/
handler.go
95 lines (77 loc) · 2.7 KB
/
handler.go
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// Package redriver allows in-code retry handling retry of SQS message, and partial failures in multi-message processing.
package redriver
import (
"errors"
"fmt"
"github.com/aws/aws-lambda-go/events"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/sqs"
log "github.com/sirupsen/logrus"
)
// Redriver is the main struct used to store policy and redrive messages.
type Redriver struct {
ConsumedQueueURL string
Retries uint64
Debug bool
}
// MessageProcessor is the required function signature for processors.
type MessageProcessor = func(event events.SQSMessage) error
func (redriver Redriver) deleteProcessedMessages(processedMessages processResults, sqsConnector *sqs.SQS) error {
for _, processedMessage := range processedMessages.successResults {
if redriver.Debug {
log.Infof("Debug mode enabled. Mocking deletion of message with ID %s", processedMessage.message.MessageId)
continue
}
_, err := sqsConnector.DeleteMessage(&sqs.DeleteMessageInput{
QueueUrl: &redriver.ConsumedQueueURL,
ReceiptHandle: &processedMessage.message.ReceiptHandle,
})
if err != nil {
return err
}
}
return nil
}
func (redriver Redriver) processMessageAsync(message events.SQSMessage, processor MessageProcessor, processResultChannel chan<- *processResult) {
go func() {
var processorError error
for i := uint64(1); i <= redriver.Retries; i++ {
processorError = processor(message)
if processorError == nil {
break
}
}
processResultChannel <- newProcessResult(message, processorError)
}()
}
// HandleMessages handles asynchronously all SQS messages, and deletes it when they are processed.
func (redriver Redriver) HandleMessages(messages []events.SQSMessage, processor MessageProcessor) error {
if redriver.Retries < 1 {
return errors.New("retries must be 1 or above")
}
var sqsConnector *sqs.SQS
if !redriver.Debug {
awsSession, err := session.NewSession()
if err != nil {
return fmt.Errorf("can't create an AWS session, reason: %s", err.Error())
}
sqsConnector = sqs.New(awsSession)
}
processedMessagesResult := newProcessResults(messages)
processResultChannel := make(chan *processResult)
defer close(processResultChannel)
for _, message := range messages {
redriver.processMessageAsync(message, processor, processResultChannel)
}
for i := 0; i < processedMessagesResult.messagesCount; i++ {
res := <-processResultChannel
processedMessagesResult.addResult(res)
}
if processedMessagesResult.hasOnlySuccessfulMessages() {
return nil
}
if err := redriver.deleteProcessedMessages(*processedMessagesResult, sqsConnector); err != nil {
return err
}
return processResultsError{Results: *processedMessagesResult}
}