Resource Transformer

A kong plugin that will analyze the request path and transforms the ids.

This plug will take the nginx request path and scan againts the configured resources. If found, and the resource ids are integers, the resource transformer will change the upstream uri to the transformed path with the transformed uuid.

Why we need this

This plugin was needed because while migrating our databases, we needed to migrate the ids of several resources to uuid. The transformation can be done at the application but we came across an issue where different services would need several keys to transform the ids to the new uuids. This required extra configuration and we wanted to isolate the keys for each service.

Installation

$ luarocks install resource-transformer

Usage

This follows the kong plugin spec so extra references can be found here.

Configuration

Enabling the plugin

This plugin is currently a global plugin and will be run against all requests.

$ curl -X POST http://kong:8001/plugins/ --data "name=resource-transformer"

Parameters

Here is a list of the parameters which can be used in this plugin's configurations:

Parameter	Default	Description
name		The name of the plugin to use, in this case resource-trasformer

Documentation

In order to use the plugin, you first need to create the resource names to look for and either respective transform uuids.

Create a transformer

$ curl -X POST -H "Content-type: application/json" --data '{"resource_name":"user", "transform_uuid":"2f4b5070-73b9-5c1c-8d3c-da8ae80051b0"}' http://kong:8001/resource-transformer/
HTTP/1.1 201 Created

{
  "transform_uuid":"2f4b5070-73b9-5c1c-8d3c-da8ae80051b0",
  "created_at":1524750123000,
  "resource_name":"user",
  "id":"bbd7ee37-9aaf-493b-86e3-d4642e4d00b3"
}

Parameter	Default	Description
resource_name required		unique The resource string to search in the uri.
transform_uuid required		required The uuid that will be used as the namespace for uuid5 generation.

This will look in the path of uri for user and if an integer id is found trailing the resource name(ex. /user/726), the 726 will be taken and coverted to a uuid5 with the transform_uuid. So uuid.generate_v5("2f4b5070-73b9-5c1c-8d3c-da8ae80051b0", "726) and the resulting uuid will be rewritten in place of the integer ids, resulting in the upstream uri to be rewritten as /user/698aa227-04b1-53be-9a46-1459d8a0f493.

List transformers

$ curl -X GET http://kong:8001/resource-transformer/
HTTP/1.1 200 OK

{
  "total":1,
  "data":[
    {
      "transform_uuid":"2f4b5070-73b9-5c1c-8d3c-da8ae80051b0",
      "created_at":1525061288000,
      "resource_name":"user",
      "id":"332f012f-5b37-4fcd-917c-d742855989af"
    }
  ]
}

Get a transformer

$ curl -X GET http://kong:8001/resource-transformer/{id_or_resource_name}
HTTP/1.1 200 OK
{
  "transform_uuid":"2f4b5070-73b9-5c1c-8d3c-da8ae80051b0",
  "created_at":1525061288000,
  "resource_name":"user",
  "id":"332f012f-5b37-4fcd-917c-d742855989af"
}

• id: The id or resource_name property of the resource-transformer entity to fetch.

Update a transformer

$ curl -X PUT -H "Content-type: application/json" --data '{"resource_name":"user", "transform_uuid":"2f4b5070-73b9-5c1c-8d3c-da8ae80051b0"}' http://kong:8001/resource-transformer/{id_or_resource_name}

Parameter	Default	Description
resource_name required		unique The resource string to search in the uri.
transform_uuid required		required The uuid that will be used as the namespace for uuid5 generation.

Delete a transformer

$ curl -X DELETE http://kong:8001/resource-transformer/{id}
HTTP/1.1 204 No Content

• id: The id or resource_name property of the resource-transformer entity to delete.

Running Tests

Development

Reference: https://github.com/Kong/kong-vagrant#development-environment

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

# clone kong repo
$ git clone https://github.com/Kong/kong

# run vagrant (eg.'KONG_PLUGIN_PATH=../kong-plugin-resource-transformer/ vagrant up')
$ KONG_PLUGIN_PATH=/path/to/plugin vagrant up 
$ vagrant ssh
$ cd /kong
$ make dev

# to enable resource-transformer plugin
$ export KONG_CUSTOM_PLUGINS=resource-transformer

# start kong
# cd /kong
$ bin/kong migrations up
$ bin/kong start

# make sure to enable resource-transformer with admin api
# for global
$ curl -X POST http://kong:8001/plugins/ --data "name=resource-transformer"

# to restart after code changes
$ bin/kong restart

Uploading to Package Manager

Luarocks

$ git tag vX.X.X
$ git push origin vX.X.X
$ luarocks upload kong-plugin-resource-transformer-X.X.X.rockspec

where X.X.X is the new version.

Authors

• Kwang Jin Kim - crazytruth

License

This project is licensed under the MIT License - see LICENSE for details.