Module log
![](https://bcentral-packageicons.azureedge.net/images/ballerina_log_2.2.0.png)
ballerina/log Ballerina library
Overview
This module provides APIs to log information when running applications.
A sample log message logged from the foo
module would look as follows:
time = 2021-05-12T11:20:29.362+05:30 level = ERROR module = myorg/foo message = "Something went wrong"
Log Levels
The log
module provides APIs to log at four levels, which are DEBUG
, ERROR
, INFO
, and WARN
. By default, all log messages are logged to the console at the INFO
level.
The log level can be configured via a Ballerina configuration file.
To set the global log level, place the entry given below in the Config.toml
file:
[ballerina.log] level = "[LOG_LEVEL]"
Each module can also be assigned its own log level. To assign a log level to a module, provide the following entry in the Config.toml
file:
[[ballerina.log.modules]] name = "[ORG_NAME]/[MODULE_NAME]" level = "[LOG_LEVEL]"
Log Output
Logs are written to the stderr
stream by default.
To publish the logs to a file, redirect the stderr
stream to a file as follows.
$ bal run program.bal 2> b7a-user.log
By default, logs are printed in the LogFmt
format. To set the output format to JSON, place the entry given below in the Config.toml
file.
[ballerina.log] format = "json"
A sample log message logged from the foo
module in JSON format would look as follows:
{"time":"2021-05-12T11:26:00.021+05:30", "level":"INFO", "module":"myorg/foo", "message":"Authenticating user"}
For information on the operations, which can be performed with the log module, see the below Functions.