harness-drone/model/queue.go
2017-06-28 13:21:22 -04:00

78 lines
1.9 KiB
Go

package model
import (
"context"
"github.com/Sirupsen/logrus"
"github.com/cncd/queue"
)
// Task defines scheduled pipeline Task.
type Task struct {
ID string `meddler:"task_id"`
Data []byte `meddler:"task_data"`
Labels map[string]string `meddler:"task_labels,json"`
}
// TaskStore defines storage for scheduled Tasks.
type TaskStore interface {
TaskList() ([]*Task, error)
TaskInsert(*Task) error
TaskDelete(string) error
}
// WithTaskStore returns a queue that is backed by the TaskStore. This
// ensures the task Queue can be restored when the system starts.
func WithTaskStore(q queue.Queue, s TaskStore) queue.Queue {
tasks, _ := s.TaskList()
for _, task := range tasks {
q.Push(context.Background(), &queue.Task{
ID: task.ID,
Data: task.Data,
Labels: task.Labels,
})
}
return &persistentQueue{q, s}
}
type persistentQueue struct {
queue.Queue
store TaskStore
}
// Push pushes an task to the tail of this queue.
func (q *persistentQueue) Push(c context.Context, task *queue.Task) error {
q.store.TaskInsert(&Task{
ID: task.ID,
Data: task.Data,
Labels: task.Labels,
})
err := q.Queue.Push(c, task)
if err != nil {
q.store.TaskDelete(task.ID)
}
return err
}
// Poll retrieves and removes a task head of this queue.
func (q *persistentQueue) Poll(c context.Context, f queue.Filter) (*queue.Task, error) {
task, err := q.Queue.Poll(c, f)
if task != nil {
logrus.Debugf("pull queue item: %s: remove from backup", task.ID)
if derr := q.store.TaskDelete(task.ID); derr != nil {
logrus.Errorf("pull queue item: %s: failed to remove from backup: %s", task.ID, derr)
} else {
logrus.Debugf("pull queue item: %s: successfully removed from backup", task.ID)
}
}
return task, err
}
// Evict removes a pending task from the queue.
func (q *persistentQueue) Evict(c context.Context, id string) error {
err := q.Queue.Evict(c, id)
if err == nil {
q.store.TaskDelete(id)
}
return err
}