feat(config): Add a config value for thread counts

common/Cargo.toml

@@ -23,6 +23,7 @@ failure = "0.1.5"
 lazy_static = "1.3.0"
 log = { version = "0.4.8", features = ["serde"] }
 human-size = "0.4.0"
+num_cpus = "1.10.1"
 parking_lot = "0.9.0"
 rand = "0.6.5"
 regex = "1.2.0"

common/src/config.rs

@@ -253,6 +253,11 @@ struct Limits {
     max_api_file_upload_size: ByteSize,
     /// The maximum payload size for chunks
     max_api_chunk_upload_size: ByteSize,
+    /// The maximum number of threads to spawn for CPU and web work, each.
+    ///
+    /// The total number of threads spawned will roughly be `2 * max_thread_count + 1`. Defaults to
+    /// the number of logical CPU cores on the host.
+    max_thread_count: usize,
 }
 
 impl Default for Limits {
@@ -263,6 +268,7 @@ impl Default for Limits {
             max_api_payload_size: ByteSize::from_megabytes(20),
             max_api_file_upload_size: ByteSize::from_megabytes(40),
             max_api_chunk_upload_size: ByteSize::from_megabytes(100),
+            max_thread_count: num_cpus::get(),
         }
     }
 }
@@ -802,6 +808,11 @@ impl Config {
         self.values.limits.max_concurrent_requests
     }
 
+    /// Returns the number of cores to use for thread pools.
+    pub fn cpu_concurrency(&self) -> usize {
+        self.values.limits.max_thread_count
+    }
+
     /// Return the Sentry DSN if reporting to Sentry is enabled.
     pub fn sentry_dsn(&self) -> Option<&Dsn> {
         if self.values.sentry.enabled {

server/Cargo.toml

@@ -30,7 +30,6 @@ lazy_static = "1.3.0"
 listenfd = "0.3.3"
 log = "0.4.8"
 native-tls = { version = "0.2.3", optional = true }
-num_cpus = "1.10.1"
 parking_lot = "0.9.0"
 r2d2 = { version = "0.8.5", optional = true }
 rdkafka = { version = "0.21.0", git = "https://github.com/fede1024/rust-rdkafka", optional = true, rev = "b1a391b3264ca8e0b0e053c6aec7a6db09af3131" }

server/src/actors/events.rs

@@ -353,7 +353,7 @@ impl EventManager {
         let rate_limiter = RateLimiter::new(&config).context(ServerErrorKind::RedisError)?;
 
         // TODO: Make the number configurable via config file
-        let thread_count = num_cpus::get();
+        let thread_count = config.cpu_concurrency();
         log::info!("starting {} event processing workers", thread_count);
 
         #[cfg(feature = "processing")]

server/src/service.rs

@@ -282,7 +282,10 @@ where
 pub fn start(state: ServiceState) -> Result<Recipient<server::StopServer>, ServerError> {
     let config = state.config();
     let mut server = server::new(move || make_app(state.clone()));
-    server = server.shutdown_timeout(SHUTDOWN_TIMEOUT).disable_signals();
+    server = server
+        .workers(config.cpu_concurrency())
+        .shutdown_timeout(SHUTDOWN_TIMEOUT)
+        .disable_signals();
 
     let connector = ClientConnector::default()
         .limit(config.max_concurrent_requests())