feat(*) added a status version field

README.md

@@ -109,6 +109,7 @@ Versioning is strictly based on [Semantic Versioning](https://semver.org/)
 * fix: properly log line numbers by using tail calls [#29](https://github.com/Kong/lua-resty-healthcheck/pull/29)
 * fix: when not providing a hostname, use IP [#48](https://github.com/Kong/lua-resty-healthcheck/pull/48)
 * fix: makefile; make install
+* feature: added a status version field
 
 ### 1.3.0 (17-Jun-2020)
 

lib/resty/healthcheck.lua

@@ -1074,11 +1074,17 @@ function checker:event_handler(event_name, ip, port, hostname)
       self:log(DEBUG, "event: target added '", hostname or "", "(", ip, ":", port, ")'")
     end
     do
-      local from = target_found.internal_health
-      local to = event_name
-      self:log(DEBUG, "event: target status '", hostname or "", "(", ip, ":", port,
-                      ")' from '", from == "healthy" or from == "mostly_healthy",
-                      "' to '",   to   == "healthy" or to   == "mostly_healthy", "'")
+      local from_status = target_found.internal_health
+      local to_status = event_name
+      local from = from_status == "healthy" or from_status == "mostly_healthy"
+      local to = to_status == "healthy" or to_status == "mostly_healthy"
+
+      if from ~= to then
+        self.status_ver = self.status_ver + 1
+      end
+
+      self:log(DEBUG, "event: target status '", hostname or "", "(", ip, ":",
+               port, ")' from '", from, "' to '", to, "', ver: ", self.status_ver)
     end
     target_found.internal_health = event_name
 
@@ -1212,6 +1218,7 @@ local defaults = {
   name = NO_DEFAULT,
   shm_name = NO_DEFAULT,
   type = NO_DEFAULT,
+  status_ver = 0,
   checks = {
     active = {
       type = "http",

t/19-status-ver.t

@@ -0,0 +1,62 @@
+use Test::Nginx::Socket::Lua 'no_plan';
+use Cwd qw(cwd);
+
+workers(2);
+master_on();
+
+my $pwd = cwd();
+
+our $HttpConfig = qq{
+    lua_package_path "$pwd/lib/?.lua;;";
+    lua_shared_dict test_shm 8m;
+    lua_shared_dict my_worker_events 8m;
+
+    init_worker_by_lua_block {
+        local we = require "resty.worker.events"
+        assert(we.configure{ shm = "my_worker_events", interval = 0.1 })
+        ngx.timer.at(0, function()
+            local healthcheck = require("resty.healthcheck")
+            local checker = healthcheck.new({
+                name = "testing",
+                shm_name = "test_shm",
+                checks = {
+                    active = {
+                        healthy  = {
+                            interval = 0.1
+                        },
+                        unhealthy  = {
+                            interval = 0.1
+                        }
+                    }
+                }
+            })
+            local ok, err = checker:add_target("127.0.0.1", 11111)
+            if not ok then
+                error(err)
+            end
+        end)
+    }
+};
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: add_target() adds an unhealthy target
+--- http_config eval: $::HttpConfig
+--- config
+    location = /t {
+        content_by_lua_block {
+            ngx.say(true)
+            ngx.sleep(0.3) -- wait twice the interval
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+checking unhealthy targets: nothing to do
+checking unhealthy targets: #1
+from 'true' to 'false', ver: 2
+from 'true' to 'false', ver: 1