Add a feature flag for testing h2c:// performance.

conf/Caddyfile

@@ -27,7 +27,7 @@
 	auto_https disable_redirects
 
 	on_demand_tls {
-		permission http http://{$GIT_PAGES_ADDRESS:localhost}:3001
+		permission http http://localhost:3001
 	}
 
 	servers :80 {
@@ -46,12 +46,18 @@
 	}
 }
 
+(backend_pages) {
+	@h2c `{env.FEATURES}.matches(r"\bh2c\b")`
+	reverse_proxy @h2c h2c://{$GIT_PAGES_ADDRESS:localhost}:3000
+	reverse_proxy http://{$GIT_PAGES_ADDRESS:localhost}:3000
+}
+
 http:// {
 	@get method GET
 	redir @get https://{host}{uri} 301
 
 	# initial PUT/POST for a new domain has to happen over HTTP
-	reverse_proxy h2c://{$GIT_PAGES_ADDRESS:localhost}:3000
+	import backend_pages
 }
 
 https:// {
@@ -60,9 +66,9 @@ https:// {
 	}
 
 	encode
-	reverse_proxy h2c://{$GIT_PAGES_ADDRESS:localhost}:3000
+	import backend_pages
 }
 
 http://localhost:2002 {
-	reverse_proxy h2c://{$GIT_PAGES_ADDRESS:localhost}:3002
+	reverse_proxy http://localhost:3002
 }

src/main.go

@@ -7,12 +7,23 @@ import (
 	"log/slog"
 	"net"
 	"net/http"
+	"os"
 	"runtime/debug"
+	"slices"
 	"strings"
 
 	"github.com/KimMachineGun/automemlimit/memlimit"
 )
 
+var features []string
+
+func FeatureActive(feature string) bool {
+	if features == nil {
+		features = strings.Split(strings.ToLower(os.Getenv("FEATURES")), ",")
+	}
+	return slices.Contains(features, strings.ToLower(feature))
+}
+
 func listen(name string, listen string) net.Listener {
 	if listen == "" {
 		return nil
@@ -57,7 +68,9 @@ func serve(listener net.Listener, serve func(http.ResponseWriter, *http.Request)
 		server := http.Server{Handler: handler}
 		server.Protocols = new(http.Protocols)
 		server.Protocols.SetHTTP1(true)
-		server.Protocols.SetUnencryptedHTTP2(true)
+		if FeatureActive("h2c") {
+			server.Protocols.SetUnencryptedHTTP2(true)
+		}
 		log.Fatalln(server.Serve(listener))
 	}
 }