zlog/ctx.go

52 lines
1.2 KiB
Go

package zlog
import (
"context"
)
var disabledLogger *Logger
func init() {
SetGlobalLevel(TraceLevel)
l := Nop()
disabledLogger = &l
}
type ctxKey struct{}
// WithContext returns a copy of ctx with l associated. If an instance of Logger
// is already in the context, the context is not updated.
//
// For instance, to add a field to an existing logger in the context, use this
// notation:
//
// ctx := r.Context()
// l := zlog.Ctx(ctx)
// l.UpdateContext(func(c Context) Context {
// return c.Str("bar", "baz")
// })
func (l Logger) WithContext(ctx context.Context) context.Context {
if lp, ok := ctx.Value(ctxKey{}).(*Logger); ok {
if lp == &l {
// Do not store same logger.
return ctx
}
} else if l.level == Disabled {
// Do not store disabled logger.
return ctx
}
return context.WithValue(ctx, ctxKey{}, &l)
}
// Ctx returns the Logger associated with the ctx. If no logger
// is associated, DefaultContextLogger is returned, unless DefaultContextLogger
// is nil, in which case a disabled logger is returned.
func Ctx(ctx context.Context) *Logger {
if l, ok := ctx.Value(ctxKey{}).(*Logger); ok {
return l
} else if l = DefaultContextLogger; l != nil {
return l
}
return disabledLogger
}