Nitro Powered Motorcycles

    @amida-tech/winston-json-formatter

    0.10.1 • Public • Published

    Winston JSON Formatter

    npm (tag) Known Vulnerabilities Jenkins CI

    A json and console formatter for winston@3.

    Quickstart:

    const { createLogger, transports } = require('winston');
    const { configuredFormatter } = require('winston-json-formatter');
    
    // Create Logger and configure options.
    
    const logger = createLogger({ 
        level: 'silly',
        transports: [
            new (transports.Console)(),
        ],
    });
    const options = { 
        service: 'test-service', 
        logger: 'Winston-JSON-Formatter',
        version: '1.0.0', 
        typeFormat: 'json'
    };
    
    // set winston logger format and print logs.
    logger.format = configuredFormatter(options);
    
    // Availale log levels
    logger.error('message');
    logger.warn('message');
    logger.info('message');
    logger.verbose('message');
    logger.debug('message');
    logger.silly('message');
    
    // Error Objects can be logged directly
    err = new Error('Heroic BSoD')
    logger.error(err)

    Configuration

    ENV

    • NODE_ENV=dev || NODE_ENV=development => options.typeFormat=console
    • Otherwise, options.typeFormat=json (default)
    Option Default Type
    options.typeFormat Default: 'json' Enum: 'console', 'json'
    options.hostname Default: os.hostname() String
    options.logger Default: 'application-logger' String
    options.node_env Default: ENV NODE_ENV String
    options.service String
    options.version String

    Test

    yarn install
    yarn test
    yarn test:coverage

    Output

    Json logging

    > const err = new Error('error message');
    > const err.code = 'SOME_CODE';
    > // The colon and space here are recommended due to this bug in winston (https://github.com/winstonjs/winston/issues/1634)
    > logger.info('log message: ', err);
    {
      "service": "test-service",
      "logger": "Winston-JSON-Formatter",
      "hostname": "host",
      "level": "info",
      "msg": "log message: error message",
      "meta": {
        "service": {
          "version": "1.0.0",
          "node_env": ""
        },
        "logger": {
          "time": "2018-11-28T02:52:06.700Z"
        },
        "event": {
          "code": "SOME_CODE"
        }
      },
      "err": {
        // There should be a member `"name": "Error"` here if it were not for winston bug (https://github.com/winstonjs/winston/issues/1635)
        "stack": "THE_ERROR_STACK"
      }
    }
    
    > const err = new Error('error message');
    > const err.code = 'SOME_CODE';
    > logger.info(err, {foo: 'bar', baz: 'qux'});
    {
      "service": "test-service",
      "logger": "Winston-JSON-Formatter",
      "hostname": "host",
      "level": "info",
      "msg": "message: error message",
      "meta": {
        "service": {
          "version": "1.0.0",
          "node_env": ""
        },
        "logger": {
          "time": "2018-11-28T02:52:06.700Z"
        },
        "event": {
          "foo": "bar",
          "baz": "qux",
          "code": "SOME_CODE"
        }
      },
      "err": {
        "name": "Error"
        "stack": "THE_ERROR_STACK"
      }
    }

    Console logging

    console log style

    # Generally, the format is:
    
    # timestamp level message
    # stack_if_one_exists
    # {
    #   other: 'members-if-they-exist'
    # }
    
    # > logger.info("log message") ------------------------------------------------------------------ 
    2019-04-12T02:10:11.091Z info log message  
    # ----
    
    
    # > logger.info(new Error("error message")) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.094Z info error message 
    Error: error message
        at Object.<anonymous> (/Users/houli/docs/gitrepos/amida-tech/winston-json-formatter/experiment.js:38:13)
        at Module._compile (module.js:653:30)
        at Object.Module._extensions..js (module.js:664:10)
        at Module.load (module.js:566:32)
        at tryModuleLoad (module.js:506:12)
        at Function.Module._load (module.js:498:3)
        at Function.Module.runMain (module.js:694:10)
        at startup (bootstrap_node.js:204:16)
        at bootstrap_node.js:625:3 
    # ----
    
    
    # > logger.info("message", new Error("error message")) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.095Z info log messageerror message 
    Error: error message
        at Object.<anonymous> (/Users/houli/docs/gitrepos/amida-tech/winston-json-formatter/experiment.js:41:28)
        at Module._compile (module.js:653:30)
        at Object.Module._extensions..js (module.js:664:10)
        at Module.load (module.js:566:32)
        at tryModuleLoad (module.js:506:12)
        at Function.Module._load (module.js:498:3)
        at Function.Module.runMain (module.js:694:10)
        at startup (bootstrap_node.js:204:16)
        at bootstrap_node.js:625:3 
    # ----
    
    
    # > logger.info({a: "a", b: "b"}) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.095Z info 
    {
      "a": "a",
      "b": "b"
    }  
    # ----
    
    
    # > logger.info(new Error("error message"), { a: "a", b: "b" } ) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.096Z info error message 
    Error: error message
        at Object.<anonymous> (/Users/houli/docs/gitrepos/amida-tech/winston-json-formatter/experiment.js:47:13)
        at Module._compile (module.js:653:30)
        at Object.Module._extensions..js (module.js:664:10)
        at Module.load (module.js:566:32)
        at tryModuleLoad (module.js:506:12)
        at Function.Module._load (module.js:498:3)
        at Function.Module.runMain (module.js:694:10)
        at startup (bootstrap_node.js:204:16)
        at bootstrap_node.js:625:3 
    {
      "a": "a",
      "b": "b"
    }
    # ----
    
    
    # Logging an object that is not an Error that does have a member named stack will confuse the logger. This is unavoidable.
    # > logger.info({ name: "some name", stack: "some stack" }) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.096Z info 
    {
      "name": "some name",
      "stack": "some stack"
    } 
    some stack 
    # ----
    
    
    # Logging an object that is not an Error that does have a member named stack will confuse the logger. This is unavoidable.
    # > logger.info("message", { name: "some name", stack: "some stack" }) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.096Z info message 
    some stack 
    # ----
    
    
    # > logger.info("message", { a: "a", b: "b" }) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.096Z info message  
    {
      "a": "a",
      "b": "b"
    }
    # ----
    
    
    # > const err = new Error("error message"); err.code = "SOME_CODE"; logger.info("message", new Error("error message")) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.097Z info messageError A 
    Error: Error A
        at Object.<anonymous> (/Users/houli/docs/gitrepos/amida-tech/winston-json-formatter/experiment.js:58:14)
        at Module._compile (module.js:653:30)
        at Object.Module._extensions..js (module.js:664:10)
        at Module.load (module.js:566:32)
        at tryModuleLoad (module.js:506:12)
        at Function.Module._load (module.js:498:3)
        at Function.Module.runMain (module.js:694:10)
        at startup (bootstrap_node.js:204:16)
        at bootstrap_node.js:625:3 
    {
      "code": "SOME_CODE"
    }
    # ----
    
    
    # > const err = new Error("error message"); err.code = "SOME_CODE"; logger.info(new Error("error message")) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.097Z info Error A 
    Error: Error A
        at Object.<anonymous> (/Users/houli/docs/gitrepos/amida-tech/winston-json-formatter/experiment.js:58:14)
        at Module._compile (module.js:653:30)
        at Object.Module._extensions..js (module.js:664:10)
        at Module.load (module.js:566:32)
        at tryModuleLoad (module.js:506:12)
        at Function.Module._load (module.js:498:3)
        at Function.Module.runMain (module.js:694:10)
        at startup (bootstrap_node.js:204:16)
        at bootstrap_node.js:625:3 
    {
      "code": "SOME_CODE"
    }
    # ----
    
    
    # > const err = new Error("error message"); err.code = "SOME_CODE"; logger.info(new Error("error message"), { a: "a", b: "b" } ) ------------------------------------------------------------------ 
    2019-04-12T02:10:11.097Z info Error A 
    Error: Error A
        at Object.<anonymous> (/Users/houli/docs/gitrepos/amida-tech/winston-json-formatter/experiment.js:58:14)
        at Module._compile (module.js:653:30)
        at Object.Module._extensions..js (module.js:664:10)
        at Module.load (module.js:566:32)
        at tryModuleLoad (module.js:506:12)
        at Function.Module._load (module.js:498:3)
        at Function.Module.runMain (module.js:694:10)
        at startup (bootstrap_node.js:204:16)
        at bootstrap_node.js:625:3 
    {
      "a": "a",
      "b": "b",
      "code": "SOME_CODE"
    }

    Miscellaneous Goodies

    This repo also provides a function to check if a particular log level is greater than the currently configured log level.

    Example useage:

    // In some service...
    
    // config.js
    module.exports = {
        logLevel: 'info',
    }
    
    // FancyCustomError.js
    import { initLogLevelGte } from 'winston-json-formatter'
    const config = require('../config/index.js')
    const logLevelGte = initLogLevelGte(config.logLevel)
    
    class FancyCustomError extends Error {
      constructor(rootErrorThatCouldHaveSecretStuffInIt, message, foo, bar) {
        super()
    
        this.message = message
    
        if (logLevelGte('debug')) {
            this.rootErrorThatCouldHaveSecretStuffInIt = rootErrorThatCouldHaveSecretStuffInIt
        }
      }
    }
    
    // someFile.js
    logger.info(new FancyCustomError(err, 'Error creating user'))
    
    // When the configured log level is 'info', you would see logged only 'Error creating user', but when the configured log level is 'debug', you would see all the guts and glory.

    Install

    npm i @amida-tech/winston-json-formatter

    DownloadsWeekly Downloads

    2

    Version

    0.10.1

    License

    Apache-2.0

    Unpacked Size

    235 kB

    Total Files

    14

    Last publish

    Collaborators

    • manhydra