Limit connections by default

.markdownlint.yaml

+default: true,

CHANGELOG.md

 CHANGELOG
 =========
 
-## [0.2.0] - 2022-03-06
+[0.2.1] - unreleased
+--------------------
 
-- Fix potential hang when the client is shutdown and a request is scheduled at the same time.
+- Limit concurrent connections to 64 and per host to 8 by default. You can
+    change that using 2 new functions.
 
-## [0.1.1] - 2021-12-20
+[0.2.0] - 2022-03-06
+--------------------
+
+- Fix potential hang when the client is shutdown and a request is scheduled at
+    the same time.
+
+[0.1.1] - 2021-12-20
+--------------------
 
 - Add wrapper function to convert error codes to strings.
 
-## [0.1.0] - 2021-11-14
+[0.1.0] - 2021-11-14
+--------------------
 
 - Initial release.

include/coeurl/client.hpp

@@ -145,6 +145,12 @@ struct Client {
     //! stops sending acks.
     void connection_timeout(long t) { connection_timeout_ = t; }
 
+    //! Maximum connections to open in parallel for this client. Set to 0 to disable the limit. Default is 64.
+    void maximum_total_connections(long count);
+    //! Maximum connections to open in parallel for each specific host for this client. Set to 0 to disable the limit.
+    //! Default is 8.
+    void maximum_connections_per_host(long count);
+
   private:
     // Call this to run the event loop. Will block until the client is shutdown.
     void run();

lib/client.cpp

@@ -232,9 +232,20 @@ Client::Client() {
     curl_multi_setopt(this->multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
     curl_multi_setopt(this->multi, CURLMOPT_TIMERDATA, this);
 
+    maximum_total_connections(64);
+    maximum_connections_per_host(8);
+
     bg_thread = std::thread([this]() { this->run(); });
 }
 
+void Client::maximum_total_connections(long count) {
+    curl_multi_setopt(this->multi, CURLMOPT_MAX_TOTAL_CONNECTIONS, count);
+}
+
+void Client::maximum_connections_per_host(long count) {
+    curl_multi_setopt(this->multi, CURLMOPT_MAX_HOST_CONNECTIONS, count);
+}
+
 Client::~Client() {
     close();