nsatwik/aws-lambda

aws-lambda

Working with python

Your python code may or may not need additional packages/libraries to run. In order to deploy your code, You need to create a deployment package (a zip file with source code and required packages/libraries) which are not included in lambda runtime environment. These are some of the ways for creating your deployment package.

Deployment package with no dependency

To create the deployment package

1. Open a command prompt and create a my-lambda-function project directory. For example, on macOS:

mkdir my-lambda-function

2. Navigate to the my-lambda-function project directory.

cd my-lambda-function

3. Copy the contents of the Python code from here and save it in a new file named lambda_function.py. Your directory structure should look like this:

my-lambda-function$
| lambda_function.py

4. Add the lambda_function.py file to the root of the .zip file.

zip my-deployment-package.zip lambda_function.py

This generates a my-deployment-package.zip file in your project directory. The command produces the following output:

adding: lambda_function.py (deflated 50%)

Deployment package with dependency

To create the deployment package

1. Open a command prompt and create a my-sourcecode project directory. For example, on macOS:

mkdir my-sourcecode

2. Navigate to the my-sourcecode project directory.

cd my-sourcecode

3. Copy the contents of the following sample Python code from here and save it in a new file named lambda_function.py:

Your directory structure should look like this:

my-sourcecode$
| lambda_function.py

4. Install the requests library to a new package directory.

pip install --target ./package requests

5. Create a deployment package with the installed library at the root.

cd package
zip -r ../my-deployment-package.zip .

This generates a my-deployment-package.zip file in your project directory. The command produces the following output:

6. Add the lambda_function.py file to the root of the zip file.

cd ..
zip my-deployment-package.zip lambda_function

Deployment package while using virtualenv

1. Activate the virtual environment. For example:

~/my-function$ source myvenv/bin/activate

2. Install libraries with pip.

(myvenv) ~/my-function$ pip install requests

3. Deactivate the virtual environment.

(myvenv) ~/my-function$ deactivate

4. Create a deployment package with the installed libraries at the root.

~/my-function$cd myvenv/lib/python3.8/site-packages
zip -r ../../../../my-deployment-package.zip .

The last command saves the deployment package to the root of the my-function directory.

Tip:

A library may appear in site-packages or dist-packages and the first folder lib or lib64. You can use the pip show command to locate a specific package.

5. Add function code files to the root of your deployment package.

~/my-function/myvenv/lib/python3.8/site-packages$ cd ../../../../
~/my-function$ zip -g my-deployment-package.zip lambda_function.py

After you complete this step, you should have the following directory structure:

my-deployment-package.zip$
  │ lambda_function.py
  │ __pycache__
  │ certifi/
  │ certifi-2020.6.20.dist-info/
  │ chardet/
  │ chardet-3.0.4.dist-info/
  ...