Add support for ignoring certain log properties

[priyank-R]

Currently, when I try to integrate pino-http on my express application with pino-elasticsearch, everything is being forwarded to elasticsearch. My elasticsearch object looks like this:

	"_source": {
		"level": 30,
		"time": "2023-05-30T06:58:23.533Z",
		"pid": 21392,
		"hostname": "XYZ",
		"req": {
			"id": 11,
			"method": "GET",
			"url": "/api/v1/public/getbooks",
			"query": {},
			"params": {},
			"headers": {
				"host": "localhost:8083",
				"connection": "keep-alive",
				"sec-ch-ua": "\"Google Chrome\";v=\"113\", \"Chromium\";v=\"113\", \"Not-A.Brand\";v=\"24\"",
				"accept": "application/json, text/plain, */*",
				"sec-ch-ua-mobile": "?0",
				"user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36",
				"sec-ch-ua-platform": "\"Windows\"",
				"origin": "http://localhost:4200",
				"sec-fetch-site": "same-site",
				"sec-fetch-mode": "cors",
				"sec-fetch-dest": "empty",
				"referer": "http://localhost:4200/",
				"accept-encoding": "gzip, deflate, br",
				"accept-language": "en-US,en;q=0.9",
				"if-none-match": "W/\"4bb-xKV3xzrbE2tNS3d+ukFNe4yK9mM\""
			},
			"remoteAddress": "::1",
			"remotePort": 59737
		},
		"user": {
			"_id": -1,
			"name": "Demo User",
			"email": "priyank.rupareliya@developer.com"
		},
		"res": {
			"statusCode": 304,
			"headers": {
				"x-powered-by": "Express",
				"access-control-allow-origin": "*",
				"etag": "W/\"4bb-xKV3xzrbE2tNS3d+ukFNe4yK9mM\""
			}
		},
		"responseTime": 1,
		"msg": "request completed"
	}

However, I just want to forward some of the properties, and ignore the rest. I want the object to look like this:

	"_source": {
		"level": 30,
		"time": "2023-05-30T06:58:23.533Z",
		"hostname": "XYZ",
		"req": {
			"id": 11,
			"method": "GET",
			"url": "/api/v1/public/getbooks",
			"query": {},
			"params": {},
			"remoteAddress": "::1",
			"remotePort": 59737
		},
		"user": {
			"_id": -1,
			"name": "Demo User",
			"email": "priyank.rupareliya@developer.com"
		},
		"res": {
			"statusCode": 304,
		},
		"responseTime": 1,
		"msg": "request completed"
	}

Currently, no option available to achieve this in pino-elasticsearch. We need something available to ignore option available in pino-pretty.

[priyank-R]

As a solution for now, I'm using the serializers options available in pino-http to manually delete req.headers and res.headers from the log object.

  logger({
    logger: customPinoLogger,
    autoLogging: true,
    customProps: (req, res) => {
      return {
        user: req.user
          ? { _id: req.user?._id, name: req.user?.name, email: req.user?.email }
          : undefined,
      };
    },
    serializers: {
      req (req) {
          delete req['headers']
          return req
      },
      res (res){
        delete res?.['headers']
        return res
      }
    }
  }),