import "jaytaylor.com/bboltqueue"Package boltqueue provides a persistent queue or priority queue based on boltdb.
Based on boltqueue.
boltqueue's PQueue type represents a priority queue. Messages may be inserted into the queue at a numeric priority between 0(highest) and 255(lowest). Messages are dequeued following priority order, then time ordering, with the oldest messages of the highest priority emerging first.
- Go v1.7 or newer
type Message struct {
}Message represents a message in the priority queue
func NewMessage(value string) *MessageNewMessage generates a new priority queue message
func NewMessageB(value []byte) *MessageNewMessageB generates a new priority queue message from a byte slice
func (m *Message) Priority() intPriority returns the priority the message had in the queue in the range of 0-255 or -1 if the message is new.
func (m *Message) ToString() stringToString outputs the string representation of the message's value
type PQueue struct {
}PQueue is a priority queue backed by a Bolt database on disk
func NewPQueue(db *bolt.DB) (*PQueue, error)NewPQueue uses an already open *bolt.DB
func NewPQueueFromFile(filename string) (*PQueue, error)NewPQueueFromFile loads or creates a new PQueue with the given filename
func (b *PQueue) Close() errorClose closes the queue and releases all resources
func (b *PQueue) Dequeue(topic string) (*Message, error)Dequeue removes the oldest, highest priority message from the queue of the named topic and returns it
func (b *PQueue) Enqueue(topic string, priority int, message *Message) errorEnqueue adds a message to the queue filed under the specified topic
func (b *PQueue) Scan(topic string, fn func(m *Message)Invokes the supplied callback function on each message for the named topic.
func (b *PQueue) ScanWithBreak(topic string, fn func(m *Message)Invokes the supplied callback function on each message for the named topic until the callback returns false.
func (b *PQueue) Requeue(topic string, priority int, message *Message) errorRequeue adds a message back into the topic queue, keeping its precedence. If added at the same priority, it should be among the first to dequeue. If added at a different priority, it will dequeue before newer messages of that priority.
func (b *PQueue) Size(topic string, priority int) (int, error)Size returns the number of entries of a given priority from 1 to 5