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Simple Log Framework for Golang (slf4g)

TOC

Principles

KISS for users

If you want to log something it should be easy, intuitive and straight forward. This should work either for very small applications (just one file) or big applications, too.

You should not care about the implementation, you want just to use it.

KISS for implementators

If you want to implement a new logger you should not be required to educate your users how to use it.

You just want to write a logger for a user-case. Someone else should take care of the public API.

Separation

A logging framework should not be both, by design: API and implementation.

You want to have one API and the possibility to use whatever implementation you want.

Interoperable

Regardless how used or implemented you want that just everything sticks together, and you're not ending up over and over again in writing new wrappers or in worst-case see different styled log messages in the console.

Every library should just work transparently with one logger.

Motivation

I've tried out many logging frameworks for Golang. They're coming with different promises, like:

  1. There are ones which tries to be "blazing fast"; focussing on be fast and non-blocking to be able to log as much log events as possible.

  2. Other ones are trying to be as minimalistic as possible. Just using a very few amount of code to work.

  3. ...

...but overall they're just violating the Principles listed above and we're ending up in just mess.

Slf4g is born out of feeling this pain every day again and be simply annoyed. It is inspired by Simple Logging Facade for Java (SLF4J), which was born out of the same pains; but obviously in Java before. Since SLF4J exists, and it is now broadly used in Java, nobody does experience this issues any longer.

Getting started

It is very easy to use slf4g (as the naming is promising ☺️):

  1. Import the API to your current project (in best with a Go Modules project)

    $ go get -u github.com/echocat/slf4g

  2. Select one of the implementation of slf4g and import it too (see Implementations). Example:

    $ go get -u github.com/echocat/slf4g/native

    ℹ️ If you do not pick one implementation the fallback logger is used. It works, too, but is obviously less powerful and is not customizable. It is comparable with the SDK based logger.

  3. Configure your application to use the selected logger implementation:

    This should be only done in main/main.go:

    package main

import (
	_ "github.com/echocat/slf4g/native"
)

func main() {
	// do your stuff...
}

  4. In each package create a logger variable, in best case you create a file named common.go or package.go which will contain it:

    package foo

import (
	"github.com/echocat/slf4g"
)

var logger = log.GetLoggerForCurrentPackage()

  5. Now you're ready to go. In every file of this package you can do stuff, like:

    package foo

func MyFunction() {
	logger.Info("Hello, world!")

	if !loaded {
		logger.With("field", 123).
		       Warn("That's not great.")
	}

	if err := doSomething(); err != nil {
		logger.WithError(err).
		       Error("Doh!")
	}
}

    For sure, you're able to simply do stuff like that (although to ensure interoperability this is not recommended):

    package foo

import (
	"github.com/echocat/slf4g"
)

func MyFunction() {
	log.Info("Hello, world!")

	if !loaded {
		log.With("field", 123).
		    Warn("That's not great.")
	}

	if err := doSomething(); err != nil {
		log.WithError(err).
		    Error("Doh!")
	}
}

Done. Enjoy!

Implementations

slf4g-native

This is the reference implementation of slf4g.

Contributing

slf4g is an open source project by echocat. So if you want to make this project even better, you can contribute to this project on Github by fork us.

If you commit code to this project, you have to accept that this code will be released under the license of this project.

License

See the LICENSE file.

Documentation

Overview

The Simple Logging Facade for Go provides an easy access who everyone who wants to log something and do not want to care how it is logged and gives others the possibility to implement their own loggers in easy way.

Usage

There are 2 common ways to use this framework.

1. By getting a logger for your current package. This is the most common way and is quite clean for one package. If the package contains too many logic it might worth it to use the 2nd approach (see below). 

package foo

import "github.com/echocat/slf4g"

var logger = log.GetLoggerForCurrentPackage()

func sayHello() {
   // will log with logger="github.com/user/foo"
   logger.Info("Hello, world!")
}

2. By getting a logger for the object the logger is for. This is the most clean approach and will give you later the maximum flexibility and control. 

package foo

import "github.com/echocat/slf4g"

var logger = log.GetLogger(myType{})

type myType struct {
   ...
}

func (mt myType) sayHello() {
   // will log with logger="github.com/user/foo.myType"
   logger.Info("Hello, world!")
}

3. By using the global packages methods which is quite equal to how the SDK base logger works. This is only recommend for small application and not for libraries you like to export. 

package foo

import "github.com/echocat/slf4g"

func sayHello() {
   // will log with logger=ROOT
   log.Info("Hello, world!")
}

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func AreEventsEqual added in v0.7.1 

func AreEventsEqual(left, right Event) (bool, error)

AreEventsEqual is comparing two given Events using DefaultEventEquality.

func Debug 

func Debug(args ...interface{})

Debug logs the provided arguments on Debug at the current root Logger.

func Debugf 

func Debugf(format string, args ...interface{})

Debugf is like Debug but wraps the message itself in a fmt.Sprintf action. By contract the actual format action will not be executed before the value will be really consumed.

func Error 

func Error(args ...interface{})

Error logs the provided arguments on Error at the current root Logger.

func Errorf 

func Errorf(format string, args ...interface{})

Errorf is like Error but wraps the message itself in a fmt.Sprintf action. By contract the actual format action will not be executed before the value will be really consumed.

func Fatal 

func Fatal(args ...interface{})

Fatal logs the provided arguments on Fatal at the current root Logger.

IMPORTANT! In contrast to many other log Golang frameworks this logging Fatal with slf4g does not lead to an os.Exit() by default. By contract the application can do that but it is doing that always GRACEFUL. All processes should be always able to do shutdown operations if needed AND possible.

func Fatalf 

func Fatalf(format string, args ...interface{})

Fatalf is like Fatal but wraps the message itself in a fmt.Sprintf action. By contract the actual format action will not be executed before the value will be really consumed.

IMPORTANT! In contrast to many other log Golang frameworks this logging Fatal with slf4g does not lead to an os.Exit() by default. By contract the application can do that but it is doing that always GRACEFUL. All processes should be always able to do shutdown operations if needed AND possible.

func GetErrorOf 

func GetErrorOf(e Event, using Provider) error

GetErrorOf returns for the given Event the contained error (if exists).

func GetLoggerOf 

func GetLoggerOf(e Event, using Provider) *string

GetLoggerOf returns for the given Event the contained logger (name) (if exists).

func GetMessageOf 

func GetMessageOf(e Event, using Provider) *string

GetMessageOf returns for the given Event the contained message (if exists).

func GetTimestampOf 

func GetTimestampOf(e Event, using Provider) *time.Time

GetTimestampOf returns for the given Event the contained timestamp (if exists).

func Info 

func Info(args ...interface{})

Info logs the provided arguments on Info at the current root Logger.

func Infof 

func Infof(format string, args ...interface{})

Infof is like Info but wraps the message itself in a fmt.Sprintf action. By contract the actual format action will not be executed before the value will be really consumed.

func IsDebugEnabled 

func IsDebugEnabled() bool

IsDebugEnabled checks if Debug is enabled at the current root Logger.

func IsErrorEnabled 

func IsErrorEnabled() bool

IsErrorEnabled checks if Error is enabled at the current root Logger.

func IsFallbackLogger added in v0.7.1 

func IsFallbackLogger(candidate CoreLogger) bool

IsFallbackLogger will return true of the given (Core)Logger is the fallback logger. This usually indicates that currently there is no other implementation of slf4g registered.

func IsFallbackProvider added in v0.7.1 

func IsFallbackProvider(candidate Provider) bool

IsFallbackProvider will return true of the given Provider is the fallback provider. This usually indicates that currently there is no other implementation of slf4g registered.

func IsFatalEnabled 

func IsFatalEnabled() bool

IsFatalEnabled checks if Fatal is enabled at the current root Logger.

func IsInfoEnabled 

func IsInfoEnabled() bool

IsInfoEnabled checks if Info is enabled at the current root Logger.

func IsLevelEnabled 

func IsLevelEnabled(level level.Level) bool

IsLevelEnabled checks if the given Level is enabled at the current root Logger.

func IsTraceEnabled 

func IsTraceEnabled() bool

IsTraceEnabled checks if Trace is enabled at the current root Logger.

func IsWarnEnabled 

func IsWarnEnabled() bool

IsWarnEnabled checks if Warn is enabled at the current root Logger.

func Trace 

func Trace(args ...interface{})

Trace logs the provided arguments on Trace at the current root Logger.

func Tracef 

func Tracef(format string, args ...interface{})

Tracef is like Trace but wraps the message itself in a fmt.Sprintf action. By contract the actual format action will not be executed before the value will be really consumed.

func Warn 

func Warn(args ...interface{})

Warn logs the provided arguments on Warn at the current root Logger.

func Warnf 

func Warnf(format string, args ...interface{})

Warnf is like Warn but wraps the message itself in a fmt.Sprintf action. By contract the actual format action will not be executed before the value will be really consumed.

Types

type CoreLogger 

type CoreLogger interface {
	// Log is called to log the given Event. It depends on the implementation
	// if this action will be synchronous or asynchronous. An Event handed over
	// to this (Core)Logger should usually be created by the NewEvent() method
	// of this instance. An implementation of CoreLogger is allowed to either
	// accept events bt foreigners or reject them with a panic. You can check
	// this using Accepts().
	//
	// skipFrames defines how many frame should be skipped to determine the real
	// caller of the log event from the call stack. In cse of delegating do not
	// forget to increase.
	Log(event Event, skipFrames uint16)

	// IsLevelEnabled returns <true> if the given Level is enabled to be logged
	// with this (Core)Logger.
	IsLevelEnabled(level.Level) bool

	// GetName returns the name of this (Core)Logger instance.
	GetName() string

	// NewEvents creates a new instance of an Event which can be modified before
	// provided back to this CoreLogger using Log().
	NewEvent(level level.Level, values map[string]interface{}) Event

	// Accepts is used to determine of this instance of a (Core)Logger might
	// accepts also Events created by foreigners. Events creates by NewEvent()
	// of this instance should always return true.
	Accepts(Event) bool

	// GetProvider will return the Provider where this (Core)Logger belongs to.
	// This is for example used to access the AllLevels or fields.KeysSpec used
	// by this (Core)Logger.
	GetProvider() Provider
}

CoreLogger defines the base functions of all Logger of the slf4g framework.

This needs to be usually implemented by loggers that interfaces with the slf4g framework and can be elevated to a full instance of Logger by calling NewLogger().

func UnwrapCoreLogger added in v0.7.0 

func UnwrapCoreLogger(in CoreLogger) CoreLogger

UnwrapCoreLogger unwraps a wrapped CoreLogger inside of another CoreLogger. For example by NewLoggerFacade.

type Event 

type Event interface {
	// GetLevel returns the Level of this event.
	GetLevel() level.Level

	// ForEach will call the provided consumer for each field which is provided
	// by this Fields instance.
	ForEach(consumer func(key string, value interface{}) error) error

	// Get will return for the given key the corresponding value if exists.
	// Otherwise, it will return nil.
	Get(key string) (value interface{}, exists bool)

	// Len returns the len of all key value pairs contained in this event which
	// can be received by using ForEach() or Get().
	Len() int

	// With returns a variant of this Event with the given key
	// value pair contained inside. If the given key already exists in the
	// current instance this means it will be overwritten.
	With(key string, value interface{}) Event

	// Withf is similar to With, but it adds classic fmt.Printf functions to it.
	// It is defined that the format itself will not be executed before the
	// consumption of the value. (See fields.Fields.ForEach() and
	// fields.Fields.Get())
	Withf(key string, format string, args ...interface{}) Event

	// WithError is similar to With, but it adds an error as field.
	WithError(error) Event

	// WithAll is similar to With, but it can consume more than one field at
	// once. Be aware: There is neither a guarantee that this instance will be
	// copied or not.
	WithAll(map[string]interface{}) Event

	// Without returns a variant of this Event without the given
	// key contained inside. In other words: If someone afterwards tries to
	// call either fields.Fields.ForEach() or fields.Fields.Get() nothing with
	// this key(s) will be returned.
	Without(keys ...string) Event
}

Event represents an event which can be logged using a Logger (or CoreLogger).

Contents

Events containing always present content provided by GetLevel().

They are providing additionally dynamic content (messages, errors, ...) which are accessible via ForEach() and Get(). None of these fields are required to exist by contract. The keys of these fields are defined by Provider.GetFieldKeysSpec(). For example using fields.KeysSpec.GetMessage() it might be possible to get the key of the message.

The keys are always of type string and should be only printable characters which can be printed in any context. Recommended are everything that matches: 

^[a-zA-Z0-9._-]+$

The values could be everything including nils.

Immutability

Fields are defined as immutable. Calling the methods With, Withf, WithAll and Without always results in a new instance of Event that could be either brand new, a copy of the source one or do inherit some stuff of the original called one; but it never modifies the called instance.

type EventEquality added in v0.7.1 

type EventEquality interface {
	// AreEventsEqual compares the two given Events for their equality.
	AreEventsEqual(left, right Event) (bool, error)

	// WithIgnoringKeys creates a new instance of this EventEquality which will
	// ignore the given keys while the equality check run.
	WithIgnoringKeys(keys ...string) EventEquality
}

EventEquality is comparing two Fields with each other and check if both are equal. 

var DefaultEventEquality EventEquality = &privateEventEqualityImpl{&EventEqualityImpl{
	CompareLevel: true,
	CompareValuesUsing: fields.NewValueEqualityFacade(func() fields.ValueEquality {
		return fields.DefaultValueEquality
	}),
}}

DefaultEventEquality is the default instance of a Equality. The initial initialization of this global variable should be able to deal with the majority of the cases. There is also a shortcut function: AreEventsEqual(left,right)

func NewEventEqualityFacade added in v0.7.1 

func NewEventEqualityFacade(provider func() EventEquality) EventEquality

NewEventEqualityFacade creates a re-implementation of EventEquality which uses the given provider to retrieve the actual instance of EventEquality in the moment when it is used. This is useful especially in cases where you want to deal with concurrency while creation of objects that need to hold a reference to a EventEquality.

type EventEqualityFunc added in v0.7.1 

type EventEqualityFunc func(left, right Event) (bool, error)

EventEqualityFunc is wrapping a given func into EventEquality.

func (EventEqualityFunc) AreEventsEqual added in v0.7.1 

func (instance EventEqualityFunc) AreEventsEqual(left, right Event) (bool, error)

AreEventsEqual implements EventEquality.AreEventsEqual().

func (EventEqualityFunc) WithIgnoringKeys added in v0.7.1 

func (instance EventEqualityFunc) WithIgnoringKeys(keys ...string) EventEquality

WithIgnoringKeys implements EventEquality.WithIgnoringKeys().

type EventEqualityImpl added in v0.7.1 

type EventEqualityImpl struct {
	// CompareLevel will configure to compare the Event.GetLevel() of both
	// events to be the same.
	CompareLevel bool

	// CompareValuesUsing is used to compare the fields of the given events. If
	// nil the values will not be compared.
	CompareValuesUsing fields.ValueEquality
}

func (*EventEqualityImpl) AreEventsEqual added in v0.7.1 

func (instance *EventEqualityImpl) AreEventsEqual(left, right Event) (bool, error)

AreEventsEqual implements EventEquality.AreEventsEqual().

func (*EventEqualityImpl) WithIgnoringKeys added in v0.7.1 

func (instance *EventEqualityImpl) WithIgnoringKeys(keys ...string) EventEquality

WithIgnoringKeys implements EventEquality.WithIgnoringKeys().

type Logger 

type Logger interface {
	CoreLogger

	// Trace logs the provided arguments on LevelTrace with this Logger.
	Trace(...interface{})

	// Tracef is like Trace but wraps the message itself in a fmt.Sprintf action.
	// By contract the actual format action will not be executed before the value
	// will be really consumed.
	Tracef(string, ...interface{})

	// IsTraceEnabled checks if LevelTrace is enabled at this Logger.
	IsTraceEnabled() bool

	// Debug logs the provided arguments on LevelDebug with this Logger.
	Debug(...interface{})

	// Debugf is like Debug but wraps the message itself in a fmt.Sprintf action.
	// By contract the actual format action will not be executed before the value
	// will be really consumed.
	Debugf(string, ...interface{})

	// IsDebugEnabled checks if LevelDebug is enabled at this Logger.
	IsDebugEnabled() bool

	// Info logs the provided arguments on LevelInfo with this Logger.
	Info(...interface{})

	// Infof is like Info but wraps the message itself in a fmt.Sprintf action.
	// By contract the actual format action will not be executed before the value
	// will be really consumed.
	Infof(string, ...interface{})

	// IsInfoEnabled checks if LevelInfo is enabled at this Logger.
	IsInfoEnabled() bool

	// Warn logs the provided arguments on LevelWarn with this Logger.
	Warn(...interface{})

	// Warnf is like Warn but wraps the message itself in a fmt.Sprintf action.
	// By contract the actual format action will not be executed before the value
	// will be really consumed.
	Warnf(string, ...interface{})

	// IsWarnEnabled checks if LevelWarn is enabled at this Logger.
	IsWarnEnabled() bool

	// Error logs the provided arguments on LevelError with this Logger.
	Error(...interface{})

	// Errorf is like Error but wraps the message itself in a fmt.Sprintf action.
	// By contract the actual format action will not be executed before the value
	// will be really consumed.
	Errorf(string, ...interface{})

	// IsErrorEnabled checks if LevelError is enabled at this Logger.
	IsErrorEnabled() bool

	// Fatal logs the provided arguments on LevelFatal with this Logger.
	//
	// IMPORTANT! In contrast to many other log Golang frameworks this logging Fatal
	// with slf4g does not lead to an os.Exit() by default. By contract the
	// application can do that but it is doing that always GRACEFUL. All processes
	// should be always able to do shutdown operations if needed AND possible.
	Fatal(...interface{})

	// Fatalf is like Fatal but wraps the message itself in a fmt.Sprintf action.
	// By contract the actual format action will not be executed before the value
	// will be really consumed.
	//
	// IMPORTANT! In contrast to many other log Golang frameworks this logging Fatal
	// with slf4g does not lead to an os.Exit() by default. By contract the
	// application can do that but it is doing that always GRACEFUL. All processes
	// should be always able to do shutdown operations if needed AND possible.
	Fatalf(string, ...interface{})

	// IsFatalEnabled checks if LevelFatal is enabled at this Logger.
	IsFatalEnabled() bool

	// With returns an variant of this Logger with the given key
	// value pair contained inside. If the given key already exists in the
	// current instance this means it will be overwritten.
	With(name string, value interface{}) Logger

	// Withf is similar to With but it adds classic fmt.Printf functions to it.
	// It is defined that the format itself will not be executed before the
	// consumption of the value.
	Withf(name string, format string, args ...interface{}) Logger

	// WithError is similar to With but it adds an error as field.
	WithError(error) Logger

	// WithAll is similar to With but it can consume more than one field at
	// once. Be aware: There is neither a guarantee that this instance will be
	// copied or not.
	WithAll(map[string]interface{}) Logger

	// Without returns a variant of this Logger without the given
	// key contained inside. In other words: If someone afterwards tries to
	// call either ForEach() or Get() nothing with this key(s) will be returned.
	Without(keys ...string) Logger
}

Logger defines an instance which executes log event actions.

Implementation hints

If you're considering to implement slf4g you're usually not required to implement a full instance of Logger. Usually you just need to implement CoreLogger and call NewLogger(with the CoreLogger) to create a full implemented instance of a Logger.

func GetLogger 

func GetLogger(nameOrReference interface{}) Logger

GetLogger returns a logger for the given name from the global Provider. If instead of a string another object is given this will be used to create a logger name from it's package name.

func GetLoggerForCurrentPackage added in v0.7.1 

func GetLoggerForCurrentPackage() Logger

GetLoggerForCurrentPackage is similar to GetLogger(name) but it extracts the name automatically from the current call stack. That means: this method should be only used for the package this logger should be for.

func GetRootLogger added in v0.6.0 

func GetRootLogger() Logger

GetLogger returns the ROOT logger from the global Provider.

func NewLogger 

func NewLogger(cl CoreLogger) Logger

NewLogger create a new fully implemented instance of a logger out of a given CoreLogger instance. If the given CoreLogger is already a fully implemented Logger it will be returned instantly.

func UnwrapLogger added in v0.7.0 

func UnwrapLogger(in CoreLogger) Logger

UnwrapLogger unwraps a wrapped Logger inside of another Logger. For example by NewLoggerFacade.

func With 

func With(name string, value interface{}) Logger

With returns a root Logger which will contain the provided field.

func WithAll added in v0.5.5 

func WithAll(of map[string]interface{}) Logger

WithAll is similar to With but it can consume more than one field at once. Be aware: There is neither a guarantee that this instance will be copied or not.

func WithError 

func WithError(err error) Logger

WithError is similar to With but it adds specially an error field.

func Withf added in v0.1.3 

func Withf(name string, format string, args ...interface{}) Logger

Withf is similar to With but it adds classic fmt.Printf functions to it. It is defined that the format itself will not be executed before the consumption of the value.

type LoggerCache added in v0.4.0 

type LoggerCache interface {
	// GetLogger returns a Logger for the given name.
	GetLogger(name string) Logger

	// GetRootLogger returns the root Logger.
	GetRootLogger() Logger

	// GetNames returns all names for all already known Logger which are
	// already received using GetLogger(name).
	GetNames() []string
}

LoggerCache could provide more than one time the same instance of a named Logger (by calling GetLogger(name string)) or the same root Logger (by calling GetRootLogger()).

func NewLoggerCache added in v0.4.0 

func NewLoggerCache(rootFactory func() Logger, factory func(name string) Logger) LoggerCache

NewLoggerCache creates a new instance of LoggerCache by the given rootFactory and factory.

type LoggerFacade added in v1.3.0 

type LoggerFacade interface {
	Logger

	// DoLog is acting as a simple log for the given level.
	DoLog(level level.Level, skipFrames uint16, args ...interface{})

	// DoLogf is acting as a formatted log for the given level.
	DoLogf(level level.Level, skipFrames uint16, format string, args ...interface{})
}

LoggerFacade is a fully implemented logger with utility methods for easier implementation of delegates.

func NewLoggerFacade added in v0.3.0 

func NewLoggerFacade(provider func() CoreLogger) LoggerFacade

NewLoggerFacade is like NewLogger but takes a provider function that can potentially return every time another instance of a CoreLogger. This is useful especially in cases where you want to deal with concurrency while creation of objects that need to hold a reference to a Logger.

type LoggingWriter added in v0.3.0 

type LoggingWriter struct {
	// Logger where to log captured events to. If this field is not set this
	// writer will simply do nothing.
	Logger CoreLogger

	// LevelExtractor is used to determine the level of the current written
	// line when reporting to configured Logger. If nil/not configured it will
	// use level.Info.
	LevelExtractor level.LineExtractor

	// Interceptor is like LevelExtractor but runs after the LineExtractor with
	// the extracted level.Level and can modify it again (if set). Additionally,
	// it can also modify the content of the to be logged message itself.
	Interceptor func([]byte, level.Level) ([]byte, level.Level, error)

	// SkipFrames is used to create the event with.
	SkipFrames uint16
}

LoggingWriter is used to capture lines which might contain log event and forward them straight to a configured Logger. This is quite useful with old/native logging frameworks which does not have generic hooks for log frameworks like slf4g.

func (*LoggingWriter) Write added in v0.3.0 

func (instance *LoggingWriter) Write(p []byte) (int, error)

Write implements io.Writer.

type Provider 

type Provider interface {
	// GetRootLogger returns the root Logger. The Provider guarantees that there
	// is always the same Logger.
	GetRootLogger() Logger

	// GetLogger returns a Logger for the given name. The Provider guarantees
	// that there is always the same Logger for the same name returned.
	GetLogger(name string) Logger

	// GetName returns the name of this Provider instance.
	GetName() string

	// GetAllLevels returns all available level.Levels which are supported by
	// this Provider.
	GetAllLevels() level.Levels

	// GetFieldKeysSpec returns the fields.KeysSpec which describes the keys of
	// fields.Fields which are supported by this Provider.
	GetFieldKeysSpec() fields.KeysSpec
}

func GetAllProviders added in v0.7.0 

func GetAllProviders() []Provider

GetAllProviders returns all knows providers registered with RegisterProvider().

func GetProvider 

func GetProvider() Provider

GetProvider returns the actual Provider.

The Provider returned by this method is guarded by a facade (see NewProviderFacade()) which ensures that usages of this Provider will always call the global configured Provider depending on whether the Provider was configured before calling this method or afterwards.

func NewProviderFacade added in v0.3.0 

func NewProviderFacade(provider func() Provider) Provider

NewProviderFacade creates a new facade of Provider with the given function that provides the actual Provider to use.

func RegisterProvider 

func RegisterProvider(p Provider) Provider

RegisterProvider registers the given provider as a usable one. If GetProvider() is called each Provider which was registered with this method will be then taken into consideration to be returned.

It is not possible to register more than one instance of a Provider with the same name.

func SetProvider 

func SetProvider(p Provider) Provider

SetProvider forces the given Provider as the actual one which will be returned when calling GetProvider(). This will lead to that each Provider registered with RegisterProvider() will be ignored.

This methods accepts also <nil>. In this case regular discovery mechanism will be enabled again when calling GetProvider().

This methods always returns the previous set value (which can be <nil>, too).

func UnregisterProvider 

func UnregisterProvider(name string) Provider

UnregisterProvider is doing the exact opposite of RegisterProvider().

func UnwrapProvider added in v0.2.0 

func UnwrapProvider(in Provider) Provider

UnwrapProvider unwraps a wrapped Provider inside of another Provider. For example by NewProviderFacade.

Source Files

View all Source files

Directories

Path Synopsis
Fields represents a collection of key value pairs.
 Fields represents a collection of key value pairs.
internal
demo
support
test/assert
Level identifies the severity of an event to be logged.
 Level identifies the severity of an event to be logged.
Package names provides utility functions to work with names.
 Package names provides utility functions to work with names.
native module
sdk
bridge
Package sdk/bridge provides methods to either hook into the SDK logger itself or create compatible instances.
 Package sdk/bridge provides methods to either hook into the SDK logger itself or create compatible instances.
bridge/hook
Importing this package anonymously will configure the whole application to use the slf4g framework on any usage of the SDK based loggers.
 Importing this package anonymously will configure the whole application to use the slf4g framework on any usage of the SDK based loggers.
testing
recording
Package recording provides the possibility to record instances of events.
 Package recording provides the possibility to record instances of events.

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