44 lines
		
	
	
		
			865 B
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			44 lines
		
	
	
		
			865 B
		
	
	
	
		
			Go
		
	
	
	
	
	
| package meter
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| 
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| import (
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| 	"context"
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| )
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| 
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| type meterKey struct{}
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| 
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| // FromContext get meter from context
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| func FromContext(ctx context.Context) (Meter, bool) {
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| 	if ctx == nil {
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| 		return nil, false
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| 	}
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| 	c, ok := ctx.Value(meterKey{}).(Meter)
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| 	return c, ok
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| }
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| 
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| // MustContext get meter from context
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| func MustContext(ctx context.Context) Meter {
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| 	m, ok := FromContext(ctx)
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| 	if !ok {
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| 		panic("missing meter")
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| 	}
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| 	return m
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| }
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| 
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| // NewContext put meter in context
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| func NewContext(ctx context.Context, c Meter) context.Context {
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| 	if ctx == nil {
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| 		ctx = context.Background()
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| 	}
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| 	return context.WithValue(ctx, meterKey{}, c)
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| }
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| 
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| // SetOption returns a function to setup a context with given value
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| func SetOption(k, v interface{}) Option {
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| 	return func(o *Options) {
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| 		if o.Context == nil {
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| 			o.Context = context.Background()
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| 		}
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| 		o.Context = context.WithValue(o.Context, k, v)
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| 	}
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| }
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