From dc7fa885a2ff2e3f44d96cc00a7471bae1681a19 Mon Sep 17 00:00:00 2001
From: Elvin Efendi <elvin.efendiyev@gmail.com>
Date: Sat, 25 May 2019 23:50:18 -0400
Subject: [PATCH] log info when endpoints change for a balancer

---
 rootfs/etc/nginx/lua/balancer/ewma.lua   | 6 ++++++
 rootfs/etc/nginx/lua/balancer/resty.lua  | 6 ++++++
 rootfs/etc/nginx/lua/balancer/sticky.lua | 6 ++++++
 3 files changed, 18 insertions(+)

diff --git a/rootfs/etc/nginx/lua/balancer/ewma.lua b/rootfs/etc/nginx/lua/balancer/ewma.lua
index 7f0bd7740..afea01914 100644
--- a/rootfs/etc/nginx/lua/balancer/ewma.lua
+++ b/rootfs/etc/nginx/lua/balancer/ewma.lua
@@ -8,6 +8,10 @@
 local util = require("util")
 local split = require("util.split")
 
+local string_format = string.format
+local ngx_log = ngx.log
+local INFO = ngx.INFO
+
 local DECAY_TIME = 10 -- this value is in seconds
 local PICK_SET_SIZE = 2
 
@@ -107,6 +111,8 @@ function _M.sync(self, backend)
     return
   end
 
+  ngx_log(INFO, string_format("[%s] peers have changed for backend %s", self.name, backend.name))
+
   self.peers = backend.endpoints
   self.ewma = {}
   self.ewma_last_touched_at = {}
diff --git a/rootfs/etc/nginx/lua/balancer/resty.lua b/rootfs/etc/nginx/lua/balancer/resty.lua
index fa236246f..a4090c4c0 100644
--- a/rootfs/etc/nginx/lua/balancer/resty.lua
+++ b/rootfs/etc/nginx/lua/balancer/resty.lua
@@ -1,5 +1,9 @@
 local util = require("util")
 
+local string_format = string.format
+local ngx_log = ngx.log
+local INFO = ngx.INFO
+
 local _M = {}
 
 function _M.new(self, o)
@@ -19,6 +23,8 @@ function _M.sync(self, backend)
     return
   end
 
+  ngx_log(INFO, string_format("[%s] nodes have changed for backend %s", self.name, backend.name))
+
   self.instance:reinit(nodes)
 end
 
diff --git a/rootfs/etc/nginx/lua/balancer/sticky.lua b/rootfs/etc/nginx/lua/balancer/sticky.lua
index cb32f2095..3db2ba3d5 100644
--- a/rootfs/etc/nginx/lua/balancer/sticky.lua
+++ b/rootfs/etc/nginx/lua/balancer/sticky.lua
@@ -4,6 +4,10 @@ local util = require("util")
 local ck = require("resty.cookie")
 local math = require("math")
 
+local string_format = string.format
+local ngx_log = ngx.log
+local INFO = ngx.INFO
+
 local _M = balancer_resty:new({ factory = resty_chash, name = "sticky" })
 local DEFAULT_COOKIE_NAME = "route"
 
@@ -98,6 +102,8 @@ function _M.sync(self, backend)
     return
   end
 
+  ngx_log(INFO, string_format("[%s] nodes have changed for backend %s", self.name, backend.name))
+
   self.cookie_session_affinity = backend.sessionAffinityConfig.cookieSessionAffinity
 end