Suppose you are a Google Apps customer and suppose you want to restrict access to some web servers to just the folks in your organization. Like, for instance, if you're building your internal apps on AWS. Pain in the ass, right? So put underpants in between the world and your backends and you can use your Google credentials to get in.

go get github.com/kellegous/underpants

Your underpants are configured through a silly little JSON file. Here's an example:

{
  "host" : "underpants.company.com",
  "oauth" : {
    "domain"        : "company.com",
    "client-id"     : "oauth-client-id",
    "client-secret" : "oauth-client-secret"
  },
  "use-strict-security-headers": true,
  "certs" : [
    {
      "crt" : "/path/to/crt.pem",
      "key" : "/path/to/key.pem"
    }
  ],
  "routes" : [
    {
      "from" : "public.company.com",
      "to"   : "localhost:8080"
    }
  ]
}

The certs section is optional and its absence will cause your underpants proxy to operate on pure HTTP. The key file may be encrypted so long as it is in encrypted PEM format with proper Proc-Type and Dek-Info headers. If you do not know what that means, just use openssl and that is what you will end up with.

You can get your oauth-client-id and oauth-client-secret by creating a project on Google's API Console.

If your configuration can stomach it, enable use-strict-security-headers to get some extra peace of mind. This will block clickjacking, disable downstream HTTP caching, and turn on Strict-Transport-Security if HTTPS.

For more granular access control, you can configure groups and their membership in the JSON file. Once groups are configured, routes will deny all users who are not a member of one of the authorized groups by default. The special * group can be used to allow any authenticated user access to the route. See underpants.sample.groups.json for a configuration sample.

Just run it; it's an executable.

underpants

• Handle non-transactional traffic, like web sockets.