retry

Documentation

Index

• Constants
• func WithSizes(size int, max int, f SizeFunc)
• type Hint
  • func Size(s int) Hint
• type SizeFunc

Examples

• WithSizes
• WithSizes (Hint)

Constants

const DoubleSize = hintInt(0)

DoubleSize is a hint to retry with double the size

Functions

func WithSizes

func WithSizes(size int, max int, f SizeFunc)

WithSizes repeatingly calls a SizeFunc with increasing sizes until either it returns nil, or the max size has been reached. If the returned hint is DoubleSize or indicating a size not greater than the current size, the size is doubled. If the hint or next size is greater than the max size, the max size is used for a last retry.

Example

var err error
WithSizes(1, 128, func(size int) Hint {
	buf := make([]string, size)
	// do something complex with buf
	err = fakeComplexOp(buf)
	return DoubleSize.If(err == errTooSmall)
})

Output:

too small: 1
too small: 2
too small: 4
too small: 8
too small: 16
good size: 32

Example (Hint)

var err error
WithSizes(1, 128, func(size int) Hint {
	buf := make([]string, size)
	// do something complex with buf
	err = fakeComplexOp2(buf, &size)
	return Size(size).If(err == errTooSmall)
})

Output:

too small: 1
good size: 30

Types

type Hint

type Hint interface {
	If(bool) Hint
	// contains filtered or unexported methods
}

Hint is a type for retry hints

func Size

func Size(s int) Hint

Size returns a hint for a specific size

type SizeFunc

type SizeFunc func(size int) (hint Hint)

SizeFunc is used to implement 'resize loops' that hides the complexity of the sizing away from most of the application. It's a function that takes a size argument and returns nil, if no retry is necessary, or a hint indicating the size for the next retry. If errors or other results are required from the function, the function can write them to function closures of the surrounding scope. See tests for examples.