Serverless PyProject Plugin

This repository contains a small Serverless plugin to enable development using pyproject.toml without Poetry.

This is done by exporting the dependencies listing from pyproject.toml into a typical requirements.txt file during a Serverless build. This file can then be picked up by other tools such as serverless-python-requirements in order to generate a Python bundle.

Installation

This plugin is available via npm, so it can be installed as usual:

$ npm i --save-dev serverless-pyproject-plugin

There's no need to include it in your production bundle, so make sure it's saved inside the development dependencies. Once installed, make sure to add it to your Serverless plugins list:

plugins:
  - serverless-pyproject-plugin

The location within the plugin list shouldn't matter, as it's not reacting to any specific Serverless events. You will also likely want to do the same with serverless-python-requirements.

Configuration

The default behaviour of this plugin is to export dependencies from your pyproject.toml directly into requirements.txt, with no configuration required. As an example consider the following pyproject.toml:

[project]
name = "my_project"
version = "0.0.0"
dependencies = [
  "fastapi[standard]~=0.115",
  "pydantic~=2.10.1",
  "pydantic-settings~=2.6"
]

[project.optional-dependencies]
lambda = [
  "mangum~=0.19"
]

This will produce the following entries inside requirements.txt:

fastapi[standard]~=0.115,
pydantic~=2.10.1,
pydantic-settings~=2.6

By default, no optional dependencies are included (as you can see via the exclusion of mangum above). You can opt into different optional dependencies via the configuration flag extras in your serverless.yml:

custom:
  pyproject:
    extras:
      - lambda

This will then include the groups you requested inside the exported file.

fastapi[standard]~=0.115,
pydantic~=2.10.1,
pydantic-settings~=2.6
mangum~=0.19

Compatibility

This plugin has been tested against the Serverless v4 release, but will likely work with many Serverless versions as it's unreliant on almost everything inside the framework itself. If you have any issues, please do file an issue!