Allow to configure some http server details

modules/restserver/src/main/resources/reference.conf

@@ -38,6 +38,17 @@ docspell.server {
     port = 7880
   }
 
+  # Options for tuning the http server
+  server-options {
+    enable-http-2 = false
+
+    # Maximum allowed connections
+    max-connections = 1024
+
+    # Timeout for waiting for the first output of the response
+    response-timeout = 45s
+  }
+
   # This is a hard limit to restrict the size of a batch that is
   # returned when searching for items. The user can set this limit
   # within the client config, but it is restricted by the server to

modules/restserver/src/main/scala/docspell/restserver/Config.scala

@@ -13,7 +13,7 @@ import docspell.ftssolr.SolrConfig
 import docspell.logging.LogConfig
 import docspell.oidc.ProviderConfig
 import docspell.pubsub.naive.PubSubConfig
-import docspell.restserver.Config.OpenIdConfig
+import docspell.restserver.Config.{OpenIdConfig, ServerOptions}
 import docspell.restserver.auth.OpenId
 import docspell.restserver.http4s.InternalHeader
 
@@ -26,6 +26,7 @@ case class Config(
     internalUrl: LenientUri,
     logging: LogConfig,
     bind: Config.Bind,
+    serverOptions: ServerOptions,
     backend: BackendConfig,
     auth: Login.Config,
     showClassificationSettings: Boolean,
@@ -50,6 +51,11 @@ case class Config(
 
 object Config {
 
+  case class ServerOptions(
+      responseTimeout: Duration,
+      enableHttp2: Boolean,
+      maxConnections: Int
+  )
   case class Bind(address: String, port: Int)
 
   case class AdminEndpoint(secret: String)

modules/restserver/src/main/scala/docspell/restserver/RestServer.scala

@@ -52,6 +52,9 @@ object RestServer {
               BlazeServerBuilder[F]
                 .bindHttp(cfg.bind.port, cfg.bind.address)
                 .withoutBanner
+                .withResponseHeaderTimeout(cfg.serverOptions.responseTimeout.toScala)
+                .enableHttp2(cfg.serverOptions.enableHttp2)
+                .withMaxConnections(cfg.serverOptions.maxConnections)
                 .withHttpWebSocketApp(
                   createHttpApp(setting, pubSub, restApp)
                 )

nix/module-server.nix

@@ -21,6 +21,11 @@ let
       address = "localhost";
       port = 7880;
     };
+    server-options = {
+      enable-http-2 = false;
+      max-connections = 1024;
+      response-timeout = "45s";
+    };
     logging = {
       minimum-level = "Info";
       format = "Fancy";
@@ -214,6 +219,30 @@ in {
         description = "Address and port bind the rest server.";
       };
 
+      server-options = mkOption {
+        type = types.submodule({
+          options = {
+            enable-http-2 = mkOption {
+              type = types.bool;
+              default = defaults.server-options.enable-http-2;
+              description = "Whether to enable http2";
+            };
+            max-connections = mkOption {
+              type = types.int;
+              default = defaults.server-options.max-connections;
+              description = "Maximum number of client connections";
+            };
+            response-timeout = mkOption {
+              type = types.str;
+              default = defaults.server-options.response-timeout;
+              description = "Timeout when waiting for the response.";
+            };
+          };
+        });
+        default = defaults.server-options;
+        description = "Tuning the http server";
+      };
+
       logging = mkOption {
         type = types.submodule({
           options = {