Create CloudFormation stack from AWS Lambda function, passing API Gateway parameters - api

Question

I am unable to get parameters in Lambda function. If I mention parameters value in lambda it works fine. when I remove parameters values from Lambda function and try from API gateway or test lambda it process default parameters values. please help
My Lambda function is :
import boto3
import time
import json
datetime = time.strftime("%Y%m%d%H%M%S")
stackname = 'myec2'
client = boto3.client('cloudformation')
response = client.create_stack(
StackName= (stackname+ '-' + datetime),
TemplateURL='https://testnaeem.s3.amazonaws.com/ec2tags.yaml',
Parameters=[
{
"ParameterKey": "MyInstanceName",
"ParameterValue": " "
},
{
"ParameterKey": "MyInstanceType",
"ParameterValue": " "
}
]
)
def lambda_handler(event, context):
return(response)
My CloudFormation template is:
---
Parameters:
MyInstanceType:
Description: Instance type description
Type: String
MyInstanceName:
Description: Instance type description
Type: String
Resources:
MyInstance:
Type: AWS::EC2::Instance
Properties:
AvailabilityZone: us-east-1a
ImageId: ami-047a51fa27710816e
InstanceType: !Ref MyInstanceType
KeyName: miankeyp
Tags:
- Key : Name
Value : !Ref MyInstanceName
- Key : app
Value : demo
Please help what changes required in the Lambda function.
My test Values are:
{
"MyInstanceName": "demott",
"MyInstanceType": "t2.micro"
}

Answer 1

I modified the code of your lambda function. Please check comments in the code for clarification:
import boto3
import time
import json
datetime = time.strftime("%Y%m%d%H%M%S")
stackname = 'myec2'
client = boto3.client('cloudformation')
def lambda_handler(event, context):
print(event) # to check what your even actually is
# it will be printed out in CloudWatch Logs for your
# function
# you have to check what the event actually looks like
# and adjust event['MyInstanceName'] and event['MyInstanceType']
# in the following code
response = client.create_stack(
StackName= (stackname+ '-' + datetime),
TemplateURL='https://testnaeem.s3.amazonaws.com/ec2tags.yaml',
Parameters=[
{
"ParameterKey": "MyInstanceName",
"ParameterValue": event['MyInstanceName']
},
{
"ParameterKey": "MyInstanceType",
"ParameterValue": event['MyInstanceType']
}
]
)
return(response)
By the way, such function and API gateway can spin up a lot of ec2 instances very quickly. So that you are aware of this.