From 47e03c07dc1b64f956a1138fac8a14f7bf9a2e50 Mon Sep 17 00:00:00 2001
From: Ching Kuo <ching.kuo@linecorp.com>
Date: Wed, 28 Oct 2020 10:39:51 +0800
Subject: [PATCH] Improve Socket for oslo.metrics

This commit includes 2 improvements for oslo.metrics UDP socket

- When starting oslo.metrics unlink the socket first before binding
- Change the mode for file so that other OpenStack process running in
  other user can access and send metrics e.g. nova, neutron

Change-Id: I27672f03d282acf1e9cb669998899a032fe4202a
---
 oslo_metrics/__main__.py | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/oslo_metrics/__main__.py b/oslo_metrics/__main__.py
index 74dec0a..eabd15f 100644
--- a/oslo_metrics/__main__.py
+++ b/oslo_metrics/__main__.py
@@ -16,6 +16,7 @@
 import os
 import select
 import socket
+import stat
 import sys
 import threading
 from wsgiref.simple_server import make_server
@@ -48,10 +49,19 @@ class MetricsListener():
     def __init__(self, socket_path):
         self.socket_path = socket_path
         self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
+        self.unlink(socket_path)
+        self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
         self.socket.bind(self.socket_path)
         self.start = True
         self.router = message_router.MessageRouter()
 
+    def unlink(self, socket_path):
+        try:
+            os.unlink(socket_path)
+        except OSError:
+            if os.path.exists(socket_path):
+                raise
+
     def serve(self):
         while self.start:
             readable, writable, exceptional = select.select(
@@ -74,7 +84,12 @@ class MetricsListener():
 
 def main():
     cfg.CONF(sys.argv[1:])
-    m = MetricsListener(cfg.CONF.oslo_metrics.metrics_socket_file)
+    socket_path = cfg.CONF.oslo_metrics.metrics_socket_file
+    m = MetricsListener(socket_path)
+    try:
+        os.chmod(socket_path, stat.S_IRWXU | stat.S_IRWXO)
+    except OSError:
+        LOG.error("Changing the mode of the file failed.... continuing")
     mt = threading.Thread(target=m.serve)
     LOG.info("Start oslo.metrics")
     mt.start()