| // Copyright 2018 The gVisor 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 log |
| |
| import ( |
| "encoding/json" |
| "fmt" |
| "time" |
| ) |
| |
| type jsonLog struct { |
| Msg string `json:"msg"` |
| Level Level `json:"level"` |
| Time time.Time `json:"time"` |
| } |
| |
| // MarshalJSON implements json.Marshaler.MarashalJSON. |
| func (lv Level) MarshalJSON() ([]byte, error) { |
| switch lv { |
| case Warning: |
| return []byte(`"warning"`), nil |
| case Info: |
| return []byte(`"info"`), nil |
| case Debug: |
| return []byte(`"debug"`), nil |
| default: |
| return nil, fmt.Errorf("unknown level %v", lv) |
| } |
| } |
| |
| // UnmarshalJSON implements json.Unmarshaler.UnmarshalJSON. It can unmarshal |
| // from both string names and integers. |
| func (lv *Level) UnmarshalJSON(b []byte) error { |
| switch s := string(b); s { |
| case "0", `"warning"`: |
| *lv = Warning |
| case "1", `"info"`: |
| *lv = Info |
| case "2", `"debug"`: |
| *lv = Debug |
| default: |
| return fmt.Errorf("unknown level %q", s) |
| } |
| return nil |
| } |
| |
| // JSONEmitter logs messages in json format. |
| type JSONEmitter struct { |
| Writer |
| } |
| |
| // Emit implements Emitter.Emit. |
| func (e JSONEmitter) Emit(_ int, level Level, timestamp time.Time, format string, v ...interface{}) { |
| j := jsonLog{ |
| Msg: fmt.Sprintf(format, v...), |
| Level: level, |
| Time: timestamp, |
| } |
| b, err := json.Marshal(j) |
| if err != nil { |
| panic(err) |
| } |
| e.Writer.Write(b) |
| } |