README
¶
boltqueue
-- import "github.com/alaska/boltqueue"
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.
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 (*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(filename string) (*PQueue, error)
NewPQueue 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() (*Message, error)
Dequeue removes the oldest, highest priority message from the queue and returns it
func (*PQueue) Enqueue
func (b *PQueue) Enqueue(priority int, message *Message) error
Enqueue adds a message to the queue
func (*PQueue) Requeue
func (b *PQueue) Requeue(priority int, message *Message) error
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.
func (*PQueue) Size
func (b *PQueue) Size(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/McSwitch/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 ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Message ¶
type Message struct {
// contains filtered or unexported fields
}
Message represents a message in the priority queue
func NewMessage ¶
NewMessage generates a new priority queue message
type Options ¶
type Options struct {
// Timeout is the amount of time to wait to obtain a file lock.
// When set to zero it will wait indefinitely. This option is only
// available on Darwin and Linux.
Timeout time.Duration
// Sets the DB.NoGrowSync flag before memory mapping the file.
NoGrowSync bool
// Open database in read-only mode. Uses flock(..., LOCK_SH |LOCK_NB) to
// grab a shared lock (UNIX).
ReadOnly bool
// Sets the DB.MmapFlags flag before memory mapping the file.
MmapFlags int
// InitialMmapSize is the initial mmap size of the database
// in bytes. Read transactions won't block write transaction
// if the InitialMmapSize is large enough to hold database mmap
// size. (See DB.Begin for more information)
//
// If <=0, the initial map size is 0.
// If initialMmapSize is smaller than the previous database size,
// it takes no effect.
InitialMmapSize int
}
Options represents the options that can be set when opening a database.
type PQueue ¶
type PQueue struct {
// contains filtered or unexported fields
}
PQueue is a priority queue backed by a Bolt database on disk
func (*PQueue) Dequeue ¶
Dequeue removes the oldest, highest priority message from the queue and returns it
Source Files