AWS SQS
Amazon Simple Queue Service (SQS) is a fully managed message queuing service for decoupling and scaling microservices, distributed systems, and serverless applications.
Table of Contents Core Concepts Common Patterns CLI Reference Best Practices Troubleshooting References Core Concepts Queue Types Type Description Use Case Standard At-least-once, best-effort ordering High throughput FIFO Exactly-once, strict ordering Order-sensitive processing Key Settings Setting Description Default Visibility Timeout Time message is hidden after receive 30 seconds Message Retention How long messages are kept 4 days (max 14) Delay Seconds Delay before message is available 0 Max Message Size Maximum message size 256 KB Dead-Letter Queue (DLQ)
Queue for messages that failed processing after maxReceiveCount attempts.
Common Patterns Create a Standard Queue
AWS CLI:
aws sqs create-queue \ --queue-name my-queue \ --attributes '{ "VisibilityTimeout": "60", "MessageRetentionPeriod": "604800", "ReceiveMessageWaitTimeSeconds": "20" }'
boto3:
import boto3
sqs = boto3.client('sqs')
response = sqs.create_queue( QueueName='my-queue', Attributes={ 'VisibilityTimeout': '60', 'MessageRetentionPeriod': '604800', 'ReceiveMessageWaitTimeSeconds': '20' # Long polling } ) queue_url = response['QueueUrl']
Create FIFO Queue aws sqs create-queue \ --queue-name my-queue.fifo \ --attributes '{ "FifoQueue": "true", "ContentBasedDeduplication": "true" }'
Configure Dead-Letter Queue
Create DLQ
aws sqs create-queue --queue-name my-queue-dlq
Get DLQ ARN
DLQ_ARN=$(aws sqs get-queue-attributes \ --queue-url https://sqs.us-east-1.amazonaws.com/123456789012/my-queue-dlq \ --attribute-names QueueArn \ --query 'Attributes.QueueArn' --output text)
Set redrive policy on main queue
aws sqs set-queue-attributes \ --queue-url https://sqs.us-east-1.amazonaws.com/123456789012/my-queue \ --attributes "{ \"RedrivePolicy\": \"{\\"deadLetterTargetArn\\":\\"${DLQ_ARN}\\",\\"maxReceiveCount\\":\\"3\\"}\" }"
Send Messages import boto3 import json
sqs = boto3.client('sqs') queue_url = 'https://sqs.us-east-1.amazonaws.com/123456789012/my-queue'
Send single message
sqs.send_message( QueueUrl=queue_url, MessageBody=json.dumps({'order_id': '12345', 'action': 'process'}), MessageAttributes={ 'MessageType': { 'DataType': 'String', 'StringValue': 'Order' } } )
Send to FIFO queue
sqs.send_message( QueueUrl='https://sqs.us-east-1.amazonaws.com/123456789012/my-queue.fifo', MessageBody=json.dumps({'order_id': '12345'}), MessageGroupId='order-12345', MessageDeduplicationId='unique-id-12345' )
Batch send (up to 10 messages)
sqs.send_message_batch( QueueUrl=queue_url, Entries=[ {'Id': '1', 'MessageBody': json.dumps({'id': 1})}, {'Id': '2', 'MessageBody': json.dumps({'id': 2})}, {'Id': '3', 'MessageBody': json.dumps({'id': 3})} ] )
Receive and Process Messages import boto3 import json
sqs = boto3.client('sqs') queue_url = 'https://sqs.us-east-1.amazonaws.com/123456789012/my-queue'
while True: # Long polling (wait up to 20 seconds) response = sqs.receive_message( QueueUrl=queue_url, MaxNumberOfMessages=10, WaitTimeSeconds=20, MessageAttributeNames=['All'], AttributeNames=['All'] )
messages = response.get('Messages', [])
for message in messages:
try:
body = json.loads(message['Body'])
print(f"Processing: {body}")
# Process message...
# Delete on success
sqs.delete_message(
QueueUrl=queue_url,
ReceiptHandle=message['ReceiptHandle']
)
except Exception as e:
print(f"Error processing message: {e}")
# Message will become visible again after visibility timeout
Lambda Integration
Create event source mapping
aws lambda create-event-source-mapping \ --function-name my-function \ --event-source-arn arn:aws:sqs:us-east-1:123456789012:my-queue \ --batch-size 10 \ --maximum-batching-window-in-seconds 5
Lambda handler:
def handler(event, context): for record in event['Records']: body = json.loads(record['body']) message_id = record['messageId']
try:
process_message(body)
except Exception as e:
# Raise to put message back in queue
raise
return {'batchItemFailures': []}
CLI Reference Queue Management Command Description aws sqs create-queue Create queue aws sqs delete-queue Delete queue aws sqs list-queues List queues aws sqs get-queue-url Get queue URL by name aws sqs get-queue-attributes Get queue settings aws sqs set-queue-attributes Update queue settings Messaging Command Description aws sqs send-message Send single message aws sqs send-message-batch Send up to 10 messages aws sqs receive-message Receive messages aws sqs delete-message Delete message aws sqs delete-message-batch Delete up to 10 messages aws sqs purge-queue Delete all messages Visibility Command Description aws sqs change-message-visibility Change timeout aws sqs change-message-visibility-batch Batch change Best Practices Message Processing Use long polling (WaitTimeSeconds=20) to reduce API calls Delete messages promptly after successful processing Configure appropriate visibility timeout (> processing time) Implement idempotent consumers for at-least-once delivery Dead-Letter Queues Always configure DLQ for production queues Set appropriate maxReceiveCount (usually 3-5) Monitor DLQ depth with CloudWatch alarms Process DLQ messages manually or with automation FIFO Queues Use message group IDs to partition ordering Enable content-based deduplication or provide dedup IDs Throughput: 300 msgs/sec without batching, 3000 with Security Use queue policies to control access Enable encryption with SSE-SQS or SSE-KMS Use VPC endpoints for private access Troubleshooting Messages Not Being Received
Causes:
Short polling returning empty All messages in flight (visibility timeout) Messages delayed (DelaySeconds)
Debug:
Check queue attributes
aws sqs get-queue-attributes \ --queue-url $QUEUE_URL \ --attribute-names All
Check approximate message counts
aws sqs get-queue-attributes \ --queue-url $QUEUE_URL \ --attribute-names \ ApproximateNumberOfMessages,\ ApproximateNumberOfMessagesNotVisible,\ ApproximateNumberOfMessagesDelayed
Messages Going to DLQ
Causes:
Processing errors Visibility timeout too short Consumer not deleting messages
Redrive from DLQ:
Enable redrive allow policy on source queue
aws sqs set-queue-attributes \ --queue-url $MAIN_QUEUE_URL \ --attributes '{"RedriveAllowPolicy": "{\"redrivePermission\":\"allowAll\"}"}'
Start redrive
aws sqs start-message-move-task \ --source-arn arn:aws:sqs:us-east-1:123456789012:my-queue-dlq \ --destination-arn arn:aws:sqs:us-east-1:123456789012:my-queue
Duplicate Processing
Solutions:
Use FIFO queues for exactly-once Implement idempotency in consumer Track processed message IDs in database Lambda Not Processing
Check event source mapping
aws lambda list-event-source-mappings \ --function-name my-function
Check for errors
aws lambda get-event-source-mapping \
--uuid
References SQS Developer Guide SQS API Reference SQS CLI Reference boto3 SQS