prometheus/vendor/github.com/go-kit/kit/log/value.go
2017-02-07 03:42:02 -08:00

63 lines
1.8 KiB
Go

package log
import (
"time"
"github.com/go-stack/stack"
)
// A Valuer generates a log value. When passed to Context.With in a value
// element (odd indexes), it represents a dynamic value which is re-evaluated
// with each log event.
type Valuer func() interface{}
// bindValues replaces all value elements (odd indexes) containing a Valuer
// with their generated value.
func bindValues(keyvals []interface{}) {
for i := 1; i < len(keyvals); i += 2 {
if v, ok := keyvals[i].(Valuer); ok {
keyvals[i] = v()
}
}
}
// containsValuer returns true if any of the value elements (odd indexes)
// contain a Valuer.
func containsValuer(keyvals []interface{}) bool {
for i := 1; i < len(keyvals); i += 2 {
if _, ok := keyvals[i].(Valuer); ok {
return true
}
}
return false
}
// Timestamp returns a Valuer that invokes the underlying function when bound,
// returning a time.Time. Users will probably want to use DefaultTimestamp or
// DefaultTimestampUTC.
func Timestamp(t func() time.Time) Valuer {
return func() interface{} { return t() }
}
var (
// DefaultTimestamp is a Valuer that returns the current wallclock time,
// respecting time zones, when bound.
DefaultTimestamp Valuer = func() interface{} { return time.Now().Format(time.RFC3339) }
// DefaultTimestampUTC is a Valuer that returns the current time in UTC
// when bound.
DefaultTimestampUTC Valuer = func() interface{} { return time.Now().UTC().Format(time.RFC3339) }
)
// Caller returns a Valuer that returns a file and line from a specified depth
// in the callstack. Users will probably want to use DefaultCaller.
func Caller(depth int) Valuer {
return func() interface{} { return stack.Caller(depth) }
}
var (
// DefaultCaller is a Valuer that returns the file and line where the Log
// method was invoked. It can only be used with log.With.
DefaultCaller = Caller(3)
)