From 49f5c335f693fb49dcc9bc052a7e469f66fa9b59 Mon Sep 17 00:00:00 2001
From: Nikolay Kim <fafhrd91@gmail.com>
Date: Sun, 11 Mar 2018 16:52:20 -0700
Subject: [PATCH] better sleep on error

---
 CHANGES.md        |  2 ++
 src/server/srv.rs | 20 ++++++++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 75a29d5d3..a1e2ed490 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,6 +8,8 @@
 
 * Fix steraming response handling for http/2
 
+* Better sleep on error support
+
 
 ## 0.4.6 (2018-03-10)
 
diff --git a/src/server/srv.rs b/src/server/srv.rs
index c578331b6..8ba058b38 100644
--- a/src/server/srv.rs
+++ b/src/server/srv.rs
@@ -741,10 +741,9 @@ fn start_accept_thread(
                                         break
                                     }
                                 },
-                                Err(err) => {
-                                    if err.kind() != io::ErrorKind::WouldBlock {
-                                        error!("Error accepting connection: {:?}", err);
-                                    }
+                                Err(ref e) if connection_error(e) => continue,
+                                Err(e) => {
+                                    error!("Error accepting connection: {:?}", e);
                                     // sleep after error
                                     thread::sleep(sleep);
                                     break
@@ -818,3 +817,16 @@ fn create_tcp_listener(addr: net::SocketAddr, backlog: i32) -> io::Result<net::T
     builder.bind(addr)?;
     Ok(builder.listen(backlog)?)
 }
+
+/// This function defines errors that are per-connection. Which basically
+/// means that if we get this error from `accept()` system call it means
+/// next connection might be ready to be accepted.
+///
+/// All other errors will incur a timeout before next `accept()` is performed.
+/// The timeout is useful to handle resource exhaustion errors like ENFILE
+/// and EMFILE. Otherwise, could enter into tight loop.
+fn connection_error(e: &io::Error) -> bool {
+    e.kind() == io::ErrorKind::ConnectionRefused ||
+        e.kind() == io::ErrorKind::ConnectionAborted ||
+        e.kind() == io::ErrorKind::ConnectionReset
+}