113 lines
3.0 KiB
Go
113 lines
3.0 KiB
Go
/*
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Copyright 2021 The Dapr Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cron
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import (
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"fmt"
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"time"
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"github.com/pkg/errors"
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"github.com/robfig/cron/v3"
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"github.com/dapr/components-contrib/bindings"
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"github.com/dapr/kit/logger"
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)
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// Binding represents Cron input binding.
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type Binding struct {
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logger logger.Logger
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schedule string
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stopCh chan bool
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parser cron.Parser
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}
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var _ = bindings.InputBinding(&Binding{})
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// NewCron returns a new Cron event input binding.
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func NewCron(logger logger.Logger) *Binding {
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return &Binding{
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logger: logger,
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stopCh: make(chan bool),
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parser: cron.NewParser(
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cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
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),
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}
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}
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// Init initializes the Cron binding
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// Examples from https://godoc.org/github.com/robfig/cron:
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// "15 * * * * *" - Every 15 sec
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// "0 30 * * * *" - Every 30 min
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func (b *Binding) Init(metadata bindings.Metadata) error {
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s, f := metadata.Properties["schedule"]
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if !f || s == "" {
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return fmt.Errorf("schedule not set")
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}
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_, err := b.parser.Parse(s)
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if err != nil {
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return errors.Wrapf(err, "invalid schedule format: %s", s)
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}
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b.schedule = s
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return nil
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}
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// Read triggers the Cron scheduler.
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func (b *Binding) Read(handler func(*bindings.ReadResponse) ([]byte, error)) error {
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c := cron.New(cron.WithParser(b.parser))
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id, err := c.AddFunc(b.schedule, func() {
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b.logger.Debugf("schedule fired: %v", time.Now())
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handler(&bindings.ReadResponse{
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Metadata: map[string]string{
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"timeZone": c.Location().String(),
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"readTimeUTC": time.Now().UTC().String(),
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},
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})
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})
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if err != nil {
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return errors.Wrapf(err, "error scheduling %s", b.schedule)
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}
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c.Start()
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b.logger.Debugf("next run: %v", time.Until(c.Entry(id).Next))
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<-b.stopCh
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b.logger.Debugf("stopping schedule: %s", b.schedule)
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c.Stop()
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return nil
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}
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// Invoke exposes way to stop previously started cron.
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func (b *Binding) Invoke(req *bindings.InvokeRequest) (*bindings.InvokeResponse, error) {
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b.logger.Debugf("operation: %v", req.Operation)
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if req.Operation != bindings.DeleteOperation {
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return nil, fmt.Errorf("invalid operation: '%v', only '%v' supported",
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req.Operation, bindings.DeleteOperation)
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}
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b.stopCh <- true
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return &bindings.InvokeResponse{
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Metadata: map[string]string{
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"schedule": b.schedule,
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"stopTimeUTC": time.Now().UTC().String(),
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},
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}, nil
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}
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// Operations method returns the supported operations by this binding.
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func (b *Binding) Operations() []bindings.OperationKind {
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return []bindings.OperationKind{
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bindings.DeleteOperation,
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}
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}
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