Move backends to cmd args, allow setting private key seed via parameter or ENV var

utils/http.go

@@ -0,0 +1,38 @@
+package utils
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+)
+
+func MakeReverseProxy(target string) (*httputil.ReverseProxy, error) {
+	u, err := url.Parse(target)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse target URL: %w", err)
+	}
+
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+
+	// https://github.com/oauth2-proxy/oauth2-proxy/blob/4e2100a2879ef06aea1411790327019c1a09217c/pkg/upstream/http.go#L124
+	if u.Scheme == "unix" {
+		// clean path up so we don't use the socket path in proxied requests
+		addr := u.Path
+		u.Path = ""
+		// tell transport how to dial unix sockets
+		transport.DialContext = func(ctx context.Context, _, _ string) (net.Conn, error) {
+			dialer := net.Dialer{}
+			return dialer.DialContext(ctx, "unix", addr)
+		}
+		// tell transport how to handle the unix url scheme
+		transport.RegisterProtocol("unix", UnixRoundTripper{Transport: transport})
+	}
+
+	rp := httputil.NewSingleHostReverseProxy(u)
+	rp.Transport = transport
+
+	return rp, nil
+}