feat: load etcd configuration when apisix starts

Fix #3370
Signed-off-by: spacewander <spacewanderlzx@gmail.com>

apisix/cli/etcd.lua

@@ -17,6 +17,7 @@
 
 local base64_encode = require("base64").encode
 local dkjson = require("dkjson")
+local constants = require("apisix.constants")
 local util = require("apisix.cli.util")
 local file = require("apisix.cli.file")
 local http = require("socket.http")
@@ -25,6 +26,7 @@ local ltn12 = require("ltn12")
 
 local type = type
 local ipairs = ipairs
+local pairs = pairs
 local print = print
 local tonumber = tonumber
 local str_format = string.format
@@ -248,11 +250,15 @@ function _M.init(env, args)
         end
 
 
-        for _, dir_name in ipairs({"/routes", "/upstreams", "/services",
-                                   "/plugins", "/consumers", "/ssl",
-                                   "/global_rules", "/stream_routes", "/proto",
-                                   "/plugin_metadata", "/plugin_configs"}) do
+        local dirs = {}
+        for name in pairs(constants.HTTP_ETCD_DIRECTORY) do
+            dirs[name] = true
+        end
+        for name in pairs(constants.STREAM_ETCD_DIRECTORY) do
+            dirs[name] = true
+        end
 
+        for dir_name in pairs(dirs) do
             local key =  (etcd_conf.prefix or "") .. dir_name .. "/"
 
             local put_url = host .. "/v3/kv/put"

apisix/constants.lua

@@ -0,0 +1,38 @@
+--
+-- Licensed to the Apache Software Foundation (ASF) under one or more
+-- contributor license agreements.  See the NOTICE file distributed with
+-- this work for additional information regarding copyright ownership.
+-- The ASF licenses this file to You under the Apache License, Version 2.0
+-- (the "License"); you may not use this file except in compliance with
+-- the License.  You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+return {
+    HTTP_ETCD_DIRECTORY = {
+        ["/upstreams"] = true,
+        ["/plugins"] = true,
+        ["/ssl"] = true,
+        ["/stream_routes"] = true,
+        ["/plugin_metadata"] = true,
+        ["/routes"] = true,
+        ["/services"] = true,
+        ["/consumers"] = true,
+        ["/global_rules"] = true,
+        ["/proto"] = true,
+        ["/plugin_configs"] = true,
+    },
+    STREAM_ETCD_DIRECTORY = {
+        ["/upstreams"] = true,
+        ["/plugins"] = true,
+        ["/ssl"] = true,
+        ["/stream_routes"] = true,
+        ["/plugin_metadata"] = true,
+    },
+}