1. More tests

2. More documentation
3. Structure refactored

event.go

@@ -1,14 +1,28 @@
 package log
 
-import "github.com/echocat/slf4g/fields"
+import (
+	"github.com/echocat/slf4g/fields"
+	"github.com/echocat/slf4g/level"
+)
 
 // Event represents an event which can be logged using a Logger (or CoreLogger).
 //
 // Contents
 //
-// Events are haven dynamic contents (such as messages, errors, ...) provided
-// by GetFields(). Only be contract always provided information are provided by
-// GetLevel() and GetCalDepth().
+// Events containing always present content provided by GetLevel() and
+// GetCallDepth().
+//
+// They are providing additionally dynamic content (messages, errors, ...)
+// which are accessible via ForEach() and Get(). None of this fields are
+// required to exists 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
 //
@@ -19,7 +33,7 @@ import "github.com/echocat/slf4g/fields"
 // instance.
 type Event interface {
 	// GetLevel returns the Level of this event.
-	GetLevel() Level
+	GetLevel() level.Level
 
 	// GetCallDepth returns the call depth inside of the call stack that should
 	// be ignored before capturing the caller position (if required). This could
@@ -33,13 +47,13 @@ type Event interface {
 	// WithContext().
 	GetContext() interface{}
 
-	// GetFields will return all fields which are associated with this Event.
-	// This could contain a message, timestamp, error and so on. None of this
-	// fields is required to exists by contract. The keys of these fields is
-	// defined by Provider.GetFieldKeysSpec(). For example using
-	// fields.KeysSpec.GetMessage() it might be possible to get the
-	// key of the message.
-	GetFields() fields.Fields
+	// 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) interface{}
 
 	// With returns an variant of this Event with the given key
 	// value pair contained inside. If the given key already exists in the
@@ -52,6 +66,9 @@ type Event interface {
 	// 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.
@@ -74,15 +91,33 @@ type Event interface {
 	WithContext(ctx interface{}) Event
 }
 
-// NewEvent creates a new instance of Event from the given Level, fields.Fields
-// and the given callDepth.
-func NewEvent(level Level, f fields.Fields, callDepth int) Event {
-	if f == nil {
-		f = fields.Empty()
+// NewEvent creates a new instance of Event from the given Provider, Level,
+// callDepth and fields.Fields.
+func NewEvent(provider Provider, level level.Level, callDepth int, f ...fields.Fields) Event {
+	var tf fields.Fields
+	if len(f) > 0 {
+		tf = f[0]
+	} else {
+		tf = fields.Empty()
 	}
-	return &eventImpl{
-		Level:     level,
-		Fields:    f,
-		CallDepth: callDepth,
+
+	var result Event = &eventImpl{
+		provider:  provider,
+		level:     level,
+		fields:    tf,
+		callDepth: callDepth,
+	}
+
+	if len(f) > 1 {
+		for _, sf := range f[1:] {
+			if err := sf.ForEach(func(k string, v interface{}) error {
+				result = result.With(k, v)
+				return nil
+			}); err != nil {
+				panic(err)
+			}
+		}
 	}
+
+	return result
 }

event_impl.go

@@ -1,28 +1,48 @@
 package log
 
-import "github.com/echocat/slf4g/fields"
+import (
+	"github.com/echocat/slf4g/fields"
+	level2 "github.com/echocat/slf4g/level"
+)
 
 type eventImpl struct {
-	Fields    fields.Fields
-	Level     Level
-	CallDepth int
-	Context   interface{}
+	provider  Provider
+	fields    fields.Fields
+	level     level2.Level
+	callDepth int
+	context   interface{}
 }
 
-func (instance *eventImpl) GetFields() fields.Fields {
-	return instance.Fields
+func (instance *eventImpl) ForEach(consumer func(key string, value interface{}) error) error {
+	if instance == nil {
+		return nil
+	}
+	if v := instance.fields; v != nil {
+		return v.ForEach(consumer)
+	}
+	return nil
+}
+
+func (instance *eventImpl) Get(key string) interface{} {
+	if instance == nil {
+		return nil
+	}
+	if v := instance.fields; v != nil {
+		return v.Get(key)
+	}
+	return nil
 }
 
-func (instance *eventImpl) GetLevel() Level {
-	return instance.Level
+func (instance *eventImpl) GetLevel() level2.Level {
+	return instance.level
 }
 
 func (instance *eventImpl) GetCallDepth() int {
-	return instance.CallDepth
+	return instance.callDepth
 }
 
 func (instance *eventImpl) GetContext() interface{} {
-	return instance.Context
+	return instance.context
 }
 
 func (instance *eventImpl) With(key string, value interface{}) Event {
@@ -37,6 +57,12 @@ func (instance *eventImpl) Withf(key string, format string, args ...interface{})
 	})
 }
 
+func (instance *eventImpl) WithError(err error) Event {
+	return instance.with(func(s fields.Fields) fields.Fields {
+		return s.With(instance.provider.GetFieldKeysSpec().GetError(), err)
+	})
+}
+
 func (instance *eventImpl) WithAll(of map[string]interface{}) Event {
 	return instance.with(func(s fields.Fields) fields.Fields {
 		return s.WithAll(of)
@@ -51,27 +77,30 @@ func (instance *eventImpl) Without(keys ...string) Event {
 
 func (instance *eventImpl) WithContext(ctx interface{}) Event {
 	return &eventImpl{
-		Fields:    instance.Fields,
-		Level:     instance.Level,
-		CallDepth: instance.CallDepth,
-		Context:   ctx,
+		provider:  instance.provider,
+		fields:    instance.fields,
+		level:     instance.level,
+		callDepth: instance.callDepth,
+		context:   ctx,
 	}
 }
 
 func (instance *eventImpl) WithCallDepth(add int) Event {
 	return &eventImpl{
-		Fields:    instance.Fields,
-		Level:     instance.Level,
-		CallDepth: instance.CallDepth + add,
-		Context:   instance.Context,
+		provider:  instance.provider,
+		fields:    instance.fields,
+		level:     instance.level,
+		callDepth: instance.callDepth + add,
+		context:   instance.context,
 	}
 }
 
 func (instance *eventImpl) with(mod func(fields.Fields) fields.Fields) Event {
 	return &eventImpl{
-		Fields:    mod(instance.Fields),
-		Level:     instance.Level,
-		CallDepth: instance.CallDepth,
-		Context:   instance.Context,
+		provider:  instance.provider,
+		fields:    mod(instance.fields),
+		level:     instance.level,
+		callDepth: instance.callDepth,
+		context:   instance.context,
 	}
 }

event_support.go

@@ -12,7 +12,7 @@ func GetMessageOf(e Event, using Provider) *string {
 	if e == nil {
 		return nil
 	}
-	pv := e.GetFields().Get(using.GetFieldKeysSpec().GetMessage())
+	pv := e.Get(using.GetFieldKeysSpec().GetMessage())
 	if pv == nil {
 		return nil
 	}
@@ -38,7 +38,7 @@ func GetErrorOf(e Event, using Provider) error {
 	if e == nil {
 		return nil
 	}
-	pv := e.GetFields().Get(using.GetFieldKeysSpec().GetError())
+	pv := e.Get(using.GetFieldKeysSpec().GetError())
 	if lv, ok := pv.(fields.Lazy); ok {
 		pv = lv.Get()
 	}
@@ -62,7 +62,7 @@ func GetTimestampOf(e Event, using Provider) *time.Time {
 	if e == nil {
 		return nil
 	}
-	pv := e.GetFields().Get(using.GetFieldKeysSpec().GetTimestamp())
+	pv := e.Get(using.GetFieldKeysSpec().GetTimestamp())
 	if lv, ok := pv.(fields.Lazy); ok {
 		pv = lv.Get()
 	}
@@ -91,7 +91,7 @@ func GetLoggerOf(e Event, using Provider) *string {
 	if e == nil {
 		return nil
 	}
-	pv := e.GetFields().Get(using.GetFieldKeysSpec().GetLogger())
+	pv := e.Get(using.GetFieldKeysSpec().GetLogger())
 	if lv, ok := pv.(fields.Lazy); ok {
 		pv = lv.Get()
 	}

fields/empty.go

@@ -9,7 +9,7 @@ type empty struct{}
 
 var emptyV = &empty{}
 
-func (instance *empty) ForEach(Consumer) error {
+func (instance *empty) ForEach(func(key string, value interface{}) error) error {
 	return nil
 }
 

fields/fields.go

@@ -17,9 +17,9 @@
 package fields
 
 type Fields interface {
-	// ForEach will call the provided Consumer for each field which is provided
+	// ForEach will call the provided consumer for each field which is provided
 	// by this Fields instance.
-	ForEach(consumer Consumer) error
+	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.
@@ -45,8 +45,3 @@ type Fields interface {
 	// call either ForEach() or Get() nothing with this key(s) will be returned.
 	Without(keys ...string) Fields
 }
-
-// Consumer will be called on each field that needs to be consumed.
-//
-// See Fields.ForEach() for more details.
-type Consumer func(key string, value interface{}) error

fields/key_spec.go

@@ -2,9 +2,20 @@ package fields
 
 // KeysSpec defines the keys for common usages inside of a Fields instance.
 type KeysSpec interface {
+	// GetTimestamp returns the key where the timestamp is stored inside, if
+	// available.
 	GetTimestamp() string
+
+	// GetMessage returns the key where the message is stored inside, if
+	// available.
 	GetMessage() string
+
+	// GetError returns the key where an error is stored inside, if
+	// available.
 	GetError() string
+
+	// GetLogger returns the key where the Logger is stored inside, which is
+	// managed a Fields instance. (if available)
 	GetLogger() string
 }
 

fields/lineage.go

@@ -15,7 +15,7 @@ func newLineage(target Fields, parent Fields) Fields {
 	return &lineage{target, parent}
 }
 
-func (instance *lineage) ForEach(consumer Consumer) error {
+func (instance *lineage) ForEach(consumer func(key string, value interface{}) error) error {
 	if instance == nil || consumer == nil {
 		return nil
 	}

fields/map.go

@@ -14,7 +14,7 @@ func WithAll(of map[string]interface{}) Fields {
 
 type mapped map[string]interface{}
 
-func (instance mapped) ForEach(consumer Consumer) error {
+func (instance mapped) ForEach(consumer func(key string, value interface{}) error) error {
 	if instance == nil || consumer == nil {
 		return nil
 	}

fields/single.go

@@ -16,7 +16,7 @@ type single struct {
 	value interface{}
 }
 
-func (instance *single) ForEach(consumer Consumer) error {
+func (instance *single) ForEach(consumer func(key string, value interface{}) error) error {
 	if instance == nil || consumer == nil {
 		return nil
 	}

fields/sorted.go

@@ -28,6 +28,21 @@ func Sort(fields Fields, sorter KeySorter) Fields {
 	return &result
 }
 
+// SortedForEach is like Sort but calls the ForEach immediately.
+func SortedForEach(input ForEachEnabled, sorter KeySorter, consumer func(key string, value interface{}) error) error {
+	if sorter == nil || isEmpty(input) {
+		return nil
+	}
+	m := asMap(input)
+	keys := make([]string, len(m))
+	for _, key := range keys {
+		if err := consumer(key, m[key]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // KeySorter is used to sort all keys. See Sort() for more details.
 type KeySorter func(keys []string)
 
@@ -36,7 +51,7 @@ type sorted struct {
 	keys []string
 }
 
-func (instance *sorted) ForEach(consumer Consumer) error {
+func (instance *sorted) ForEach(consumer func(key string, value interface{}) error) error {
 	if instance == nil || consumer == nil {
 		return nil
 	}

fields/support.go

@@ -1,6 +1,10 @@
 package fields
 
-func asMap(f Fields) mapped {
+type ForEachEnabled interface {
+	ForEach(func(key string, value interface{}) error) error
+}
+
+func asMap(f ForEachEnabled) mapped {
 	switch v := f.(type) {
 	case mapped:
 		return v
@@ -19,7 +23,7 @@ func asMap(f Fields) mapped {
 	return result
 }
 
-func isEmpty(given Fields) bool {
+func isEmpty(given ForEachEnabled) bool {
 	if given == nil {
 		return true
 	}