CODEWITHSUNDEEP
pythonamazon-web-servicesaws-lambdaamazon-sqsserverless-framework
Phong Vu
Phong Vu

Reputation: 2896

SQS Lambda serverless: the Sqs Message is not consumed

I deployed a Python Post API lambda, using Serverless framework.

Detail of code as below:

app.py

from flask import Flask, jsonify, request

app = Flask(__name__)

@app.route('/process', methods=['POST'])
def process():
    content = request.json
    print content
    return jsonify(content)

if __name__ == "__main__":
    app.run()

serverless.yml

service: my-service
plugins:
  - serverless-python-requirements
  - serverless-wsgi
custom:
  wsgi:
    app: app.app
    packRequirements: false
  pythonRequirements:
    dockerizePip: false
package:
  exclude:
    - node_modules/**
    - venv/**
provider:
  name: aws
  runtime: python2.7
  stage: dev
  region: eu-west-1

functions:
  app:
    handler: wsgi.handler
    events:
      - http: ANY /
      - http: 'ANY {proxy+}'

I configured the SQS to trigger the lambda. I send a SQS Message, the lambda is triggered (I checked it from CloudWatch), but the SQS message is stuck in flight. It seems that SQS cannot be consumed by lambda.

Any suggestion is appreciated

****UPDATE*****

After check the CloudWatch carefully, I found some exceptions

u'headers': KeyError
Traceback (most recent call last):
File "/var/task/wsgi.py", line 100, in handler
return serverless_wsgi.handle_request(wsgi_app, event, context)
File "/var/task/serverless_wsgi.py", line 73, in handle_request
headers = Headers(event[u"headers"])
KeyError: u'headers'

Upvotes: 2

Views: 1114

Answers (1)

vfcoelho182
vfcoelho182

Reputation: 49

Looking at your logs, it seems that Flask's WSGI is expecting a headers node within the payload you're receiving, which would be there should your event be an HTTP event. That's not the case when you wire two AWS services directly. The event object will be different for each service. Since you are not handling HTTP requests, I would suggest you to remove Flask from this lambda.

Your code then would look like this:


import json

def process(event,context):
    content = request.json
    print(event)
    return json.dumps(content,ensure_ascii=False)


service: my-service
plugins:
  - serverless-python-requirements
package:
  exclude:
    - node_modules/**
    - venv/**
provider:
  name: aws
  runtime: python2.7
  stage: dev
  region: eu-west-1

functions:
  app:
    handler: app.process
    events:
      - sqs:
          arn: arn:partition:service:region:account-id:resource-id
          batchSize: 1

Your SQS queue ARN is displayed on your queue details on AWS Console.

Here is a complimentary read:

SLS and SQS Queues

Upvotes: 1

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