# Log

## Introduction

This sample shows how to use log APIs to print log information and save the information to the application installation directory.

## APIs

```
    import logger from '@ohos/log'
    import { LogLevel } from '@ohos/log'
    import { Configure }  from '@ohos/log'
```

## Usage Instruction

1. Configure log printing parameters.

```
  Configure = {
    cheese: {
        types: string[],
        filename: string
    }
    defaults: {
        appenders: string,
        level: LogLevel
    }
  }
  // If types is set to file, logs are saved to the file named by filename. appenders indicates the log tag, and level indicates the lowest log level.
```

2. Initialize a **logger** instance.

```
   logger.setConfigure(configure: Configure)
   // configure indicates the parameter configuration.
```

3. Print log information of the debug level.

```
   logger.debug(value)
   // value indicates the log content.
```

4. Print log information of the info level.

```
   logger.info(value)
   // value indicates the log content.
```

5. Print log information of the warn level.

```
   logger.warn(value)
   // value indicates the log content.
```

6. Print log information of the error level.

```
   logger.error(value)
   // value indicates the log content.
```

7. Print log information of the fatal level.

```
   logger.fatal(value, bool)
   // value indicates the log content.
```

## Constraints

1. This sample requires API version 8 or later.

2. This sample requires DevEco Studio 3.0 Beta4 (Build Version: 3.0.0.992, built on July 14, 2022) to compile and run.

# 日志打印

### 简介

提供日志打印类，并将日志信息保存至应用安装目录下。

### 相关概念

日志打印：hilog日志系统，使应用/服务可以按照指定级别、标识和格式字符串输出日志内容，帮助开发者了解应用/服务的运行状态，更好地调试程序。

### 相关权限

不涉及。

##### 导入接口

```
    import logger from '@ohos/log'
    import { LogLevel } from '@ohos/log'
    import { Configure }  from '@ohos/log'
```

##### 接口说明

1. configure参数设置

```
  Configure = {
    cheese: {
        types: string[],
        filename: string
    }
    defaults: {
        appenders: string,
        level: LogLevel
    }
  }
  //types为file时将日志输出保存到以filename参数命名的文件中；appenders为日志打印tag；level为打印日志文件的最低等级
```

2. logger类初始化

```
   logger.setConfigure(configure： Configure)
   //configure为配置参数
```

3. debug类型打印日志

```
   logger.debug(value)
   //value为打印日志内容
```

4. info类型打印日志

```
   logger.info(value)
   //value为打印日志内容
```

5. warn类型打印日志

```
   logger.warn(value)
   //value为打印日志内容
```

6. error类型打印日志

```
   logger.error(value)
   //value为打印日志内容
```

7. fatal类型打印日志

```
   logger.fatal(value, bool)
   //value为打印日志内容
```

### 兼容性

1.本示例支持 OpenHarmony API version 8 及以上版本。

2.本示例需要使用DevEco Studio 3.0 Beta4 (Build Version: 3.0.0.992, built on July 14, 2022)才可编译运行。