Error running in Lambda: No module named 'slack_bolt'

I was advised by Slack API support to use Bolt to wrap my Python Lambda function so that I could provide the 3s response time required by Slack, whilst continuing processing my updates - in this case, performing IP whitelist updates in multiple AWS accounts.

I had a working version of my script (barring the timeout) so I took a look at the examples and then retrofitted Bolt which was very straightforward, at least initially.

When I came to run it though, I got errors saying: [ERROR] Runtime.ImportModuleError: Unable to import module 'ip-whitelist': No module named 'slack_bolt'

I then downloaded the Lambda example directly from GitHub and tried that without modifications, and got the exact same error.

I do have slack_bolt installed as you can see below, but I can see the requirements.txt doesn’t include it in the sample. Even when I do add it, it doesn’t work.

The Slack API support asked me to raise a query here instead as this is a Bolt-specific issue.

All I’m trying to achieve is to get a 200 OK back from my Lambda to Slack to prevent a timeout message, whilst my script completes.

My final attempt (as listed below) was to skip the local run and just get the example file to run in Lambda. That too failed with the same issue. A colleague had the same problem, so it doesn’t appear to be a problem with my local Python environment.

Reproducible in:

The slack_bolt version

slack-bolt==1.10.0 slack-sdk==3.12.0

Python runtime version

Python 3.9.9

OS info

ProductName: macOS ProductVersion: 12.0.1 BuildVersion: 21A559 Darwin Kernel Version 21.1.0: Wed Oct 13 17:33:01 PDT 2021; root:xnu-8019.41.5~1/RELEASE_ARM64_T6000

(This is my local install, clearly, and I have the same error running it locally using AWS SAM as I do with the example file directly uploaded to Lambda).

Steps to reproduce:

(Share the commands to run, source code, and project settings (e.g., setup.py))

1. Downloaded the Bolt Python example for AWS Lambda from here
2. Created a new Lambda function with Python 3.9
3. Uploaded lazy_aws_lambda.py and requirements.txt (without modifications)
4. Set the target as lazy_aws_lambda.handler
5. Deployed and tested the Lambda function with a dummy test event
6. Got an error during build (see logs)

Expected result:

The app should compile and run.

Actual result:

Test Event Name
test

Response
{
  "errorMessage": "Unable to import module 'lazy_aws_lambda': No module named 'slack_bolt'",
  "errorType": "Runtime.ImportModuleError",
  "requestId": "b4ae96db-450a-46f2-8c14-e2d6238711b1",
  "stackTrace": []
}

Function Logs
START RequestId: b4ae96db-450a-46f2-8c14-e2d6238711b1 Version: $LATEST
[ERROR] Runtime.ImportModuleError: Unable to import module 'lazy_aws_lambda': No module named 'slack_bolt'
Traceback (most recent call last):END RequestId: b4ae96db-450a-46f2-8c14-e2d6238711b1
REPORT RequestId: b4ae96db-450a-46f2-8c14-e2d6238711b1	Duration: 1.39 ms	Billed Duration: 2 ms	Memory Size: 128 MB	Max Memory Used: 37 MB	Init Duration: 118.91 ms

Requirements

lazy_aws_lambda.py.txt requirements.txt

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