gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/log/json_k8s.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package log
    16  
    17  import (
    18  	"encoding/json"
    19  	"fmt"
    20  	"runtime"
    21  	"strings"
    22  	"time"
    23  )
    24  
    25  type k8sJSONLog struct {
    26  	Log   string    `json:"log"`
    27  	Level Level     `json:"level"`
    28  	Time  time.Time `json:"time"`
    29  }
    30  
    31  // K8sJSONEmitter logs messages in json format that is compatible with
    32  // Kubernetes fluent configuration.
    33  type K8sJSONEmitter struct {
    34  	*Writer
    35  }
    36  
    37  // Emit implements Emitter.Emit.
    38  func (e K8sJSONEmitter) Emit(depth int, level Level, timestamp time.Time, format string, v ...any) {
    39  	logLine := fmt.Sprintf(format, v...)
    40  	if _, file, line, ok := runtime.Caller(depth + 1); ok {
    41  		if slash := strings.LastIndexByte(file, byte('/')); slash >= 0 {
    42  			file = file[slash+1:] // Trim any directory path from the file.
    43  		}
    44  		logLine = fmt.Sprintf("%s:%d] %s", file, line, logLine)
    45  	}
    46  	j := k8sJSONLog{
    47  		Log:   logLine,
    48  		Level: level,
    49  		Time:  timestamp,
    50  	}
    51  	b, err := json.Marshal(j)
    52  	if err != nil {
    53  		panic(err)
    54  	}
    55  	e.Writer.Write(b)
    56  }