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Kong

kong-authz is an authorization plugin for Kong based on lua-casbin. This plugin enables request authorization in Kong API Gateway using Casbin's powerful and flexible access control models.

Prerequisites​

The following need to be installed in advance:

معلومات

The Casbin policy is read from a file by default. If you want to use Casbin policy from a database, choose either 4daysorm-adapter or luasql-adapter.

Installation​

Ensure you have Casbin's system dependencies installed:

  • For systems with apt package manager:
sudo apt install gcc libpcre3 libpcre3-dev
  • For Alpine-based systems:
sudo apk add gcc pcre pcre-dev libc-dev

Install Casbin's latest release from LuaRocks:

sudo luarocks install casbin

Install the kong-authz plugin:

sudo luarocks install https://raw.githubusercontent.com/casbin-lua/kong-authz/master/kong-authz-0.0.1-1.rockspec

Add the plugin to your kong.conf file by appending kong-authz (with a comma) to the plugins variable:

# kong.conf
plugins = bundled, kong-authz

Finally, start or restart Kong:

kong start [-c /path/to/kong.conf]

Configuration​

You can add this plugin on top of any service/API or globally by sending a request through the Kong Admin API.

File-Based Policy Storage​

Add the plugin globally with file-based policy storage:

curl -i -X POST \
  --url http://localhost:8001/plugins/ \
  --data 'name=kong-authz' \
  --data 'config.model_path=/path/to/model_path.conf' \
  --data 'config.policy_path=/path/to/policy_path.csv' \
  --data 'config.username=user'

Database Policy Storage with LuaSQL​

Add the plugin to a specific service with LuaSQL adapter:

curl -i -X POST \
  --url http://localhost:8001/services/example-service/plugins/ \
  --data 'name=kong-authz' \
  --data 'config.model_path=/mnt/kong/examples/authz_model.conf' \
  --data 'config.username=user' \
  --data 'config.adapter=luasql' \
  --data 'config.db_info.db_type=mysql' \
  --data 'config.db_info.database=casbin' \
  --data 'config.db_info.username=root' \
  --data 'config.db_info.password=********' \
  --data 'config.db_info.host=127.0.0.1' \
  --data 'config.db_info.port=3306'

Database Policy Storage with 4DaysORM​

Add the plugin to a specific service with 4DaysORM adapter:

curl -i -X POST \
  --url http://localhost:8001/services/example-service/plugins/ \
  --data 'name=kong-authz' \
  --data 'config.model_path=/mnt/kong/examples/authz_model.conf' \
  --data 'config.username=user' \
  --data 'config.adapter=4daysorm' \
  --data 'config.db_info.db_type=mysql' \
  --data 'config.db_info.database=casbin' \
  --data 'config.db_info.username=root' \
  --data 'config.db_info.password=********' \
  --data 'config.db_info.host=127.0.0.1' \
  --data 'config.db_info.port=3306'

How Authorization Works​

The authorization determines a request based on {subject, object, action}, which means what subject can perform what action on what object. In this plugin:

  1. subject: the logged-in username as passed in the header
  2. object: the URL path for the web resource like "dataset1/item1"
  3. action: HTTP method like GET, POST, PUT, DELETE, or high-level actions you defined like "read-file", "write-blog"

For details on writing authorization policies, refer to the Casbin documentation.

Example Usage​

Here's a complete example of setting up kong-authz for a service:

  1. Set up an example service:
curl -i -X POST \
  --url http://localhost:8001/services/ \
  --data 'name=example-service' \
  --data 'url=http://mockbin.org'
  1. Set up a route for the service:
curl -i -X POST \
  --url http://localhost:8001/services/example-service/routes \
  --data 'hosts[]=example.com'
  1. Configure the kong-authz plugin:
curl -i -X POST \
  --url http://localhost:8001/services/example-service/plugins/ \
  --data 'name=kong-authz' \
  --data 'config.model_path=/path/to/authz_model.conf' \
  --data 'config.policy_path=/path/to/authz_policy.csv' \
  --data 'config.username=user'
  1. Test the authorization by sending a request:
curl -i -X GET \
  --url http://localhost:8000/ \
  --header 'Host: example.com' \
  --header 'user: anonymous'

When run for the first time, it will create a Casbin Enforcer using the model and policy paths. If this returns any non-500 error, the configuration is successful. Otherwise, check the error.log file in your Kong setup.

Resources​