Configure Logging

In order to configure the logging, you can use the following approaches:

• Environment Variables
• Programmatically

You can load the yaml logging configuration files as shown below.

func init() {
    err := logy.LoadConfigFromYaml("logy.config.yaml")

    if err != nil {
        panic(err)
    }
}

As an alternative, you can configure the logging by invoking logy.LoadConfig() function.

func init() {
    err := logy.LoadConfig(&logy.Config{
        Level:    logy.LevelTrace,
        Handlers: logy.Handlers{"console", "file"},
        Console: &logy.ConsoleConfig{
            Level:   logy.LevelTrace,
            Enabled: true,
            // this will be ignored because console json logging is enabled
            Format: "%d{2006-01-02 15:04:05.000} %l [%x{traceId},%x{spanId}] %p : %s%e%n",
            Color:   true,
            Json:    &logy.JsonConfig{
                Enabled: true,
                KeyOverrides: logy.KeyOverrides{
                    "timestamp": "@timestamp",
                },
                AdditionalFields: logy.JsonAdditionalFields{
                    "application-name": "my-logy-app",
                },
            },
        },
        File: &logy.FileConfig{
            Enabled: true,
            Name: "file_trace.log",
            Path: "/var",
            // this will be ignored because file json logging is enabled
            Format: "d{2006-01-02 15:04:05} %p %s%e%n",
            Json:    &logy.JsonConfig{
                Enabled: true,
                KeyOverrides: logy.KeyOverrides{
                    "timestamp": "@timestamp",
                },
                AdditionalFields: logy.JsonAdditionalFields{
                    "application-name": "my-logy-app",
                },
            },
        },
    })

    if err != nil {
        panic(err)
    }

}

Logging Package

Logging is done on a per-package basis. Each package can be independently configured. A configuration which applies to a package will also apply to all sub-categories of that package, unless there is a more specific matching sub-package configuration.

For every package the same settings that are configured on ( console / file / syslog ) apply.

Property	Description	Type	Default
logy.package.package-path.level	The log level for this package	bool	TRACE
logy.package.package-path.use-parent-handlers	Specify whether this logger should user its parent handlers	bool	true
logy.package.package-path.handlers	The names of the handlers to link to this package	list of string

Root Logger Configuration

The root logger is handled separately, and is configured via the following properties:

Property	Description	Type	Default
logy.level	The log level for every log package	bool	TRACE
logy.handlers	The names of handlers to link to the root	list of string	[console]

Logging Format

By default, Logy uses a pattern-based logging format.

You can customize the format for each log handler using a dedicated configuration property. For the console handler, the property is logy.console.format.

The following table shows the logging format string symbols that you can use to configure the format of the log messages.

Supported logging format symbols:

Symbol	Summary	Description
%%	%	A simple %%character
%c	Logger name	The logger name
%C	Package name	The package name
%d{layout}	Date	Date with the given layout string
%e	Error	The error stack trace
%F	Source file	The source file name
%i	Process ID	The current process PID
%l	Source location	The source location(file name, line number, method name)
%L	Source line	The source line number
%m	Full Message	The log message including error trace
%M	Source method	The source method name
%n	Newline	The line separator string
%N	Process name	The name of the current process
%p	Level	The logging level of the message
%s	Simple message	The log message without error trace
%X{property-name}	Mapped Context Value	The value from Mapped Context property-key=property-value
%x{property-name}	Mapped Context Value without key	The value without key from Mapped Context in format property-value
%X	Mapped Context Values	All the values from Mapped Context in format property-key1=property-value1,property-key2=property-value2
%x	Mapped Context Values without keys	All the values without keys from Mapped Context in format property-value1,property-value2

Console Handler Properties

You can configure the console handler with the following configuration properties:

Property	Description	Type	Default
logy.console.enabled	Enable the console logging	bool	true
logy.console.target	Override keys with custom values	Target(stdout, stderr, discard)	stdout
logy.console.format	The console log format. Note that this value will be ignored if json is enabled for console	string	d{2006-01-02 15:04:05.000000} %p %c : %m%n
logy.console.color	Enable color coded output if the target terminal supports it	bool	true
logy.console.level	The console log level	Level(OFF,ERROR,WARN,INFO,DEBUG,TRACE,ALL)	TRACE
logy.console.json.enabled	Enable the JSON console formatting	bool	false
logy.console.json.excluded-keys	Keys to be excluded from the Json output	list of string
logy.console.json.key-overrides.property-name	Override keys with custom values	map[string]string
logy.console.json.additional-fields.property-name	Additional field values	map[string]any

File Handler Properties

You can configure the file handler with the following configuration properties:

Property	Description	Type	Default
logy.file.enabled	Enable the file logging	bool	false
logy.file.format	The file log format. Note that this value will be ignored if json is enabled for file	string	d{2006-01-02 15:04:05.000000} %p %c : %m%n
logy.file.name	The name of the file in which logs will be written	string	logy.log
logy.file.path	The path of the file in which logs will be written	string	Working directory
logy.file.level	The level of logs to be written into the file	Level(OFF,ERROR,WARN,INFO,DEBUG,TRACE,ALL)	TRACE
logy.file.json.enabled	Enable the JSON file formatting	bool	false
logy.file.json.excluded-keys	Keys to be excluded from the Json output	list of string
logy.file.json.key-overrides.property-name	Override keys with custom values	map[string]string
logy.file.json.additional-fields.property-name	Additional field values	map[string]any

Syslog Handler Properties

You can configure the syslog handler with the following configuration properties:

Property	Description	Type	Default
logy.syslog.enabled	Enable the syslog logging	bool	false
logy.syslog.endpoint	The IP address and port of the syslog server	host:port	localhost:514
logy.syslog.app-name	The app name used when formatting the message in RFC5424 format	string
logy.syslog.hostname	The name of the host the messages are being sent from	string
logy.syslog.facility	The facility used when calculating the priority of the message in RFC5424 and RFC3164 format	Facility(kernel,user-level,mail-system,system-daemons,security,syslogd,line-printer,network-news,uucp,clock-daemon,security2,ftp-daemon,ntp,log-audit,log-alert,clock-daemon2,local-use-0,local-use-1,local-use-2,local-use-3,local-use-4,local-use-5,local-use-6,local-use-7	user-level
logy.syslog.log-type	The message format type used when formatting the message	SysLogType(rfc5424,rfc3164)	rfc5424
logy.syslog.protocol	The protocol used to connect to the syslog server	Protocol(tcp,udp)	tcp
logy.syslog.block-on-reconnect	Enable or disable blocking when attempting to reconnect the syslog server	bool	false
logy.syslog.format	The log message format	string	d{2006-01-02 15:04:05.000000} %p %c : %m%n
logy.syslog.level	The level of the logs to be logged by syslog logger	Level(OFF,ERROR,WARN,INFO,DEBUG,TRACE,ALL)	TRACE