Invoke lua script on EnRoute Standalone Gateway

Published January 22, 2021
Last Modified January 29, 2021

EnRoute Universal Gateway

EnRoute Universal Gateway is a flexible API gateway built to support traditional and cloud-native use cases. It is designed to run either as an Kubernetes Ingress Gateway, Standalone Gateway, Horizontally scaling L7 API gateway or a Mesh of Gateways. EnRoute can support a wide range of topologies. Depending on the need of the user, the environment, the application, either one or many of these solutions can be deployed. EnRoute also supports plugins/filters to extend functionality and enforce policies. The features page lists the available plugins for the Gateway. More details about each of the plugin can also be found on plugin pages.

A consistent policy framework across all these network components makes the EnRoute Universal Gateway a versatile and powerful solution.

This article covers how to get started with the EnRoute Standalone Gateway.

What this article covers.

Setting up EnRoute gateway is shown in four simple steps. This is the third step where a lua script is attached to a service object. This lua script is invoked on request and response path.

Step-1 Understanding EnRoute gateway through a simple example
Step-2 Secure your service using SSL. Create and attach a SSL certificate
Step-3 Invoke a lua script for every request and response. Create and attach a lua filter to service
Step-4 Rate limit requests destined for a service. Create and attach a rate-limit filter to route

Create lua filter

First we create a filter of type http_filter_lua

curl -s -X POST localhost:1323/filter \
     -d 'Filter_name=lua_filter_demo' \
     -d 'Filter_type=http_filter_lua'

{
  "data": {
    "insert_saaras_db_filter": {
      "affected_rows": 1
    }
  }
}

Next we create a file to hold lua script

cat >script.lua <<EOL
function envoy_on_request(request_handle)
   request_handle:logInfo("Hello World request");
end

function envoy_on_response(response_handle)
   response_handle:logInfo("Hello World response");
end
EOL

curl -X POST \
  -F 'Config=@script.lua' \
  http://localhost:1323/filter/lua_filter_demo/config

{
  "data": {
    "insert_saaras_db_filter": {
      "affected_rows": 1
    }
  }
}

Next we attach the lua filter to the service

curl -s -X POST localhost:1323/service/demo/filter/lua_filter_demo

{
  "data": {
    "insert_saaras_db_service_filter": {
      "affected_rows": 3
    }
  }
}

Dump service to see lua filter is attached to the service

curl -s localhost:1323/service/dump/demo

{
  "data": {
    "saaras_db_service": [
      {
        "service_id": 1,
        "service_name": "demo",
        "fqdn": "enroute.local",
        "create_ts": "2021-01-25T19:08:57.670403+00:00",
        "routes": [
          {
            "route_id": 1,
            "route_name": "gs_route",
            "route_upstreams": [
              {
                "upstream": {
                  "upstream_id": 1,
                  "upstream_name": "server1",
                  "upstream_ip": "127.0.0.1",
                  "upstream_port": 50051
                }
              }
            ],
            "route_filters": [],
            "route_prefix": "/"
          }
        ],
        "service_secrets": [
          {
            "secret": {
              "secret_id": 1,
              "secret_name": "enroute_secret",
              "secret_sni": "",
              "secret_key": "-----BEGIN PRIVATE KEY-----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\n5f8NWp7AZFruk47mjnf2Y40+uw==\n-----END PRIVATE KEY-----\n",
              "secret_cert": "-----BEGIN CERTIFICATE-----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\n-----END CERTIFICATE-----\n"
            }
          }
        ],
        "service_filters": [
          {
            "filter": {
              "filter_name": "lua_filter_demo",
              "filter_type": "http_filter_lua"
            }
          }
        ]
      }
    ]
  }
}

Send traffic

Send a request to the listener

curl -k -vvv https://enroute.local:8443 --resolve enroute.local:8443:127.0.0.1

Check envoy stats

curl -k -vvv http://localhost:9001/stats

Next steps

EnRoute standalone gateway provides simple APIs to configure Envoy proxy. Additionally you can -

Step-1 Understanding EnRoute gateway through a simple example
Step-2 Secure your service using SSL. Create and attach a SSL certificate
Step-3 Invoke a lua script for every request and response. Create and attach a lua filter to service
Step-4 Rate limit requests destined for a service. Create and attach a rate-limit filter to route

Invoke lua script on EnRoute Standalone Gateway