forked from h2ik/go-sqs-poller
/
worker.go
153 lines (130 loc) · 3.94 KB
/
worker.go
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package worker
import (
"context"
"fmt"
"log"
"sync"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/service/sqs"
)
// HandlerFunc is used to define the Handler that is run on for each message
type HandlerFunc func(msg *sqs.Message) error
// HandleMessage wraps a function for handling sqs messages
func (f HandlerFunc) HandleMessage(msg *sqs.Message) error {
return f(msg)
}
// Handler interface
type Handler interface {
HandleMessage(msg *sqs.Message) error
}
// InvalidEventError struct
type InvalidEventError struct {
event string
msg string
}
func (e InvalidEventError) Error() string {
return fmt.Sprintf("[Invalid Event: %s] %s", e.event, e.msg)
}
// NewInvalidEventError creates InvalidEventError struct
func NewInvalidEventError(event, msg string) InvalidEventError {
return InvalidEventError{event: event, msg: msg}
}
// QueueAPI interface is the minimum interface required from a queue implementation to invoke New worker.
// Invoking worker.New() takes in a queue name which is why GetQueueUrl is needed.
type QueueAPI interface {
GetQueueUrl(*sqs.GetQueueUrlInput) (*sqs.GetQueueUrlOutput, error)
QueueDeleteReceiverAPI
}
// QueueDeleteReceiverAPI interface is the minimum interface required to run a worker.
// When a worker is in its Receive loop, it requires this interface.
type QueueDeleteReceiverAPI interface {
DeleteMessage(*sqs.DeleteMessageInput) (*sqs.DeleteMessageOutput, error)
ReceiveMessage(*sqs.ReceiveMessageInput) (*sqs.ReceiveMessageOutput, error)
}
// Worker struct
type Worker struct {
Config *Config
Log LoggerIFace
SqsClient QueueDeleteReceiverAPI
}
// Config struct
type Config struct {
MaxNumberOfMessage int64
QueueName string
QueueURL string
WaitTimeSecond int64
}
// New sets up a new Worker
func New(client QueueAPI, config *Config) *Worker {
config.populateDefaultValues()
config.QueueURL = getQueueURL(client, config.QueueName)
return &Worker{
Config: config,
Log: &logger{},
SqsClient: client,
}
}
// Start starts the polling and will continue polling till the application is forcibly stopped
func (worker *Worker) Start(ctx context.Context, h Handler) {
for {
select {
case <-ctx.Done():
log.Println("worker: Stopping polling because a context kill signal was sent")
return
default:
worker.Log.Debug("worker: Start Polling")
params := &sqs.ReceiveMessageInput{
QueueUrl: aws.String(worker.Config.QueueURL), // Required
MaxNumberOfMessages: aws.Int64(worker.Config.MaxNumberOfMessage),
AttributeNames: []*string{
aws.String("All"), // Required
},
WaitTimeSeconds: aws.Int64(worker.Config.WaitTimeSecond),
}
resp, err := worker.SqsClient.ReceiveMessage(params)
if err != nil {
log.Println(err)
continue
}
if len(resp.Messages) > 0 {
worker.run(h, resp.Messages)
}
}
}
}
// poll launches goroutine per received message and wait for all message to be processed
func (worker *Worker) run(h Handler, messages []*sqs.Message) {
numMessages := len(messages)
worker.Log.Info(fmt.Sprintf("worker: Received %d messages", numMessages))
var wg sync.WaitGroup
wg.Add(numMessages)
for i := range messages {
go func(m *sqs.Message) {
// launch goroutine
defer wg.Done()
if err := worker.handleMessage(m, h); err != nil {
worker.Log.Error(err.Error())
}
}(messages[i])
}
wg.Wait()
}
func (worker *Worker) handleMessage(m *sqs.Message, h Handler) error {
var err error
err = h.HandleMessage(m)
if _, ok := err.(InvalidEventError); ok {
worker.Log.Error(err.Error())
} else if err != nil {
return err
}
params := &sqs.DeleteMessageInput{
QueueUrl: aws.String(worker.Config.QueueURL), // Required
ReceiptHandle: m.ReceiptHandle, // Required
}
_, err = worker.SqsClient.DeleteMessage(params)
if err != nil {
return err
}
worker.Log.Debug(fmt.Sprintf("worker: deleted message from queue: %s", aws.StringValue(m.ReceiptHandle)))
return nil
}