Make the client threadpool user-customizable

In addition to making the threadpool used by client shards customizable
by the user, make only a single threadpool (as opposed to one per shard)
and share it across all shards.

4 files changed, 38 insertions, 15 deletions

diff --git a/src/client/bridge/gateway/shard_manager.rs b/src/client/bridge/gateway/shard_manager.rs
index 5dbe0c3..2068bef 100644
--- a/src/client/bridge/gateway/shard_manager.rs
+++ b/src/client/bridge/gateway/shard_manager.rs
@@ -12,6 +12,7 @@ use super::{
     ShardQueuerMessage,
     ShardRunnerInfo,
 };
+use threadpool::ThreadPool;
 use typemap::ShareMap;
 
 #[cfg(feature = "framework")]
@@ -40,6 +41,7 @@ impl ShardManager {
         data: Arc<ParkingLotMutex<ShareMap>>,
         event_handler: Arc<H>,
         framework: Arc<Mutex<Option<Box<Framework + Send>>>>,
+        threadpool: ThreadPool,
     ) -> Self where H: EventHandler + Send + Sync + 'static {
         let (thread_tx, thread_rx) = mpsc::channel();
         let (shard_queue_tx, shard_queue_rx) = mpsc::channel();
@@ -56,6 +58,7 @@ impl ShardManager {
             rx: shard_queue_rx,
             token: token.clone(),
             ws_url: ws_url.clone(),
+            threadpool,
         };
 
         thread::spawn(move || {
@@ -81,6 +84,7 @@ impl ShardManager {
         token: Arc<Mutex<String>>,
         data: Arc<ParkingLotMutex<ShareMap>>,
         event_handler: Arc<H>,
+        threadpool: ThreadPool,
     ) -> Self where H: EventHandler + Send + Sync + 'static {
         let (thread_tx, thread_rx) = mpsc::channel();
         let (shard_queue_tx, shard_queue_rx) = mpsc::channel();
@@ -96,6 +100,7 @@ impl ShardManager {
             rx: shard_queue_rx,
             token: token.clone(),
             ws_url: ws_url.clone(),
+            threadpool,
         };
 
         thread::spawn(move || {
diff --git a/src/client/bridge/gateway/shard_queuer.rs b/src/client/bridge/gateway/shard_queuer.rs
index f35acb7..ea49de4 100644
--- a/src/client/bridge/gateway/shard_queuer.rs
+++ b/src/client/bridge/gateway/shard_queuer.rs
@@ -14,6 +14,7 @@ use super::{
     ShardRunner,
     ShardRunnerInfo,
 };
+use threadpool::ThreadPool;
 use typemap::ShareMap;
 
 #[cfg(feature = "framework")]
@@ -34,6 +35,7 @@ pub struct ShardQueuer<H: EventHandler + Send + Sync + 'static> {
     pub manager_tx: Sender<ShardManagerMessage>,
     pub runners: Arc<ParkingLotMutex<HashMap<ShardId, ShardRunnerInfo>>>,
     pub rx: Receiver<ShardQueuerMessage>,
+    pub threadpool: ThreadPool,
     pub token: Arc<Mutex<String>>,
     pub ws_url: Arc<Mutex<String>>,
 }
@@ -88,6 +90,7 @@ impl<H: EventHandler + Send + Sync + 'static> ShardQueuer<H> {
                 self.framework.clone(),
                 self.data.clone(),
                 self.event_handler.clone(),
+                self.threadpool.clone(),
             )
         } else {
             ShardRunner::new(
@@ -95,6 +98,7 @@ impl<H: EventHandler + Send + Sync + 'static> ShardQueuer<H> {
                 self.manager_tx.clone(),
                 self.data.clone(),
                 self.event_handler.clone(),
+                self.threadpool.clone(),
             )
         }};
 
diff --git a/src/client/bridge/gateway/shard_runner.rs b/src/client/bridge/gateway/shard_runner.rs
index 6f6b050..1b1de0e 100644
--- a/src/client/bridge/gateway/shard_runner.rs
+++ b/src/client/bridge/gateway/shard_runner.rs
@@ -30,16 +30,17 @@ pub struct ShardRunner<H: EventHandler + Send + Sync + 'static> {
 
 impl<H: EventHandler + Send + Sync + 'static> ShardRunner<H> {
     #[cfg(feature = "framework")]
-    pub fn new(shard: LockedShard,
-               manager_tx: Sender<ShardManagerMessage>,
-               framework: Arc<Mutex<Option<Box<Framework + Send>>>>,
-               data: Arc<ParkingLotMutex<ShareMap>>,
-               event_handler: Arc<H>) -> Self {
+    pub fn new(
+        shard: LockedShard,
+        manager_tx: Sender<ShardManagerMessage>,
+        framework: Arc<Mutex<Option<Box<Framework + Send>>>>,
+        data: Arc<ParkingLotMutex<ShareMap>>,
+        event_handler: Arc<H>,
+        threadpool: ThreadPool,
+    ) -> Self {
         let (tx, rx) = mpsc::channel();
         let shard_info = shard.lock().shard_info();
 
-        let name = format!("threadpool {:?}", shard_info);
-
         Self {
             runner_rx: rx,
             runner_tx: tx,
@@ -49,20 +50,21 @@ impl<H: EventHandler + Send + Sync + 'static> ShardRunner<H> {
             manager_tx,
             shard,
             shard_info,
-            threadpool: ThreadPool::with_name(name, 15),
+            threadpool,
         }
     }
 
     #[cfg(not(feature = "framework"))]
-    pub fn new(shard: LockedShard,
-               manager_tx: Sender<ShardManagerMessage>,
-               data: Arc<ParkingLotMutex<ShareMap>>,
-               event_handler: Arc<H>) -> Self {
+    pub fn new(
+        shard: LockedShard,
+        manager_tx: Sender<ShardManagerMessage>,
+        data: Arc<ParkingLotMutex<ShareMap>>,
+        event_handler: Arc<H>,
+        threadpool: ThreadPool,
+    ) -> Self {
         let (tx, rx) = mpsc::channel();
         let shard_info = shard.lock().shard_info();
 
-        let name = format!("threadpool {:?}", shard_info);
-
         Self {
             runner_rx: rx,
             runner_tx: tx,
@@ -71,7 +73,7 @@ impl<H: EventHandler + Send + Sync + 'static> ShardRunner<H> {
             manager_tx,
             shard,
             shard_info,
-            threadpool: ThreadPool::with_name(name, 15),
+            threadpool,
         }
     }
 
diff --git a/src/client/mod.rs b/src/client/mod.rs
index d1de13e..f2fb297 100644
--- a/src/client/mod.rs
+++ b/src/client/mod.rs
@@ -44,6 +44,7 @@ use std::sync::atomic::{AtomicBool, Ordering, ATOMIC_BOOL_INIT};
 use parking_lot::Mutex;
 use std::collections::HashMap;
 use std::mem;
+use threadpool::ThreadPool;
 use typemap::ShareMap;
 use http;
 use internal::prelude::*;
@@ -244,6 +245,11 @@ pub struct Client<H: EventHandler + Send + Sync + 'static> {
     /// [`Client::start_shard`]: #method.start_shard
     /// [`Client::start_shards`]: #method.start_shards
     pub shard_runners: Arc<Mutex<HashMap<ShardId, ShardRunnerInfo>>>,
+    /// The threadpool shared by all shards.
+    ///
+    /// Defaults to 5 threads, which should suffice small bots. Consider
+    /// increasing this number as your bot grows.
+    pub threadpool: ThreadPool,
     token: Arc<sync::Mutex<String>>,
 }
 
@@ -287,12 +293,16 @@ impl<H: EventHandler + Send + Sync + 'static> Client<H> {
         http::set_token(&token);
         let locked = Arc::new(sync::Mutex::new(token));
 
+        let name = "serenity client".to_owned();
+        let threadpool = ThreadPool::with_name(name, 5);
+
         feature_framework! {{
             Client {
                 data: Arc::new(Mutex::new(ShareMap::custom())),
                 event_handler: Arc::new(handler),
                 framework: Arc::new(sync::Mutex::new(None)),
                 shard_runners: Arc::new(Mutex::new(HashMap::new())),
+                threadpool,
                 token: locked,
             }
         } else {
@@ -300,6 +310,7 @@ impl<H: EventHandler + Send + Sync + 'static> Client<H> {
                 data: Arc::new(Mutex::new(ShareMap::custom())),
                 event_handler: Arc::new(handler),
                 shard_runners: Arc::new(Mutex::new(HashMap::new())),
+                threadpool,
                 token: locked,
             }
         }}
@@ -761,6 +772,7 @@ impl<H: EventHandler + Send + Sync + 'static> Client<H> {
             self.event_handler.clone(),
             #[cfg(feature = "framework")]
             self.framework.clone(),
+            self.threadpool.clone(),
         );
 
         self.shard_runners = manager.runners.clone();