feat: add check health running mode function (#149)

Author: shuaijinchao

health_check.md

@@ -9,6 +9,7 @@ Implement a passive health check mechanism, that when the connection/read/write
 * [init](#init)
 * [report_failure](#report_failure)
 * [get_target_status](#get_target_status)
+* [get_check_mode](#get_check_mode)
 
 ###  init
 
@@ -28,6 +29,15 @@ Reports a health failure which will count against the number of occurrences requ
 
 Get the current status of the target.
 
+###  get_check_mode
+
+`syntax: mode = health_check.get_check_mode()`
+
+Get the current health check running mode. When `mode` is `round-robin`, it means running in [Round robin](#round-robin-based-health-check) mode, and `shared-dict` means running in [Policy](#policy-based-health-check) mode operation.
+
+When using this method to get the health check running mode, you can use `health_check.ROUND_ROBIN_MODE` and `health_check.SHARED_DICT_MODE` to judge and compare.
+
+
 ## Config
 
 | name         | Type    | Requirement | Default | Description                                                  |

lib/resty/etcd/health_check.lua

@@ -4,7 +4,12 @@ local type          = type
 local now           = os.time
 local conf
 
+local HEALTH_CHECK_MODE_ROUND_ROBIN = "round-robin"
+local HEALTH_CHECK_MODE_SHARED_DICT = "shared-dict"
+
 local _M = {}
+_M.ROUND_ROBIN_MODE = HEALTH_CHECK_MODE_ROUND_ROBIN
+_M.SHARED_DICT_MODE = HEALTH_CHECK_MODE_SHARED_DICT
 
 local round_robin_unhealthy_target_hosts
 
@@ -102,6 +107,18 @@ end
 _M.report_failure = report_failure
 
 
+local function get_check_mode()
+    -- round-robin: nginx worker memory round-robin based health check
+    -- shared-dict: nginx shared memory policy based health check
+    if conf and conf.shm_name then
+        return HEALTH_CHECK_MODE_SHARED_DICT
+    else
+        return HEALTH_CHECK_MODE_ROUND_ROBIN
+    end
+end
+_M.get_check_mode = get_check_mode
+
+
 function _M.init(opts)
     opts = opts or {}
     if not conf or opts.shm_name ~= conf.shm_name then

t/v3/health_check.t

@@ -767,3 +767,46 @@ http://127.0.0.1:42379: connection refused
 http://127.0.0.1:22379: OK
 --- error_log eval
 qr/update endpoint: http:\/\/127.0.0.1:42379 to unhealthy/
+
+
+
+=== TEST 19: test health check running mode
+--- http_config eval: $::HttpConfig
+--- config
+    location /t {
+        content_by_lua_block {
+            local etcd, err = require "resty.etcd" .new({
+                protocol = "v3",
+                http_host = {
+                    "http://127.0.0.1:12379",
+                    "http://127.0.0.1:22379",
+                    "http://127.0.0.1:32379",
+                },
+            })
+
+            local health_check = require("resty.etcd.health_check")
+            local mode = health_check.get_check_mode()
+            if mode == health_check.ROUND_ROBIN_MODE then
+                ngx.say("passed")
+            end
+
+            health_check.init({
+                shm_name = "etcd_cluster_health_check",
+            })
+
+            mode = health_check.get_check_mode()
+            if mode == health_check.SHARED_DICT_MODE then
+                ngx.say("passed")
+            end
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+passed
+--- grep_error_log eval
+qr/healthy check use \S+ \w+/
+--- grep_error_log_out
+healthy check use round robin
+healthy check use ngx.shared dict