I lambda function that returns a bunch of requests that I want to send to an external service. This external service has an api with the following rate limit:
Paramters:
type: enum
content: list of n elements
Rate limit:
For each type, there can be no more than 3 concurrent slots. Each slot will be will need to wait n milliseconds between requests.
I want to throttle the requests being sent. My deign is to use sqs to queue the request payloads and set an autoscaling lambda to consume them. The sqs configuration includes a max_concurrency, but I dont see a way to configure that based on the message content.
Is there a way to implement the rate limit throttling described above using SQS? Or should I use another solution like Amazon MSK?
Example:
For below queue, I want a lambda function to be able to concurrently process 3 messages for type 1, 3 messages for type 2, and so on.
queue:
type=1, payload
type=1, payload
type=1, payload
type=1, payload
type=2, payload
type=2, payload
type=2, payload
type=3, payload
2
Answers
You would need to:
sleepcommand to the end of your Lambda function to wait the required timeThe Reserved Concurrency – AWS Lambda will ensure that a maximum of 3 functions can run at the same time.
The
sleepwill delay the start of the next function. Unfortunately, it means that the Lambda function will be running for a longer time and you will be paying for the Lambda function to effectively do nothing.If you want to process messages differently, you would need to:
OR