Kong is a cloud-native, fast, scalable, and distributed Microservice Abstraction Layer (also known as an API Gateway or API Middleware). Made available as an open-source project in 2015, its core values are high performance and extensibility.

Actively maintained, Kong is widely used in production at companies ranging from startups to Global 5000 as well as government organizations.

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Summary

• Why Kong?
• Features
• Distributions
• Development
• Enterprise Support & Demo
• License

Why Kong?

If you are building for the web, mobile, or IoT (Internet of Things) you will likely end up needing common functionality to run your actual software. Kong can help by acting as a gateway (or a sidecar) for microservices requests while providing load balancing, logging, authentication, rate-limiting, transformations, and more through plugins.

Kong has been built with the following leading principles:

• High Performance: Sub-millisecond processing latency to support
• mission-critical use cases and high throughput.
• Extensibility: With a pluggable architecture to extend Kong in Lua or GoLang with Kong's Plugin SDK.
• Portability: To run on every platform, every cloud, and to natively support Kubernetes via our modern Ingress Controller.

Features

• Cloud-Native: Platform agnostic, Kong can run on any platform - from bare metal to containers - and it can run on every cloud natively.
• Kubernetes-Native: Declaratively configure Kong with native Kubernetes CRDs using the official Ingress Controller to route and connect all L4 + L7 traffic.
• Dynamic Load Balancing: Load balance traffic across multiple upstream services.
• Hash-based Load Balancing: Load balance with consistent hashing/sticky sessions.
• Circuit-Breaker: Intelligent tracking of unhealthy upstream services.
• Health Checks: Active and passive monitoring of your upstream services.
• Service Discovery: Resolve SRV records in third-party DNS resolvers like Consul.
• Serverless: Invoke and secure AWS Lambda or OpenWhisk functions directly from Kong.
• WebSockets: Communicate to your upstream services via WebSockets.
• gRPC: Communicate to your gRPC services and observe your traffic with logging and observability plugins
• OAuth2.0: Easily add OAuth2.0 authentication to your APIs.
• Logging: Log requests and responses to your system over HTTP, TCP, UDP, or to disk.
• Security: ACL, Bot detection, allow/deny IPs, etc...
• Syslog: Logging to System log.
• SSL: Setup a Specific SSL Certificate for an underlying service or API.
• Monitoring: Live monitoring provides key load and performance server metrics.
• Forward Proxy: Make Kong connect to intermediary transparent HTTP proxies.
• Authentications: HMAC, JWT, Basic, and more.
• Rate-limiting: Block and throttle requests based on many variables.
• Transformations: Add, remove, or manipulate HTTP requests and responses.
• Caching: Cache and serve responses at the proxy layer.
• CLI: Control your Kong cluster from the command line.
• REST API: Kong can be operated with its RESTful API for maximum flexibility.
• Geo-Replicated: Configs are always up-to-date across different regions.
• Failure Detection & Recovery: Kong is unaffected if one of your Cassandra nodes goes down.
• Clustering: All Kong nodes auto-join the cluster keeping their config updated across nodes.
• Scalability: Distributed by nature, Kong scales horizontally by simply adding nodes.
• Performance: Kong handles load with ease by scaling and using NGINX at the core.
• Plugins: Extendable architecture for adding functionality to Kong and APIs.

For more info about plugins and integrations, you can check out the Kong Hub.

Distributions

Kong comes in many shapes. While this repository contains its core's source code, other repos are also under active development:

• Kubernetes Ingress Controller for Kong: Use Kong for Kubernetes Ingress.
• Kong Docker: A Dockerfile for running Kong in Docker.
• Kong Packages: Pre-built packages for Debian, Red Hat, and OS X distributions (shipped with each release).
• Kong Gojira: a tool for testing/developing multiple versions of Kong using containers.
• Kong Vagrant: A Vagrantfile for provisioning a development-ready environment for Kong.
• Kong Homebrew: Homebrew Formula for Kong.
• Kong CloudFormation: Kong in a 1-click deployment for AWS EC2.
• Kong AWS AMI: Kong AMI on the AWS Marketplace.
• Kong on Microsoft Azure: Run Kong using Azure Resource Manager.
• Kong on Heroku: Deploy Kong on Heroku in one click.
• Kong on IBM Cloud - How to deploy Kong on IBM Cloud
• Kong and Instaclustr: Let Instaclustr manage your Cassandra cluster.
• Master Builds: Docker images for each commit in the master branch.

You can find every supported distribution at the official installation page.

Development

We encourage community contributions to Kong. To make sure it is a smooth experience (both for you and for the Kong team), please read CONTRIBUTING.md, DEVELOPER.md, CODE_OF_CONDUCT.md, and COPYRIGHT before you start.

If you are planning on developing on Kong, you'll need a development installation. The master branch holds the latest unreleased source code.

You can read more about writing your own plugins in the Plugin Development Guide, or browse an online version of Kong's source code documentation in the Plugin Development Kit (PDK) Reference.

For a quick start with custom plugin development, check out Pongo and the plugin template explained in detail below.

Docker

You can use Docker / docker-compose and a mounted volume to develop Kong by following the instructions on Kong/kong-build-tools.

Kong Gojira

Gojira is a CLI that uses docker-compose internally to make the necessary setup of containers to get all dependencies needed to run a particular branch of Kong locally, as well as easily switching across versions, configurations and dependencies. It has support for running Kong in Hybrid (CP/DP) mode, testing migrations, running a Kong cluster, among other features.

Kong Pongo

Pongo is another CLI like Gojira, but specific for plugin development. It is docker-compose based and will create local test environments including all dependencies. Core features are running tests, integrated linter, config initialization, CI support, and custom dependencies.

Kong Plugin Template

The plugin template provides a basic plugin and is considered a best-practices plugin repository. When writing custom plugins we strongly suggest you start by using this repository as a starting point. It contains the proper file structures, configuration files, and CI setup to get up and running quickly. This repository seamlessly integrates with Pongo.

Vagrant

You can use a Vagrant box running Kong and Postgres that you can find at Kong/kong-vagrant.

Source Install

Kong mostly is an OpenResty application made of Lua source files, but also requires some additional third-party dependencies. We recommend installing those by following the source install instructions at https://docs.konghq.com/install/source/.

Instead of following the second step (Install Kong), clone this repository and install the latest Lua sources instead of the currently released ones:

$ git clone https://github.com/Kong/kong
$ cd kong/

# you might want to switch to the development branch. See CONTRIBUTING.md
$ git checkout master

# install the Lua sources
$ luarocks make

Running for development

Check out the development section of the default configuration file for properties to tweak in order to ease the development process for Kong.

Modifying the lua_package_path and lua_package_cpath directives will allow Kong to find your custom plugin's source code wherever it might be in your system.

Tests

Install the development dependencies (busted, luacheck) with:

$ make dev

Kong relies on three test suites using the busted testing library:

• Unit tests
• Integration tests, which require Postgres and Cassandra to be up and running
• Plugins tests, which require Postgres to be running

The first can simply be run after installing busted and running:

$ make test

However, the integration and plugins tests will spawn a Kong instance and perform their tests against it. As so, consult/edit the spec/kong_tests.conf configuration file to make your test instance point to your Postgres/Cassandra servers, depending on your needs.

You can run the integration tests (assuming both Postgres and Cassandra are running and configured according to spec/kong_tests.conf) with:

$ make test-integration

And the plugins tests with:

$ make test-plugins

Finally, all suites can be run at once by simply using:

$ make test-all

Consult the run_tests.sh script for a more advanced example usage of the test suites and the Makefile.

Finally, a very useful tool in Lua development (as with many other dynamic languages) is performing static linting of your code. You can use luacheck (installed with make dev) for this:

$ make lint

Makefile

When developing, you can use the Makefile for doing the following operations:

Enterprise Support & Demo

If you are working in a large organization you should learn more about Kong Enterprise.

License

Copyright 2016-2021 Kong Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.