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