Documentation
¶
Overview ¶
Package logf provides logging functionality with small scope of features like custom shared formatting, scopes (fields) and levels (info, error, debug). This is very simple wrapper over io.Writer with provided Formatter and scope added.
Example ¶
package main
import (
"errors"
"os"
"github.com/Prastiwar/Go-flow/logf"
)
func main() {
// Create new logger with optional settiings like output, formatter, scope fields
logger := logf.NewLogger(
logf.WithOutput(os.Stdout),
logf.WithFormatter(logf.NewTextFormatter()),
// logf.WithFields(logf.Fields{logf.LogTime: logf.NewTimeField(time.RFC3339)}), // can add log time to message
)
// Create logger based on parent logger with additional scope
logger = logf.WithScope(
logger,
logf.Fields{
"children": true,
},
)
logger.Error("error message")
logger.Errorf("error occurred: %v", errors.New("invalid call"))
logger.Info("info message")
logger.Infof("count: %v", 1)
logger.Debug("debug message")
logger.Debugf("debug message: %v", 1)
}
Output: [ERR] error message {"children":true} [ERR] error occurred: invalid call {"children":true} [INFO] info message {"children":true} [INFO] count: 1 {"children":true} [DEBUG] debug message {"children":true} [DEBUG] debug message: 1 {"children":true}
Index ¶
Examples ¶
Constants ¶
const ( // LogTime is shared key used for time field. LogTime = "log_time" // Level is shared key used for level field. Level = "level" InfoLevel = "INFO" // informational log level. ErrorLevel = "ERR" // error, failure log level. DebugLevel = "DEBUG" // diagnostics log level. )
Variables ¶
This section is empty.
Functions ¶
func NewTimeField ¶
func NewTimeField(format string) *timeField
NewTimeField returns a new time field which should always return the current time with specified format on log formatting.
func SetDefault ¶ added in v0.5.0
func SetDefault(factory func() Logger)
SetDefault configures behaviour of Default() function to return logger instance using specified factory
Types ¶
type Fields ¶
type Fields map[string]interface{}
Fields is used to parse scope for each log as key value pair.
func MergeFields ¶
MergeFields returns a new instace of Fields which contains values from source and upserts fields to it.
type Formatter ¶
Formatter is implemented by any value that has a Format method. The implementation controls how to format message with Fields as an output string.
type JsonFormatter ¶
type JsonFormatter struct {
// contains filtered or unexported fields
}
JsonFormatter implements Formatter interface. Provides message formatting as JSON output.
func NewJsonFormatter ¶
func NewJsonFormatter(pretty bool) *JsonFormatter
NewJsonFormatter returns a new Json Formatter with specified indentation mode.
type Logger ¶
type Logger interface {
// Output returns writer used as a logger output.
Output() io.Writer
// Scope returns Fields used as a logger scope.
Scope() Fields
// Formatter returns Formatter used by logger.
Formatter() Formatter
// Error prints a message with error level indicating any defect or failure.
Error(v interface{})
// Errorf prints a message with specified format with error level indicating any defect or failure.
Errorf(format string, args ...any)
// Info prints a message with info level indicating any information or warning.
Info(v interface{})
// Infof prints a message with specified format with info level indicating any information or warning.
Infof(format string, args ...any)
// Debug prints a message with debug level indicating any information used for diagnostics or troubleshooting.
Debug(v interface{})
// Debugf prints a message with specified format debug level indicating any information used for diagnostics or troubleshooting.
Debugf(format string, args ...any)
}
Logger is implemented by any value that has a defined methods for logging, output, scope and formatter. The implementation controls which how specified levels are printed into output.
func Default ¶ added in v0.5.0
func Default() Logger
Default returns logger instance by call to factory initialized using SetDefault() function. If it was not initialized it simply returns NewLogger()
func From ¶ added in v0.5.0
From returns Logger stored in ctx using WithLogger function. In case logger was not stored it simply returns instance from Default() function
func NewLogger ¶
func NewLogger(opts ...LoggerOption) Logger
NewLogger returns a new Logger instance with configured options
type LoggerOption ¶
type LoggerOption func(*LoggerOptions)
LoggerOption is function which mutates the LoggerOptions specific field.
func WithFields ¶
func WithFields(f Fields) LoggerOption
WithFormatter returns a new LoggerOption to configure log initial scope.
func WithFormatter ¶
func WithFormatter(f Formatter) LoggerOption
WithFormatter returns a new LoggerOption to configure log message formatter.
func WithOutput ¶
func WithOutput(w io.Writer) LoggerOption
WithOutput returns a new LoggerOption to configure log writer output.
type LoggerOptions ¶
LoggerOptions is set of optional parameters which can configure new Logger.
func NewLoggerOptions ¶
func NewLoggerOptions(opts ...LoggerOption) *LoggerOptions
NewLoggerOptions returns a new LoggerOptions.
type TextFormatter ¶
type TextFormatter struct {
// contains filtered or unexported fields
}
TextFormatter implements Formatter which outputs message as raw text formaat with control over side where fields are put.
func NewTextFormatter ¶
func NewTextFormatter() *TextFormatter
NewTextFormatter returns a new Text Formatter with Level and LogTime as field keys which values will be outputted on the left side of message. If you want customize these keys - use NewTextFormatterWith
func NewTextFormatterWith ¶
func NewTextFormatterWith(leftFieldNames ...string) *TextFormatter
NewTextFormatterWith returns a new Text Formatter with field keys which are outputted on the left side of message.
Source Files