ExpressJS logger that wraps pino with additional features like middlewares for unique request ids and automatic logging of request beginnings and endings.
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 | ❌ | ❌ | ✅ |
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:
- v0-v3: AsyncHook through the package cls-hooked
- v4: AsyncLocalStorage internal node API
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"}
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
The exported createLogger function takes one optional argument,
configuration and
returns a logger instance.
Default (pino): { mixin // we use this for add metadata log }
Options for logger instance, check documentation of each package for more details (pino)
Default : 'pino'
Package used as logger, available options are: ['pino']
const { createLogger } = require('express-wolox-logger');
const logger = createLogger({
loggerOption: 'pino',
options: {
customLevels: {
foo: 35
},
useOnlyCustomLevels: true,
level: 'foo'
}
})
logger.foo('hello world');
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]
We provide an ExpressJs middleware that automatically logs when a request starts and ends. Simply import it and use it like any other middleware.
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"}
The exported expressRequestIdMiddleware function takes one argument, options and returns a middleware.
Logger function used for start and end log actions with the default message format.
Function used in start log actions, mainly for custom messages.
Function used in end log actions, mainly for custom messages.
Default: [SECURE]
String to replace obfuscated body.
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.
{
obfuscateBody: {
'/some_url': { // this should be a regex of url to obfuscate
POST: true // method to obfuscate
}
}
}
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"}
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"}
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.
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(...);
The exported expressRequestIdMiddleware function takes one optional argument, options and returns a middleware.
Default: x-request-id
Header from where the id is taken
Default: shortid.generate
Function used for generate ids in each request.
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" }
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.
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
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"}
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
If you are wondering how to upgrade to a major version check this upgrade guide
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Run the tests (
npm test) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request
This project is maintained by Wolox and it was written by Wolox.
express-wolox-logger is available under the MIT license.
Copyright (c) 2020 Wolox
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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
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