go-logger
Yet another Go logger library.
Version 2
The new version of this library implements some breaking changes:
- The initialization options contains some changes. Once the logger is initialized, the rest of the code should be
compatible with the
v1version. - Added per-target logging level. Now you can optionally specify a different logging level for console and file logging. For example, you can just send limited logs to a third-party provider to avoid high costs and keep a detailed local file log for debugging purposes.
-
timestampandlevelfields are always added to a JSON log. DO NOT include them when the input is a struct. - Verbosity level for the default logger is now
Infoinstead ofWarning.
How to use
- Import the library
import (
logger "github.com/randlabs/go-logger/v2"
)- Then use
logger.Createto create a logger object with desired options. - Optionally, you can also use the default logger which outputs only to console by accessing
logger.Default().
Logger options:
The Options struct accepts several modifiers that affects the logger behavior:
| Field | Meaning |
|---|---|
Console |
Establishes some options for the console output. |
File |
Enable file logging. Optional. Details below. |
SysLog |
Enable SysLog logging. Optional. Details below. |
Level |
Set the initial logging level to use. |
DebugLevel |
Set the initial logging level for debug output to use. |
UseLocalTime |
Use the local computer time instead of UTC. |
ErrorHandler |
A callback to call if an internal error is encountered. |
ConsoleOptions:
| Field | Meaning |
|---|---|
Disable |
Disabled console output. |
Level |
Optional logging level to use in the console output. |
DebugLevel |
Optional logging level for debug output to use in the console output. |
FileOptions:
| Field | Meaning |
|---|---|
Prefix |
Filename prefix to use when a file is created. Defaults to the binary name. |
Directory |
Destination directory to store log files. |
DaysToKeep |
Amount of days to keep old logs. |
Level |
Optional logging level to use in the file output. |
DebugLevel |
Optional logging level for debug output to use in the file output. |
SysLogOptions:
| Field | Meaning |
|---|---|
AppName |
Application name to use. Defaults to the binary name. |
Host |
Syslog server host name. |
Port |
Syslog server port. Defaults to 514, 1468 or 6514 depending on the network protocol used. |
UseTcp |
Use TCP instead of UDP. |
UseTls |
Uses a secure connection. Implies TCP. |
UseRFC5424 |
Send messages in the new RFC 5424 format instead of the original RFC 3164 specification. |
MaxMessageQueueSize |
Set the maximum amount of messages to keep in memory if connection to the server is lost. |
TlsConfig |
An optional pointer to a tls.Config object to provide the TLS configuration for use. |
Level |
Optional logging level to use in the syslog output. |
DebugLevel |
Optional logging level for debug output to use in the syslog output. |
Example
package example
import (
"fmt"
logger "github.com/randlabs/go-logger/v2"
)
// Define a custom JSON message. Timestamp and level will be automatically added by the logger.
type JsonMessage struct {
Message string `json:"message"`
}
func main() {
// Create the logger
lg, err := logger.Create(logger.Options{
File: &logger.FileOptions{
Directory: "./logs",
DaysToKeep: 7,
},
Level: logger.LogLevelDebug,
DebugLevel: 1,
})
if err != nil {
// Use default logger to send the error
logger.Default().Error(fmt.Sprintf("unable to initialize. [%v]", err))
return
}
// Defer logger shut down
defer lg.Destroy()
// Send some logs using the plain text format
lg.Error("This is an error message sample")
lg.Warning("This is a warning message sample")
lg.Info("This is an information message sample")
lg.Debug(1, "This is a debug message sample at level 1 which should be printed")
lg.Debug(2, "This is a debug message sample at level 2 which should NOT be printed")
// Send some other logs using the JSON format
lg.Error(JsonMessage{
Message: "This is an error message sample",
})
lg.Warning(JsonMessage{
Message: "This is a warning message sample",
})
lg.Info(JsonMessage{
Message: "This is an information message sample",
})
lg.Debug(1, JsonMessage{
Message: "This is a debug message sample at level 1 which should be printed",
})
lg.Debug(2, JsonMessage{
Message: "This is a debug message sample at level 2 which should NOT be printed",
})
}License
See LICENSE file for details.
