configurable workers

This server will only see occasional traffic so it makes sense to spawn
only limited number of workers as opposed to spawning one worker/thread,
which is the default behavior.

I recommend at least two workers.

Cargo.lock

@@ -926,6 +926,7 @@ dependencies = [
  "git2",
  "lazy_static",
  "log",
+ "num_cpus",
  "pretty_env_logger",
  "serde 1.0.130",
  "serde_json",

Cargo.toml

@@ -32,3 +32,5 @@ lazy_static = "1.4"
 url = "2.2"
 
 derive_more = "0.99"
+
+num_cpus = "1.13"

config/default.toml

@@ -15,3 +15,4 @@ ip= "0.0.0.0"
 domain = "localhost"
 allow_registration = true
 proxy_has_tls = false
+#workers = 2

src/main.rs

@@ -67,14 +67,13 @@ async fn main() -> std::io::Result<()> {
                 actix_middleware::DefaultHeaders::new()
                     .header("Permissions-Policy", "interest-cohort=()"),
             )
-            //       .wrap(get_survey_session())
-            //       .wrap(get_identity_service())
             .wrap(actix_middleware::NormalizePath::new(
                 actix_middleware::TrailingSlash::Trim,
             ))
             .configure(services)
         //        .app_data(data.clone())
     })
+    .workers(SETTINGS.server.workers.unwrap_or(num_cpus::get()))
     .bind(SETTINGS.server.get_ip())
     .unwrap()
     .run()

src/settings.rs

@@ -30,6 +30,7 @@ pub struct Server {
     pub domain: String,
     pub ip: String,
     pub proxy_has_tls: bool,
+    pub workers: Option<usize>,
 }
 
 impl Server {