本文整理匯總了Golang中github.com/djbarber/ipfs-hack/Godeps/_workspace/src/golang.org/x/net/context.Context.Deadline方法的典型用法代碼示例。如果您正苦於以下問題：Golang Context.Deadline方法的具體用法？Golang Context.Deadline怎麽用？Golang Context.Deadline使用的例子？那麽, 這裏精選的方法代碼示例或許可以為您提供幫助。您也可以進一步了解該方法所在類github.com/djbarber/ipfs-hack/Godeps/_workspace/src/golang.org/x/net/context.Context的用法示例。
在下文中一共展示了Context.Deadline方法的1個代碼示例，這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚，您的評價將有助於係統推薦出更棒的Golang代碼示例。
示例1: WithDeadlineFraction
// WithDeadlineFraction returns a Context with a fraction of the
// original context's timeout. This is useful in sequential pipelines
// of work, where one might try options and fall back to others
// depending on the time available, or failure to respond. For example:
//
// // getPicture returns a picture from our encrypted database
// // we have a pipeline of multiple steps. we need to:
// // - get the data from a database
// // - decrypt it
// // - apply many transforms
// //
// // we **know** that each step takes increasingly more time.
// // The transforms are much more expensive than decryption, and
// // decryption is more expensive than the database lookup.
// // If our database takes too long (i.e. >0.2 of available time),
// // there's no use in continuing.
// func getPicture(ctx context.Context, key string) ([]byte, error) {
// // fractional timeout contexts to the rescue!
//
// // try the database with 0.2 of remaining time.
// ctx1, _ := ctxext.WithDeadlineFraction(ctx, 0.2)
// val, err := db.Get(ctx1, key)
// if err != nil {
// return nil, err
// }
//
// // try decryption with 0.3 of remaining time.
// ctx2, _ := ctxext.WithDeadlineFraction(ctx, 0.3)
// if val, err = decryptor.Decrypt(ctx2, val); err != nil {
// return nil, err
// }
//
// // try transforms with all remaining time. hopefully it's enough!
// return transformer.Transform(ctx, val)
// }
//
//
func WithDeadlineFraction(ctx context.Context, fraction float64) (
context.Context, context.CancelFunc) {
d, found := ctx.Deadline()
if !found { // no deadline
return context.WithCancel(ctx)
}
left := d.Sub(time.Now())
if left < 0 { // already passed...
return context.WithCancel(ctx)
}
left = time.Duration(float64(left) * fraction)
return context.WithTimeout(ctx, left)
}