Table of Contents

1. Branches
2. set up local environment
3. Running Serverless

There are two branches, other than the master branch. One is to show step_functions and the other is dynamodb.

To make this repo run, you will need npm to install serverless cli and packages and also python to get the third party packages on deployment.

Note: the repo has a .justfile which you can think of as a makefile. To run the "recipes" in the .justfile you will need just - you can brew install just if you are on a mac.

You can brew install npm if you are on a mac and then install the packages.
Either : just serverless-plugins or npm install -d

Python is needed for building the zip file with the third party packages. Your local python version does not effect the running of the lambda. That is defined as the runtime in the serverless.yml.

If you would like, you can follow the instructions to set up the local environment as the repo is set up. Or alternatively, you can also change the files to match what you already have set up locally.

If you choose to change the files:

• change the serverless.yml line runtime: python3.9 to your python version
• change the python version in pyproject.toml python = "~3.9"
• install poetry: pip install poetry

For setting up your environment to match the configuration of the files:

To have python 3.9 as the version for your virtual env, you can set up pyenv and allow the .python-version file set your local python version. Install pyenv, brew install pyenv.

Then to ensure that pyenv has installed the desired python version:

• run just install-python
  • install the python version based on what version is in the pyenv .python-version file

Set up your local python virtual env with poetry

• run pip install poetry
• run just virtualenv-install
  • create the python virtualenv with poetry

The repo is designed to deploy the lambda to localstack. The basics are that it is a docker container running locally to replicate a cloud provider (like aws). localstack service url

Steps

• in one terminal : start the localstack docker container
  • just localstack-up
• in another terminal: deploy your serverless set up
  • just sls-first-time-local
  • this will first create the s3 bucket on localstack where the lambda will be pushed to
  • then it will do all of the "serverless stuff" : pip install third party packages that will get zipped with the lambda, create the zip of the lambda and third party packages, etc
• just sls-invoke-local
  • this will trigger the lambda in localstack

If you have localstack api key, add it as an env var before running just localstack-up go to https://app.localstack.cloud to see the resources

Clean up:

• ctrl-c in the terminal running localstack
• just localstack-down to "clean up" after the docker compose run