https://github.com/ubie-oss/nslog

A structured logger for NestJS
https://github.com/ubie-oss/nslog

Last synced: about 2 months ago
JSON representation

A structured logger for NestJS

• Host: GitHub
• URL: https://github.com/ubie-oss/nslog
• Owner: ubie-oss
• License: mit
• Created: 2024-03-15T01:52:50.000Z (6 months ago)
• Default Branch: main
• Last Pushed: 2024-07-12T10:59:09.000Z (2 months ago)
• Last Synced: 2024-07-16T18:58:45.016Z (2 months ago)
• Language: TypeScript
• Size: 822 KB
• Stars: 21
• Watchers: 5
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Codeowners: .github/CODEOWNERS
  • Security: SECURITY.md

Awesome Lists containing this project

README

        
# nslog

nslog is a structured logger for NestJS. In production, you can output logs in JSON format, making it compatible with services like [Cloud Logging](https://cloud.google.com/logging/docs/structured-logging). In local development, you can output logs in a color-coded format in the terminal for easy viewing.

## Example

### JSON format

![json](https://github.com/ubie-oss/nslog/raw/main/assets/json.png)

### Text format

![text](https://github.com/ubie-oss/nslog/raw/main/assets/text.png)

## Installation

```

npm install --save @ubie/nslog

```

## Usage

```typescript

import { NestFactory } from "@nestjs/core";

import { StructuredLogger } from "@ubie/nslog";

async function bootstrap() {

  const app = await NestFactory.create(AppModule, { bufferLogs: true });

  app.useLogger(new StructuredLogger({ logLevel: "debug", format: "json" }));

  await app.listen(3000);

}

```

```typescript

import { Logger, Injectable } from "@nestjs/common";

@Injectable()

class MyService {

  private readonly logger = new Logger(MyService.name);

  doSomething() {

    this.logger.log("Doing something...");

  }

}

```

see also: https://docs.nestjs.com/techniques/logger

### Additional common parameter

If you have common parameters that you want to output in all logs, you can override the `printMessage`.

```typescript

import { Injectable } from "@nestjs/common";

import {

  PrintMessageArgs,

  StructuredLogger,

  StructuredLoggerOptions,

} from "./structured-logger";

@Injectable()

class MyLogger extends StructuredLogger {

  protected printMessage(args: PrintMessageArgs): void {

    args.params.push({ requestId: getRequestId() });

    super.printMessage(args);

  }

}

```

### Error logging

Passing an Error object to `logger.error` is handled specially.

```typescript

const new Error("something went wrong");

logger.error(err);

```

This will be output as follows.

```json

{

  "severity": "ERROR",

  "message": "something went wrong",

  "stack_trace": "Error: something went wrong\n    at Object. (/path/to/app.js:1:13)\n    at Module._compile (node:internal/modules/cjs/loader:1376:14)\n    at Module._extensions..js (node:internal/modules/cjs/loader:1435:10)\n    at Module.load (node:internal/modules/cjs/loader:1207:32)\n    at Module._load (node:internal/modules/cjs/loader:1023:12)\n    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:135:12)\n    at node:internal/main/run_main_module:28:49"

}

```

## License

[MIT License](https://github.com/ubie-oss/nslog/blob/main/LICENSE).