# ![Falcon](assets/logo.webp)

Falcon is a multi-process, multi-fiber rack-compatible HTTP server built on top of [async](https://github.com/socketry/async), [async-container](https://github.com/socketry/async-container) and [async-http](https://github.com/socketry/async-http). Each request is executed within a lightweight fiber and can block on up-stream requests without stalling the entire server process. Falcon supports HTTP/1 and HTTP/2 natively.

[![Development Status](https://github.com/socketry/falcon/workflows/Test/badge.svg)](https://github.com/socketry/falcon/actions?workflow=Test)

## Motivation

Initially, when I developed [async](https://github.com/socketry/async), I saw an opportunity to implement [async-http](https://github.com/socketry/async-http): providing both client and server components. After experimenting with these ideas, I decided to build an actual web server for comparing and validating performance primarily out of interest. Falcon grew out of those experiments and permitted the ability to test existing real-world code on top of [async](https://github.com/socketry/async).

Once I had something working, I saw an opportunity to simplify my development, testing and production environments, replacing production (Nginx+Passenger) and development (Puma) with Falcon. Not only does this simplify deployment, it helps minimize environment-specific bugs.

My long term vision for Falcon is to make a web application platform which trivializes server deployment. Ideally, a web application can fully describe all its components: HTTP servers, databases, periodic jobs, background jobs, remote management, etc. Currently, it is not uncommon for all these facets to be handled independently in platform specific ways. This can make it difficult to set up new instances as well as make changes to underlying infrastructure. I hope Falcon can address some of these issues in a platform agnostic way.

As web development is something I'm passionate about, having a server like Falcon is empowering.

## Priority Business Support

Falcon can be an important part of your business or project, both improving performance and saving money. As such, priority business support is available to make every project a success. The support agreement will give you:

  - Direct support and assistance via Slack and email.
  - Advance notification of bugs and security issues.
  - Priority consideration of feature requests and bug reports.
  - Better software by funding development and testing.

Please visit [Socketry.io](https://socketry.io) to register and subscribe.

## Usage

Please see the [project documentation](https://socketry.github.io/falcon/) for more details.

  - [Getting Started](https://socketry.github.io/falcon/guides/getting-started/index) - This guide explains how to use Falcon for Ruby web application development.

  - [Rails Integration](https://socketry.github.io/falcon/guides/rails-integration/index) - This guide explains how to host Rails applications with Falcon.

  - [Deployment](https://socketry.github.io/falcon/guides/deployment/index) - This guide explains how to use Falcon in production environments.

  - [Extended Features](https://socketry.github.io/falcon/guides/extended-features/index) - This guide explains some of the extended features and functionality of Falcon.

  - [Performance Tuning](https://socketry.github.io/falcon/guides/performance-tuning/index) - This guide explains the performance characteristics of Falcon.

  - [How It Works](https://socketry.github.io/falcon/guides/how-it-works/index) - This guide gives an overview of how Falcon handles an incoming web request.

## Releases

Please see the [project releases](https://socketry.github.io/falcon/releases/index) for all releases.

### v0.49.0

  - [Falcon Server Container Health Checks](https://socketry.github.io/falcon/releases/index#falcon-server-container-health-checks)
  - [Falcon Server Process Title](https://socketry.github.io/falcon/releases/index#falcon-server-process-title)

### v0.48.4

  - Improve compatibility of rackup handler w.r.t. sinatra.

### v0.47.8

  - Fix Falcon Supervisor implementation: due to invalid code, it was unable to start.

### Compatibility Fixes

During the `v0.44.0` release cycle, the workflows for testing older rack releases were accidentally dropped. As such, `v0.44.0` was not compatible with older versions of rack. This release restores compatibility with older versions of rack.

Specifically, `protocol-rack` now provides `Protocol::Rack::Adapter.parse_file` to load Rack applications. Rack 2's `Rack::Builder.parse_file` returns both the application and a set of options (multi-value return). Rack 3 changed this to only return the application, as the prior multi-value return was confusing at best. This change allows `protocol-rack` to work with both versions of rack, and `falcon` adopts that interface.

### Falcon Serve Options

In addition, `falcon serve` provides two new options:

1.  `--[no]-restart` which controls what happens when `async-container` instances crash. By default, `falcon serve` will restart the container when it crashes. This can be disabled with `--no-restart`.

2.  `--graceful-stop [timeout]` which allows you to specify a timeout for graceful shutdown. This is useful when you want to stop the server, but allow existing connections to finish processing before the server stops. This feature is highly experimental and doesn't work correctly in all cases yet, but we are aiming to improve it.

### Falcon Host

`async-service` is a new gem that exposes a generic service interface on top of `async-container`. Previously, `falcon host` used `async-container` directly and `build-environment` for configuration. In order to allow for more generic service definitions and configuration, `async-service` now provides a similar interface to `build-environment` and exposes this in a way that can be used for services other tha falcon. This makes it simpler to integrate multiple services into a single application.

The current configuration format uses definitions like this:

``` ruby
rack 'hello.localhost', :self_signed_tls
```

This changes to:

``` ruby
service 'hello.localhost' do
	include Falcon::Environment::Rack
	include Falcon::Environment::SelfSignedTLS
end
```

## Contributing

We welcome contributions to this project.

1.  Fork it.
2.  Create your feature branch (`git checkout -b my-new-feature`).
3.  Commit your changes (`git commit -am 'Add some feature'`).
4.  Push to the branch (`git push origin my-new-feature`).
5.  Create new Pull Request.

### Developer Certificate of Origin

In order to protect users of this project, we require all contributors to comply with the [Developer Certificate of Origin](https://developercertificate.org/). This ensures that all contributions are properly licensed and attributed.

### Community Guidelines

This project is best served by a collaborative and respectful environment. Treat each other professionally, respect differing viewpoints, and engage constructively. Harassment, discrimination, or harmful behavior is not tolerated. Communicate clearly, listen actively, and support one another. If any issues arise, please inform the project maintainers.
