README
¶
Fader
In-Memory storage that distributes items via UDP multicast.
Interface
type Fader interface {
Put([]byte, time.Time, []byte) error
Get([]byte) (time.Time, []byte)
Earliest() ([]byte, time.Time, []byte)
Select([]byte) [][]byte
Size() int
Close() error
}
A remove function is missing, because every stored item is supposed to expire after a defined period of time. See the memory fader implementation for details.
Memory Fader
An implementation of the Fader interface, that stores all items in memory using container/heap. The
constructor function takes a time.Duration that specifies the period after which a stored item is removed.
memoryFader := fader.NewMemory(1*time.Second)
defer memoryFader.Close()
memoryFader.Put([]byte("key"), time.Now(), []byte("value"))
memoryFader.Size() // => 1
time.Sleep(2*time.Second)
memoryFader.Size() // => 0
Multicast Fader
Another implementation of the Fader interface. It does not store item directly, but delegates them to a given
parent instance. Additionally, every Store operation is converted into an UDP packet which is sent to the
given multicast group. The packet is encrypted using the given key.
multicastFaderOne := fader.NewMulticast(memoryFaderOne, "224.0.0.1:1888", key)
defer multicastFaderOne.Close()
multicastFaderTwo := fader.NewMulticast(memoryFaderTwo, "224.0.0.1:1888", key)
defer multicastFaderTwo.Close()
multicastFaderOne.Put([]byte("key"), time.Now(), []byte("value"))
multicastFaderOne.Size() // => 1
time.Sleep(10*time.Millisecond)
multicastFaderTwo.Size() // => 1
Contribution
Any contribution is welcome! Feel free to open an issue or do a pull request.
Documentation
¶
Overview ¶
Package fader provides an interface to store and fetch items. The implementation is responsible for the removal after a expiry period.
Example for a memory fader, that expires items after 2 seconds
memoryFader := fader.NewMemory(2*time.Second)
defer memoryFader.Close()
memoryFader.Put([]byte("key"), time.Now(), []byte("value"))
memoryFader.Size() // => 1
time.Sleep(3*time.Second)
memoryFader.Size() // => 0
The multicast fader can be used to distribute `Put` operations via a multicast group. Other instances that listen to the same group, will perform that operation on their own, so that each instance end up with the same data.
multicastFaderOne := fader.NewMulticast(memoryFaderOne, "224.0.0.1:1888", key)
defer multicastFaderOne.Close()
multicastFaderTwo := fader.NewMulticast(memoryFaderTwo, "224.0.0.1:1888", key)
defer multicastFaderTwo.Close()
multicastFaderOne.Put([]byte("key"), time.Now(), []byte("value"))
multicastFaderOne.Size() // => 1
time.Sleep(10*time.Millisecond)
multicastFaderTwo.Size() // => 1
Index ¶
- Variables
- type Fader
- type Memory
- func (m *Memory) Clear()
- func (m *Memory) Close() error
- func (m *Memory) Earliest() ([]byte, time.Time, []byte)
- func (m *Memory) Get(key []byte) (time.Time, []byte)
- func (m *Memory) Put(key []byte, t time.Time, value []byte) error
- func (m *Memory) Select(key []byte) ([]time.Time, [][]byte)
- func (m *Memory) Size() int
- type Multicast
- func (m *Multicast) Clear()
- func (m *Multicast) Close() error
- func (m *Multicast) Earliest() ([]byte, time.Time, []byte)
- func (m *Multicast) Get(key []byte) (time.Time, []byte)
- func (m *Multicast) Put(key []byte, time time.Time, value []byte) error
- func (m *Multicast) Select(key []byte) ([]time.Time, [][]byte)
- func (m *Multicast) Size() int
- type ReceivedHandler
Constants ¶
This section is empty.
Variables ¶
var ErrInvalidKeyLength = errors.New("invalid key length")
ErrInvalidKeyLength is returns if a key with an invalid length is provided. Valid lengths are 16, 24 and 32.
Functions ¶
This section is empty.
Types ¶
type Fader ¶
type Fader interface {
Put([]byte, time.Time, []byte) error
Get([]byte) (time.Time, []byte)
Earliest() ([]byte, time.Time, []byte)
Select([]byte) ([]time.Time, [][]byte)
Size() int
Clear()
Close() error
}
Fader defines the fader interface.
type Memory ¶
type Memory struct {
// contains filtered or unexported fields
}
Memory implements a memory fader.
func NewMemory ¶
NewMemory creates a Fader instance that stores all data in the Memory. The expiresIn parameter defines after which period a stored item will be removed.
func (*Memory) Clear ¶ added in v0.3.0
func (m *Memory) Clear()
Clear removes all items from the fader.
func (*Memory) Get ¶
Get returns time and value for the provided key. If no such key exists, a value of nil is returned.
type Multicast ¶
type Multicast struct {
// contains filtered or unexported fields
}
Multicast implements a multicast faader.
func NewMulticast ¶
func NewMulticast( parent Fader, address string, key []byte, id []byte, itemReceivedHandler ReceivedHandler, ) (*Multicast, error)
NewMulticast creates a Fader instance that delegates all calls to a parent Fader instance. Additional to that, all store-operations are published to a Multicast group which is specified by the given address. All packets will encrypted with AES-GCM using the given key. The length of the key's byte-slice, can be 16, 24 or 32 and will define if AES-128, AES-192 or AES-256 is used. A 10-byte long id can be set to avoid collisions. If no id is nil, a random id will be generated. The argument can take a function that is called every time an item is received. If the function is nil or returns true, the received item will be stored in the parent fader. Otherwise, the item will be dismissed.
func (*Multicast) Clear ¶ added in v0.3.0
func (m *Multicast) Clear()
Clear performs a clear on the parent fader.
func (*Multicast) Earliest ¶
Earliest returns key, time and value of the earliest item in the fader.
func (*Multicast) Get ¶
Get returns time and value for the provided key. If no such key exists, a value of nil is returned.
Source Files
Directories