Lambda layer to enable using the famous NLTK Python package with Lambda.

Credit to customink/lambda-python-nltk-layer.

When using NLTK in AWS Lambda, you may encounter the following error due to NLTK needing to download data files, but the file system in AWS Lambda is read-only:

[Errno 30] Read-only file system: '/home/sbx_user1051'

To resolve this issue, you can create a custom layer similar to customink/lambda-python-nltk-layer.

However, if your Lambda function is packaged as a Docker image, you can resolve it as follows:

To use Lambda NLTK with Docker images, package your web app (HTTP API) in a Dockerfile, and add one line to copy NLTK data files to /opt/nltk_data inside your container:

Pre-compiled Lambda NLTK data is provided in the ECR public repo: public.ecr.aws/m5s2b0d4/nltk_lambda_layer.

COPY --from=public.ecr.aws/m5s2b0d4/nltk_lambda_layer:latest /nltk_data /opt/nltk_data

Then add one line to configure the environment variable NLTK_DATA:

ENV NLTK_DATA=/opt/nltk_data

Below is a Dockerfile for an example python application.