README
¶
bboltqueue
import "jaytaylor.com/bboltqueue"
Package boltqueue provides a persistent queue or priority queue based on boltdb.
Based on boltqueue.
Priority Queue
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.
Requirements
- Go v1.7 or newer
Usage
type Message
type Message struct {
}
Message represents a message in the priority queue
func NewMessage
func NewMessage(value string) *Message
NewMessage generates a new priority queue message
func NewMessageB
func NewMessageB(value []byte) *Message
NewMessageB generates a new priority queue message from a byte slice
func (*Message) Priority
func (m *Message) Priority() int
Priority returns the priority the message had in the queue in the range of 0-255 or -1 if the message is new.
func (*Message) ToString
func (m *Message) ToString() string
ToString outputs the string representation of the message's value
type PQueue
type PQueue struct {
}
PQueue is a priority queue backed by a Bolt database on disk
func NewPQueue
func NewPQueue(db *bolt.DB) (*PQueue, error)
NewPQueue uses an already open *bolt.DB
func NewPQueueFromFile
func NewPQueueFromFile(filename string) (*PQueue, error)
NewPQueueFromFile loads or creates a new PQueue with the given filename
func (*PQueue) Close
func (b *PQueue) Close() error
Close closes the queue and releases all resources
func (*PQueue) Dequeue
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 (*PQueue) Enqueue
func (b *PQueue) Enqueue(topic string, priority int, message *Message) error
Enqueue adds a message to the queue filed under the specified topic
func (*PQueue) Scan
func (b *PQueue) Scan(topic string, fn func(m *Message)
Invokes the supplied callback function on each message for the named topic.
func (*PQueue) ScanWithBreak
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 (*PQueue) Requeue
func (b *PQueue) Requeue(topic string, priority int, message *Message) error
Requeue 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 (*PQueue) Size
func (b *PQueue) Size(topic string, priority int) (int, error)
Size returns the number of entries of a given priority from 1 to 5
Documentation
¶
Overview ¶
Package boltqueue provides a persistent queue or priority queue based on boltdb (https://github.com/boltdb/bolt)
Priority Queue ¶
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.
Index ¶
- type Message
- type PQueue
- func (b *PQueue) Close() error
- func (b *PQueue) Dequeue(topic string) (*Message, error)
- func (b *PQueue) Enqueue(topic string, priority int, messages ...*Message) error
- func (b *PQueue) Len(topic string, priority int) (int, error)
- func (b *PQueue) Requeue(topic string, priority int, messages ...*Message) error
- func (b *PQueue) Scan(topic string, fn func(m *Message)) error
- func (b *PQueue) ScanWithBreak(topic string, fn func(m *Message) bool) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Message ¶
Message represents a message in the priority queue
func NewMessage ¶
NewMessage generates a new priority queue message
func NewMessageB ¶
NewMessageB generates a new priority queue message from a byte slice
type PQueue ¶
type PQueue struct {
// contains filtered or unexported fields
}
PQueue is a priority queue backed by a Bolt database on disk
func NewPQueue ¶
func NewPQueue(db *bolt.DB) *PQueue
NewPQueue consumes an existing opened *bold.DB.
func NewPQueueFromFile ¶
NewPQueueFromFile loads or creates a new PQueue with the given filename
func (*PQueue) Dequeue ¶
Dequeue removes the oldest, highest priority message from the queue and returns it
func (*PQueue) Requeue ¶
Requeue adds a message back into the 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.
Source Files