components-contrib/bindings/cron/cron.go

105 lines
2.7 KiB
Go

// ------------------------------------------------------------
// Copyright (c) Microsoft Corporation and Dapr Contributors.
// Licensed under the MIT License.
// ------------------------------------------------------------
package cron
import (
"fmt"
"time"
"github.com/pkg/errors"
"github.com/robfig/cron/v3"
"github.com/dapr/components-contrib/bindings"
"github.com/dapr/kit/logger"
)
// Binding represents Cron input binding.
type Binding struct {
logger logger.Logger
schedule string
stopCh chan bool
parser cron.Parser
}
var _ = bindings.InputBinding(&Binding{})
// NewCron returns a new Cron event input binding.
func NewCron(logger logger.Logger) *Binding {
return &Binding{
logger: logger,
stopCh: make(chan bool),
parser: cron.NewParser(
cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
),
}
}
// Init initializes the Cron binding
// Examples from https://godoc.org/github.com/robfig/cron:
// "15 * * * * *" - Every 15 sec
// "0 30 * * * *" - Every 30 min
func (b *Binding) Init(metadata bindings.Metadata) error {
s, f := metadata.Properties["schedule"]
if !f || s == "" {
return fmt.Errorf("schedule not set")
}
_, err := b.parser.Parse(s)
if err != nil {
return errors.Wrapf(err, "invalid schedule format: %s", s)
}
b.schedule = s
return nil
}
// Read triggers the Cron scheduler.
func (b *Binding) Read(handler func(*bindings.ReadResponse) ([]byte, error)) error {
c := cron.New(cron.WithParser(b.parser))
id, err := c.AddFunc(b.schedule, func() {
b.logger.Debugf("schedule fired: %v", time.Now())
handler(&bindings.ReadResponse{
Metadata: map[string]string{
"timeZone": c.Location().String(),
"readTimeUTC": time.Now().UTC().String(),
},
})
})
if err != nil {
return errors.Wrapf(err, "error scheduling %s", b.schedule)
}
c.Start()
b.logger.Debugf("next run: %v", time.Until(c.Entry(id).Next))
<-b.stopCh
b.logger.Debugf("stopping schedule: %s", b.schedule)
c.Stop()
return nil
}
// Invoke exposes way to stop previously started cron.
func (b *Binding) Invoke(req *bindings.InvokeRequest) (*bindings.InvokeResponse, error) {
b.logger.Debugf("operation: %v", req.Operation)
if req.Operation != bindings.DeleteOperation {
return nil, fmt.Errorf("invalid operation: '%v', only '%v' supported",
req.Operation, bindings.DeleteOperation)
}
b.stopCh <- true
return &bindings.InvokeResponse{
Metadata: map[string]string{
"schedule": b.schedule,
"stopTimeUTC": time.Now().UTC().String(),
},
}, nil
}
// Operations method returns the supported operations by this binding.
func (b *Binding) Operations() []bindings.OperationKind {
return []bindings.OperationKind{
bindings.DeleteOperation,
}
}