From b4c210ac58a6da0936c906d076fe71529e6d98f4 Mon Sep 17 00:00:00 2001
From: Michael Johnson <johnsomor@gmail.com>
Date: Wed, 23 Aug 2023 00:13:39 +0000
Subject: [PATCH] Fix a possible receive timeout

This patch fixes a possible receive timeout caused by a slow response from the
driver agent. For example if the database is very slow.

Change-Id: I9079030a5fef9dc44da242adab3c568666777451
---
 octavia_lib/api/drivers/driver_lib.py            | 16 ++++++++++++----
 .../tests/unit/api/drivers/test_driver_lib.py    |  2 +-
 ...e-receive-timeout-error-f6d2454c48eb10cf.yaml |  5 +++++
 3 files changed, 18 insertions(+), 5 deletions(-)
 create mode 100644 releasenotes/notes/Fix-possible-receive-timeout-error-f6d2454c48eb10cf.yaml

diff --git a/octavia_lib/api/drivers/driver_lib.py b/octavia_lib/api/drivers/driver_lib.py
index 99b6612..bf43c2f 100644
--- a/octavia_lib/api/drivers/driver_lib.py
+++ b/octavia_lib/api/drivers/driver_lib.py
@@ -58,11 +58,19 @@ class DriverLibrary():
 
     def _recv(self, sock):
         size_str = b''
-        char = sock.recv(1)
         begin = time.time()
-        while char != b'\n':
-            size_str += char
-            char = sock.recv(1)
+        while True:
+            try:
+                char = sock.recv(1)
+            except socket.timeout:
+                # We could have an overloaded DB and the query may take too
+                # long, so as long as DRIVER_AGENT_TIMEOUT hasn't expired,
+                # let's keep trying while not blocking everything.
+                pass
+            else:
+                if char == b'\n':
+                    break
+                size_str += char
             if time.time() - begin > DRIVER_AGENT_TIMEOUT:
                 raise driver_exceptions.DriverAgentTimeout(
                     fault_string=('The driver agent did not respond in {} '
diff --git a/octavia_lib/tests/unit/api/drivers/test_driver_lib.py b/octavia_lib/tests/unit/api/drivers/test_driver_lib.py
index c248fa2..267a7f1 100644
--- a/octavia_lib/tests/unit/api/drivers/test_driver_lib.py
+++ b/octavia_lib/tests/unit/api/drivers/test_driver_lib.py
@@ -45,7 +45,7 @@ class TestDriverLib(base.TestCase):
     @mock.patch('builtins.memoryview')
     def test_recv(self, mock_memoryview):
         mock_socket = mock.MagicMock()
-        mock_socket.recv.side_effect = [b'1', b'\n', b'2', b'\n', b'3', b'\n']
+        mock_socket.recv.side_effect = [b'1', b'\n', b'2', b'3', b'\n']
         mock_socket.recv_into.return_value = 1
         mv_mock = mock.MagicMock()
         mock_memoryview.return_value = mv_mock
diff --git a/releasenotes/notes/Fix-possible-receive-timeout-error-f6d2454c48eb10cf.yaml b/releasenotes/notes/Fix-possible-receive-timeout-error-f6d2454c48eb10cf.yaml
new file mode 100644
index 0000000..1b39ce1
--- /dev/null
+++ b/releasenotes/notes/Fix-possible-receive-timeout-error-f6d2454c48eb10cf.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixed a possible receive timeout if the driver agent didn't respond inside
+    five seconds. For example if you have a very slow database.