GoBlog/queue.go

57 lines
1.7 KiB
Go

package main
import (
"database/sql"
"errors"
"time"
"github.com/araddon/dateparse"
)
type queueItem struct {
id int
name string
content []byte
schedule *time.Time
}
func (db *database) enqueue(name string, content []byte, schedule time.Time) error {
if len(content) == 0 {
return errors.New("empty content")
}
_, err := db.exec("insert into queue (name, content, schedule) values (@name, @content, @schedule)",
sql.Named("name", name), sql.Named("content", content), sql.Named("schedule", schedule.UTC().Format(time.RFC3339)))
return err
}
func (db *database) reschedule(qi *queueItem, dur time.Duration) error {
_, err := db.exec("update queue set schedule = @schedule, content = @content where id = @id", sql.Named("schedule", qi.schedule.Add(dur).UTC().Format(time.RFC3339)), sql.Named("content", qi.content), sql.Named("id", qi.id))
return err
}
func (db *database) dequeue(qi *queueItem) error {
_, err := db.exec("delete from queue where id = @id", sql.Named("id", qi.id))
return err
}
func (db *database) peekQueue(name string) (*queueItem, error) {
row, err := db.queryRow("select id, name, content, schedule from queue where schedule <= @schedule and name = @name order by schedule asc limit 1", sql.Named("name", name), sql.Named("schedule", time.Now().UTC().Format(time.RFC3339)))
if err != nil {
return nil, err
}
qi := &queueItem{}
var timeString string
if err = row.Scan(&qi.id, &qi.name, &qi.content, &timeString); err != nil {
if errors.Is(err, sql.ErrNoRows) {
return nil, nil
}
return nil, err
}
t, err := dateparse.ParseIn(timeString, time.UTC)
if err != nil {
return nil, err
}
qi.schedule = &t
return qi, nil
}