localserver

Helpers for creating test HTTPS servers and clients on localhost.

Use case

If you're writing a proxy or some sort of routing component, you'll need to spin up some test servers. In the real world we only speak TLS, never plaintext. It follows that we'd like to use TLS in our integration tests, since using an encrypted transport gives us a more realistic setup.

However, dealing with X.509 certificates and keys is kind of a pain. On top of that, configuring TLS for Go's standard http.Server requires some boilerplate. This project tries to alleviate a little bit of that. We provide functions and configurable types that reside in memory, speaking HTTP1 and HTTP2 over TLS.

Example

Create a CA that can sign certs for a host called server1.

ca, err := NewCA(WithDNSNames([]string{"server1"}))

Create a signed cert for server1 with the CA object.

cert, err := ca.CreateSignedCert("server1")

Create a localhost HTTP2 server on a random high port. We provide a handler that echoes back our HTTP headers as a map. We provide the CA and the cert created earlier.

fn := func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(200)
    // Header is an alias: type Header map[string][]string
    data, _ := json.Marshal(r.Header)
    w.Write(data)
}
svr := NewLocalServer(fn, cert, ca)
svr.StartHTTP2() // doesn't block
defer svr.Stop()

Now that svr is listening on localhost, we can talk to it over HTTPS with a client that trusts the same CA. Note that since we've spun up our test sever on a random port, we must use the AddrPort method to get the actual port.

client := NewHTTP2Client(ca)
url := fmt.Sprintf("https://server1:%s/", svr.AddrPort())
resp, err := client.Get(url)

Importantly, we have to set server1 as an alias to localhost in /etc/hosts, or otherwise ensure that the name server1 resolves to localhost.