				Items: []v1.Pod{
+					{ObjectMeta: v1.ObjectMeta{Name: "foo"}},
+					{ObjectMeta: v1.ObjectMeta{Name: "bar"}},
+				},
+			},
+			expectedOutput: `NAME
+foo
+bar
+`,
+		},
+		{
+			columns: []Column{
+				{
+					Header:    "NAME",
+					FieldSpec: "{.metadata.name}",
+				},
+				{
+					Header:    "API_VERSION",
+					FieldSpec: "{.apiVersion}",
+				},
+			},
+			obj: &v1.Pod{ObjectMeta: v1.ObjectMeta{Name: "foo"}, TypeMeta: v1.TypeMeta{APIVersion: "baz"}},
+			expectedOutput: `NAME      API_VERSION
+foo       baz
+`,
+		},
+	}
+
+	for _, test := range tests {
+		printer := &CustomColumnsPrinter{
+			Columns: test.columns,
+		}
+		buffer := &bytes.Buffer{}
+		if err := printer.PrintObj(test.obj, buffer); err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if buffer.String() != test.expectedOutput {
+			t.Errorf("\nexpected:\n'%s'\nsaw\n'%s'\n", test.expectedOutput, buffer.String())
+		}
+	}
+}

pkg/kubectl/resource_printer.go

@@ -34,6 +34,7 @@ import (
 	"github.com/golang/glog"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/meta"
+	"k8s.io/kubernetes/pkg/api/v1"
 	"k8s.io/kubernetes/pkg/conversion"
 	"k8s.io/kubernetes/pkg/expapi"
 	"k8s.io/kubernetes/pkg/labels"
@@ -1335,20 +1336,26 @@ func NewJSONPathPrinter(tmpl string) (*JSONPathPrinter, error) {
 
 // PrintObj formats the obj with the JSONPath Template.
 func (j *JSONPathPrinter) PrintObj(obj runtime.Object, w io.Writer) error {
-	data, err := json.Marshal(obj)
-	if err != nil {
-		return err
-	}
-	out := map[string]interface{}{}
-	if err := json.Unmarshal(data, &out); err != nil {
-		return err
+	var queryObj interface{}
+	switch obj.(type) {
+	case *v1.List, *api.List:
+		data, err := json.Marshal(obj)
+		if err != nil {
+			return err
+		}
+		queryObj = map[string]interface{}{}
+		if err := json.Unmarshal(data, &queryObj); err != nil {
+			return err
+		}
+	default:
+		queryObj = obj
 	}
-	if err = j.JSONPath.Execute(w, out); err != nil {
+
+	if err := j.JSONPath.Execute(w, queryObj); err != nil {
 		fmt.Fprintf(w, "Error executing template: %v\n", err)
 		fmt.Fprintf(w, "template was:\n\t%v\n", j.rawTemplate)
-		fmt.Fprintf(w, "raw data was:\n\t%v\n", string(data))
-		fmt.Fprintf(w, "object given to template engine was:\n\t%+v\n", out)
-		return fmt.Errorf("error executing jsonpath '%v': '%v'\n----data----\n%+v\n", j.rawTemplate, err, out)
+		fmt.Fprintf(w, "object given to jsonpath engine was:\n\t%#v\n", queryObj)
+		return fmt.Errorf("error executing jsonpath '%v': '%v'\n----data----\n%+v\n", j.rawTemplate, err, obj)
 	}
 	return nil
 }

pkg/kubectl/resource_printer_test.go

@@ -102,6 +102,13 @@ func TestPrinter(t *testing.T) {
 	//test inputs
 	simpleTest := &TestPrintType{"foo"}
 	podTest := &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}
+	podListTest := &api.PodList{
+		Items: []api.Pod{
+			{ObjectMeta: api.ObjectMeta{Name: "foo"}},
+			{ObjectMeta: api.ObjectMeta{Name: "bar"}},
+		},
+	}
+	emptyListTest := &api.PodList{}
 	testapi, err := api.Scheme.ConvertToVersion(podTest, testapi.Version())
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
@@ -119,6 +126,8 @@ func TestPrinter(t *testing.T) {
 		{"test template", "template", "{{if .id}}{{.id}}{{end}}{{if .metadata.name}}{{.metadata.name}}{{end}}",
 			podTest, "foo"},
 		{"test jsonpath", "jsonpath", "{.metadata.name}", podTest, "foo"},
+		{"test jsonpath list", "jsonpath", "{.items[*].metadata.name}", podListTest, "foo bar"},
+		{"test jsonpath empty list", "jsonpath", "{.items[*].metadata.name}", emptyListTest, ""},
 		{"test name", "name", "", podTest, "/foo\n"},
 		{"emits versioned objects", "template", "{{.kind}}", testapi, "Pod"},
 	}
@@ -132,7 +141,7 @@ func TestPrinter(t *testing.T) {
 			t.Errorf("unexpected error: %#v", err)
 		}
 		if buf.String() != test.Expect {
-			t.Errorf("in %s, expect %q, got %q", test.Name, test.Expect, buf.String(), buf.String())
+			t.Errorf("in %s, expect %q, got %q", test.Name, test.Expect, buf.String())
 		}
 	}
 

pkg/kubectl/sorting_printer.go

@@ -87,6 +87,23 @@ func (r *RuntimeSort) Swap(i, j int) {
 	r.objs[i], r.objs[j] = r.objs[j], r.objs[i]
 }
 
+func isLess(i, j reflect.Value) (bool, error) {
+	switch i.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return i.Int() < j.Int(), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return i.Uint() < j.Uint(), nil
+	case reflect.Float32, reflect.Float64:
+		return i.Float() < j.Float(), nil
+	case reflect.String:
+		return i.String() < j.String(), nil
+	case reflect.Ptr:
+		return isLess(i.Elem(), j.Elem())
+	default:
+		return false, fmt.Errorf("unsortable type: %v", i.Kind())
+	}
+}
+
 func (r *RuntimeSort) Less(i, j int) bool {
 	iObj := r.objs[i]
 	jObj := r.objs[j]
@@ -106,18 +123,9 @@ func (r *RuntimeSort) Less(i, j int) bool {
 	iField := iValues[0][0]
 	jField := jValues[0][0]
 
-	switch iField.Kind() {
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return iField.Int() < jField.Int()
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-		return iField.Uint() < jField.Uint()
-	case reflect.Float32, reflect.Float64:
-		return iField.Float() < jField.Float()
-	case reflect.String:
-		return iField.String() < jField.String()
-	default:
+	less, err := isLess(iField, jField)
+	if err != nil {
 		glog.Fatalf("Field %s in %v is an unsortable type: %s", r.field, iObj, iField.Kind().String())
 	}
-	// default to preserving order
-	return i < j
+	return less
 }

pkg/kubectl/sorting_printer_test.go

@@ -20,11 +20,13 @@ import (
 	"reflect"
 	"testing"
 
-	"k8s.io/kubernetes/pkg/api"
+	api "k8s.io/kubernetes/pkg/api/v1"
 	"k8s.io/kubernetes/pkg/runtime"
 )
 
 func TestSortingPrinter(t *testing.T) {
+	intPtr := func(val int) *int { return &val }
+
 	tests := []struct {
 		obj   runtime.Object
 		sort  runtime.Object
@@ -71,7 +73,7 @@ func TestSortingPrinter(t *testing.T) {
 					},
 				},
 			},
-			field: "{.ObjectMeta.Name}",
+			field: "{.metadata.name}",
 		},
 		{
 			name: "reverse-order",
@@ -113,7 +115,7 @@ func TestSortingPrinter(t *testing.T) {
 					},
 				},
 			},
-			field: "{.ObjectMeta.Name}",
+			field: "{.metadata.name}",
 		},
 		{
 			name: "random-order-numbers",
@@ -121,17 +123,17 @@ func TestSortingPrinter(t *testing.T) {
 				Items: []api.ReplicationController{
 					{
 						Spec: api.ReplicationControllerSpec{
-							Replicas: 5,
+							Replicas: intPtr(5),
 						},
 					},
 					{
 						Spec: api.ReplicationControllerSpec{
-							Replicas: 1,
+							Replicas: intPtr(1),
 						},
 					},
 					{
 						Spec: api.ReplicationControllerSpec{
-							Replicas: 9,
+							Replicas: intPtr(9),
 						},
 					},
 				},
@@ -140,22 +142,22 @@ func TestSortingPrinter(t *testing.T) {
 				Items: []api.ReplicationController{
 					{
 						Spec: api.ReplicationControllerSpec{
-							Replicas: 1,
+							Replicas: intPtr(1),
 						},
 					},
 					{
 						Spec: api.ReplicationControllerSpec{
-							Replicas: 5,
+							Replicas: intPtr(5),
 						},
 					},
 					{
 						Spec: api.ReplicationControllerSpec{
-							Replicas: 9,
+							Replicas: intPtr(9),
 						},
 					},
 				},
 			},
-			field: "{.Spec.Replicas}",
+			field: "{.spec.replicas}",
 		},
 	}
 	for _, test := range tests {

pkg/util/jsonpath/jsonpath.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"io"
 	"reflect"
+	"strings"
 
 	"k8s.io/kubernetes/third_party/golang/template"
 )
@@ -258,9 +259,46 @@ func (j *JSONPath) evalUnion(input []reflect.Value, node *UnionNode) ([]reflect.
 	return result, nil
 }
 
+func (j *JSONPath) findFieldInValue(value *reflect.Value, node *FieldNode) (reflect.Value, error) {
+	t := value.Type()
+	var inlineValue *reflect.Value
+	for ix := 0; ix < t.NumField(); ix++ {
+		f := t.Field(ix)
+		jsonTag := f.Tag.Get("json")
+		parts := strings.Split(jsonTag, ",")
+		if len(parts) == 0 {
+			continue
+		}
+		if parts[0] == node.Value {
+			return value.Field(ix), nil
+		}
+		if len(parts[0]) == 0 {
+			val := value.Field(ix)
+			inlineValue = &val
+		}
+	}
+	if inlineValue != nil {
+		if inlineValue.Kind() == reflect.Struct {
+			// handle 'inline'
+			match, err := j.findFieldInValue(inlineValue, node)
+			if err != nil {
+				return reflect.Value{}, err
+			}
+			if match.IsValid() {
+				return match, nil
+			}
+		}
+	}
+	return value.FieldByName(node.Value), nil
+}
+
 // evalField evaluates filed of struct or key of map.
 func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.Value, error) {
 	results := []reflect.Value{}
+	// If there's no input, there's no output
+	if len(input) == 0 {
+		return results, nil
+	}
 	for _, value := range input {
 		var result reflect.Value
 		value, isNil := template.Indirect(value)
@@ -269,7 +307,10 @@ func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.
 		}
 
 		if value.Kind() == reflect.Struct {
-			result = value.FieldByName(node.Value)
+			var err error
+			if result, err = j.findFieldInValue(&value, node); err != nil {
+				return nil, err
+			}
 		} else if value.Kind() == reflect.Map {
 			result = value.MapIndex(reflect.ValueOf(node.Value))
 		}