Logging

Here is a little help on how the logging works and what should be taken into account during development to detect at any time if something goes wrong.

Logging framework: Winston

How to log

Central entry point of each logging is the file in the backend ./backend/utils/logger.js. This should generally be integrated into each file with adapting the service-field to allow an assignment of the log:

const logger = require("../utils/logger.js")("service");

Within the code all information can now be logged directly via the logger variable. The logging levels are based on the RFC5424 standard and can be used as followed:

logger.log('warn', "127.0.0.1 - there's no place like home");
logger.log('error', "127.0.0.1 - there's no place like home");
logger.info("127.0.0.1 - there's no place like home");
logger.warn("127.0.0.1 - there's no place like home");
logger.error("127.0.0.1 - there's no place like home");

See Using Logging Levels for more information.

Note

For socket and service classes the logger is already integrated and can be used directly with this.logger.

Where are the logs stored?

The logs are saved as a file, entered into the database, and also output to the console (if set in .env). For this purpose the environment variables can be adjusted:

# Logging
LOGGING_PATH=./logs
LOGGING_LEVEL=info
LOGGING_ALLOW_FRONTEND=true

See the .env file in the root directory more information!

During logging, three files are created in the specified folder:

File	Description
activity.log	Contains all logs (by app log level)
error.log	Only errors are saved here.
complete.log	Contains all logs (by log level ENV LOGGING_LEVEL)

In addition, all logs based on the environment variable LOGGING_LEVEL are entered into the database.

Logging with user information

Currently, the database also supports logging with user information already contained in the database. For this purpose, additional meta data must be added to the logger, for which there are two ways:

// Adding meta data directly during logging
logger.info("Just a info message with user information", {user: <uid> });

// or using a child logger
const child_logger = logger.child({user: <uid>});
child_logger.info("Just a info message with user information");

Note

The User ID <uid> must exists in the database table user!

Logging through websocket

There is also the possibility to log information directly from the frontend through the websocket. After that, logs can be easily emitted to the websocket in each vue component with:

this.$socket.emit('log', {level: 'info', message: 'Just a info message from the frontend!'})

Note

For this the environment variable LOGGING_ALLOW_FRONTEND must be explicitly set to true!