如何使用ruby aws sdk获取活动的lambda工人数？

Question

So, using AWS Lambda with ruby sdk I can this to call a function:

Aws::Lambda::Client.new.invoke_async params

is there any way to query for the number of currently running lambda instances?

Aws::Lambda::Client.new.number_of_running_instances # returns 17

Answer 1

You can use the CloudWatch Metrics API to list AWS Lambda Metrics , including number of concurrent executions (namespace: AWS/Lambda , metric: ConcurrentExecutions ), however there is a caveat. As stated in the documentation of the ConcurrentExecutions metric:

Emitted as an aggregate metric for all functions in the account, and for functions that have a custom concurrency limit specified. [...] Measures the sum of concurrent executions for a given function at a given point in time. Must be viewed as an average metric if aggregated across a time period.

Consequently, you must Manage Concurrency by setting a concurrency limit on your Lambda function before you can view the concurrent execution for a specific function. On the other hand, based on the comments to the question, this may solve the problem you are facing with the choked database. As a side effect, you may have to deal with throttled Lambda invocations instead.