Martin Helmich
Mittwald CM Service GmbH & Co. KG

This code is GPL-licensed.

This repository contains a service gateway that can be used both as a single-signon gateway or API gateway for a microservice architecture. It implements features like load balancing, rate limiting and (rudimentary) HTTP caching. It uses Consul for service discovery and configuration management.

For building, you will need a halfway current Go SDK (tested with 1.4 and 1.5). Then simply go install:

> go install github.com/mittwald/servicegateway

This will produce a (more or less) static binary that you can deploy without any dependencies.

Alternatively, use the Makefile that is shipped within this repository to build the binary and/or a Docker image containing this application:

> make
> make docker

The basic configuration is read from a configuration file that by default is expected to be located in /etc/servicegateway.json. However, you can override that location using the -config command line parameter.

Check the example-configs directory for example configurations for usage as API gateway and Single-SignOn gateway.

Most of the configuration options (that are not required for the actual program startup) can also be provided by Consul, an open-source service discovery engine. Configuration can be stored in Consul's key-value store.

Consul uses a hierarchical key-value store. All configuration items for the servicegateway must be stored under a common key prefix that is supplied via the -consul-base command-line parameter. This affects the following configuration items:

1. Rate-limiting configuration (key <base-prefix>/ratelimiting)
2. Caching configuration (key <base-prefix>/caching)
3. Upstream application (keys <base-prefix>/application/<app-identifier>)

Each upstream application is its own key/value pair with the value being a JSON document describing the application.

You can configure the key prefix in which the service gateway should look for configured applications using the -consul-base parameter:

./servicegateway -consul-base gateway/applications

You can create a new application like follows (substitute <name> with an arbitrary identifier for your application):

> curl -X PUT -d @app.json http://localhost:8500/v1/kv/gateway/applications/<name>

This PUTs the contents of the following file app.json into the Consul key/value store:

{
  "backend": {
    "url": "http://httpbin.org"
  },
  "caching": {
    "auto_flush": true,
    "enabled": true,
    "ttl": 3600
  },
  "routing": {
    "type": "path",
    "path": "/bin"
  },
  "rate_limiting": true
}

Important: Configuration changes made in Consul will become effective immediately, without needing to restart the service gateway.

See the documentation reference.

tbw.

tbw.