AWS | Recursive Function Example

This is an example of a function that will recursively call itself.

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Rupak Ganguly

Recursive Lambda function Invocation

This is an example of a function that will recursively call itself.

Warning It's possible to run into infinite loops with recursive calls.

Test your functions locally before deploying to production.

Use cases

Running a function recursively will allow you to pass state information to the next function call.

Setup

1. Deploy the function with sls deploy

The sls deploy command will give you back the function ARN (Amazon Resource Name) needed for the function to recursively call itself.

The message should look something like:

Service Information
service: recursive-invocation-example
stage: dev
region: us-east-1
api keys:
  None
endpoints:
  None
functions:
  recursive-invocation-example-dev-recursiveExample: arn:aws:lambda:us-east-1:488110005556:function:recursive-invocation-example-dev-recursiveExample

The ARN in this example is arn:aws:lambda:us-east-1:488110005556:function:recursive-invocation-example-dev-recursiveExample. If you need to retrieve this data again run the serverless info command.

2. Take your newly created function's ARN and replace the custom: functionARN value yourFunctionARN value in serverless.yml with your ARN.

Before:

# in serverless.yml
custom:
  functionARN: yourFunctionARN

After:

# in serverless.yml
custom:
  functionARN: arn:aws:lambda:us-east-1:488110005556:function:recursive-invocation-example-dev-recursiveExample

3. Uncomment the IAM statement in serverless.yml

# in serverless.yml
provider:
  name: aws
  runtime: nodejs4.3
  iamRoleStatements:
    -  Effect: "Allow"
       Action:
         - "lambda:InvokeFunction"
       Resource: ${self:custom.functionARN}

The custom: functionARN value is referenced as a serverless variable in the IAM statement the variable syntax ${self:custom.functionARN}

For more information on serverless variables. Read the variable docs.

4. Redeploy the function to enable the new IAM role.

Run sls deploy again to redeploy the service and apply the new IAM role needed for the function to call itself.

Invoking

Important Make sure to set a limit on the number of invocations and test locally first to avoid infinite recursive loops in AWS.

Invoke the function:

sls invoke -f recursiveExample -p event.json

See the logs of the recursive calls:

sls logs -f recursiveExample

The logs output should look something like:

START RequestId: 43a9d5b46c-11e6-b6bc-718f7ec807df Version: $LATEST
2026 22:39:37.769 (-08:00)  43a9d5b46c-11e6-b6bc-718f7ec807df  received { numberOfCalls: 5 }
2026 22:39:37.792 (-08:00)  43a9d5b46c-11e6-b6bc-718f7ec807df  recursive call
END RequestId: 43a9d5b46c-11e6-b6bc-718f7ec807df
REPORT RequestId: 43a9d5b46c-11e6-b6bc-718f7ec807df  Duration: 270.23 ms Billed Duration: 300 ms   Memory Size: 1024 MB  Max Memory Used: 32 MB

START RequestId: 446bedb46c-11e6-88fd-1bd64622e38d Version: $LATEST
2026 22:39:37.966 (-08:00)  446bedb46c-11e6-88fd-1bd64622e38d  received { numberOfCalls: 4 }
2026 22:39:37.966 (-08:00)  446bedb46c-11e6-88fd-1bd64622e38d  recursive call
END RequestId: 446bedb46c-11e6-88fd-1bd64622e38d
REPORT RequestId: 446bedb46c-11e6-88fd-1bd64622e38d  Duration: 119.04 ms Billed Duration: 200 ms   Memory Size: 1024 MB  Max Memory Used: 32 MB

START RequestId: 4479f6b46c-11e6-b27d58a248a566 Version: $LATEST
2026 22:39:38.122 (-08:00)  4479f6b46c-11e6-b27d58a248a566  received { numberOfCalls: 3 }
2026 22:39:38.122 (-08:00)  4479f6b46c-11e6-b27d58a248a566  recursive call
END RequestId: 4479f6b46c-11e6-b27d58a248a566
REPORT RequestId: 4479f6b46c-11e6-b27d58a248a566  Duration: 40.55 ms  Billed Duration: 100 ms   Memory Size: 1024 MB  Max Memory Used: 32 MB

START RequestId: 44914fb46c-11e6-ae2b-65715f0c0d90 Version: $LATEST
2026 22:39:38.196 (-08:00)  44914fb46c-11e6-ae2b-65715f0c0d90  received { numberOfCalls: 2 }
2026 22:39:38.196 (-08:00)  44914fb46c-11e6-ae2b-65715f0c0d90  recursive call
END RequestId: 44914fb46c-11e6-ae2b-65715f0c0d90
REPORT RequestId: 44914fb46c-11e6-ae2b-65715f0c0d90  Duration: 32.38 ms  Billed Duration: 100 ms   Memory Size: 1024 MB  Max Memory Used: 32 MB

START RequestId: 449c72f5-b46c-11e6-a441cb6f0603cc Version: $LATEST
2026 22:39:38.268 (-08:00)  449c72f5-b46c-11e6-a441cb6f0603cc  received { numberOfCalls: 1 }
2026 22:39:38.268 (-08:00)  449c72f5-b46c-11e6-a441cb6f0603cc  recursive call
END RequestId: 449c72f5-b46c-11e6-a441cb6f0603cc
REPORT RequestId: 449c72f5-b46c-11e6-a441cb6f0603cc  Duration: 49.82 ms  Billed Duration: 100 ms   Memory Size: 1024 MB  Max Memory Used: 32 MB

START RequestId: 44a8f64b-b46c-11e6-b0535b4cab8224 Version: $LATEST
2026 22:39:38.350 (-08:00)  44a8f64b-b46c-11e6-b0535b4cab8224  received { numberOfCalls: 0 }
2026 22:39:38.350 (-08:00)  44a8f64b-b46c-11e6-b0535b4cab8224  recursive call finished
END RequestId: 44a8f64b-b46c-11e6-b0535b4cab8224
REPORT RequestId: 44a8f64b-b46c-11e6-b0535b4cab8224  Duration: 0.56 ms Billed Duration: 100 ms   Memory Size: 1024 MB  Max Memory Used: 32 MB

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