README
¶
logrusiowriter
io.Writer implementation using logrus
Motivation
Many golang libraries use the golang's log package to print their logs. This means that if your application
uses logrus to print structured logging, those packages will print a format that is (probably) incompatible with yours,
and you may end losing logs in your logs collector because they can't be parsed properly.
Solution
Print the logs written using log.Printf through logrus, by setting log.SetOutput to an io.Writer implementation
that uses logrus as output, i.e.:
log.SetOutput(logrusiowriter.New())
See example_*_test.go files to find testable examples that serve as documentation.
Documentation
¶
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var OnLevelParseError = func(err error) logrus.Level { logrus.Errorf("Can't parse level: %s", err) return logrus.InfoLevel }
OnLevelParseError will be invoked if logrus is unable to parse the string level provided in the configuration The default behavior is to log it with logrus and return a default Info level, you can change this to log in some other system or to panic Changing this is not thread safe, so it might be a good idea to change it in a init() function
Functions ¶
func New ¶
func New(cfg ...Configurer) io.Writer
New creates a new io.Writer, and configures it with the provided configurers Provided Configurers overwrite previous values as they're applied If no Configurers provided, the writer will log with Info level and no fields using the logrus.StandardLogger
Example ¶
removeTimestampAndSetOutputToStdout(logrus.StandardLogger())
log.SetOutput(logrusiowriter.New())
log.SetFlags(0) // no date on standard logger
log.Printf("Standard log")
Output: level=info msg="Standard log"
Types ¶
type Config ¶
type Config struct {
Level string `default:"info"`
Fields logrus.Fields `default:"logger:stdlib"`
TrailingNewLineTrimming bool `default:"true"`
}
Config holds the configuration to be used with WithConfig() configurer This struct is useful to embed into configuration structs parsed with libraries like envconfig
type Configurer ¶
type Configurer func(*writer)
Configurer configures the writer, use one of the With* functions to obtain one
func WithConfig ¶
func WithConfig(cfg Config) Configurer
WithConfig creates a configurer from the configuration provided as a struct If it's unable to parse the Level provided as a string, it will invoke the OnLevelParseError function and set the level returned by that function (a default value)
Example ¶
removeTimestampAndSetOutputToStdout(logrus.StandardLogger())
config := logrusiowriter.Config{
Level: "warning",
Fields: map[string]interface{}{
"config": "struct",
},
}
writer := logrusiowriter.New(
logrusiowriter.WithConfig(config),
)
_, _ = fmt.Fprint(writer, "Hello World!")
Output: level=warning msg="Hello World!" config=struct
func WithConfigInterface ¶
func WithConfigInterface(cfg interface {
Level() logrus.Level
Fields() logrus.Fields
Logger() logrus.FieldLogger
}) Configurer
WithConfigInterface creates a configurer from the configuration provided as an interface
Example ¶
removeTimestampAndSetOutputToStdout(logrus.StandardLogger())
writer := logrusiowriter.New(
logrusiowriter.WithConfigInterface(configProvider{}),
)
_, _ = fmt.Fprint(writer, "Hello World!")
Output: level=trace msg="Hello World!" config=interface
func WithFields ¶
func WithFields(fields logrus.Fields) Configurer
WithFields configures the fields with the ones provided
Example ¶
removeTimestampAndSetOutputToStdout(logrus.StandardLogger())
writer := logrusiowriter.New(
logrusiowriter.WithFields(logrus.Fields{
"config": "fields",
"other": 288,
}),
)
_, _ = fmt.Fprint(writer, "Hello World!")
Output: level=info msg="Hello World!" config=fields other=288
func WithLevel ¶
func WithLevel(lvl logrus.Level) Configurer
WithLevel configures the level with the one provided
Example ¶
removeTimestampAndSetOutputToStdout(logrus.StandardLogger()) writer := logrusiowriter.New( logrusiowriter.WithLevel(logrus.ErrorLevel), ) _, _ = fmt.Fprint(writer, "Hello World!")
Output: level=error msg="Hello World!"
func WithLogger ¶
func WithLogger(logger logrus.FieldLogger) Configurer
WithLogger configures the logger with the one provided
Example ¶
logger := logrus.New() removeTimestampAndSetOutputToStdout(logger) logger.SetLevel(logrus.TraceLevel) writer := logrusiowriter.New( logrusiowriter.WithLogger(logger), ) _, _ = fmt.Fprint(writer, "Hello World!")
Output: level=info msg="Hello World!"
func WithTrailingNewLineTrimming ¶ added in v1.1.0
func WithTrailingNewLineTrimming(trim bool) Configurer
WithTrailingNewLineTrimming configures trailing newline trimming. This is true by default, because log.Print adds a newline in the end of its messages, which does not make sense inside of a logrus log
Source Files