Kong -My Custom Plugin Is Not Showing in Plugin list

Question

using docker to run the Kong ,I am created the custom Plugin To Validate the header

Key :Test123

using docker to run the Kong ,I am created the custom Plugin To Validate the header

Key :Test123

\---------------------------handler.lua-------------------------------------------

local kong = kong
local CustomPlugin = {
  PRIORITY = 1000,
  VERSION = “0.1”,
}

function CustomPlugin:access(conf)
  CustomPlugin.super.access(self)
  – Validate the static header
  local header_value = kong.request.get_header(“Key”)
  if header_value \~= “Test123” then
– Return an error response if the header is missing or invalid
    return kong.response.exit(401, { message = “Unauthorized: Invalid or missing ‘Key’ header” })
  end

– If the header is valid, the request will continue to the upstream service

  kong.log.debug(“Header validation passed. Continuing to the upstream service.”)

end

return CustomPlugin

\--------------------------------------schema--------------------------------------

local typedefs = require “kong.db.schema.typedefs”

return {
  name = “custom-plugin”,
  fields = {
    { config = {
      type = “record”,
      fields = {}
    } }
  }
}

\----------------------------/etc/kong/kong.conf--------------------------------------------

plugins = bundled,custom-plugin

Used cmd

docker cp ./custom-plugin c3b65b77458c:/usr/local/share/lua/5.1/kong/plugins

docker cp ./kong c3b65b77458c:/usr/local/etc

and restart the container but Not working any solution?

Answer 1

Kong has some really good documentation on creating new plugins, I suggest you follow that: https://docs.konghq.com/gateway/latest/plugin-development/get-started/

I took your plugin and got it to show in the plugin list and tested its logic too, I would do the following:

NOTE: I ran this on Kong OSS

1. Start off with the plugin template project supplied by Kong to get the right structure of your plugin: https://github.com/Kong/kong-plugin/tree/master
2. Change the name to CustomPlugin and custom-plugin if you want and copy your files across. I made a few changes that werent right (and be careful of Windows characters for - and ")

Firstly this line needs to change if header_value \~= “Test123” then to if header_value ~= “Test123” then

And secondly in your schema.lua I would follow the format and defaults from the project above

local typedefs = require "kong.db.schema.typedefs"

local PLUGIN_NAME = "custom-plugin"


local schema = {
  name = PLUGIN_NAME,
  fields = {
    -- the 'fields' array is the top-level entry with fields defined by Kong
    { consumer = typedefs.no_consumer },  -- this plugin cannot be configured on a consumer (typical for auth plugins)
    { protocols = typedefs.protocols_http },
    { config = {
      -- The 'config' record is the custom part of the plugin schema
      type = "record",
      fields = {},
    },
    },
  },
}

return schema

3. Then follow this page on how to deploy your plugin, creating a Dockerfile exactly as they have in the root directory of your plugin project deploying docker plugin

I changed the Dockerfile to use OSS version of Kong instead

FROM kong/kong:3.7

Build the new image using the following command

docker build --force-rm --no-cache -t kong-gateway_my-plugin:3.7-0.0.1 .

4. Finally spin it all up using the Kong docker compose file they have as a starting point: docker-compose.yaml

You can bring everything up using KONG_DATABASE=postgres KONG_DOCKER_TAG=kong-gateway_my-plugin:3.7-0.0.1 docker compose --profile database up -d. The KONG_PLUGINS env var is being set in the image so no need to set it in your docker compose

I have tested this and it works and I can see your plugin in Kong Manager. I created a simple service with the plugin and it does what you expect as well

Here is the Kong YAML

_format_version: "3.0"
services:
- connect_timeout: 60000
  enabled: true
  host: httpbin.org
  name: httpbin
  path: /anything
  port: 443
  protocol: https
  read_timeout: 60000
  retries: 5
  routes:
  - https_redirect_status_code: 426
    name: httpbin
    path_handling: v0
    paths:
    - /demo
    plugins:
    - enabled: true
      name: custom-plugin
      protocols:
      - grpc
      - grpcs
      - http
      - https
    preserve_host: false
    protocols:
    - http
    - https
    regex_priority: 0
    request_buffering: true
    response_buffering: true
    strip_path: true
  write_timeout: 60000

And testing it

~ % http :8000/demo
HTTP/1.1 401 Unauthorized
Connection: keep-alive
Content-Length: 63
Content-Type: application/json; charset=utf-8
Date: Thu, 29 Aug 2024 07:37:37 GMT
Server: kong/3.7.1
X-Kong-Request-Id: 791727449efce37e9480880c361b4d5a
X-Kong-Response-Latency: 0

{
    "message": "Unauthorized: Invalid or missing ‘Key’ header"
}


~ % http :8000/demo Key:Test12
HTTP/1.1 401 Unauthorized
Connection: keep-alive
Content-Length: 63
Content-Type: application/json; charset=utf-8
Date: Thu, 29 Aug 2024 07:37:43 GMT
Server: kong/3.7.1
X-Kong-Request-Id: 3152863624953f23f08e1d01d81b2304
X-Kong-Response-Latency: 2

{
    "message": "Unauthorized: Invalid or missing ‘Key’ header"
}


~ % http :8000/demo Key:Test123
HTTP/1.1 200 OK
Access-Control-Allow-Credentials: true
Access-Control-Allow-Origin: *
Connection: keep-alive
Content-Length: 590
Content-Type: application/json
Date: Thu, 29 Aug 2024 07:37:45 GMT
Server: gunicorn/19.9.0
Via: kong/3.7.1
X-Kong-Proxy-Latency: 3
X-Kong-Request-Id: b52ddf6fcaa90115e3018d6d01ac0674
X-Kong-Upstream-Latency: 490

{
    "args": {},
    "data": "",
    "files": {},
    "form": {},
    "headers": {
        "Accept": "*/*",
        "Accept-Encoding": "gzip, deflate",
        "Host": "httpbin.org",
        "Key": "Test123",
        "User-Agent": "HTTPie/3.2.2",
        "X-Amzn-Trace-Id": "Root=1-66d02549-78154f64339407db0d2d580f",
        "X-Forwarded-Host": "localhost",
        "X-Forwarded-Path": "/demo",
        "X-Forwarded-Prefix": "/demo",
        "X-Kong-Request-Id": "b52ddf6fcaa90115e3018d6d01ac0674"
    },
    "json": null,
    "method": "GET",
    "origin": "192.168.65.1, 82.132.213.98",
    "url": "https://localhost/anything"
}