AWS Lambda Layer Python Installation issues

[Kowareyasuki]

Hi guys, I want to install Strands as a layer for my aws lambda but what happen is when i follow this documentation on installing strands and zipping it, it installs the old version of strands sdk to v1.1 which prevents me from using most of the latest changes.

the instruction i followed came from this one: https://github.com/strands-agents/docs/tree/main/docs/examples/cdk/deploy_to_lambda

where i just use pip install -r requirements.txt --python-version 3.12 --platform manylinux2014_aarch64 --target ./packaging/_dependencies --only-binary=:all:

now it installs the old version (v1.1) which prevents me from using the new systemcontentblock feature and stuffs i coded for latest sdk.

and i followed this step and used arm64 lambda: https://github.com/strands-agents/docs/blob/main/docs/user-guide/deploy/deploy_to_aws_lambda.md

this is the new error i get but i can confirm i have pydantic core exist in the zip file.

Status: Failed
Test Event Name: sample
Response:
{
"errorMessage": "Unable to import module 'lambda_function': No module named 'pydantic_core._pydantic_core'",
"errorType": "Runtime.ImportModuleError",
"requestId": "",
"stackTrace": []
}

Is there a way to Install the latest sdk version? thank you!

[strands-agent]

Hi @Kowareyasuki! 👋

This is a common issue with Lambda layers and pydantic. Here are some solutions:

Issue 1: Old version installing

To ensure you get the latest version, explicitly specify it:

pip install "strands-agents>=1.21.0" --python-version 3.12 --platform manylinux2014_aarch64 --target ./packaging/_dependencies --only-binary=:all:

Or create a requirements.txt with the pinned version:

strands-agents>=1.21.0

Issue 2: pydantic_core import error

The No module named 'pydantic_core._pydantic_core' error typically occurs when:

1. Architecture mismatch: You're building for aarch64 (ARM) but running on x86_64 (or vice versa). Make sure your Lambda is configured for arm64 if using manylinux2014_aarch64.

2. Missing compiled extensions: Try including both platforms in your build:

# For arm64 Lambda
pip install strands-agents --python-version 3.12 --platform manylinux2014_aarch64 --target ./python --only-binary=:all:

3. Docker-based build (most reliable):

docker run --rm -v $(pwd):/var/task public.ecr.aws/sam/build-python3.12:latest \
  pip install strands-agents -t /var/task/python

Recommended Approach

For reliable Lambda layers, use AWS SAM or CDK with Docker builds. Example with Docker:

FROM public.ecr.aws/sam/build-python3.12:latest
RUN pip install strands-agents -t /opt/python

This ensures all native extensions (like pydantic_core) are compiled for the correct Lambda runtime.

Let me know if you're still having issues! 🦆

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