micro/sync/task/task.go
2019-05-31 00:43:23 +01:00

84 lines
1.4 KiB
Go

// Package task provides an interface for distributed jobs
package task
import (
"context"
"fmt"
"time"
)
// Task represents a distributed task
type Task interface {
// Run runs a command immediately until completion
Run(Command) error
// Status provides status of last execution
Status() string
}
// Command to be executed
type Command struct {
Name string
Func func() error
}
// Schedule represents a time or interval at which a task should run
type Schedule struct {
// When to start the schedule. Zero time means immediately
Time time.Time
// Non zero interval dictates an ongoing schedule
Interval time.Duration
}
type Options struct {
// Pool size for workers
Pool int
// Alternative options
Context context.Context
}
type Option func(o *Options)
func (c Command) Execute() error {
return c.Func()
}
func (c Command) String() string {
return c.Name
}
func (s Schedule) Run() <-chan time.Time {
d := s.Time.Sub(time.Now())
ch := make(chan time.Time, 1)
go func() {
// wait for start time
<-time.After(d)
// zero interval
if s.Interval == time.Duration(0) {
ch <- time.Now()
close(ch)
return
}
// start ticker
for t := range time.Tick(s.Interval) {
ch <- t
}
}()
return ch
}
func (s Schedule) String() string {
return fmt.Sprintf("%d-%d", s.Time.Unix(), s.Interval)
}
// WithPool sets the pool size for concurrent work
func WithPool(i int) Option {
return func(o *Options) {
o.Pool = i
}
}