formatter_test.go

/*
Copyright 2018 The Kubernetes Authors.
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 debugger

import (
	"flag"
	"fmt"
	"os"

	"github.com/go-logr/logr"

	"k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/component-base/config"
	"k8s.io/component-base/logs"
	_ "k8s.io/component-base/logs/json/register"
	"k8s.io/klog/v2"
)

type formatter struct {
	*v1.Pod
}

func (f formatter) String() string {
	return fmt.Sprintf("%s/%s", f.Namespace, f.Name)
}

func (f formatter) MarshalLog() interface{} {
	return struct {
		Namespace, Name string
	}{
		Namespace: f.Namespace,
		Name:      f.Name,
	}
}

var _ logr.Marshaler = formatter{}

func init() {
	klog.InitFlags(nil)
}

func ExampleFormatter() {
	pod := &v1.Pod{}
	pod.UID = types.UID("some-uid")
	pod.Namespace = "ns"
	pod.Name = "pod-name"

	// Print as JSON to stdout.
	os.Stderr = os.Stdout
	options := logs.Options{
		Config: config.LoggingConfiguration{
			Format: "json",
		},
	}
	if err := options.ValidateAndApply(); err != nil {
		fmt.Printf("unexpected error: %v\n", err)
	}
	klog.InfoS("JSON output", "pod", formatter{pod})

	options.Config.Format = "text"
	if err := options.ValidateAndApply(); err != nil {
		fmt.Printf("unexpected error: %v\n", err)
	}
	flag.Set("skip_headers", "true")
	flag.Set("alsologtostderr", "false")
	flag.Set("logtostderr", "false")
	klog.SetOutput(os.Stdout)

	klog.InfoS("text output", "pod", formatter{pod})
	// Output:
	// {"ts":1636380925129.9956,"caller":"debugger/formatter_test.go:70","msg":"JSON output","v":0,"pod":{"Namespace":"ns","Name":"pod-name"}}
	// "text output" pod="ns/pod-name"
}