site/vendor/github.com/Xe/ln/logger.go

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package ln
import (
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"context"
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"os"
"time"
"github.com/pkg/errors"
)
// Logger holds the current priority and list of filters
type Logger struct {
Filters []Filter
}
// DefaultLogger is the default implementation of Logger
var DefaultLogger *Logger
func init() {
var defaultFilters []Filter
// Default to STDOUT for logging, but allow LN_OUT to change it.
out := os.Stdout
if os.Getenv("LN_OUT") == "<stderr>" {
out = os.Stderr
}
defaultFilters = append(defaultFilters, NewWriterFilter(out, nil))
DefaultLogger = &Logger{
Filters: defaultFilters,
}
}
// F is a key-value mapping for structured data.
type F map[string]interface{}
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// Extend concatentates one F with one or many Fer instances.
func (f F) Extend(other ...Fer) {
for _, ff := range other {
for k, v := range ff.F() {
f[k] = v
}
}
}
// F makes F an Fer
func (f F) F() F {
return f
}
// Fer allows any type to add fields to the structured logging key->value pairs.
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type Fer interface {
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F() F
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}
// Event represents an event
type Event struct {
Time time.Time
Data F
Message string
}
// Log is the generic logging method.
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func (l *Logger) Log(ctx context.Context, xs ...Fer) {
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event := Event{Time: time.Now()}
addF := func(bf F) {
if event.Data == nil {
event.Data = bf
} else {
for k, v := range bf {
event.Data[k] = v
}
}
}
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for _, f := range xs {
addF(f.F())
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}
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ctxf, ok := FFromContext(ctx)
if ok {
addF(ctxf)
}
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if os.Getenv("LN_DEBUG_ALL_EVENTS") == "1" {
frame := callersFrame()
if event.Data == nil {
event.Data = make(F)
}
event.Data["_lineno"] = frame.lineno
event.Data["_function"] = frame.function
event.Data["_filename"] = frame.filename
}
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l.filter(ctx, event)
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}
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func (l *Logger) filter(ctx context.Context, e Event) {
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for _, f := range l.Filters {
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if !f.Apply(ctx, e) {
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return
}
}
}
// Error logs an error and information about the context of said error.
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func (l *Logger) Error(ctx context.Context, err error, xs ...Fer) {
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data := F{}
frame := callersFrame()
data["_lineno"] = frame.lineno
data["_function"] = frame.function
data["_filename"] = frame.filename
data["err"] = err
cause := errors.Cause(err)
if cause != nil {
data["cause"] = cause.Error()
}
xs = append(xs, data)
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l.Log(ctx, xs...)
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}
// Fatal logs this set of values, then exits with status code 1.
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func (l *Logger) Fatal(ctx context.Context, xs ...Fer) {
xs = append(xs, F{"fatal": true})
l.Log(ctx, xs...)
os.Exit(1)
}
// FatalErr combines Fatal and Error.
func (l *Logger) FatalErr(ctx context.Context, err error, xs ...Fer) {
xs = append(xs, F{"fatal": true})
data := F{}
frame := callersFrame()
data["_lineno"] = frame.lineno
data["_function"] = frame.function
data["_filename"] = frame.filename
data["err"] = err
cause := errors.Cause(err)
if cause != nil {
data["cause"] = cause.Error()
}
xs = append(xs, data)
l.Log(ctx, xs...)
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os.Exit(1)
}
// Default Implementation
// Log is the generic logging method.
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func Log(ctx context.Context, xs ...Fer) {
DefaultLogger.Log(ctx, xs...)
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}
// Error logs an error and information about the context of said error.
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func Error(ctx context.Context, err error, xs ...Fer) {
DefaultLogger.Error(ctx, err, xs...)
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}
// Fatal logs this set of values, then exits with status code 1.
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func Fatal(ctx context.Context, xs ...Fer) {
DefaultLogger.Fatal(ctx, xs...)
}
// FatalErr combines Fatal and Error.
func FatalErr(ctx context.Context, err error, xs ...Fer) {
DefaultLogger.FatalErr(ctx, err, xs...)
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}