Express Wolox Logger

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

Basic Usage

const { logger } = require('express-wolox-logger');

logger.info('hello world');
logger.error('something bad happened');

This will output:

[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): hello world
[2019-06-14 17:35:13.772 +0000] ERROR (17439 on my-pc.local): something bad happened

Advanced Usage

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

configuration (Object)

options (Object)

Default (pino): { prettyPrint: { translateTime: true, colorize: false } }

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:

[2019-06-14 17:35:13.770 +0000] INFO  (17439 on my-pc.local): Started GET /logger/test with params: {}, query: {}, body: {}.
[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): hello world
[2019-06-14 17:35:13.772 +0000] ERROR (17439 on my-pc.local): something bad happened
[2019-06-14 17:35:13.781 +0000] INFO  (17439 on my-pc.local): 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.

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:

[2019-06-14 17:35:13.770 +0000] INFO  (17439 on my-pc.local): Started POST /secure with params: {}, query: {}, body: [SECRET].
[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): hello world
[2019-06-14 17:35:13.781 +0000] INFO  (17439 on my-pc.local): Ended POST /secure with status: 200 in 10 ms
[2019-06-14 17:35:13.770 +0000] INFO  (17439 on my-pc.local): Started GET /secure with params: {}, query: {}, body: {}.
[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): hello world
[2019-06-14 17:35:13.781 +0000] INFO  (17439 on my-pc.local): 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:

[2019-06-14 17:35:13.770 +0000] INFO  (17439 on my-pc.local): Started POST /secure with params: {}, query: {}, body: [SECRET].
[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): hello world
[2019-06-14 17:35:13.781 +0000] INFO  (17439 on my-pc.local): Ended POST /secure with status: 200 in 10 ms
[2019-06-14 17:35:13.770 +0000] INFO  (17439 on my-pc.local): Started GET /secure with params: {}, query: {}, body: [SECRET].
[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): hello world
[2019-06-14 17:35:13.781 +0000] INFO  (17439 on my-pc.local): 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:

[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): [GNc7JovB7] hello world
[2019-06-14 17:35:13.772 +0000] ERROR (17439 on my-pc.local): [GNc7JovB7] something bad happened

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: nanoid(10)

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:

[2019-06-14 17:35:13.772 +0000] INFO  (17439 on my-pc.local): [a2936029-9bd4-402d-ba43-a4873f228274] hello world
[2019-06-14 17:35:13.772 +0000] ERROR (17439 on my-pc.local): [a2936029-9bd4-402d-ba43-a4873f228274] something bad happened

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.

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.

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.