@fastify/one-line-logger

@fastify/one-line-logger helps you format fastify's log into a nice one-line message:

YYYY-MM-dd HH:mm:ss.SSSTZ - <level> - <method> <route path> - <message>

A standard incoming request log line like:

{"level": 30,"time": 1660151282194,"pid": 1557,"hostname": "foo","reqId": "req-1","req": {"method": "GET","url": "/path","hostname": "localhost:8080","remoteAddress": "127.0.0.1"},"msg": "incoming request"}

Will format to:

2022-08-11 01:08:02.194+0100 - info - GET / - incoming request

Install

npm i @fastify/one-line-logger

Getting started

const server = fastify({
  logger: {
    transport: {
      target: "@fastify/one-line-logger",
    },
  },
});

Colors

Colors are enabled by default when supported. To manually disable the colors you need to set the transport.colorize option to false. For more options check the colorette docs.

const server = fastify({
  logger: {
    transport: {
      target: "@fastify/one-line-logger",
      colorize: false,
    },
  },
});

Custom levels

Custom levels could be used by passing it into logger opts

const server = fastify({
  logger: {
    transport: {
      target: "@fastify/one-line-logger",
    },
    customLevels: {
      foo: 35,
      bar: 45,
    },
  },
});

server.get("/", (request, reply) => {
  request.log.info("time to foobar");
  request.log.foo("FOO!");
  request.log.bar("BAR!");
  reply.send({ foobar: true });
});

Custom level colors

Custom level colors can be used by passing it into logger opts. They can also overwrite the default level's colors. Check all the supported colors here.

const server = fastify({
  logger: {
    transport: {
      target: "@fastify/one-line-logger",
      options: {
        colors: {
          35: "bgYellow",
          45: "magenta",
          60: "bgRedBright" // overwriting the `fatal` log color
        }
      }
    },
    customLevels: {
      foo: 35,
      bar: 45,
    },
  },
});

server.get("/", (request, reply) => {
  request.log.fatal("An error occurred");
  request.log.foo("FOO!");
  request.log.bar("BAR!");
  reply.send({ foobar: true });
});

Time-only format

To output only the time without the date and timezone:

const server = fastify({
  logger: {
    transport: {
      target: "@fastify/one-line-logger",
      options: { timeOnly: true }
    }
  }
});

Output: 01:08:02.194 - info - GET / - incoming request

Custom time format

Use the customTimeFormat option with a dateformat pattern:

const server = fastify({
  logger: {
    transport: {
      target: "@fastify/one-line-logger",
      options: { customTimeFormat: "HH:MM:ss" }
    }
  }
});

Common patterns:

• "HH:MM:ss" → 01:08:02
• "yyyy-mm-dd HH:MM:ss" → 2022-08-11 01:08:02
• "isoDateTime" → 2022-08-11T01:08:02+0100

Note: timeOnly and customTimeFormat are mutually exclusive and cannot be used together.

License

Licensed under MIT.