Access database which is running in EC2 instance through AWS-lambda function - postgresql

Question

I wrote the lambda function in python3.6 to access the postgresql database which is running in EC2 instance.
psycopg2.connect(user="<USER NAME>",
password="<PASSWORD>",
host="<EC2 IP Address>",
port="<PORT NUMBER>",
database="<DATABASE NAME>")
created deployment package with required dependencies as zip file and uploaded into AWS lambda.To build dependency i followed THIS reference guide.
And also configured Virtual Private Cloud (VPC) as default one and also included Ec2 instance details, but i couldn't get the connection from database. when trying to connect database from lambda result in timeout.
Lambda function:
from __future__ import print_function
import json
import ast,datetime
import psycopg2
def lambda_handler(event, context):
received_event = json.dumps(event, indent=2)
load = ast.literal_eval(received_event)
try:
connection = psycopg2.connect(user="<USER NAME>",
password="<PASSWORD>",
host="<EC2 IP Address>",
# host="localhost",
port="<PORT NUMBER>",
database="<DATABASE NAME>")
cursor = connection.cursor()
postgreSQL_select_Query = "select * from test_table limit 10"
cursor.execute(postgreSQL_select_Query)
print("Selecting rows from mobile table using cursor.fetchall")
mobile_records = cursor.fetchall()
print("Print each row and it's columns values")
for row in mobile_records:
print("Id = ", row[0], )
except (Exception,) as error :
print ("Error while fetching data from PostgreSQL", error)
finally:
#closing database connection.
if(connection):
cursor.close()
connection.close()
print("PostgreSQL connection is closed")
return {
'statusCode': 200,
'body': json.dumps('Hello from Lambda!'),
'dt' : str(datetime.datetime.now())
}
I googled quite a lot, But i couldn't found any workaround for this.is there any way to accomplish this requirement?

Answer 1

Your configuration would need to be:
A database in a VPC
The Lambda function configured to use the same VPC as the database
A security group on the Lambda function (Lambda-SG)
A security group on the Database (DB-SG) that permits inbound connects from Lambda-SG on the relevant database port
That is, DB-SG refers to Lambda-SG.

Answer 2

For lambda to connect to any resources inside a VPC, it needs to setup ENIs to the related private subnets of the VPC. Have you set up the VPC association and security groups of the EC2 correctly?
You can refer https://docs.aws.amazon.com/lambda/latest/dg/vpc.html