Proxy-Wasm Go JQ Filter

A plugin for the Kong Microservice API Gateway to transform payloads using JQ. It is a Proxy-Wasm filter that uses the jqgo library for transforming JSON Responses.

Tested and working for

Kong Version	Tests passing
3.4.x	✅

Installation

Using docker

docker build --tag kong-wasm-test  .

Running Kong

docker run --rm --name kong \
     -e "KONG_LOG_LEVEL=info" \
     -e "KONG_WASM=on" \
     -e "KONG_DATABASE=off" \
     -e "KONG_DECLARATIVE_CONFIG=/kong/config/kong.yml" \
     -e "KONG_PROXY_ACCESS_LOG=/dev/stdout" \
     -e "KONG_ADMIN_ACCESS_LOG=/dev/stdout" \
     -e "KONG_PROXY_ERROR_LOG=/dev/stderr" \
     -e "KONG_ADMIN_ERROR_LOG=/dev/stderr" \
     -e "KONG_ADMIN_LISTEN=0.0.0.0:8001, 0.0.0.0:8444 ssl" \
     -e "KONG_UNTRUSTED_LUA_SANDBOX_REQUIRES=cjson,cjson.safe" \
     -e "KONG_UNTRUSTED_LUA_SANDBOX_ENVIRONMENT=table.concat" \
     -v `pwd`/local/kong_config.yml:/kong/config/kong.yml \
     -p 6200:8000 \
     -p 6443:8443 \
     -p 8001:8001 \
     -p 127.0.0.1:8444:8444 \
     kong-wasm-test

Usage

Filter Structure

filter_chains:
  - name: my-filter-chain
    tags: [ns.sample]
    filters:
     - name: jq-filter
       config: >-
            {
            "Query": ".data | fromjson | .[] | select(.Priority == \"Urgent\") | .Id"
            }

Parameters

Parameter	Required	Default	Description
name	yes		The name of the filter to use, in this case jq-filter.
config	yes		A JSON object represented as a string.
config.Query	no	"."	The JQ query to perform on the response payload.

Example

curl -d @local/sample_payload.json \
  -H "Content-Type: application/json" \
  http://127.0.0.1:6200/post

Result:

["1", "3"]

Testing

Prerequisites

• tinygo - a Go compiler that can produce WebAssembly code.

Build

Once the Go environment is set up and tinygo is in the PATH, build the filter running make.

This will produce a .wasm file in the root of the project.

Running Tests

tinygo test