Gateway Proxy

Overview

The Gateway Proxy is a standalone application to be deployed separately. The proxy enables communication to an outbound server through it's REST API. If a request is send to it’s endpoint it will forward the request to upstream servers.

The proxy is build on top of Spring Boot. It's connection routing aware and offers authentication via OAuth20, Oauth10A, a Bearer Token forward mechanism and fixed headers.

Configuration

The proxy can be configured using environment variables and a configuration files. The configuration file for setting connection routing properties is called connection-routing.yml and has to be in the same directory as the gateway proxy jar package.

Allowing requests to all target servers

By default the proxy only works for outbound connections to URLs configured in the connection-routing-yml file. All other requests are blocked. Setting the environment variable PROXY_ALLOW_UNKNOWN_TARGETs to true allows requests to be proxied to all target URLs.

Logging verbosity

Logging verbosity can be controlled by an environment variable called PROXY_GATEWAY_LOG_LEVEL. Set this to DEBUG for full verbosity and to INFO for more concise logging output.

Running the Application

The application is provided as a docker container at registry.mid.de/smartfacts/smartfacts-gateway-proxy:latest. A docker-compose.yml file can be used to run the gateway proxy in a Docker environment and provide volumes to inject SSL certificates and a connection-routing.yml file. The following example docker-compose.yml file exposes the proxy on port 8418 of the docker host. It uses the certificates stored in /tmp/certificates. It uses the connection-routing.yml file at /tmp/connection-routing.yml

Docker Compose configuration file

services:
    gateway-proxy:
        image: registry.mid.de/smartfacts/smartfacts-gateway-proxy:<VERSION>
        ports:
            - 8418:8080
        environment:
            - USE_SYSTEM_CA_CERTS=1
        volumes:
            - /tmp/cacerts:/certificates
            - /tmp/connection-routing.yml:/opt/smartfacts-gateway-proxy/connection-routing.yml

Starting the docker container

Change to the directory containing the docker-compose.yml configuration file. In order to access the MID Docker registry you need an access token from MID.

#> docker login registry.mid.de
#> docker compose up gateway-proxy

Proxy HTTP endpoint

The proxy application exposes the endpoint /proxy/stream to relay HTTP GET, POST, PUT, DELETE, PATCH and HEAD requests. Only requests to outbound servers that are configured in the connection-routing.yml configuration file are allowed by default. This behavior can be controlled by the environment variable PROXY_ALLOW_UNKNOWN_TARGETS.

Usage

Request sent to the endpoint /proxy/stream with a Request Parameter named target are proxied. The target request parameter has to be set to an outbound
server URL. The outbound server URL has to be url encoded. Responses from the outbound server are streamed through the proxy back to the user-agent.

Examples

1. Proxy a GET request to http://example.com/foo:

   #> curl -X GET http://proxy.host/proxy/stream?target=http%3a%2f%2fexample.com/foo

2. Proxy a Post request with a JSON body to http://example.com/bar:

    #> curl -X POST -H "Content-Type: appliction/json" -d '{"my-data": "baz"}' http://proxy.host/proxy/stream?target=http%3a%2f%2fexample.com/bar

Reference

Environment variables

Connection Routing

Please refer to the connection routing documentation.

Links:

• Connection Routing

• Spring Boot