Serverless deploy with serverless-python-requirements does not work

Question

I am trying to deploy a python lambda function using serverless. I need the psycopg2 library so I used the serverless-python-requirements plugin and added it to my serverless.yml file.

plugins:
  - serverless-python-requirements
custom:
    pythonRequirements:
        dockerizePip: non-linux

I can deploy the function successfully:

Serverless: Installing requirements from 
/Users/Desktop/postgresql/.serverless/requirements/requirements.txt ...
Serverless: Docker Image: lambci/lambda:build-python3.6
Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Injecting required Python packages to package...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service .zip file to S3 (43.07 MB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...

..............
Serverless: Stack update finished...

But when I check my Cloudwatch logs, it says that there is "No module named 'psycopg2' ".

The structure of my zip file is:

    |--node_modules
    |--.gitignore
    |--handler.py
    |--package-lock.json
    |--package.json
    |--serverless.yml

No .serverless/ dir was created when I ran serverless deploy...

Any help would be greatly appreciated!

Answer 1

The plugin serverless-python-requirements uses cache. Make sure to clean it before package your service. Furthermore, psycopg requires to be compiled with a lambda environment:

# serverless.yaml
custom:
    pythonRequirements:
        dockerizePip: true

# bash
$ serverless requirements cleanCache
$ serverless deploy --stage <stage>

Answer 2

Did you installed python dependencies correctly?

serverless is trying to install requirements from Serverless: Installing requirements from /Users/Desktop/postgresql/.serverless/requirements/requirements.txt

I would suggest following

• create virtualenv virtualenv ./env
• activate it source env/bin/activate
• install your depdencies pip install psycopg2
• freeze your local dependencies pip freeze > requirements.txt

Assuming your code is importing your dependency, deploy using serverless.