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    express-wolox-logger

    4.0.1 • Public • Published

    Express Wolox Logger

    Build Status

    ExpressJS logger that wraps pino with additional features like middlewares for unique request ids and automatic logging of request beginnings and endings.

    Node versions support

    Below is a table with each version an the minimum version that is needed:

    Node 8 Node 10 Node 12.17+
    v1
    v2
    v3
    v4

    Logging context

    In order to implement the context logging (like the request-id and the log metadata) we rely on experimental features of NodeJS, specifically on async_hooks, some versions use different APIs:

    Basic Usage

    const { logger } = require('express-wolox-logger');
    
    logger.info('hello world');
    logger.error('something bad happened');
    

    This will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"something bad happened"}
    

    Pretty print

    By default, we use NDJSON for logging, but if you want to format the logs in another way you can check the pretty section of pino

    Advanced Usage

    The exported createLogger function takes one optional argument, configuration and returns a logger instance.

    configuration (Object)

    options (Object)

    Default (pino): { mixin // we use this for add metadata log }

    Options for logger instance, check documentation of each package for more details (pino)

    loggerOption (String)

    Default : 'pino'

    Package used as logger, available options are: ['pino']

    Example

    const { createLogger } = require('express-wolox-logger');
    
    const logger = createLogger({ 
        loggerOption: 'pino',
        options: {
            customLevels: {
                foo: 35
            },
            useOnlyCustomLevels: true,
            level: 'foo'
        } 
    })
    
    logger.foo('hello world');
    

    Benchmarks

    There is a script included to excecute a benchmark test on the logger functionallity. The script name is bench and test 10*iterations logger calls with different messages types and sizes to print. It can have none or one argument indicating the number of iterations to test, being 100 the default iterations value:

    npm run bench [iterations]
    

    Middlewares

    Logs for request beginning and end

    We provide an ExpressJs middleware that automatically logs when a request starts and ends. Simply import it and use it like any other middleware.

    Basic Usage

    const { logger, expressMiddleware } = require('express-wolox-logger');
    
    app.use(expressMiddleware({ loggerFn: logger.info }));
    

    This in conjunction with the basic logs will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Started GET /logger/test with params: {}, query: {}, body: {}"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"something bad happened"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Ended GET /logger/test with status: 200 in 10 ms"}
    

    Advanced Usage

    The exported expressRequestIdMiddleware function takes one argument, options and returns a middleware.

    options (Object)

    loggerFn (Function)

    Logger function used for start and end log actions with the default message format.

    startFn (Function)

    Function used in start log actions, mainly for custom messages.

    endFn (Function)

    Function used in end log actions, mainly for custom messages.

    obfuscatePlaceholder (String)

    Default: [SECURE]

    String to replace obfuscated body.

    obfuscateBody (Object|Boolean)

    Default: true

    Options for obfuscate body of request, could be a boolean (true or false) that applies to all requests or a object to an specific endpoint and method.

    Example

    {
      obfuscateBody: {
        '/some_url': { // this should be a regex of url to obfuscate
          POST: true // method to obfuscate
        }
      }
    }
    

    Obfuscating body of specific request

    const { logger, expressMiddleware } = require('express-wolox-logger');
    
    app.use(expressMiddleware({ loggerFn: logger.info, obfuscatePlaceholder: '[SECRET]', obfuscateBody: { '/secure': { POST: true } } }));
    

    This in conjunction with the basic logs will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Started POST /secure with params: {}, query: {}, body: [SECRET]"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Ended POST /secure with status: 200 in 10 ms"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Started GET /secure with params: {}, query: {}, body: {}"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Ended GET /secure with status: 200 in 10 ms"}
    

    Obfuscating body of all requests

    const { logger, expressMiddleware } = require('express-wolox-logger');
    
    app.use(expressMiddleware({ loggerFn: logger.info, obfuscatePlaceholder: '[SECRET]', obfuscateBody: true }));
    

    This in conjunction with the basic logs will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Started POST /secure with params: {}, query: {}, body: [SECRET]"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Ended POST /secure with status: 200 in 10 ms"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Started GET /secure with params: {}, query: {}, body: [SECRET]"}
    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"Ended GET /secure with status: 200 in 10 ms"}
    

    Request Ids

    We also provide an ExpressJs middleware that appends a request id to all logs made for a single request. This is useful for better tracking logs when there are several requests going on concurrently. Again, simply import it and use it like any other middleware.

    Basic Usage

    const { expressRequestIdMiddleware } = require('express-wolox-logger');
    
    app.use(expressRequestIdMiddleware());
    

    This, in conjunction with the basic logs will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world","requestId":"GNc7JovB7"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"something bad happened","requestId":"GNc7JovB7" }
    

    Note, that if you are using Sequelize, you need to configure it to use the logger's CLS namespace, otherwise the requests ids will not persist through sequelize promises. The same may apply to other frameworks.

    For sequelize, just set the namespace before creating a new sequelize instance:

    const Sequelize = require('sequelize');
    const { namespace } = require('express-wolox-logger');
    
    Sequelize.useCLS(namespace);
    const sequelize = new Sequelize(...);
    

    Advanced Usage

    The exported expressRequestIdMiddleware function takes one optional argument, options and returns a middleware.

    options (Object)

    headerName (String)

    Default: x-request-id

    Header from where the id is taken

    idGenerator (Function)

    Default: shortid.generate

    Function used for generate ids in each request.

    Example

    const uuid = require('uuid');
    const { expressRequestIdMiddleware } = require('express-wolox-logger');
    
    app.use(expressRequestIdMiddleware({ headerName: 'id', idGenerator: uuid }));
    

    This, in conjunction with the basic logs will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world","requestId":"a2936029-9bd4-402d-ba43-a4873f228274"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"something bad happened","requestId":"a2936029-9bd4-402d-ba43-a4873f228274" }
    

    Forwarding the request Id

    As a bonus, the previously mentioned request id is taken from the x-request-id header if supplied, which lets said request id be transferred across services. You can do this by importing the getRequestId function and supplying it to the header when making requests.

    const axios = require('axios'),
     { getRequestId } = require('express-wolox-logger');
    
    axios.get(URL, { headers: { 'x-request-id': getRequestId() } });
    

    This will result in the requestId being logged through your services until the request chain ends.

    We used axios for this example but other requets packages like request-promise work exactly the same way.

    Logging Metadata

    We provide some functions to allow logging some extra metadata like the request-id or any custom field that you need for tracking in all your app logs

    Example

    const { addLogMetadata, getLogMetadata } = require('express-wolox-logger');
    
    app.use((req, res, next) => {
      addLogMetadata({ some_custom_field: res.locals.some_field, other_custom_field: 'APP_FLOW' })
      next();
    })
    

    This, in conjunction with the basic logs will output:

    {"level":30,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"hello world","some_custom_field": "some_value", "other_custom_field": "APP_FLOW"}
    {"level":22,"time":1591139401676,"pid":45656,"hostname":"192.168.1.4","msg":"something bad happened","some_custom_field": "some_value", "other_custom_field": "APP_FLOW"}
    

    Migrate from winston to express-wolox-logger

    If you are wondering how to migrate from wolox express-js boostrap configuration with winston to this package refer to the step by step migration guide

    Upgrade

    If you are wondering how to upgrade to a major version check this upgrade guide

    Contributing

    1. Fork it
    2. Create your feature branch (git checkout -b my-new-feature)
    3. Run the tests (npm test)
    4. Commit your changes (git commit -am 'Add some feature')
    5. Push to the branch (git push origin my-new-feature)
    6. Create new Pull Request

    About

    This project is maintained by Wolox and it was written by Wolox.

    Wolox

    License

    express-wolox-logger is available under the MIT license.

    Copyright (c) 2020 Wolox
    
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
    
    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
    

    Install

    npm i express-wolox-logger

    DownloadsWeekly Downloads

    995

    Version

    4.0.1

    License

    MIT

    Unpacked Size

    33.8 kB

    Total Files

    22

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