By Venkata Reddy Bhavanam
Author LinkedIn:https://www.linkedin.com/in/venkatareddybhavanam/
This is the second post on installing a custom plugin in Kong API Gateway. Please check out the 1st post if you need a quick introduction to Kong and how to install a custom plugin in a VM.
In this post, we’ll learn how to install a custom plugin in Docker.
We’ll use the same custom plugin code as we used in the previous post.
Kong Plugin Development
Copying the code over here for completeness. The folder structure:
api-version/
├── handler.lua
└── schema.lua
The plugin name api-version and the contents of schema.lua
local typedefs = require "kong.db.schema.typedefs" local PLUGIN_NAME = "api-version" local schema = { name = "api-version", fields = { { consumer = typedefs.no_consumer }, -- this plugin cannot be configured on a consumer (typical for auth plugins) { protocols = typedefs.protocols_http }, { config = { type = "record", fields = { { request_header = typedefs.header_name { required = true, default = "Hello-World" } }, { response_header = typedefs.header_name { required = true, default = "Bye-World" } }, }, entity_checks = { { at_least_one_of = { "request_header", "response_header" }, }, { distinct = { "request_header", "response_header"} }, }, }, }, }, } return schema Contents of handler.lua:
local typedefs = require "kong.db.schema.typedefs" local PLUGIN_NAME = "api-version" local schema = { name = "api-version", fields = { { consumer = typedefs.no_consumer }, -- this plugin cannot be configured on a consumer (typical for auth plugins) { protocols = typedefs.protocols_http }, { config = { type = "record", fields = { { request_header = typedefs.header_name { required = true, default = "Hello-World" } }, { response_header = typedefs.header_name { required = true, default = "Bye-World" } }, }, entity_checks = { { at_least_one_of = { "request_header", "response_header" }, }, { distinct = { "request_header", "response_header"} }, }, }, }, }, } return schema Building the docker image:
We’ll take a base Kong image, add the plugin(and dependencies, if any), and use the final image. The Dockerfile
FROM kong/kong-gateway:3.2.2.1
**USER root** # luarocks install dependency-name # to install any dependencies for cusotm plugin RUN mkdir /usr/local/share/lua/5.1/kong/plugins/api-versionCOPY ./api-version /usr/local/share/lua/5.1/kong/plugins/api-version Here, we are taking Kong base image kong/kong-gateway:3.2.2.1 and adding our plugin code.
We can now build it and run it with the following:
docker build -t kong-demo . docker run -d --name kong-demo \ -p "8000-8001:8000-8001" \ -e "KONG_ADMIN_LISTEN=0.0.0.0:8001" \ -e "KONG_PROXY_LISTEN=0.0.0.0:8000" \ -e "KONG_DATABASE=off" \ -e "KONG_LOG_LEVEL=debug" \ -e "KONG_PLUGINS=bundled,api-version" \ kong-demo As you can see, we specify the custom plugin name along with the bundled plugins using KONG_PLUGINSenvironment variable.
Kong can be run either in DB mode using Postgres (and Cassandra, but it will be deprecated) or DB Less mode. We’ll use db-less mode and the following declarative config to create a service, route, and apply the plugin for this demo.
config.yaml _format_version: "3.0" _transform: trueservices: - name: demo url: https://mockbin.org plugins: - name: api-version routes: - name: demo-route paths: - /echo Create the config with an API call to the admin API.
curl -X POST http://localhost:8001/config -F config=@config.yaml
Verify the custom plugin works by visiting the proxy URL. We’ll use HTTPie
http :8000/echo --headers HTTP/1.1 200 OK Bye-World: 0.1 ... That’s it. In the next post, we’ll see how to install the custom plugin in Kubernetes.
For more information: https://zelarsoft.com/
Top comments (0)