Aws Lambda "Runtime.HandlerNotFound" python - python-3.x

Question

I am new to python and AWS lambda. I am trying to run this script from the lambda function but I am getting error:
Runtime.HandlerNotFound
This script is working fine if I run it from the ec2 instance, but when I run the same script from AWS lambda it throws an error.
I would be really thankful if someone guides me on what I did wrong.
Thank you
import boto3
import requests
import time
AWS_Access_Key_ID =
AWS_Secret_Access_Key =
DELAY_TIME=10 # 10 Seconds
region = 'us-east-2'
# instances = ['']
instances = {
'instance id': 'http://link',
'instance id': 'http://link'
}
ec2 = None
try:
ec2 = boto3.client('ec2', aws_access_key_id=AWS_Access_Key_ID, aws_secret_access_key=AWS_Secret_Access_Key, region_name=region)
# ec2 = boto3.resource('ec2',aws_access_key_id=AWS_Access_Key_ID, aws_secret_access_key=AWS_Secret_Access_Key, region_name=region)
except Exception as e:
print(e)
print("AWS CREDS ERROR, Exiting...")
exit()
def startInstances(instancesIds):
if(type(instancesIds) != list):
instancesIds = [instancesIds]
try:
response = ec2.start_instances(InstanceIds=instancesIds, DryRun=False)
print(response)
print("Instances Started")
except ClientError as e:
print(e)
print("Instances Failed to Start")
def stopInstances(instancesIds):
if(type(instancesIds) != list):
instancesIds = [instancesIds
]
try:
response = ec2.stop_instances(InstanceIds=instancesIds, DryRun=False)
print(response)
print("Instances Stopped")
except ClientError as e:
print(e)
print("Instances Failed to Stop")
def check():
for x in instances:
retry = 0
live = False
print("Checking Webiste " + instances[x])
while(retry < 5):
try:
r = requests.get(instances[x] ,verify=True)
if(r.status_code == 200):
live = True
break
except:
print("Not Live, retry time " + str(retry + 1))
print("Delaying request for " + str(DELAY_TIME) + " seconds...")
retry += 1
time.sleep(DELAY_TIME)
if(live):
print("Website is live")
# call function to start the ec2 instance
startInstances(x)
else:
# call function to stop the ec2 instance
print('Website is dead')
stopInstances(x)
print("")
def main():
check()
if __name__ == '__main__':
main()

Answer 1

https://docs.aws.amazon.com/lambda/latest/dg/python-handler.html You need to specify what is the name of the handler function, which is the function that AWS lambda will call. Then you need to implement that function in your Python script.

Answer 2

I had a similar problem recently. I was able to define a lambda handler function in my python code that solved the problem. Got the guidance from this post
in short, add this code (adjust naming conventions accordingly):
import botocore
import boto3
def lambda_handler(event, context):
s3 = boto3.resource('s3')
bucket = s3.Bucket('bucketname')
exists = True
try:
s3.meta.client.head_bucket(Bucket='bucketname')
except botocore.exceptions.ClientError as e:
# If a client error is thrown, then check that it was a 404 error.
# If it was a 404 error, then the bucket does not exist.
error_code = int(e.response['Error']['Code'])
if error_code == 404:
exists = False