Logepi
A tiny, Togepi-sized, logging library for Node.js apps & APIs.
How to install
Using npm
$ npm install --save logepi
Using yarn
$ yarn install logepi
How to use
The library is comprised of two major components:
- A
Log
static class which creates an instance of a Winston logger, exposing several methods to output messages with different loglevels. Middleware
functions to add automatic logging of request/response flows for HTTP servers. Currently the library supports Koa and Express.
There's also a TypeScript declaration file available for TS-based apps.
Log
API
Using the Importing the library
// commonjs styleconst Log = ; // ES modules style;
Log an error
Log;
Log a warning
Log;
Log at INFO level
Log;
Log at VERBOSE level
Log;
Log at DEBUG log
Log;
Setting up an output level
In order to filter what messages are printed to the console transport, you can use the Log.setOutputLevel()
method:
// Limit messages to "error" level.Log;
You can also use the LogLevel
enum, with uppercased keys (INFO
, WARN
, ERROR
, VERBOSE
, DEBUG
).
Using the Koa middleware
Import the library
// commonjs styleconst KoaLoggingMiddleware = ; // ES modules style;
Inject it into your app
app // ...make sure it's the *last* middleware... ;
Using the Express middleware
Import the library
// commonjs styleconst ExpressLoggingMiddleware = ; // ES modules style;
Inject it into your app
app // ...make sure it's the *last* middleware... ;
Adding tags to logs
Logepi offers a way to inject tagged data in a logline, with the format [key:value]
. When logging, use the tags
key on the data
argument of any of the Log API methods. There's an example right in the next section.
Configuring logging middlewares
All middlewares expose the same configuration object:
/** * Allows to configure log levels for requests and responses. */ logLevels: /** * Sets the log level for all incoming requests. */ request: "info" /** * Sets the log level for all outgoing responses, according to their status code. */ response: status2xx: "info" // For 200-399 codes status4xx: "warn" // For 400-499 codes status5xx: "error" // For 500-599 codes
How does it look?
Note: Logs are single-lined, but for clarity's sake, they're shown in multiple lines.
Manual logging
Log;
outputs:
[timestamp:2019-01-11T21:04:41.915Z]
[level:info]
[message:API is now ready]
[port:9000]
Incoming request
[timestamp:2019-01-11T21:00:45.442Z]
[level:info]
[message:IncomingRequest]
[url:/api/apps]
[queryParams:undefined]
[body:{}]
[headers:{"host":"localhost:9000","connection":"keep-alive","upgrade-insecure-requests":"1","user-agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36","accept":"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8","accept-encoding":"gzip, deflate, br","accept-language":"es-ES,es;q=0.9,en;q=0.8,en-US;q=0.7"}]
Outgoing response
[timestamp:2019-01-11T21:00:45.446Z]
[level:info]
[message:OutgoingResponse]
[status:200]
[body:{"ok":true,"data":{"foo":true}}]
[headers:{"host":"localhost:9000","connection":"keep-alive","upgrade-insecure-requests":"1","user-agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36","accept":"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8","accept-encoding":"gzip, deflate, br","accept-language":"es-ES,es;q=0.9,en;q=0.8,en-US;q=0.7"}]
Issues
Feel free to report any issues and we'll figure out a way to make it work.
Want to contribute?
That's great! Open an issue first and let's discuss what you want to add or, by all means, fork this project! :)
License
This project is licensed under the MIT License.