Cannot access S3 bucket using flask+lambda

Question

I made a lambda function with the following code (runtime python3.7). The role of the lambda has "AmazonS3FullAccess". However, I got "botocore.exceptions.ConnectTimeoutError" at the line "ret= client.list_objects_v2(Bucket='myfiles');".

What is the problem? How can flask+lambda access S3 objects?

```
import awsgi
from flask import Flask
import boto3;

app = Flask(__name__)

def lambda_handler(event,context):
    return awsgi.response(app,event,context);

@app.route("/",methods=["GET"])
def index():
  s3 = boto3.resource('s3');
  client = s3.meta.client;
  ret= client.list_objects_v2(Bucket='myfiles');
  print(ret);
  return "hello world";

```

Accepted Answer

Is your lambda function VPC enabled? If not, you should not have any issues connecting to S3 from your lambda function, unless there are bucket policies preventing access.

If your lambda function is VPC enabled, you can create a NAT Gateway in your VPC as mentioned here - https://aws.amazon.com/premiumsupport/knowledge-center/internet-access-lambda-function/

Another better option is to create an interface VPC endpoint for S3 in your VPC. That way the lambda function will be able to connect to the S3 endpoint over the Amazon network without needing to go over the internet - https://docs.aws.amazon.com/AmazonS3/latest/userguide/privatelink-interface-endpoints.html

Cannot access S3 bucket using flask+lambda

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