How to invoke lambda version based on versions provided as input - amazon-web-services

Question

I have a use case where client sends a request with the following payload:
payload = {
identifier: arn:aws:lambda:{region}:{account}:function:{function-name}:{version}
data = ""
}
I want to invoke lambdas based on identifier. There are some consideration:
data in payload can very from Kbs to few MBs
Lambda which need to be invoked can increase
I was thinking of having an api gateway which recieves request from the client which is then connected to a parent lambda A which invokes other child lambdas B and C based on identifier provided by the client. However I am not sure if the child lambda can handle few Mbs of data. Also is it a good way to chain lambdas in the following way
I was looking into how I can asynchronously invoke lambdas but I couldn't find anywhere where it allows to invoke lambdas based on versions. Any suggestions in this regard would be helpful thanks.

Answer 1

You can invoke another Lambda from Lambda based on version.
However, the problem with asynchronous invocation is that the payload size limit is less than what you need. According to the documentation, the size limit of invocation payload is 256 KB for asynchronous calls and 6 MB for synchronous calls.
I don’t know which language do you prefer, but invoking Lambda from another Lambda based on version with Python’s boto3 can look like this:
import json
from boto3 import client as boto3_client
client = boto3_client('lambda')
def lambda_handler(event, context):
# ...
client.invoke(
# your lambda identifier with version
FunctionName=your_function_name,
# to invoke a function asynchronously, set InvocationType to 'Event'
InvocationType='Event',
Payload=json.dumps(your_payload)
)
# ...
As stated by the documentation, the 'FunctionName' parameter is the
name of the Lambda function, version, or alias. […] You can append a
version number or alias to any of the formats. The length constraint
applies only to the full ARN. If you specify only the function name,
it is limited to 64 characters in length.
The invoke function accepts the following name formats for 'FunctionName' argument:
Function name – my-function (name-only), my-function:v1 (with alias).
Function ARN – arn:aws:lambda:us-west-2:123456789012:function:my-function.
Partial ARN – 123456789012:function:my-function.