queue

README

Go package provides a common interface for working with task queues.

Documentation:

    http://godoc.org/github.com/cncd/queue
    http://godoc.org/github.com/cncd/queue/gcp

Documentation

Index

• Variables
• type Filter
• type InfoT
• type Queue
  • func New() Queue
• type Task

Variables

var (
	// ErrCancel indicates the task was cancelled.
	ErrCancel = errors.New("queue: task cancelled")

	// ErrNotFound indicates the task was not found in the queue.
	ErrNotFound = errors.New("queue: task not found")
)

Types

type Filter

type Filter func(*Task) bool

Filter filters tasks in the queue. If the Filter returns false, the Task is skipped and not returned to the subscriber.

type InfoT

type InfoT struct {
	Pending []*Task `json:"pending"`
	Running []*Task `json:"running"`
	Stats   struct {
		Workers  int `json:"worker_count"`
		Pending  int `json:"pending_count"`
		Running  int `json:"running_count"`
		Complete int `json:"completed_count"`
	} `json:"stats"`
}

InfoT provides runtime information.

type Queue

type Queue interface {
	// Push pushes an task to the tail of this queue.
	Push(c context.Context, task *Task) error

	// Poll retrieves and removes a task head of this queue.
	Poll(c context.Context, f Filter) (*Task, error)

	// Extend extends the deadline for a task.
	Extend(c context.Context, id string) error

	// Done signals the task is complete.
	Done(c context.Context, id string) error

	// Error signals the task is complete with errors.
	Error(c context.Context, id string, err error) error

	// Evict removes a pending task from the queue.
	Evict(c context.Context, id string) error

	// Wait waits until the task is complete.
	Wait(c context.Context, id string) error

	// Info returns internal queue information.
	Info(c context.Context) InfoT
}

Queue defines a task queue for scheduling tasks among a pool of workers.

func New

func New() Queue

New returns a new fifo queue.

type Task

type Task struct {
	// ID identifies this task.
	ID string `json:"id,omitempty"`

	// Data is the actual data in the entry.
	Data []byte `json:"data"`

	// Labels represents the key-value pairs the entry is lebeled with.
	Labels map[string]string `json:"labels,omitempty"`
}

Task defines a unit of work in the queue.